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109-1037: Mechanical engineering 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

218-421: A block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. Plutarch 's Parallel Lives recounts a scene where Archimedes proved the effectiveness of compound pulleys and the block-and-tackle system by using one to pull a fully laden ship towards him as if it

327-443: A gear ratio and thus the speed increases or reductions and the mechanical advantage that they can deliver, the diameters of pulleys determine those same factors. Cone pulleys and step pulleys (which operate on the same principle, although the names tend to be applied to flat belt versions and V-belt versions, respectively) are a way to provide multiple drive ratios in a belt-and-pulley system that can be shifted as needed, just as

436-568: 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

545-451: A transmission provides this function with a gear train that can be shifted. V-belt step pulleys are the most common way that drill presses deliver a range of spindle speeds. With belts and pulleys, friction is one of the most important forces. Some uses for belts and pulleys involve peculiar angles (leading to bad belt tracking and possibly slipping the belt off the pulley) or low belt-tension environments, causing unnecessary slippage of

654-502: 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

763-483: A chain sprocket, spur gear , or timing belt) so that the mechanical advantage is approximately given by the ratio of the pitch diameter of the sheaves only, not fixed exactly by the ratio of teeth as with gears and sprockets. In the case of a drum-style pulley, without a groove or flanges, the pulley often is slightly convex to keep the flat belt centered. It is sometimes referred to as a crowned pulley. Though once widely used on factory line shafts , this type of pulley

872-408: A change of direction of a rope that does not stretch or wear. In this case, a force balance on a free body that includes the load, W , and n supporting sections of a rope with tension T , yields: The ratio of the load to the input tension force is the mechanical advantage MA of the pulley system, Thus, the mechanical advantage of the system is equal to the number of sections of rope supporting

981-674: 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

1090-452: 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

1199-516: 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

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1308-893: 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

1417-411: 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

1526-401: 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

1635-399: A load—the rope may be a light line or a strong cable. This system is included in the list of simple machines identified by Renaissance scientists. If the rope and pulley system does not dissipate or store energy, then its mechanical advantage is the number of parts of the rope that act on the load. This can be shown as follows. Consider the set of pulleys that form the moving block and

1744-420: 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

1853-492: 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

1962-470: 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

2071-838: 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

2180-500: 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

2289-592: 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

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2398-1011: 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,

2507-412: 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

2616-406: 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

2725-430: 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

2834-534: 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

2943-516: A pulley to the fixed block of a gun tackle the direction of the pulling force is reversed though the mechanical advantage remains the same, Diagram 3a. This is an example of the Luff tackle. The mechanical advantage of a pulley system can be analysed using free body diagrams which balance the tension force in the rope with the force of gravity on the load. In an ideal system, the massless and frictionless pulleys do not dissipate energy and allow for

3052-476: 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

3161-459: 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

3270-646: 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:

3379-403: 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

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3488-436: 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

3597-458: 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

3706-410: 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

3815-423: 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

3924-519: 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

4033-603: 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

4142-401: 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

4251-476: Is still found driving the rotating brush in upright vacuum cleaners , in belt sanders and bandsaws . Agricultural tractors built up to the early 1950s generally had a belt pulley for a flat belt (which is what Belt Pulley magazine was named after). It has been replaced by other mechanisms with more flexibility in methods of use, such as power take-off and hydraulics . Just as the diameters of gears (and, correspondingly, their number of teeth) determine

4360-420: 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

4469-425: 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

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4578-421: 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

4687-1047: 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

4796-516: 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

4905-465: 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

5014-517: 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

5123-584: 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

5232-521: 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

5341-497: 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

5450-560: 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,

5559-562: 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

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5668-516: 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,

5777-472: 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

5886-551: 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

5995-554: 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

6104-533: 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

6213-507: 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

6322-413: 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

6431-427: 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

6540-595: 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

6649-564: 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

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6758-567: 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

6867-409: 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

6976-399: The belt and hence extra wear to the belt. To solve this, pulleys are sometimes lagged. Lagging is the term used to describe the application of a coating, cover or wearing surface with various textured patterns which is sometimes applied to pulley shells. Lagging is often applied in order to extend the life of the shell by providing a replaceable wearing surface or to improve the friction between

7085-409: The block and tackle is equal to the number of sections of the rope that support the moving block. In the diagram on the right, the ideal mechanical advantage of each of the block and tackle assemblies shown is as follows: A rope and pulley system—that is, a block and tackle —is characterised by the use of a single continuous rope to transmit a tension force around one or more pulleys to lift or move

7194-428: The bodies in the system form lines in space that do not intersect and have distinct common normals. A flexure mechanism consists of a series of rigid bodies connected by compliant elements (also known as flexure joints) that is designed to produce a geometrically well-defined motion upon application of a force. Pulley A pulley may have a groove or grooves between flanges around its circumference to locate

7303-411: 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

7412-416: The cable or belt. The drive element of a pulley system can be a rope , cable , belt, or chain . The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991–1802 BC) and Mesopotamia in the early 2nd millennium BC. In Roman Egypt , Hero of Alexandria (c. 10–70 AD) identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form

7521-509: 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

7630-428: 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

7739-428: 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

7848-578: 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

7957-417: 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

8066-536: 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

8175-470: 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

8284-606: 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

8393-474: 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

8502-448: 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

8611-493: 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

8720-561: 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

8829-414: The gun tackle can be increased by interchanging the fixed and moving blocks so the rope is attached to the moving block and the rope is pulled in the direction of the lifted load. In this case the block and tackle is said to be "rove to advantage." Diagram 3 shows that now three rope parts support the load W which means the tension in the rope is W/3 . Thus, the mechanical advantage is three. By adding

8938-417: 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

9047-529: 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

9156-423: The load. A belt and pulley system is characterized by two or more pulleys in common to a belt . This allows for mechanical power , torque , and speed to be transmitted across axles. If the pulleys are of differing diameters, a mechanical advantage is realized. A belt drive is analogous to that of a chain drive ; however, a belt sheave may be smooth (devoid of discrete interlocking members as would be found on

9265-758: 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

9374-408: 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

9483-419: 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

9592-418: The parts of the rope that support this block. If there are p of these parts of the rope supporting the load W, then a force balance on the moving block shows that the tension in each of the parts of the rope must be W/p. This means the input force on the rope is T = W/p. Thus, the block and tackle reduces the input force by the factor p. The simplest theory of operation for a pulley system assumes that

9701-452: 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,

9810-403: 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

9919-459: The pulleys and lines are weightless and that there is no energy loss due to friction. It is also assumed that the lines do not stretch. In equilibrium, the forces on the moving block must sum to zero. In addition the tension in the rope must be the same for each of its parts. This means that the two parts of the rope supporting the moving block must each support half the load. These are different types of pulley systems: The mechanical advantage of

10028-467: 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

10137-608: 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

10246-513: 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

10355-525: 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

10464-487: 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

10573-631: 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

10682-404: 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

10791-399: 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

10900-409: 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

11009-564: 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

11118-590: 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

11227-693: 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

11336-580: 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

11445-613: 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

11554-440: Was gliding through water. A block is a set of pulleys (wheels) assembled so that each pulley rotates independently from every other pulley. Two blocks with a rope attached to one of the blocks and threaded through the two sets of pulleys form a block and tackle . A block and tackle is assembled so one block is attached to the fixed mounting point and the other is attached to the moving load. The ideal mechanical advantage of

11663-509: 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

11772-456: 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

11881-431: 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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