Mechanical engineering

Mechanical engineering

Overview

Mechanical engineering is a discipline of engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

 that applies the principles of physics
Branches of physics
Physics deals with a wide variety of systems, there are certain theories that are used by all physicists. Each of these theories were experimentally tested numerous times and found correct as an approximation of Nature...

 and materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

 for analysis, design, manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...

, and maintenance of mechanical
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

 systems
Physical system
In physics, the word system has a technical meaning, namely, it is the portion of the physical universe chosen for analysis. Everything outside the system is known as the environment, which in analysis is ignored except for its effects on the system. The cut between system and the world is a free...

. It is the branch of engineering that involves the production and usage of heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

 and mechanical power for the design, production, and operation of machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

s and tools
Machine tool
A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...

. It is one of the oldest and broadest engineering disciplines.

The engineering field requires an understanding of core concepts including mechanics
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....

, kinematics
Kinematics
Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

, thermodynamics
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

, materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

, and structural analysis
Structural analysis
Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, machinery, furniture, attire, soil strata, prostheses and...

.
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Encyclopedia

Mechanical engineering is a discipline of engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

 that applies the principles of physics
Branches of physics
Physics deals with a wide variety of systems, there are certain theories that are used by all physicists. Each of these theories were experimentally tested numerous times and found correct as an approximation of Nature...

 and materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

 for analysis, design, manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...

, and maintenance of mechanical
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

 systems
Physical system
In physics, the word system has a technical meaning, namely, it is the portion of the physical universe chosen for analysis. Everything outside the system is known as the environment, which in analysis is ignored except for its effects on the system. The cut between system and the world is a free...

. It is the branch of engineering that involves the production and usage of heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

 and mechanical power for the design, production, and operation of machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

s and tools
Machine tool
A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...

. It is one of the oldest and broadest engineering disciplines.

The engineering field requires an understanding of core concepts including mechanics
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....

, kinematics
Kinematics
Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

, thermodynamics
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

, materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

, and structural analysis
Structural analysis
Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, machinery, furniture, attire, soil strata, prostheses and...

. Mechanical engineers use these core principles along with tools like computer-aided engineering
Computer-aided engineering
Computer-aided engineering is the broad usage of computer software to aid in engineering tasks. It includes computer-aided design , computer-aided analysis , computer-integrated manufacturing , computer-aided manufacturing , material requirements planning , and computer-aided planning .- Overview...

 and product lifecycle management
Product lifecycle management
In industry, product lifecycle management is the process of managing the entire lifecycle of a product from its conception, through design and manufacture, to service and disposal...

 to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

, transport
Transport
Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...

 systems, aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

, watercraft
Watercraft
A watercraft is a vessel or craft designed to move across or through water. The name is derived from the term "craft" which was used to describe all types of water going vessels...

, robotics
Robotics
Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...

, medical devices and more.

Mechanical engineering emerged as a field during the industrial revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

 in Europe in the 18th century; however, its development can be traced back several thousand years around the world. Mechanical engineering science emerged in the 19th century as a result of developments in the field of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

. The field has continually evolved to incorporate advancements in technology, and mechanical engineers today are pursuing developments in such fields as composites, mechatronics
Mechatronics
Mechatronics is the combination of mechanical engineering, electronic engineering, computer engineering, software engineering, control engineering, and systems design engineering in order to design, and manufacture useful products. Mechatronics is a multidisciplinary field of engineering, that is...

, and nanotechnology
Nanotechnology
Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometres...

. Mechanical engineering overlaps with aerospace engineering
Aerospace engineering
Aerospace engineering is the primary branch of engineering concerned with the design, construction and science of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering...

, civil engineering
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

, electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

, petroleum engineering
Petroleum engineering
Petroleum engineering is an engineering discipline concerned with the activities related to the production of hydrocarbons, which can be either crude oil or natural gas. Subsurface activities are deemed to fall within the upstream sector of the oil and gas industry, which are the activities of...

, and chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...

 to varying amounts.

Development


Applications of mechanical engineering are found in the records of many ancient and medieval societies throughout the globe. In ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

, the works of Archimedes
Archimedes
Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...

 (287 BC–212 BC) deeply influenced mechanics in the Western tradition and Heron of Alexandria
Hero of Alexandria
Hero of Alexandria was an ancient Greek mathematician and engineerEnc. Britannica 2007, "Heron of Alexandria" who was active in his native city of Alexandria, Roman Egypt...

 (c. 10–70 AD) created the first steam engine. In China, Zhang Heng
Zhang Heng
Zhang Heng was a Chinese astronomer, mathematician, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar from Nanyang, Henan. He lived during the Eastern Han Dynasty of China. He was educated in the capital cities of Luoyang and Chang'an, and began his career as a...

 (78–139 AD) improved a water clock
Water clock
A water clock or clepsydra is any timepiece in which time is measured by the regulated flow of liquid into or out from a vessel where the amount is then measured.Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions...

 and invented a seismometer
Seismometer
Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...

, and Ma Jun
Ma Jun
Ma Jun , style name Deheng , was a Chinese mechanical engineer and government official during the Three Kingdoms era of China...

 (200–265 AD) invented a chariot with differential gears. The medieval Chinese horologist and engineer Su Song
Su Song
Su Song was a renowned Chinese polymath who specialized himself as a statesman, astronomer, cartographer, horologist, pharmacologist, mineralogist, zoologist, botanist, mechanical and architectural engineer, poet, antiquarian, and ambassador of the Song Dynasty .Su Song was the engineer of a...

 (1020–1101 AD) incorporated an escapement
Escapement
In mechanical watches and clocks, an escapement is a device that transfers energy to the timekeeping element and enables counting the number of oscillations of the timekeeping element...

 mechanism into his astronomical clock tower
Clock tower
A clock tower is a tower specifically built with one or more clock faces. Clock towers can be either freestanding or part of a church or municipal building such as a town hall. Some clock towers are not true clock towers having had their clock faces added to an already existing building...

 two centuries before any escapement can be found in clocks of medieval Europe, as well as the world's first known endless power-transmitting chain drive
Chain drive
Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles...

