Mechanical Engineering

Mechanical Engineering
Names mechanical engineer
Activity sectors mechanics, applied mechanics, fluid dynamics
Competencies technical knowledge, management skills
Education required see professional requirements

Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the design, production, and operation of machines and tools.[1] It is one of the oldest and broadest engineering disciplines.

The engineering field requires an understanding of core concepts including mechanics, kinematics, thermodynamics, materials science, structural analysis, and electricity. Mechanical engineers use these core principles along with tools like computer-aided engineering and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, aircraft, watercraft, robotics, medical devices, and others.

Mechanical engineering emerged as a field during the chemical engineering to varying amounts.


[edit] Development

Mechanical engineers design and build power plants

vehicles of all sizes.

Applications of mechanical engineering are found in the records of many ancient and medieval societies throughout the globe. In [3]

During the years from 7th to 15th century, the era called the Islamic Golden Age, there were remarkable contributions from Muslim inventors 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. He is also considered to be the inventor of such mechanical devices which now form the very basic of mechanisms, such as the crankshaft and camshaft.[4]

Important breakthroughs in the foundations of mechanical engineering occurred in England during the 17th century when Sir Edmund Halley, much to the benefit of all mankind.

During the early 19th century in Johann Von Zimmermann (1820–1901) founded the first factory for grinding machines in Chemnitz (Germany) in 1848.

In the [8]

[edit] Education

Degrees in mechanical engineering are offered at universities worldwide. In Brazil, Ireland, Philippines, China, Greece, Turkey, North America, South Asia, India and the United Kingdom, mechanical engineering programs typically take four to five years of study and result in a Bachelor of Applied Science (B.A.Sc) degree, in or with emphasis in mechanical engineering. In Spain, Portugal and most of South America, where neither BSc nor BTech programs have been adopted, the formal name for the degree is “Mechanical Engineer”, and the course work is based on five or six years of training. In Italy the course work is based on five years of training, but in order to qualify as an Engineer you have to pass a state exam at the end of the course.

In Australia, mechanical engineering degrees are awarded as Bachelor of Engineering (Mechanical) or similar nomenclature[9] 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 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 the United States, most undergraduate mechanical engineering programs are [11] and most other countries offering engineering degrees have similar accreditation societies.

Some mechanical engineers go on to pursue a postgraduate degree such as a Master of Engineering, Master of Technology, Master of Science, Master of Engineering Management (MEng.Mgt or MEM), a Doctor of Philosophy in engineering (EngD, PhD) 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 the entry point to academia.[12] The Engineer’s degree exists at a few institutions at an intermediate level between the master’s degree and the doctorate.

[edit] Coursework

Standards set by each country’s accreditation society are intended to provide uniformity in fundamental subject material, promote competence among graduating engineers, and to maintain confidence in the engineering profession as a whole. Engineering programs in the U.S., for example, are required by ABET to show that their students can “work professionally in both thermal and mechanical systems areas.”[13] 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 the university’s major area(s) of research.

The fundamental subjects of mechanical engineering usually include:

Mechanical engineers are also expected to understand and be able to apply basic concepts from chemistry, physics, differential geometry, among others.

In addition to the core mechanical engineering curriculum, many mechanical engineering programs offer more specialized programs and classes, such as robotics, transport and logistics, cryogenics, fuel technology, automotive engineering, biomechanics, vibration, optics and others, if a separate department does not exist for these subjects.[16]

Most mechanical engineering programs also require varying amounts of research or community projects to gain practical problem-solving experience. In the United States it is common for mechanical engineering students to complete one or more [18]

[edit] License

Engineers may seek citation needed]

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

In the United States, the requirements and steps of this process are set forth by the Institution of Mechanical Engineers.

In most modern countries, certain engineering tasks, such as the design of bridges, electric power plants, and chemical plants, must be approved by a [20]

In other countries, such as Australia, 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.[21]

[edit] Salaries and workforce statistics

The total number of engineers employed in the U.S. in 2009 was roughly 1.6 million. Of these, 239,000 were mechanical engineers (14.9%), the second largest discipline by size behind civil (278,000). The total number of mechanical engineering jobs in 2009 was projected to grow 6% over the next decade, with average starting salaries being $58,800 with a bachelor’s degree.[23]

In 2007, Canadian engineers made an average of CAD$29.83 per hour with 4% unemployed. The average for all occupations was $18.07 per hour with 7% unemployed. Twelve percent of these engineers were self-employed, and since 1997 the proportion of female engineers had risen to 6%.[24]

[edit] Modern tools

An oblique view of a four-cylinder inline crankshaft with pistons

Many mechanical engineering companies, especially those in industrialized nations, have begun to incorporate computer-aided design (CAD). This method has many benefits, including easier and more exhaustive visualization of products, the ability to create virtual assemblies of parts, and the ease of use in designing mating interfaces and tolerances.

