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100-435: In mechanical engineering , dissipation is the irreversible conversion of mechanical energy into thermal energy with an associated increase in entropy. Processes with defined local temperature produce entropy at a certain rate. The entropy production rate times local temperature gives the dissipated power . Important examples of irreversible processes are: heat flow through a thermal resistance , fluid flow through

200-560: A professional engineer 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, and

300-502: A (near-) synonym both by Harris and in later language derives ultimately (via Old French ) from Latin ingenium 'ingenuity, an invention'. The hand axe , made by chipping flint to form a wedge , in the hands of a human transforms force and movement of the tool into a transverse splitting forces and movement of the workpiece. The hand axe is the first example of a wedge , the oldest of the six classic simple machines , from which most machines are based. The second oldest simple machine

400-642: A course in an engineering trade like fitter from the Industrial Training Institute (ITIs) to receive a "ITI Trade Certificate" and also pass the All India Trade Test (AITT) with an engineering trade conducted by the National Council of Vocational Training (NCVT) by which one is awarded a "National Trade Certificate". A similar system is used in Nepal. Some mechanical engineers go on to pursue

500-452: A drafter or draftsman. Drafting has historically been a two-dimensional process, but computer-aided design (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 (CAM) or combined CAD/CAM program. Optionally, an engineer may also manually manufacture

600-517: 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. Once theory is applied to a mechanical design, physical testing is often performed to verify calculated results. Structural analysis may be used in an office when designing parts, in the field to analyze failed parts, or in laboratories where parts might undergo controlled failure tests. Thermodynamics

700-880: A field during the Industrial Revolution in Europe in the 18th century; however, its development can be traced back several thousand years around the world. In the 19th century, developments in physics led to the development of mechanical engineering science. The field has continually evolved to incorporate advancements; today mechanical engineers are pursuing developments in such areas as composites , mechatronics , and nanotechnology . It also overlaps with aerospace engineering , metallurgical engineering , civil engineering , structural engineering , electrical engineering , manufacturing engineering , chemical engineering , industrial engineering , and other engineering disciplines to varying amounts. Mechanical engineers may also work in

800-402: A flow resistance, diffusion (mixing), chemical reactions , and electric current flow through an electrical resistance ( Joule heating ). Dissipative thermodynamic processes are essentially irreversible because they produce entropy . Planck regarded friction as the prime example of an irreversible thermodynamic process. In a process in which the temperature is locally continuously defined,

900-411: 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

1000-401: A lever is modeled as a hinged or revolute joint . Wheel: The wheel is an important early machine, such as the chariot . A wheel uses the law of the lever to reduce the force needed to overcome friction when pulling a load. To see this notice that the friction associated with pulling a load on the ground is approximately the same as the friction in a simple bearing that supports the load on

1100-420: A machine is "a device for applying power or changing its direction."McCarthy and Soh describe a machine as a system that "generally consists of a power source and a mechanism for the controlled use of this power." Human and animal effort were the original power sources for early machines. Waterwheel: Waterwheels appeared around the world around 300 BC to use flowing water to generate rotary motion, which

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1200-492: A machine is likely to work. 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 (United States, Canada, Japan, South Korea, Bangladesh and South Africa), Chartered Engineer (in

1300-470: A machine provides a way to understand the performance of devices ranging from levers and gear trains to automobiles and robotic systems. The German mechanician Franz Reuleaux wrote, "a machine is a combination of resistant bodies so arranged that by their means the mechanical forces of nature can be compelled to do work accompanied by certain determinate motion." Notice that forces and motion combine to define power . More recently, Uicker et al. stated that

1400-838: A mechanical system is assembled from components called machine elements . These elements provide structure for the system and control its movement. The structural components are, generally, the frame members, bearings, splines, springs, seals, fasteners and covers. The shape, texture and color of covers provide a styling and operational interface between the mechanical system and its users. The assemblies that control movement are also called " mechanisms ." Mechanisms are generally classified as gears and gear trains , which includes belt drives and chain drives , cam and follower mechanisms, and linkages , though there are other special mechanisms such as clamping linkages, indexing mechanisms , escapements and friction devices such as brakes and clutches . The number of degrees of freedom of