.

During the years from 7th to 15th century, the era called the Islamic Golden Age
Islamic Golden Age
During the Islamic Golden Age philosophers, scientists and engineers of the Islamic world contributed enormously to technology and culture, both by preserving earlier traditions and by adding their own inventions and innovations...

, there were remarkable contributions from Muslim inventors in the field of mechanical technology. Al-Jazari
Al-Jazari
Abū al-'Iz Ibn Ismā'īl ibn al-Razāz al-Jazarī was a Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, mathematician and astronomer from Al-Jazira, Mesopotamia, who lived during the Islamic Golden Age...

, who was one of them, wrote his famous Book of Knowledge of Ingenious Mechanical Devices in 1206, and presented many mechanical designs. He is also considered to be the inventor of such mechanical devices which now form the very basic of mechanisms, such as the crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

 and camshaft
Camshaft
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...

.

Important breakthroughs in the foundations of mechanical engineering occurred in England during the 17th century when Sir Isaac Newton both formulated the three Newton's Laws of Motion
Newton's laws of motion
Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces...

 and developed Calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

. Newton was reluctant to publish his methods and laws for years, but he was finally persuaded to do so by his colleagues, such as Sir Edmund Halley, much to the benefit of all mankind.

During the early 19th century in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, the development of machine tools led mechanical engineering to develop as a separate field within engineering, providing manufacturing machines and the engines to power them. The first British professional society of mechanical engineers was formed in 1847 Institution of Mechanical Engineers
Institution of Mechanical Engineers
The Institution of Mechanical Engineers is the British engineering society based in central London, representing mechanical engineering. It is licensed by the Engineering Council UK to assess candidates for inclusion on ECUK's Register of professional Engineers...

, thirty years after the civil engineers formed the first such professional society Institution of Civil Engineers
Institution of Civil Engineers
Founded on 2 January 1818, the Institution of Civil Engineers is an independent professional association, based in central London, representing civil engineering. Like its early membership, the majority of its current members are British engineers, but it also has members in more than 150...

. On the European continent, Johann Von Zimmermann (1820–1901) founded the first factory for grinding machines in Chemnitz (Germany) in 1848.

In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the American Society of Mechanical Engineers
American Society of Mechanical Engineers
The American Society of Mechanical Engineers is a professional body, specifically an engineering society, focused on mechanical engineering....

 (ASME) was formed in 1880, becoming the third such professional engineering society, after the American Society of Civil Engineers
American Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...

 (1852) and the American Institute of Mining Engineers (1871). The first schools in the United States to offer an engineering education were the United States Military Academy
United States Military Academy
The United States Military Academy at West Point is a four-year coeducational federal service academy located at West Point, New York. The academy sits on scenic high ground overlooking the Hudson River, north of New York City...

 in 1817, an institution now known as Norwich University
Norwich University
Norwich University is a private university located in Northfield, Vermont . The university was founded in 1819 at Norwich, Vermont, as the American Literary, Scientific and Military Academy. It is the oldest of six Senior Military Colleges, and is recognized by the United States Department of...

 in 1819, and Rensselaer Polytechnic Institute
Rensselaer Polytechnic Institute
Stephen Van Rensselaer established the Rensselaer School on November 5, 1824 with a letter to the Rev. Dr. Samuel Blatchford, in which van Rensselaer asked Blatchford to serve as the first president. Within the letter he set down several orders of business. He appointed Amos Eaton as the school's...

 in 1825. Education in mechanical engineering has historically been based on a strong foundation in mathematics and science.

Education


Degrees in mechanical engineering are offered at universities worldwide. In Brazil, Ireland, Philippines, China, Greece, Turkey, North America, South Asia, India and the United Kingdom, mechanical engineering programs typically take four to five years of study and result in a Bachelor of Science
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...

 (B.Sc), Bachelor of Science Engineering (B.ScEng), Bachelor of Engineering
Bachelor of Engineering
The Bachelor of Engineering is an undergraduate academic degree awarded to a student after three to five years of studying engineering at universities in Armenia, Australia, Bangladesh, Bulgaria, Canada, China, Denmark, Egypt, Finland , Germany, Hong Kong, India, Indonesia, Ireland, Jordan, Korea,...

 (B.Eng), Bachelor of Technology
Bachelor of Technology
The Bachelor of Technology is an undergraduate academic degree conferred after completion of a three or four year program of studies at an accredited university or accredited university-level institution...

 (B.Tech), or Bachelor of Applied Science
Bachelor of Applied Science
The Bachelor of Applied Science, often abbreviated as BAS, BSAS. BASc or BAppSc is an undergraduate degree awarded for a course of study that generally lasts three to four years in the United Kingdom and Australia, and four to six years in Canada, the Netherlands and the United States.-Usage:In...

 (B.A.Sc) degree, in or with emphasis in mechanical engineering. In Spain, Portugal and most of South America, where neither BSc nor BTech programs have been adopted, the formal name for the degree is "Mechanical Engineer", and the course work is based on five or six years of training. In Italy the course work is based on five years of training, but in order to qualify as an Engineer you have to pass a state exam at the end of the course.

In Australia, mechanical engineering degrees are awarded as Bachelor of Engineering (Mechanical). The degree takes four years of full time study to achieve. To ensure quality in engineering degrees, the Australian Institution of Engineers accredits engineering degrees awarded by Australian universities. Before the degree can be awarded, the student must complete at least 3 months of on the job work experience in an engineering firm. Similar systems are also present in South Africa and are overseen by the Engineering Council of South Africa (ECSA).

In the United States, most undergraduate mechanical engineering programs are accredited by the Accreditation Board for Engineering and Technology
Accreditation Board for Engineering and Technology
ABET, Inc., formerly the Accreditation Board for Engineering and Technology, is a non-profit organization that accredits post-secondary education programs in applied science, computing, engineering, and technology...

