Engineering is the discipline, art, skill and profession of acquiring and applying
scientific,
mathematical,
economic, social, and practical knowledge, in order to
design and build structures, machines, devices, systems, materials and
processes.
The
American Engineers' Council for Professional Development (ECPD, the predecessor of
ABET)
[1] has defined "engineering" as:
the creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property.[2][3]
One who practices engineering is called an
engineer, and those licensed to do so may have more formal designations such as
Professional Engineer,
Chartered Engineer,
Incorporated Engineer,
Ingenieur or
European Engineer. The broad discipline of engineering encompasses a range of more specialized
sub disciplines, each with a more specific emphasis on certain fields of application and particular areas of technology.
History
Engineering has existed since ancient times as humans devised fundamental inventions such as the pulley, lever, and wheel. Each of these inventions is consistent with the modern definition of engineering, exploiting basic mechanical principles to develop useful tools and objects.
The term
engineering itself has a much more recent etymology, deriving from the word
engineer, which itself dates back to 1325, when an
engine’er (literally, one who operates an
engine) originally referred to “a constructor of military engines.”
[4] In this context, now obsolete, an “engine” referred to a military machine,
i.e., a mechanical contraption used in war (for example, a
catapult). Notable exceptions of the obsolete usage which have survived to the present day are military engineering corps,
e.g., the
U.S. Army Corps of Engineers.
The word “engine” itself is of even older origin, ultimately deriving from the
Latin ingenium (c. 1250), meaning “innate quality, especially mental power, hence a clever invention.”
[5]
Later, as the design of civilian structures such as bridges and buildings matured as a technical discipline, the term
civil engineering[3] entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the older discipline of
military engineering.
[edit] Ancient era
The
Pharos of Alexandria, the
pyramids in
Egypt, the
Hanging Gardens of Babylon, the
Acropolis and the
Parthenon in
Greece, the
Roman aqueducts,
Via Appia and the
Colosseum,
Teotihuacán and the cities and pyramids of the
Mayan,
Inca and
Aztec Empires, the
Great Wall of China, among many others, stand as a testament to the ingenuity and skill of the ancient civil and military engineers.
The earliest civil engineer known by name is
Imhotep.
[3] As one of the officials of the
Pharaoh,
Djosèr, he probably designed and supervised the construction of the
Pyramid of Djoser (the
Step Pyramid) at
Saqqara in
Egypt around
2630-
2611 BC.
[6] He may also have been responsible for the first known use of
columns in
architecture[citation needed].
Ancient Greece developed machines in both the civilian and military domains. The
Antikythera mechanism, the first known
mechanical computer,
[7][8] and the mechanical
inventions of
Archimedes are examples of early mechanical engineering. Some of Archimedes' inventions as well as the Antikythera mechanism required sophisticated knowledge of
differential gearing or
epicyclic gearing, two key principles in machine theory that helped design the
gear trains of the Industrial revolution, and are still widely used today in diverse fields such as
robotics and
automotive engineering.
[9]
Chinese, Greek and Roman armies employed complex military machines and inventions such as
artillery which was developed by the Greeks around the 4th century B.C.,
[10] the
trireme, the
ballista and the
catapult. In the Middle Ages, the
Trebuchet was developed.
[edit] Renaissance era
The first
electrical engineer is considered to be
William Gilbert, with his 1600 publication of
De Magnete, who was the originator of the term "
electricity".
[11]
The first
steam engine was built in 1698 by
mechanical engineer Thomas Savery.
[12] The development of this device gave rise to the
industrial revolution in the coming decades, allowing for the beginnings of
mass production.
With the rise of engineering as a
profession in the eighteenth century, the term became more narrowly applied to fields in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering the fields then known as the
mechanic arts became incorporated into engineering.
[edit] Modern era
Electrical engineering can trace its origins in the experiments of
Alessandro Volta in the 1800s, the experiments of
Michael Faraday,
Georg Ohm and others and the invention of the
electric motor in 1872. The work of
James Maxwell and
Heinrich Hertz in the late 19th century gave rise to the field of
Electronics. The later inventions of the
vacuum tube and the
transistor further accelerated the development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other Engineering specialty.
[3]
The inventions of Thomas Savery and the Scottish engineer
James Watt gave rise to modern
Mechanical Engineering. The development of specialized machines and their maintenance tools during the industrial revolution led to the rapid growth of Mechanical Engineering both in its birthplace
Britain and abroad.
[3]
Chemical Engineering, like its counterpart Mechanical Engineering, developed in the nineteenth century during the
Industrial Revolution.