1500-500: A mechanism, or its mobility, depends on the number of links and joints and the types of joints used to construct the mechanism. The general mobility of a mechanism is the difference between the unconstrained freedom of the links and the number of constraints imposed by the joints. It is described by the Chebychev–Grübler–Kutzbach criterion . The transmission of rotation between contacting toothed wheels can be traced back to

1600-583: A minimum of 4 years post graduate on the job competency development and a peer-reviewed project report to become a Chartered Mechanical Engineer (CEng, MIMechE) through the Institution of Mechanical Engineers . CEng MIMechE can also be obtained via an examination route administered by the City and Guilds of London Institute . In most developed countries, certain engineering tasks, such as the design of bridges, electric power plants, and chemical plants, must be approved by

1700-1011: A part using the technical drawings. However, with the advent of computer numerically controlled (CNC) manufacturing, parts can now be fabricated without the need for constant technician input. Manually manufactured parts generally consist of spray coatings , surface 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 (CFD). Many mechanical engineering companies, especially those in industrialized nations, have incorporated computer-aided engineering (CAE) programs into their existing design and analysis processes, including 2D and 3D solid modeling computer-aided design (CAD). This method has many benefits, including easier and more exhaustive visualization of products,

1800-412: A point farther from the pivot is greater than the velocity of a point near the pivot, forces applied far from the pivot are amplified near the pivot by the associated decrease in speed. If a is the distance from the pivot to the point where the input force is applied and b is the distance to the point where the output force is applied, then a/b is the mechanical advantage of the lever. The fulcrum of

1900-406: A postgraduate degree such as a Master of Engineering , Master of Technology , Master of Science , Master of Engineering Management (M.Eng.Mgt. or M.E.M.), a Doctor of Philosophy in engineering (Eng.D. or Ph.D.) or an engineer's degree . The master's and engineer's degrees may or may not include research . The Doctor of Philosophy includes a significant research component and is often viewed as

2000-430: A pressure vessel; the expanding steam drives a piston or a turbine. This principle can be seen in the aeolipile of Hero of Alexandria. This is called an external combustion engine . An automobile engine is called an internal combustion engine because it burns fuel (an exothermic chemical reaction) inside a cylinder and uses the expanding gases to drive a piston . A jet engine uses a turbine to compress air which

2100-520: A programmable drum machine , where they could be made to play different rhythms and different drum patterns. During the Renaissance , the dynamics of the Mechanical Powers , as the simple machines were called, began to be studied from the standpoint of how much useful work they could perform, leading eventually to the new concept of mechanical work . In 1586 Flemish engineer Simon Stevin derived

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2200-473: A separate field within engineering. They brought with them manufacturing machines and the engines to power them. The first British professional society of mechanical engineers was formed in 1847 Institution of Mechanical Engineers , thirty years after the civil engineers formed the first such professional society Institution of Civil Engineers . On the European continent , Johann von Zimmermann (1820–1901) founded

2300-455: A specific application of output forces and movement, (iii) a controller with sensors that compare the output to a performance goal and then directs the actuator input, and (iv) an interface to an operator consisting of levers, switches, and displays. This can be seen in Watt's steam engine in which the power is provided by steam expanding to drive the piston. The walking beam, coupler and crank transform

2400-646: A system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors that monitor performance and plan movement, often called mechanical systems . Renaissance natural philosophers identified six simple machines which were the elementary devices that put a load into motion, and calculated the ratio of output force to input force, known today as mechanical advantage . Modern machines are complex systems that consist of structural elements, mechanisms and control components and include interfaces for convenient use. Examples include:

2500-403: A wide range of vehicles , such as trains , automobiles , boats and airplanes ; appliances in the home and office, including computers, building air handling and water handling systems ; as well as farm machinery , machine tools and factory automation systems and robots . The English word machine comes through Middle French from Latin machina , which in turn derives from