 (ABET) to ensure similar course requirements and standards among universities. The ABET web site lists 276 accredited mechanical engineering programs as of June 19, 2006. Mechanical engineering programs in Canada are accredited by the Canadian Engineering Accreditation Board (CEAB), and most other countries offering engineering degrees have similar accreditation societies.

Some mechanical engineers go on to pursue a postgraduate degree such as a Master of Engineering
Master of Engineering
A Master of Engineering or Master of Technology or Master of Science in Engineering A Master of Engineering (Magister in Ingeniaria) (abbreviated M.Eng., ME or MEng) or Master of Technology (abbreviated M.Tech. or MTech) or Master of Science in Engineering A Master of Engineering (Magister in...

, Master of Technology, Master of Science
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...

, Master of Engineering Management
Master of Engineering Management
The Master of Engineering Management degree, often abbreviated MEM, can be either an academic or professional master's degree that bridges the gap between the field of engineering and the field of business. A variation is the Master of Science in Engineering *and* Management...

 (MEng.Mgt or MEM), a Doctor of Philosophy
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...

 in engineering (EngD, PhD) or an engineer's degree
Engineer's degree
An engineer's degree is an advanced academic degree in engineering that is conferred in Europe, some countries of Latin America, and a few institutions in the United States....

. The master's and engineer's degrees may or may not include research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...

. The Doctor of Philosophy includes a significant research component and is often viewed as the entry point to academia
Academia
Academia is the community of students and scholars engaged in higher education and research.-Etymology:The word comes from the akademeia in ancient Greece. Outside the city walls of Athens, the gymnasium was made famous by Plato as a center of learning...

. The Engineer's degree exists at a few institutions at an intermediate level between the master's degree and the doctorate.

Coursework


Standards set by each country's accreditation society are intended to provide uniformity in fundamental subject material, promote competence among graduating engineers, and to maintain confidence in the engineering profession as a whole. Engineering programs in the U.S., for example, are required by ABET to show that their students can "work professionally in both thermal and mechanical systems areas." The specific courses required to graduate, however, may differ from program to program. Universities and Institutes of technology
Institute of technology
Institute of technology is a designation employed in a wide range of learning institutions awarding different types of degrees and operating often at variable levels of the educational system...

 will often combine multiple subjects into a single class or split a subject into multiple classes, depending on the faculty available and the university's major area(s) of research.

The fundamental subjects of mechanical engineering usually include:
  • Statics
    Statics
    Statics is the branch of mechanics concerned with the analysis of loads on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity...

     and dynamics
    Dynamics (mechanics)
    In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion...

  • Strength of materials
    Strength of materials
    In materials science, the strength of a material is its ability to withstand an applied stress without failure. The applied stress may be tensile, compressive, or shear. Strength of materials is a subject which deals with loads, deformations and the forces acting on a material. A load applied to a...

     and solid mechanics
    Solid mechanics
    Solid mechanics is the branch of mechanics, physics, and mathematics that concerns the behavior of solid matter under external actions . It is part of a broader study known as continuum mechanics. One of the most common practical applications of solid mechanics is the Euler-Bernoulli beam equation...

  • Instrumentation
    Instrumentation
    Instrumentation is defined as the art and science of measurement and control of process variables within a production, or manufacturing area....

     and measurement
    Measurement
    Measurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...

  • Electrotechnology
  • Electronics
    Electronics
    Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

  • Thermodynamics
    Thermodynamics
    Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

    , heat transfer
    Heat transfer
    Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...

    , energy conversion
    Energy conversion
    Transforming energy is when the energy changes into another form.In physics, the term energy describes the capacity to produce changes within a system, without regard to limitations in transformation imposed by entropy...

    , and HVAC
    HVAC
    HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

  • Combustion
    Combustion
    Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

    , automotive engines, fuels
  • Fluid mechanics
    Fluid mechanics
    Fluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...

     and fluid dynamics
    Fluid dynamics
    In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...

  • Mechanism
    Mechanism (engineering)
    A mechanism is a device designed to transform input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components such as gears and gear trains, belt and chain drives, cam and follower mechanisms, and linkages as well as friction devices...

     design (including kinematics
    Kinematics
    Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

     and dynamics
    Dynamics (mechanics)
    In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion...

    )
  • Manufacturing engineering
    Manufacturing engineering
    Manufacturing engineering is a field dealing with different manufacturing practices and the research and development of processes, machines and equipment.-Overview:...

    , technology, or processes
  • Hydraulics
    Hydraulics
    Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...

     and pneumatics
    Pneumatics
    Pneumatics is a branch of technology, which deals with the study and application of use of pressurized gas to effect mechanical motion.Pneumatic systems are extensively used in industry, where factories are commonly plumbed with compressed air or compressed inert gases...

  • Mathematics
    Mathematics
    Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

     - in particular, calculus
    Calculus
    Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

    , differential equations, and linear algebra
    Linear algebra
    Linear algebra is a branch of mathematics that studies vector spaces, also called linear spaces, along with linear functions that input one vector and output another. Such functions are called linear maps and can be represented by matrices if a basis is given. Thus matrix theory is often...

    .
  • Engineering design
    Design
    Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...

  • Product design
    Product design
    -Introduction:Product design is the process of creating a new product to be sold by a business or enterprise to its customers. It is concerned with the efficient and effective generation and development of ideas through a process that leads to new products.Product designers conceptualize and...

  • Mechatronics
    Mechatronics
    Mechatronics is the combination of mechanical engineering, electronic engineering, computer engineering, software engineering, control engineering, and systems design engineering in order to design, and manufacture useful products. Mechatronics is a multidisciplinary field of engineering, that is...

     and control theory
    Control theory
    Control theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems. The desired output of a system is called the reference...