Other CAE programs commonly used by mechanical engineers include computer-aided manufacturing (CAM).

Using CAE programs, a mechanical design team can quickly and cheaply iterate the design process to develop a product that better meets cost, performance, and other constraints. No physical prototype need be created until the design nears completion, allowing hundreds or thousands of designs to be evaluated, instead of a relative few. In addition, CAE analysis programs can model complicated physical phenomena which cannot be solved by hand, such as viscoelasticity, complex contact between mating parts, or non-Newtonian flows.

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

[edit] Subdisciplines

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

[edit] Mechanics

Mechanics is, in the most general sense, the study of stresses. Subdisciplines of mechanics include

Mechanical engineers typically use mechanics in the design or analysis phases of engineering. If the engineering project were the design of a vehicle, statics might be employed to design the frame of the vehicle, in order to evaluate where the stresses will be most intense. Dynamics might be used when designing the car’s engine, to evaluate the forces in the intake system for the engine.

[edit] Mechatronics and robotics

Training FMS with learning robot SCORBOT-ER 4u, workbench CNC Mill and CNC Lathe

Mechatronics is an interdisciplinary branch of mechanical engineering, bits. Integrated software controls the process and communicates the contents of the CD to the computer.

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

Robots are used extensively in space exploration, and many other fields. Robots are also sold for various residential applications, from recreation to domestic applications.

[edit] Structural analysis

Structural analysis is the branch of mechanical engineering (and also civil engineering) devoted to examining why and how objects fail and to fix the objects and their performance. Structural failures occur in two general modes: static failure, and fatigue failure. Static structural failure occurs when, upon being loaded (having a force applied) the object being analyzed either breaks or is deformed 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 a failure has occurred, or when designing to prevent failure. Engineers often use online documents and books such as those published by ASM[26] to aid them in determining the type of failure and possible causes.

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

[edit] Thermodynamics and thermo-science

Thermodynamics 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 the wheels.

Thermodynamics principles are used by mechanical engineers in the fields of insulation, and others.

[edit] Design and drafting

A CAD model of a mechanical double seal

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

Drafting is used in nearly every subdiscipline of mechanical engineering, and by many other branches of engineering and architecture. Three-dimensional models created using CAD software are also commonly used in computational fluid dynamics (CFD).

[edit] Frontiers of research

Mechanical engineers are constantly pushing the boundaries of what is physically possible in order to produce safer, cheaper, and more efficient machines and mechanical systems. Some technologies at the cutting edge of mechanical engineering are listed below (see also exploratory engineering).

[edit] Micro electro-mechanical systems (MEMS)

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

[edit] Friction stir welding (FSW)

Friction stir welding, a new type of [29]

[edit] Composites

Composite cloth consisting of woven carbon fiber

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

[edit] Mechatronics

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

[edit] Nanotechnology

At the smallest scales, mechanical engineering becomes nanotechnology —one speculative goal of which is to create a molecular assembler to build molecules and materials via mechanosynthesis. For now that goal remains within exploratory engineering. Areas of current mechanical engineering research in nanotechnology include nanofilters,[30] nanofilms,[31] and nanostructures,[32] among others.

[edit] Finite element analysis

This field is not new, as the basis of Finite Element Analysis (FEA) or Finite Element Method (FEM) dates back to 1941. But evolution of computers has made FEA/FEM a viable option for analysis of structural problems. Many commercial codes such as Calculix is an open source and free finite element program. Some 3D modeling and CAD software packages have added FEA modules.

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

[edit] Biomechanics

Biomechanics is the application of mechanical principles to biological systems, such as humans, animals, plants, organs, and cells.[33]

Biomechanics is closely related to materials sciences can supply correct approximations to the mechanics of many biological systems.

[edit] Computational fluid dynamics

Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. With high-speed supercomputers, better solutions can be achieved. Ongoing research yields software that improves the accuracy and speed of complex simulation scenarios such as transonic or turbulent flows. Initial validation of such software is performed using a wind tunnel with the final validation coming in full-scale testing, e.g. flight tests.