2600-436: Is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolecules, such as molecular machines . Machines can be driven by animals and people , by natural forces such as wind and water , and by chemical , thermal , or electrical power, and include

2700-459: Is an applied science used in several branches of engineering, including mechanical and chemical engineering. At its simplest, thermodynamics is the study of energy, its use and transformation through a system . Typically, engineering thermodynamics is concerned with changing energy from one form to another. As an example, automotive engines convert chemical energy ( enthalpy ) from the fuel into heat, and then into mechanical work that eventually turns

2800-410: Is burned with fuel so that it expands through a nozzle to provide thrust to an aircraft , and so is also an "internal combustion engine." Power plant: The heat from coal and natural gas combustion in a boiler generates steam that drives a steam turbine to rotate an electric generator . A nuclear power plant uses heat from a nuclear reactor to generate steam and electric power . This power

2900-414: Is called energy dissipation." – François Roddier The term is also applied to the loss of energy due to generation of unwanted heat in electric and electronic circuits. In computational physics , numerical dissipation (also known as " Numerical diffusion ") refers to certain side-effects that may occur as a result of a numerical solution to a differential equation. When the pure advection equation, which

3000-423: Is called the cam (also see cam shaft ) and the link that is driven through the direct contact of their surfaces is called the follower. The shape of the contacting surfaces of the cam and follower determines the movement of the mechanism. A linkage is a collection of links connected by joints. Generally, the links are the structural elements and the joints allow movement. Perhaps the single most useful example

3100-523: Is credited with the invention of the wheel by several, mainly old sources. However, some recent sources either suggest that it was invented independently in both Mesopotamia and Eastern Europe or credit prehistoric Eastern Europeans with the invention of the wheel The lever mechanism first appeared around 5,000 years ago in the Near East, where it was used in a simple balance scale , and to move large objects in ancient Egyptian technology . The lever

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3200-603: Is distributed through a network of transmission lines for industrial and individual use. Motors: Electric motors use either AC or DC electric current to generate rotational movement. Electric servomotors are the actuators for mechanical systems ranging from robotic systems to modern aircraft . Fluid Power: Hydraulic and pneumatic systems use electrically driven pumps to drive water or air respectively into cylinders to power linear movement . Electrochemical: Chemicals and materials can also be sources of power. They may chemically deplete or need re-charging, as

3300-414: Is free of dissipation, is solved by a numerical approximation method, the energy of the initial wave may be reduced in a way analogous to a diffusional process. Such a method is said to contain 'dissipation'. In some cases, "artificial dissipation" is intentionally added to improve the numerical stability characteristics of the solution. A formal, mathematical definition of dissipation, as commonly used in

3400-401: Is made by chipping stone, generally flint, to form a bifacial edge, or wedge . A wedge is a simple machine that transforms lateral force and movement of the tool into a transverse splitting force and movement of the workpiece. The available power is limited by the effort of the person using the tool, but because power is the product of force and movement, the wedge amplifies the force by reducing

3500-420: Is the case with batteries , or they may produce power without changing their state, which is the case for solar cells and thermoelectric generators . All of these, however, still require their energy to come from elsewhere. With batteries, it is the already existing chemical potential energy inside. In solar cells and thermoelectrics, the energy source is light and heat respectively. The mechanism of

3600-426: 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

3700-421: Is the planar four-bar linkage . However, there are many more special linkages: A planar mechanism is a mechanical system that is constrained so the trajectories of points in all the bodies of the system lie on planes parallel to a ground plane. The rotational axes of hinged joints that connect the bodies in the system are perpendicular to this ground plane. A spherical mechanism is a mechanical system in which

3800-1016: Is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science , to design , analyze, manufacture, and maintain mechanical systems . It is one of the oldest and broadest of the engineering branches . Mechanical engineering requires an understanding of core areas including mechanics , dynamics , thermodynamics , materials science , design , structural analysis , and electricity . In addition to these core principles, mechanical engineers use tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), computer-aided engineering (CAE), and product lifecycle management to design and analyze manufacturing plants , industrial equipment and machinery , heating and cooling systems , transport systems, motor vehicles , aircraft , watercraft , robotics , medical devices , weapons , and others. Mechanical engineering emerged as