  • Material Engineering
  • Design engineering, Drafting
    Engineering drawing
    An engineering drawing, a type of technical drawing, is used to fully and clearly define requirements for engineered items.Engineering drawing produces engineering drawings . More than just the drawing of pictures, it is also a language—a graphical language that communicates ideas and information...

    , computer-aided design
    Computer-aided design
    Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

     (CAD) (including solid modeling
    Solid modeling
    Solid modeling is a consistent set of principles for mathematical and computer modeling of three dimensional solids. Solid modeling is distinguished from related areas of Geometric modeling and Computer graphics by its emphasis on physical fidelity...

    ), and computer-aided manufacturing
    Computer-aided manufacturing
    Computer-aided manufacturing is the use of computer software to control machine tools and related machinery in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a...

     (CAM)


Mechanical engineers are also expected to understand and be able to apply basic concepts from chemistry, physics, chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...

, civil engineering
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

, and electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

. Most mechanical engineering programs include multiple semesters of calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

, as well as advanced mathematical concepts including differential equations, partial differential equations, linear algebra
Linear algebra
Linear algebra is a branch of mathematics that studies vector spaces, also called linear spaces, along with linear functions that input one vector and output another. Such functions are called linear maps and can be represented by matrices if a basis is given. Thus matrix theory is often...

, abstract algebra
Abstract algebra
Abstract algebra is the subject area of mathematics that studies algebraic structures, such as groups, rings, fields, modules, vector spaces, and algebras...

, and differential geometry, among others.

In addition to the core mechanical engineering curriculum, many mechanical engineering programs offer more specialized programs and classes, such as robotics
Robotics
Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...

, transport
Transport
Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...

 and logistics
Logistics
Logistics is the management of the flow of goods between the point of origin and the point of destination in order to meet the requirements of customers or corporations. Logistics involves the integration of information, transportation, inventory, warehousing, material handling, and packaging, and...

, cryogenics
Cryogenics
In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. A person who studies elements under extremely cold temperature is called a cryogenicist. Rather than the relative temperature scales of Celsius and Fahrenheit,...

, fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

 technology, automotive engineering
Automotive engineering
Modern automotive engineering, along with aerospace engineering and marine engineering, is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles,...

, biomechanics
Biomechanics
Biomechanics is the application of mechanical principles to biological systems, such as humans, animals, plants, organs, and cells. Perhaps one of the best definitions was provided by Herbert Hatze in 1974: "Biomechanics is the study of the structure and function of biological systems by means of...

, vibration
Oscillation
Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...

, optics
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...

 and others, if a separate department does not exist for these subjects.

Most mechanical engineering programs also require varying amounts of research or community projects to gain practical problem-solving experience. In the United States it is common for mechanical engineering students to complete one or more internships while studying, though this is not typically mandated by the university. Cooperative education
Cooperative education
Cooperative education is a structured method of combining classroom-based education with practical work experience. A cooperative education experience, commonly known as a "co-op", provides academic credit for structured job experience...

 is another option.

License


Engineers may seek license by a state, provincial, or national government. The purpose of this process is to ensure that engineers possess the necessary technical knowledge, real-world experience, and knowledge of the local legal system to practice engineering at a professional level. Once certified, the engineer is given the title of Professional Engineer
Professional Engineer
Regulation of the engineering profession is established by various jurisdictions of the world to protect the safety, well-being and other interests of the general public, and to define the licensure process through which an engineer becomes authorized to provide professional services to the...

 (in the United States, Canada, Japan, South Korea, Bangladesh and South Africa), Chartered Engineer (in the United Kingdom, Ireland, India and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (much of the European Union). Not all mechanical engineers choose to become licensed; those that do can be distinguished as Chartered or Professional Engineers by the post-nominal title
Post-nominal letters
Post-nominal letters, also called post-nominal initials, post-nominal titles or designatory letters, are letters placed after the name of a person to indicate that the individual holds a position, educational degree, accreditation, office, or honour. An individual may use several different sets of...

 P.E., P.Eng., or C.Eng., as in: Mike Thompson, P.Eng.

In the U.S., to become a licensed Professional Engineer, an engineer must pass the comprehensive FE (Fundamentals of Engineering) exam, work a given number of years as an Engineering Intern (EI) or Engineer-in-Training (EIT), and finally pass the "Principles and Practice" or PE (Practicing Engineer or Professional Engineer) exams.

In the United States, the requirements and steps of this process are set forth by the National Council of Examiners for Engineering and Surveying
National Council of Examiners for Engineering and Surveying
The National Council of Examiners for Engineering and Surveying is a national non-profit organization composed of engineering and land surveying licensing boards representing all U.S. states and territories...

 (NCEES), a national non-profit representing all states. In the UK, current graduates require a BEng
Beng
Beng may refer to:*Beng Spies, a voice actor*Kwek Leng Beng , Singaporean billionaire*Lim Eng Beng , former Philippine Basketball Association player*Ong Beng Hee , professional squash player...

 plus an appropriate masters degree or an integrated MEng
Meng
Meng can refer to the following:* Master of Engineering , an academic or professional master's degree in the field of engineering, the symbol used for the labiodental nasal consonantal sound...

 degree, a minimum of 4 years post graduate on the job competency development, and a peer reviewed project report in the candidates specialty area in order to become chartered through the Institution of Mechanical Engineers
Institution of Mechanical Engineers
The Institution of Mechanical Engineers is the British engineering society based in central London, representing mechanical engineering. It is licensed by the Engineering Council UK to assess candidates for inclusion on ECUK's Register of professional Engineers...

.

In most modern countries, certain engineering tasks, such as the design of bridges, electric power plants, and chemical plants, must be approved by a Professional Engineer
Professional Engineer
Regulation of the engineering profession is established by various jurisdictions of the world to protect the safety, well-being and other interests of the general public, and to define the licensure process through which an engineer becomes authorized to provide professional services to the...

 or a Chartered Engineer. "Only a licensed engineer, for instance, may prepare, sign, seal and submit engineering plans and drawings to a public authority for approval, or to seal engineering work for public and private clients." This requirement can be written into state and provincial legislation, such as in the Canadian provinces, for example the Ontario or Quebec's Engineer Act.