[edit] Related fields

Manufacturing engineering and Aerospace Engineering are sometimes grouped with mechanical engineering. A bachelor’s degree in these areas will typically have a difference of a few specialized classes.

[edit] See also

[edit] Associations

[edit] Wikibooks

[edit] Notes and references

  1. ^ engineering “mechanical engineering. (n.d.)”. The American Heritage Dictionary of the English Language, Fourth Edition. Retrieved: May 8, 2010.
  2. ^ “Heron of Alexandria”. Encyclopedia Britannica 2010 – Encyclopedia Britannica Online. Accessed: 09 May 2010.
  3. ^ Needham, Joseph (1986). Science and Civilization in China: Volume 4. Taipei: Caves Books, Ltd.
  4. ^ Al-Jazarí. The Book of Knowledge of Ingenious Mechanical Devices: Kitáb fí ma’rifat al-hiyal al-handasiyya. Springer, 1973. ISBN 90-277-0329-9.
  5. ^ Engineering – Encyclopædia Britannica, accessed 06 May 2008
  6. ^ R. A. Buchanan. The Economic History Review, New Series, Vol. 38, No. 1 (Feb., 1985), pp. 42–60.
  7. ^ ASME history, accessed 06 May 2008.
  8. ^ The Columbia Encyclopedia, Sixth Edition. 2001-07, engineering, accessed 06 May 2008
  9. ^ “Mechanical Engineering”. Retrieved 8 December 2011.
  10. ^ ABET searchable database of accredited engineering programs, Accessed June 19, 2006.
  11. ^ Accredited engineering programs in Canada by the Canadian Council of Professional Engineers, Accessed April 18, 2007.
  12. ^ Types of post-graduate degrees offered at MIT – Accessed 19 June 2006.
  13. ^ 2008-2009 ABET Criteria, p. 15.
  14. ^ University of Tulsa Required ME Courses – Undergraduate Majors and Minors. Department of Mechanical Engineering, University of Tulsa, 2010. Accessed: 17 December 2010.
  15. ^ Harvard Mechanical Engineering Page. Accessed: 19 June 2006.
  16. ^ Mechanical Engineering courses, MIT. Accessed 14 June 2008.
  17. ^ [1]. Apollo Reseach Institute, Future Work Skills 2020, Accessed November 5, 2012.
  18. ^ [2] Aalto University School of Engineering, Design Factory – Researchers Blog, Accessed November 5, 2012.
  19. ^ “Why Get Licensed?”. National Society of Professional Engineers. Retrieved May 6, 2008.
  20. ^ “Engineers Act”. Quebec Statutes and Regulations (CanLII). Retrieved July 24, 2005.
  21. ^ “Codes of Ethics and Conduct”. Online Ethics Center. Archived from the original on June 19, 2005. Retrieved July 24, 2005.
  22. 2010-11 Edition, Engineers – Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, Accessed: 9 May 2010.
  23. ^ Document National Sector NAICS Industry-Specific estimates (xls) Accessed: 9 May 2010.
  24. ^ Mechanical Engineers – Mechanical Engineering, Accessed: October 25, 2012.
  25. ^ Note: fluid mechanics can be further split into fluid statics and fluid dynamics, and is itself a subdiscipline of continuum mechanics. The application of fluid mechanics in engineering is called hydraulics and pneumatics.
  26. ^ ASM International‘s site containing more than 20,000 searchable documents, including articles from the ASM Handbook series and Advanced Materials & Processes
  27. ^ Advances in Friction Stir Welding for Aerospace Applications
  28. ^ PROPOSAL NUMBER: 08-1 A1.02-9322 – NASA 2008 SBIR
  29. ^ Nova-Tech LLC
  30. ^ Nilsen, Kyle. (2011) “Development of Low Pressure Filter Testing Vessel and Analysis of Electrospun Nanofiber Membranes for Water Treatment”
  31. ^ Mechanical Characterization of Aluminium Nanofilms, Microelectronic Engineering, Volume 88, Issue 5, May 2011, pp. 844–847.
  32. ^ Columbia University and National Science Foundation, Accessed June 20, 2012.
  33. ^ R. McNeill Alexander (2005) Mechanics of animal movement, Current Biology Volume 15, Issue 16, 23 August 2005, Pages R616-R619

[edit] Further reading

  • Burstall, Aubrey F. (1965). A History of Mechanical Engineering. The MIT Press. ISBN 0-262-52001-X.

[edit] External links

Source: Wikipedia

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