3900-1020: The Accreditation Board for Engineering and Technology (ABET) to ensure similar course requirements and standards among universities. The ABET web site lists 302 accredited mechanical engineering programs as of 11 March 2014. 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. In Australia , mechanical engineering degrees are awarded as Bachelor of Engineering (Mechanical) or similar nomenclature, although there are an increasing number of specialisations. The degree takes four years of full-time study to achieve. To ensure quality in engineering degrees, Engineers Australia accredits engineering degrees awarded by Australian universities in accordance with

4000-510: The Antikythera mechanism of Greece and the south-pointing chariot of China . Illustrations by the renaissance scientist Georgius Agricola show gear trains with cylindrical teeth. The implementation of the involute tooth yielded a standard gear design that provides a constant speed ratio. Some important features of gears and gear trains are: A cam and follower is formed by the direct contact of two specially shaped links. The driving link

4100-462: The Continent . The Dutch mathematician and physicist Christiaan Huygens invented the pendulum clock in 1657, which was the first reliable timekeeper for almost 300 years, and published a work dedicated to clock designs and the theory behind them. In England, Isaac Newton formulated Newton's Laws of Motion and developed the calculus , which would become the mathematical basis of physics. Newton

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4200-509: The Greek ( Doric μαχανά makhana , Ionic μηχανή mekhane 'contrivance, machine, engine', a derivation from μῆχος mekhos 'means, expedient, remedy' ). The word mechanical (Greek: μηχανικός ) comes from the same Greek roots. A wider meaning of 'fabric, structure' is found in classical Latin, but not in Greek usage. This meaning is found in late medieval French, and is adopted from

4300-565: The Twelfth Dynasty (1991–1802 BC). The screw , the last of the simple machines to be invented, first appeared in Mesopotamia during the Neo-Assyrian period (911–609) BC. The Egyptian pyramids were built using three of the six simple machines, the inclined plane, the wedge, and the lever. Three of the simple machines were studied and described by Greek philosopher Archimedes around

4400-510: The United States Military Academy in 1817, an institution now known as Norwich University in 1819, and Rensselaer Polytechnic Institute in 1825. Education in mechanical engineering has historically been based on a strong foundation in mathematics and science. Degrees in mechanical engineering are offered at various universities worldwide. Mechanical engineering programs typically take four to five years of study depending on

4500-491: The lever , pulley and screw as simple machines . By the time of the Renaissance this list increased to include the wheel and axle , wedge and inclined plane . The modern approach to characterizing machines focusses on the components that allow movement, known as joints . Wedge (hand axe): Perhaps the first example of a device designed to manage power is the hand axe , also called biface and Olorgesailie . A hand axe

4600-549: The "Principles and Practice" or PE (Practicing Engineer or Professional Engineer) exams. The requirements and steps of this process are set forth by the National Council of Examiners for Engineering and Surveying (NCEES), composed of engineering and land surveying licensing boards representing all U.S. states and territories. In the UK, current graduates require a BEng plus an appropriate master's degree or an integrated MEng degree,

4700-399: The "lost" energy raises the temperature of the system. For example, a wave that loses amplitude is said to dissipate. The precise nature of the effects depends on the nature of the wave: an atmospheric wave , for instance, may dissipate close to the surface due to friction with the land mass, and at higher levels due to radiative cooling . The concept of dissipation was introduced in

4800-550: The 13th to 14th centuries. During the Islamic Golden Age (7th to 15th century), Muslim inventors made remarkable contributions in the field of mechanical technology. Al-Jazari , who was one of them, wrote his famous Book of Knowledge of Ingenious Mechanical Devices in 1206 and presented many mechanical designs. In the 17th century, important breakthroughs in the foundations of mechanical engineering occurred in England and