In other countries, such as Australia, no such legislation exists; however, practically all certifying bodies maintain a code of ethics
Ethical code
An ethical code is adopted by an organization in an attempt to assist those in the organization called upon to make a decision understand the difference between 'right' and 'wrong' and to apply this understanding to their decision...

 independent of legislation that they expect all members to abide by or risk expulsion.

Salaries and workforce statistics


The total number of engineers employed in the U.S. in 2009 was roughly 1.6 million. Of these, 239,000 were mechanical engineers (14.9%), the second largest discipline by size behind civil (278,000). The total number of mechanical engineering jobs in 2009 was projected to grow 6% over the next decade, with average starting salaries being $58,800 with a bachelor's degree. The median annual income of mechanical engineers in the U.S. workforce was roughly $74,900. This number was highest when working for the government ($86,250), and lowest in education ($63,050).

In 2007, Canadian engineers made an average of CAD$29.83 per hour with 4% unemployed. The average for all occupations was $18.07 per hour with 7% unemployed. Twelve percent of these engineers were self-employed, and since 1997 the proportion of female engineers had risen to 6%.

Modern tools


Many mechanical engineering companies, especially those in industrialized nations, have begun to incorporate computer-aided engineering
Computer-aided engineering
Computer-aided engineering is the broad usage of computer software to aid in engineering tasks. It includes computer-aided design , computer-aided analysis , computer-integrated manufacturing , computer-aided manufacturing , material requirements planning , and computer-aided planning .- Overview...

 (CAE) programs into their existing design and analysis processes, including 2D and 3D solid modeling
Solid modeling
Solid modeling is a consistent set of principles for mathematical and computer modeling of three dimensional solids. Solid modeling is distinguished from related areas of Geometric modeling and Computer graphics by its emphasis on physical fidelity...

 computer-aided design
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

 (CAD). This method has many benefits, including easier and more exhaustive visualization of products, the ability to create virtual assemblies of parts, and the ease of use in designing mating interfaces and tolerances.

Other CAE programs commonly used by mechanical engineers include product lifecycle management
Product lifecycle management
In industry, product lifecycle management is the process of managing the entire lifecycle of a product from its conception, through design and manufacture, to service and disposal...

 (PLM) tools and analysis tools used to perform complex simulations. Analysis tools may be used to predict product response to expected loads, including fatigue life and manufacturability. These tools include finite element analysis (FEA), computational fluid dynamics
Computational fluid dynamics
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with...

 (CFD), and computer-aided manufacturing
Computer-aided manufacturing
Computer-aided manufacturing is the use of computer software to control machine tools and related machinery in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a...

 (CAM).

Using CAE programs, a mechanical design team can quickly and cheaply iterate the design process to develop a product that better meets cost, performance, and other constraints. No physical prototype need be created until the design nears completion, allowing hundreds or thousands of designs to be evaluated, instead of a relative few. In addition, CAE analysis programs can model complicated physical phenomena which cannot be solved by hand, such as viscoelasticity, complex contact between mating parts, or non-Newtonian flows
Non-Newtonian fluid
A non-Newtonian fluid is a fluid whose flow properties differ in any way from those of Newtonian fluids. Most commonly the viscosity of non-Newtonian fluids is not independent of shear rate or shear rate history...

.

As mechanical engineering begins to merge with other disciplines, as seen in mechatronics
Mechatronics
Mechatronics is the combination of mechanical engineering, electronic engineering, computer engineering, software engineering, control engineering, and systems design engineering in order to design, and manufacture useful products. Mechatronics is a multidisciplinary field of engineering, that is...

, multidisciplinary design optimization
Multidisciplinary design optimization
Multi-disciplinary design optimization is a field of engineering that uses optimization methods to solve design problems incorporating a number of disciplines. As defined by Prof. Carlo Poloni, MDO is "the art of finding the best compromise"...

 (MDO) is being used with other CAE programs to automate and improve the iterative design process. MDO tools wrap around existing CAE processes, allowing product evaluation to continue even after the analyst goes home for the day. They also utilize sophisticated optimization algorithms to more intelligently explore possible designs, often finding better, innovative solutions to difficult multidisciplinary design problems.

Subdisciplines


The field of mechanical engineering can be thought of as a collection of many mechanical engineering science disciplines. Several of these subdisciplines which are typically taught at the undergraduate level are listed below, with a brief explanation and the most common application of each. Some of these subdisciplines are unique to mechanical engineering, while others are a combination of mechanical engineering and one or more other disciplines. Most work that a mechanical engineer does uses skills and techniques from several of these subdisciplines, as well as specialized subdisciplines. Specialized subdisciplines, as used in this article, are more likely to be the subject of graduate studies or on-the-job training than undergraduate research. Several specialized subdisciplines are discussed in this section.

Mechanics



Mechanics is, in the most general sense, the study of force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

s and their effect upon matter
Matter
Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume...

. Typically, engineering mechanics is used to analyze and predict the acceleration and deformation (both elastic and plastic) of objects under known forces (also called loads) or stresses
Stress (physics)
In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...

. Subdisciplines of mechanics include
  • Statics
    Statics
    Statics is the branch of mechanics concerned with the analysis of loads on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity...

    , the study of non-moving bodies under known loads, how forces affect static bodies
  • Dynamics
    Dynamics (mechanics)
    In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion...

     (or kinetics), the study of how forces affect moving bodies
  • Mechanics of materials, the study of how different materials deform under various types of stress
  • Fluid mechanics
    Fluid mechanics
    Fluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...