[3] Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants.
[3] The role of the chemical engineer was the design of these chemical plants and processes.
[3]
Aeronautical Engineering deals with
aircraft design while
Aerospace Engineering is a more modern term that expands the reach envelope of the discipline by including
spacecraft design.
[13] Its origins can be traced back to the aviation pioneers around the turn of the century from the 19th century to the 20th although the work of
Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering.
[14]
The first
PhD in engineering (technically,
applied science and engineering) awarded in the United States went to
Willard Gibbs at
Yale University in 1863; it was also the second PhD awarded in science in the U.S.
[15]
Only a decade after the successful flights by the
Wright brothers, there was extensive development of aeronautical engineering through development of military aircraft that were used in
World War I . Meanwhile, research to provide fundamental background science continued by combining
theoretical physics with experiments.
In 1990, with the rise of
computer technology, the first
search engine was built by
computer engineer Alan Emtage.
[edit] Main branches of engineering
Engineering, much like other science, is a broad discipline which is often broken down into several sub-disciplines. These disciplines concern themselves with differing areas of engineering work. Although initially an engineer will usually be trained in a specific discipline, throughout an engineer's career the engineer may become multi-disciplined, having worked in several of the outlined areas. Engineering is often characterized as having four main branches:
[16][17]
- Chemical engineering – The exploitation of both engineering and chemical principles in order to carry out large scale chemical process.
- Civil engineering – The design and construction of public and private works, such as infrastructure (airports, roads, railways, water supply and treatment etc.), bridges, dams, and buildings.
- Electrical engineering – The design and study of various electrical and electronic systems, such as electrical circuits, generators, motors, electromagnetic/electromechanical devices, electronic devices, electronic circuits, optical fibers, optoelectronic devices, computer systems, telecommunications, instrumentation, controls, and electronics.
- Mechanical engineering – The design of physical or mechanical systems, such as power and energy systems, aerospace/aircraft products, weapon systems, transportation products engines, compressors, powertrains, kinematic chains, vacuum technology, and vibration isolation equipment.
Beyond these four, sources vary on other main branches. Historically,
naval engineering and
mining engineering were major branches. Modern fields sometimes included as major branches include
aerospace,
systems,
architectural,
biomedical,
[18] industrial,
materials science[19] and
nuclear engineering.
[20][citation needed]
New specialties sometimes combine with the traditional fields and form new branches. A new or emerging area of application will commonly be defined temporarily as a permutation or subset of existing disciplines; there is often gray area as to when a given sub-field becomes large and/or prominent enough to warrant classification as a new "branch." One key indicator of such emergence is when major universities start establishing departments and programs in the new field.
For each of these fields there exists considerable overlap, especially in the areas of the application of sciences to their disciplines such as physics, chemistry and mathematics.
[edit] Methodology
Design of a
turbine requires collaboration of engineers from many fields, as the system is subject to mechanical, electro-magnetic and chemical processes. The
blades,
rotor and stator as well as the
steam cycle all need to be carefully designed and optimized.
Engineers apply the sciences of physics and mathematics to find suitable solutions to problems or to make improvements to the status quo. More than ever, engineers are now required to have knowledge of relevant sciences for their design projects, as a result, they keep on learning new material throughout their career.
If multiple options exist, engineers weigh different design choices on their merits and choose the solution that best matches the requirements. The crucial and unique task of the engineer is to identify, understand, and interpret the constraints on a design in order to produce a successful result. It is usually not enough to build a technically successful product; it must also meet further requirements.
Constraints may include available resources, physical, imaginative or technical limitations, flexibility for future modifications and additions, and other factors, such as requirements for cost,
safety, marketability, productibility, and
serviceability. By understanding the constraints, engineers derive
specifications for the limits within which a viable object or system may be produced and operated.
[edit] Problem solving
Engineers use their knowledge of
science,
mathematics,
logic,
economics, and
appropriate experience or
tacit knowledge to find suitable solutions to a problem. Creating an appropriate
mathematical model of a problem allows them to analyze it (sometimes definitively), and to test potential solutions.
Usually multiple reasonable solutions exist, so engineers must evaluate the different
design choices on their merits and choose the solution that best meets their requirements.
Genrich Altshuller, after gathering statistics on a large number of
patents, suggested that
compromises are at the heart of "
low-level" engineering designs, while at a higher level the best design is one which eliminates the core contradiction causing the problem.
Engineers typically attempt to predict how well their designs will perform to their specifications prior to full-scale production. They use, among other things:
prototypes,
scale models,
simulations,
destructive tests,
nondestructive tests, and
stress tests. Testing ensures that products will perform as expected.