4900-516: The 3rd century BC: the lever, pulley and screw. Archimedes discovered the principle of mechanical advantage in the lever. Later Greek philosophers defined the classic five simple machines (excluding the inclined plane) and were able to roughly calculate their mechanical advantage. Hero of Alexandria ( c.  10 –75 AD) in his work Mechanics lists five mechanisms that can "set a load in motion"; lever, windlass , pulley, wedge, and screw, and describes their fabrication and uses. However,

5000-469: 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

5100-547: The French into English in the mid-16th century. In the 17th century, the word machine could also mean a scheme or plot, a meaning now expressed by the derived machination . The modern meaning develops out of specialized application of the term to stage engines used in theater and to military siege engines , both in the late 16th and early 17th centuries. The OED traces the formal, modern meaning to John Harris ' Lexicon Technicum (1704), which has: The word engine used as

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5200-546: The Greeks' understanding was limited to statics (the balance of forces) and did not include dynamics (the tradeoff between force and distance) or the concept of work . The earliest practical wind-powered machines, the windmill and wind pump , first appeared in the Muslim world during the Islamic Golden Age , in what are now Iran, Afghanistan, and Pakistan, by the 9th century AD. The earliest practical steam-powered machine

5300-524: The Muslim world. A music sequencer , a programmable musical instrument , was the earliest type of programmable machine. The first music sequencer was an automated flute player invented by the Banu Musa brothers, described in their Book of Ingenious Devices , in the 9th century. In 1206, Al-Jazari invented programmable automata / robots . He described four automaton musicians, including drummers operated by

5400-510: The U.S. workforce was $ 80,580. The median income was highest when working for the government ($ 92,030), and lowest in education ($ 57,090). In 2014, the total number of mechanical engineering jobs was projected to grow 5% over the next decade. As of 2009, the average starting salary was $ 58,800 with a bachelor's degree. 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

5500-414: 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 will often combine multiple subjects into a single class or split a subject into multiple classes, depending on the faculty available and

5600-429: The UK, no such legislation exists; however, practically all certifying bodies maintain a code of ethics independent of legislation, that they expect all members to abide by or risk expulsion. The total number of engineers employed in the U.S. in 2015 was roughly 1.6 million. Of these, 278,340 were mechanical engineers (17.28%), the largest discipline by size. In 2012, the median annual income of mechanical engineers in

5700-576: The United Kingdom, Ireland, India and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (much of the European Union). In the U.S., to become a licensed Professional Engineer (PE), an engineer must pass the comprehensive FE (Fundamentals of Engineering) exam, work a minimum of 4 years as an Engineering Intern (EI) or Engineer-in-Training (EIT) , and pass

5800-559: 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 is another option. Future work skills research puts demand on study components that feed student's creativity and innovation. Mechanical engineers research, design, develop, build, and test mechanical and thermal devices, including tools, engines, and machines. Mechanical engineers typically do

5900-569: 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 (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 (CFD), and computer-aided manufacturing (CAM). Machine A machine

6000-409: The axle of a wheel. However, the wheel forms a lever that magnifies the pulling force so that it overcomes the frictional resistance in the bearing. The classification of simple machines to provide a strategy for the design of new machines was developed by Franz Reuleaux , who collected and studied over 800 elementary machines. He recognized that the classical simple machines can be separated into

6100-411: The bodies move in a way that the trajectories of points in the system lie on concentric spheres. The rotational axes of hinged joints that connect the bodies in the system pass through the center of these circle. A spatial mechanism is a mechanical system that has at least one body that moves in a way that its point trajectories are general space curves. The rotational axes of hinged joints that connect

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6200-510: The core mechanical engineering curriculum, many mechanical engineering programs offer more specialized programs and classes, such as control systems , robotics, transport and logistics , cryogenics , fuel technology, automotive engineering , biomechanics , vibration, optics 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

6300-429: The crack is large enough to cause ultimate failure . 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

6400-428: 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 pistons and cams as the engine cycles. Mechanics of materials might be used to choose appropriate materials for

6500-571: The double acting steam engine practical. The Boulton and Watt steam engine and later designs powered steam locomotives , steam ships , and factories . The Industrial Revolution was a period from 1750 to 1850 where changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times. It began in the United Kingdom , then subsequently spread throughout Western Europe , North America , Japan , and eventually