    , the study of how fluids react to forces
  • Kinematics
    Kinematics
    Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

    , the study of the motion of bodies (objects) and systems (groups of objects), while ignoring the forces that cause the motion. Kinematics is often used in the design and analysis of mechanisms
    Mechanism (engineering)
    A mechanism is a device designed to transform input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components such as gears and gear trains, belt and chain drives, cam and follower mechanisms, and linkages as well as friction devices...

    .
  • Continuum mechanics
    Continuum mechanics
    Continuum mechanics is a branch of mechanics that deals with the analysis of the kinematics and the mechanical behavior of materials modelled as a continuous mass rather than as discrete particles...

    , a method of applying mechanics that assumes that objects are continuous (rather than discrete)


Mechanical engineers typically use mechanics in the design or analysis phases of engineering. If the engineering project were the design of a vehicle, statics might be employed to design the frame of the vehicle, in order to evaluate where the stresses will be most intense. Dynamics might be used when designing the car's engine, to evaluate the forces in the piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

s and cam
Cam
A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...

s as the engine cycles. Mechanics of materials might be used to choose appropriate materials for the frame and engine. Fluid mechanics might be used to design a ventilation system for the vehicle (see HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

), or to design the intake
Intake
An intake , or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power...

 system for the engine.

Mechatronics and robotics



Mechatronics is an interdisciplinary branch of mechanical engineering, electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

 and software engineering
Software engineering
Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...

 that is concerned with integrating electrical and mechanical engineering to create hybrid systems. In this way, machines can be automated through the use of electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s, servo-mechanisms
Servomechanism
thumb|right|200px|Industrial servomotorThe grey/green cylinder is the [[Brush |brush-type]] [[DC motor]]. The black section at the bottom contains the [[Epicyclic gearing|planetary]] [[Reduction drive|reduction gear]], and the black object on top of the motor is the optical [[rotary encoder]] for...

, and other electrical systems in conjunction with special software. A common example of a mechatronics system is a CD-ROM drive. Mechanical systems open and close the drive, spin the CD and move the laser, while an optical system reads the data on the CD and converts it to bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

s. Integrated software controls the process and communicates the contents of the CD to the computer.

Robotics is the application of mechatronics to create robots, which are often used in industry to perform tasks that are dangerous, unpleasant, or repetitive. These robots may be of any shape and size, but all are preprogrammed and interact physically with the world. To create a robot, an engineer typically employs kinematics (to determine the robot's range of motion) and mechanics (to determine the stresses within the robot).

Robots are used extensively in industrial engineering
Industrial engineering
Industrial engineering is a branch of engineering dealing with the optimization of complex processes or systems. It is concerned with the development, improvement, implementation and evaluation of integrated systems of people, money, knowledge, information, equipment, energy, materials, analysis...

. They allow businesses to save money on labor, perform tasks that are either too dangerous or too precise for humans to perform them economically, and to ensure better quality. Many companies employ assembly lines of robots,especially in Automotive Industries and some factories are so robotized that they can run by themselves
Lights out (manufacturing)
Lights out or lights-out manufacturing is a manufacturing methodology , rather than a specific process.Factories that run lights out are fully automated and require no human presence on-site. Thus, these factories can be run with the lights off. Many factories are capable of lights-out production,...

. Outside the factory, robots have been employed in bomb disposal, space exploration
Space exploration
Space exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....

, and many other fields. Robots are also sold for various residential applications.

Structural analysis


Structural analysis is the branch of mechanical engineering (and also civil engineering) devoted to examining why and how objects fail and to fix the objects and their performance. Structural failures occur in two general modes: static failure, and fatigue failure. Static structural failure occurs when, upon being loaded (having a force applied) the object being analyzed either breaks or is deformed plastically, depending on the criterion for failure. Fatigue failure occurs when an object fails after a number of repeated loading and unloading cycles. Fatigue failure occurs because of imperfections in the object: a microscopic crack on the surface of the object, for instance, will grow slightly with each cycle (propagation) until the crack is large enough to cause ultimate failure
Ultimate failure
In mechanical engineering, ultimate failure describes the breaking of a material. In general there are two types of failure: fracture and buckling. Fracture of a material occurs when either an internal or external crack elongates the width or length of the material. In ultimate failure this will...

.

Failure is not simply defined as when a part breaks, however; it is defined as when a part does not operate as intended. Some systems, such as the perforated top sections of some plastic bags, are designed to break. If these systems do not break, failure analysis might be employed to determine the cause.

Structural analysis is often used by mechanical engineers after a failure has occurred, or when designing to prevent failure. Engineers often use online documents and books such as those published by ASM to aid them in determining the type of failure and possible causes.

Structural analysis may be used in the office when designing parts, in the field to analyze failed parts, or in laboratories where parts might undergo controlled failure tests.

Thermodynamics and thermo-science


Thermodynamics
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

 is an applied science used in several branches of engineering, including mechanical and chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...

. At its simplest, thermodynamics is the study of energy, its use and transformation through a system
Physical system
In physics, the word system has a technical meaning, namely, it is the portion of the physical universe chosen for analysis. Everything outside the system is known as the environment, which in analysis is ignored except for its effects on the system. The cut between system and the world is a free...

. Typically, engineering thermodynamics is concerned with changing energy from one form to another. As an example, automotive engines convert chemical energy (enthalpy
Enthalpy
Enthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.Enthalpy is a...

) from the fuel into heat, and then into mechanical work that eventually turns the wheels.

Thermodynamics principles are used by mechanical engineers in the fields of heat transfer
Heat transfer
Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...

, thermofluids
Thermofluids
Thermal fluids is a branch of science and engineering divided into four sections:*Heat transfer*Thermodynamics*Fluid mechanics*CombustionThe term consists of two words: "Thermal", meaning heat, and "fluids", which refers to liquids, gases and vapors. Pressure, volume, and density all play an...

, and energy conversion
Energy conversion
Transforming energy is when the energy changes into another form.In physics, the term energy describes the capacity to produce changes within a system, without regard to limitations in transformation imposed by entropy...