6600-418: The entry point to academia . The Engineer's degree exists at a few institutions at an intermediate level between the master's degree and the doctorate. 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

6700-537: The factory, robots have been employed in bomb disposal, space exploration , and many other fields. Robots are also sold for various residential applications, from recreation to domestic applications. 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

6800-471: The field of biomedical engineering , specifically with biomechanics , transport phenomena , biomechatronics , bionanotechnology , and modelling of biological systems. The application of mechanical engineering can be seen in the archives of various ancient and medieval societies. The six classic simple machines were known in the ancient Near East . The wedge and the inclined plane (ramp) were known since prehistoric times. Mesopotamian civilization

6900-418: The field of thermodynamics by William Thomson (Lord Kelvin) in 1852. Lord Kelvin deduced that a subset of the above-mentioned irreversible dissipative processes will occur unless a process is governed by a "perfect thermodynamic engine". The processes that Lord Kelvin identified were friction, diffusion, conduction of heat and the absorption of light. Mechanical engineering Mechanical engineering

7000-586: The first factory for grinding machines in Chemnitz , Germany in 1848. In the United States, the American Society of Mechanical Engineers (ASME) was formed in 1880, becoming the third such professional engineering society, after the American Society of Civil Engineers (1852) and the American Institute of Mining Engineers (1871). The first schools in the United States to offer an engineering education were

7100-474: The following: Mechanical engineers design and oversee the manufacturing of many products ranging from medical devices to new batteries. They also design power-producing machines such as electric generators, internal combustion engines, and steam and gas turbines as well as power-using machines, such as refrigeration and air-conditioning systems. Like other engineers, mechanical engineers use computers to help create and analyze designs, run simulations and test how

7200-449: 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 education, and training, but in order to qualify as an Engineer one has to pass a state exam at the end of the course. In Greece, the coursework is based on a five-year curriculum. In the United States, most undergraduate mechanical engineering programs are accredited by

7300-493: The frame and engine. Fluid mechanics might be used to design a ventilation system for the vehicle (see HVAC ), or to design the intake system for the engine. Mechatronics is a combination of mechanics and electronics. It is an interdisciplinary branch of mechanical engineering, electrical engineering and software engineering that is concerned with integrating electrical and mechanical engineering to create hybrid automation systems. In this way, machines can be automated through

7400-547: The global Washington Accord . 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 India , to become an engineer, one needs to have an engineering degree like a B.Tech. or B.E., have a diploma in engineering, or by completing

7500-417: The lever, pulley and wheel and axle that are formed by a body rotating about a hinge, and the inclined plane, wedge and screw that are similarly a block sliding on a flat surface. Simple machines are elementary examples of kinematic chains or linkages that are used to model mechanical systems ranging from the steam engine to robot manipulators. The bearings that form the fulcrum of a lever and that allow

7600-529: The linear movement of the piston into rotation of the output pulley. Finally, the pulley rotation drives the flyball governor which controls the valve for the steam input to the piston cylinder. The adjective "mechanical" refers to skill in the practical application of an art or science, as well as relating to or caused by movement, physical forces, properties or agents such as is dealt with by mechanics . Similarly Merriam-Webster Dictionary defines "mechanical" as relating to machinery or tools. Power flow through

7700-707: The local density of rate of entropy production times local temperature gives the local density of dissipated power. A particular occurrence of a dissipative process cannot be described by a single individual Hamiltonian formalism. A dissipative process requires a collection of admissible individual Hamiltonian descriptions, exactly which one describes the actual particular occurrence of the process of interest being unknown. This includes friction and hammering, and all similar forces that result in decoherency of energy—that is, conversion of coherent or directed energy flow into an indirected or more isotropic distribution of energy. "The conversion of mechanical energy into heat