. Mechanical engineers use thermo-science to design engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

s and power plants, heating, ventilation, and air-conditioning (HVAC) systems, heat exchanger
Heat exchanger
A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...

s, heat sink
Heat sink
A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...

s, radiator
Radiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...

s, refrigeration
Refrigeration
Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...

, insulation
Thermal insulation
Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...

, and others.

Design and Drafting



Drafting
Technical drawing
Technical drawing, also known as drafting or draughting, is the act and discipline of composing plans that visually communicate how something functions or has to be constructed.Drafting is the language of industry....

 or technical drawing is the means by which mechanical engineers design products and create instructions for manufacturing parts. A technical drawing can be a computer model or hand-drawn schematic showing all the dimensions necessary to manufacture a part, as well as assembly notes, a list of required materials, and other pertinent information. A U.S. mechanical engineer or skilled worker who creates technical drawings may be referred to as a drafter or draftsman. Drafting has historically been a two-dimensional process, but computer-aided design
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

 (CAD) programs now allow the designer to create in three dimensions.

Instructions for manufacturing a part must be fed to the necessary machinery, either manually, through programmed instructions, or through the use of a computer-aided manufacturing
Computer-aided manufacturing
Computer-aided manufacturing is the use of computer software to control machine tools and related machinery in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a...

 (CAM) or combined CAD/CAM program. Optionally, an engineer may also manually manufacture a part using the technical drawings, but this is becoming an increasing rarity, with the advent of computer numerically controlled (CNC) manufacturing. Engineers primarily manually manufacture parts in the areas of applied spray coatings, finishes, and other processes that cannot economically or practically be done by a machine.

Drafting is used in nearly every subdiscipline of mechanical engineering, and by many other branches of engineering and architecture. Three-dimensional models created using CAD software are also commonly used in finite element analysis (FEA) and computational fluid dynamics
Computational fluid dynamics
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with...

 (CFD).

Frontiers of research


Mechanical engineers are constantly pushing the boundaries of what is physically possible in order to produce safer, cheaper, and more efficient machines and mechanical systems. Some technologies at the cutting edge of mechanical engineering are listed below (see also exploratory engineering
Exploratory engineering
Exploratory engineering is a term coined by K. Eric Drexler to describe the process of designing and analyzing detailed hypothetical models of systems that are not feasible with current technologies or methods, but do seem to be clearly within the bounds of what science considers to be possible...

).

Micro electro-mechanical systems (MEMS)


Micron-scale mechanical components such as springs, gears, fluidic and heat transfer devices are fabricated from a variety of substrate materials such as silicon, glass and polymers like SU8. Examples of MEMS components are the accelerometers that are used as car airbag sensors, modern cell phones, gyroscopes for precise positioning and microfluidic devices used in biomedical applications.

Friction stir welding (FSW)


Friction stir welding, a new type of welding
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

, was discovered in 1991 by The Welding Institute
The Welding Institute
The Welding Institute or TWI is a research and technology organisation with a specialty in welding. The Welding Institute is based in Cambridgeshire, England, since 1946, and has several offices around the world....

 (TWI). This innovative steady state (non-fusion) welding technique joins materials previously un-weldable, including several aluminum alloys. It may play an important role in the future construction of airplanes, potentially replacing rivets. Current uses of this technology to date include welding the seams of the aluminum main Space Shuttle external tank, Orion Crew Vehicle test article, Boeing Delta II and Delta IV Expendable Launch Vehicles and the SpaceX Falcon 1 rocket, armor plating for amphibious assault ships, and welding the wings and fuselage panels of the new Eclipse 500 aircraft from Eclipse Aviation among an increasingly growing pool of uses.

Composites



Composites or composite materials are a combination of materials which provide different physical characteristics than either material separately. Composite material research within mechanical engineering typically focuses on designing (and, subsequently, finding applications for) stronger or more rigid materials while attempting to reduce weight, susceptibility to corrosion, and other undesirable factors. Carbon fiber reinforced composites, for instance, have been used in such diverse applications as spacecraft and fishing rods.

Mechatronics


Mechatronics is the synergistic combination of mechanical engineering, Electronic Engineering
Electronic engineering
Electronics engineering, also referred to as electronic engineering, is an engineering discipline where non-linear and active electrical components such as electron tubes, and semiconductor devices, especially transistors, diodes and integrated circuits, are utilized to design electronic...

, and software engineering. The purpose of this interdisciplinary engineering field is the study of automation from an engineering perspective and serves the purposes of controlling advanced hybrid systems.

Nanotechnology


At the smallest scales, mechanical engineering becomes nanotechnology —one speculative goal of which is to create a molecular assembler
Molecular assembler
A molecular assembler, as defined by K. Eric Drexler, is a "proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision". Some biological molecules such as ribosomes fit this definition. This is because they receive instructions from messenger RNA and...

 to build molecules and materials via mechanosynthesis
Mechanosynthesis
Mechanosynthesis is any chemical synthesis in which reaction outcomes are determined by the use of mechanical constraints to direct reactive molecules to specific molecular sites.-Introduction:...

. For now that goal remains within exploratory engineering
Exploratory engineering
Exploratory engineering is a term coined by K. Eric Drexler to describe the process of designing and analyzing detailed hypothetical models of systems that are not feasible with current technologies or methods, but do seem to be clearly within the bounds of what science considers to be possible...

.

Finite element analysis


This field is not new, as the basis of Finite Element Analysis (FEA) or Finite Element Method (FEM) dates back to 1941. But evolution of computers has made FEM a viable option for analysis of structural problems. Many commercial codes such as ANSYS, Nastran
Nastran
NASTRAN is a finite element analysis program that was originally developed for NASA in the late 1960s under United States government funding for the Aerospace industry. The MacNeal-Schwendler Corporation was one of the principal and original developers of the public domain NASTRAN code...

 and ABAQUS
Abaqus
Abaqus FEA is a suite of software applications for finite element analysis and computer-aided engineering, originally released in 1978...

 are widely used in industry for research and design of components.