7800-709: The mathematical study of measure-preserving dynamical systems , is given in the article wandering set . Dissipation is the process of converting mechanical energy of downward-flowing water into thermal and acoustical energy. Various devices are designed in stream beds to reduce the kinetic energy of flowing waters to reduce their erosive potential on banks and river bottoms . Very often, these devices look like small waterfalls or cascades , where water flows vertically or over riprap to lose some of its kinetic energy . Important examples of irreversible processes are: Waves or oscillations , lose energy over time , typically from friction or turbulence . In many cases,

7900-751: The mechanical advantage of the inclined plane, and it was included with the other simple machines. The complete dynamic theory of simple machines was worked out by Italian scientist Galileo Galilei in 1600 in Le Meccaniche ("On Mechanics"). He was the first to understand that simple machines do not create energy , they merely transform it. The classic rules of sliding friction in machines were discovered by Leonardo da Vinci (1452–1519), but remained unpublished in his notebooks. They were rediscovered by Guillaume Amontons (1699) and were further developed by Charles-Augustin de Coulomb (1785). James Watt patented his parallel motion linkage in 1782, which made

8000-408: The movement. This amplification, or mechanical advantage is the ratio of the input speed to output speed. For a wedge this is given by 1/tanα, where α is the tip angle. The faces of a wedge are modeled as straight lines to form a sliding or prismatic joint . Lever: The lever is another important and simple device for managing power. This is a body that pivots on a fulcrum. Because the velocity of

8100-419: The output of one crank to the input of another. Additional links can be attached to form a six-bar linkage or in series to form a robot. A mechanical system manages power to accomplish a task that involves forces and movement. Modern machines are systems consisting of (i) a power source and actuators that generate forces and movement, (ii) a system of mechanisms that shape the actuator input to achieve

8200-452: The place and university and result in a Bachelor of Engineering (B.Eng. or B.E.), Bachelor of Science (B.Sc. or B.S.), Bachelor of Science Engineering (B.Sc.Eng.), Bachelor of Technology (B.Tech.), Bachelor of Mechanical Engineering (B.M.E.), or Bachelor of Applied Science (B.A.Sc.) degree, in or with emphasis in mechanical engineering. In Spain, Portugal and most of South America, where neither B.S. nor B.Tech. programs have been adopted,

8300-403: The primary elements of a machine. Starting with four types of joints, the rotary joint, sliding joint, cam joint and gear joint, and related connections such as cables and belts, it is possible to understand a machine as an assembly of solid parts that connect these joints called a mechanism . Two levers, or cranks, are combined into a planar four-bar linkage by attaching a link that connects

8400-467: The rest of the world. Starting in the later part of the 18th century, there began a transition in parts of Great Britain 's previously manual labour and draft-animal-based economy towards machine-based manufacturing. It started with the mechanisation of the textile industries, the development of iron-making techniques and the increased use of refined coal . The idea that a machine can be decomposed into simple movable elements led Archimedes to define

8500-599: The seventh century BC in Meroe . Kushite sundials applied mathematics in the form of advanced trigonometry. The earliest practical water-powered machines, the water wheel and watermill , first appeared in the Persian Empire , in what are now Iraq and Iran, by the early 4th century BC. In ancient Greece , the works of Archimedes (287–212 BC) influenced mechanics in the Western tradition. The geared Antikythera mechanisms

8600-504: The stresses within the robot). Robots are used extensively in industrial automation engineering. 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 . Outside

8700-525: The subject of graduate studies or on-the-job training than undergraduate research. Several specialized subdisciplines are discussed in this section. Mechanics is, in the most general sense, the study of forces and their effect upon matter . 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 . Subdisciplines of mechanics include Mechanical engineers typically use mechanics in

8800-487: 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

8900-631: The university's major area(s) of research. The fundamental subjects required for mechanical engineering usually include: Mechanical engineers are also expected to understand and be able to apply basic concepts from chemistry, physics, tribology , chemical engineering , civil engineering , and electrical engineering . All mechanical engineering programs include multiple semesters of mathematical classes including calculus, and advanced mathematical concepts including differential equations , partial differential equations , linear algebra , differential geometry , and statistics , among others. In addition to

9000-404: The use of electric motors , servo-mechanisms , 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 bits . Integrated software controls the process and communicates the contents of