Other techniques such as finite difference method (FDM) and finite-volume method (FVM) are employed to solve problems relating heat and mass transfer, fluid flows, fluid surface interaction etc.

Biomechanics


Biomechanics is the application of mechanical principles to biological systems, such as human
Human
Humans are the only living species in the Homo genus...

s, animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s, plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, organs
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

, and cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.

Biomechanics is closely related to engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

, because it often uses traditional engineering sciences to analyse biological systems. Some simple applications of Newtonian mechanics
Classical mechanics
In physics, classical mechanics is one of the two major sub-fields of mechanics, which is concerned with the set of physical laws describing the motion of bodies under the action of a system of forces...

 and/or materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

s can supply correct approximations to the mechanics of many biological systems.

Related fields


Manufacturing engineering
Manufacturing engineering
Manufacturing engineering is a field dealing with different manufacturing practices and the research and development of processes, machines and equipment.-Overview:...

 and Aerospace Engineering
Aerospace engineering
Aerospace engineering is the primary branch of engineering concerned with the design, construction and science of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering...

 are sometimes grouped with mechanical engineering. A bachelor's degree in these areas will typically have a difference of a few specialized classes.

See also


  • Building officials
    Building officials
    Building officials of developed countries are generally are the jurisdictional administrator of building and construction codes, engineering calculation supervision, permits, facilities management, and accepted construction procedures.-Qualifications:...

  • Building services engineering
    Building services engineering
    Building services engineering, technical building services, architectural engineering, or building engineering is the engineering of the internal environment and environmental impact of a building...

  • Electric vehicle conversion
    Electric vehicle conversion
    An electric vehicle conversion is the modification of a conventional internal combustion engine vehicle to electric propulsion, creating an all-electric or plug-in hybrid electric vehicle.-Elements of a conversion:...

  • Engineering drawing
    Engineering drawing
    An engineering drawing, a type of technical drawing, is used to fully and clearly define requirements for engineered items.Engineering drawing produces engineering drawings . More than just the drawing of pictures, it is also a language—a graphical language that communicates ideas and information...

  • Fields of engineering
  • List of historic mechanical engineering landmarks
  • List of inventors

  • List of mechanical engineering topics
  • List of mechanical engineers
  • Mechanical engineering technology
    Mechanical engineering technology
    Mechanical engineering technology is the application of physical principles and current technological developments to the creation of useful machinery and operation design. Technologies such as solid models may be used as the basis for finite element analysis and / or computational fluid dynamics ...

  • Patent
    Patent
    A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

  • Related journals
  • Retrofit
    Retrofit
    Retrofitting refers to the addition of new technology or features to older systems.* power plant retrofit, improving power plant efficiency / increasing output / reducing emissions...

  • Simple machine
    Simple machine
    A simple machine is a mechanical device that changes the direction or magnitude of a force.In general, they can be defined as the simplest mechanisms that use mechanical advantage to multiply force. A simple machine uses a single applied force to do work against a single load force...


Associations

  • American Society of Heating, Refrigerating and Air-Conditioning Engineers
    American Society of Heating, Refrigerating and Air-Conditioning Engineers
    The American Society of Heating, Refrigerating and Air Conditioning Engineers is an international technical society for all individuals and organizations interested in heating, ventilation, air-conditioning, and refrigeration...

     (ASHRAE)
  • American Society of Mechanical Engineers
    American Society of Mechanical Engineers
    The American Society of Mechanical Engineers is a professional body, specifically an engineering society, focused on mechanical engineering....

     (ASME)
  • Pi Tau Sigma
    Pi Tau Sigma
    Pi Tau Sigma is an International Mechanical Engineering Honor Society. Pi Tau Sigma's core values are:*Integrity ,*Service , and...

     (Mechanical Engineering Honor Society)
  • Society of Automotive Engineers
    SAE International
    SAE International is an organization for engineering professionals in the aerospace, automotive, and commercial vehicle industries. The Society is a standards development organization for the engineering of powered vehicles of all kinds, including cars, trucks, boats, aircraft, and others.SAE...

  • Society of Women Engineers
    Society of Women Engineers
    The Society of Women Engineers , founded in 1950, is a not-for-profit educational and service organization. SWE is the driving force that establishes engineering as a highly desirable career aspiration for women. SWE empowers women to succeed and advance in those aspirations and be recognized for...

  • Institution of Mechanical Engineers
    Institution of Mechanical Engineers
    The Institution of Mechanical Engineers is the British engineering society based in central London, representing mechanical engineering. It is licensed by the Engineering Council UK to assess candidates for inclusion on ECUK's Register of professional Engineers...

     (IMechE) (British)
  • Chartered Institution of Building Services Engineers
    Chartered Institution of Building Services Engineers
    The Chartered Institution of Building Services Engineers is a British professional engineering body based in London, England that represents building services engineers...

     (CIBSE) (British)
  • Pakistan Engineering Council
    Pakistan Engineering Council
    The Pakistan Engineering Council is an executive and administrative premier engineering regulatory authority for professional and registered engineers, and technicians in Pakistan. It is located at Islamabad, Pakistan. As a statutory authority it regulates the education and accreditation of...

     (PEC)
  • UCTEA-CMO (Chamber of Mechanical Engineers) (Turkish)
  • Philippine Society of Mechanical Engineers (PSME)

Wikibooks



  • Aeronautical Engineering
  • Astronautical Engineering
  • Automotive Engineering
  • Elasticity
  • Engineering Mechanics
  • Solid Mechanics
  • Engineering Thermodynamics
  • Fluid Mechanics

  • Engineering Acoustics
  • Engineering Thermodynamics
  • Heat Transfer
  • Introduction to elasticity
  • Microtechnology
  • Nanotechnology
  • Pro Engineer
  • Strength of Materials


External links