9100-399: The wheel and axle and pulleys to rotate are examples of a kinematic pair called a hinged joint. Similarly, the flat surface of an inclined plane and wedge are examples of the kinematic pair called a sliding joint. The screw is usually identified as its own kinematic pair called a helical joint. This realization shows that it is the joints, or the connections that provide movement, that are

9200-410: The wheels. Thermodynamics principles are used by mechanical engineers in the fields of heat transfer , thermofluids , and energy conversion . Mechanical engineers use thermo-science to design engines and power plants , heating, ventilation, and air-conditioning (HVAC) systems, heat exchangers , heat sinks , radiators , refrigeration , insulation , and others. Drafting or technical drawing

9300-555: The world's first known endless power-transmitting chain drive . The cotton gin was invented in India by the 6th century AD, and the spinning wheel was invented in the Islamic world by the early 11th century, Dual-roller gins appeared in India and China between the 12th and 14th centuries. The worm gear roller gin appeared in the Indian subcontinent during the early Delhi Sultanate era of

9400-578: Was a steam jack driven by a steam turbine , described in 1551 by Taqi ad-Din Muhammad ibn Ma'ruf in Ottoman Egypt . The cotton gin was invented in India by the 6th century AD, and the spinning wheel was invented in the Islamic world by the early 11th century, both of which were fundamental to the growth of the cotton industry . The spinning wheel was also a precursor to the spinning jenny . The earliest programmable machines were developed in

9500-682: Was also used in the shadoof water-lifting device, the first crane machine, which appeared in Mesopotamia circa 3000 BC. The earliest evidence of pulleys date back to Mesopotamia in the early 2nd millennium BC. The Sakia was developed in the Kingdom of Kush during the 4th century BC. It relied on animal power reducing the tow on the requirement of human energy. Reservoirs in the form of Hafirs were developed in Kush to store water and boost irrigation. Bloomeries and blast furnaces were developed during

9600-582: Was an Analog computer invented around the 2nd century BC. In Roman Egypt , Heron of Alexandria (c. 10–70 AD) created the first steam-powered device ( Aeolipile ). In China , Zhang Heng (78–139 AD) improved a water clock and invented a seismometer , and Ma Jun (200–265 AD) invented a chariot with differential gears. The medieval Chinese horologist and engineer Su Song (1020–1101 AD) incorporated an escapement mechanism into his astronomical clock tower two centuries before escapement devices were found in medieval European clocks. He also invented

9700-613: Was applied to milling grain, and powering lumber, machining and textile operations . Modern water turbines use water flowing through a dam to drive an electric generator . Windmill: Early windmills captured wind power to generate rotary motion for milling operations. Modern wind turbines also drives a generator. This electricity in turn is used to drive motors forming the actuators of mechanical systems. Engine: The word engine derives from "ingenuity" and originally referred to contrivances that may or may not be physical devices. A steam engine uses heat to boil water contained in

9800-505: Was reluctant to publish his works for years, but he was finally persuaded to do so by his colleagues, such as Edmond Halley . Gottfried Wilhelm Leibniz , who earlier designed a mechanical calculator , is also credited with developing the calculus during the same time period. During the early 19th century Industrial Revolution, machine tools were developed in England, Germany , and Scotland . This allowed mechanical engineering to develop as

9900-451: Was the inclined plane (ramp), which has been used since prehistoric times to move heavy objects. The other four simple machines were invented in the ancient Near East . The wheel , along with the wheel and axle mechanism, was invented in Mesopotamia (modern Iraq) during the 5th millennium BC. The lever mechanism first appeared around 5,000 years ago in the Near East , where it

10000-431: Was used in a simple balance scale , and to move large objects in ancient Egyptian technology . The lever was also used in the shadoof water-lifting device, the first crane machine, which appeared in Mesopotamia c.  3000 BC , and then in ancient Egyptian technology c.  2000 BC . The earliest evidence of pulleys date back to Mesopotamia in the early 2nd millennium BC, and ancient Egypt during

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