Engineers take on the responsibility of producing designs that will perform as well as expected and will not cause unintended harm to the public at large. Engineers typically include a
factor of safety in their designs to reduce the risk of unexpected failure. However, the greater the safety factor, the less efficient the design may be.
The study of failed products is known as
forensic engineering, and can help the
product designer in evaluating his or her design in the light of real conditions. The discipline is of greatest value after disasters, such as
bridge collapses, when careful analysis is needed to establish the cause or causes of the failure.
[edit] Computer use
A computer simulation of high velocity air flow around the
Space Shuttle during re-entry. Solutions to the flow require
modelling of the combined effects of the
fluid flow and
heat equations.
As with all modern scientific and technological endeavors, computers and software play an increasingly important role. As well as the typical business
application software there are a number of computer aided applications (
Computer-aided technologies) specifically for engineering. Computers can be used to generate models of fundamental physical processes, which can be solved using
numerical methods.
One of the most widely used tools in the profession is
computer-aided design (CAD) software which enables engineers to create 3D models, 2D drawings, and schematics of their designs. CAD together with
Digital mockup (DMU) and
CAE software such as
finite element method analysis or
analytic element method allows engineers to create models of designs that can be analyzed without having to make expensive and time-consuming physical prototypes.
These allow products and components to be checked for flaws; assess fit and assembly; study ergonomics; and to analyze static and dynamic characteristics of systems such as stresses, temperatures, electromagnetic emissions, electrical currents and voltages, digital logic levels, fluid flows, and kinematics. Access and distribution of all this information is generally organized with the use of
Product Data Management software.
[21]
There are also many tools to support specific engineering tasks such as
Computer-aided manufacture (CAM) software to generate
CNC machining instructions;
Manufacturing Process Management software for production engineering;
EDA for
printed circuit board (PCB) and circuit
schematics for electronic engineers;
MRO applications for maintenance management; and
AEC software for civil engineering.
In recent years the use of computer software to aid the development of goods has collectively come to be known as
Product Lifecycle Management (PLM).
[22]
[edit] Social context
Engineering is a subject that ranges from large collaborations to small individual projects. Almost all engineering projects are beholden to some sort of financing agency: a company, a set of investors, or a government. The few types of engineering that are minimally constrained by such issues are
pro bono engineering and
open design engineering.
By its very nature engineering is bound up with society and human behavior. Every product or construction used by modern society will have been influenced by engineering design. Engineering design is a very powerful tool to make changes to environment, society and economies, and its application brings with it a great responsibility. Many
engineering societies have established codes of practice and
codes of ethics to guide members and inform the public at large.
Engineering projects can be subject to controversy. Examples from different engineering disciplines include the development of
nuclear weapons, the
Three Gorges Dam, the design and use of
Sport utility vehicles and the extraction of
oil. In response, some western engineering companies have enacted serious
corporate and social responsibility policies.
Engineering is a key driver of human development.
[23] Sub-Saharan Africa in particular has a very small engineering capacity which results in many African nations being unable to develop crucial infrastructure without outside aid. The attainment of many of the
Millennium Development Goals requires the achievement of sufficient engineering capacity to develop infrastructure and sustainable technological development.
[24]
All overseas development and relief NGOs make considerable use of engineers to apply solutions in disaster and development scenarios. A number of charitable organizations aim to use engineering directly for the good of mankind:
[edit] Relationships with other disciplines
[edit] Science
Scientists study the world as it is; engineers create the world that has never been.
There exists an overlap between the sciences and engineering practice; in engineering, one applies science. Both areas of endeavor rely on accurate observation of
materials and phenomena. Both use mathematics and classification criteria to analyze and communicate observations.
Scientists may also have to complete engineering tasks, such as designing experimental apparatus or building prototypes. Conversely, in the process of developing technology engineers sometimes find themselves exploring new phenomena, thus becoming, for the moment, scientists.
In the book
What Engineers Know and How They Know It,
[28] Walter Vincenti asserts that engineering research has a character different from that of scientific research. First, it often deals with areas in which the basic
physics and/or
chemistry are well understood, but the problems themselves are too complex to solve in an exact manner.
Examples are the use of numerical approximations to the
Navier-Stokes equations to describe aerodynamic flow over an aircraft, or the use of
Miner's rule to calculate fatigue damage. Second, engineering research employs many semi-
empirical methods that are foreign to pure scientific research, one example being the method of parameter variation
[citation needed].
As stated by Fung et al. in the revision to the classic engineering text, Foundations of
Solid Mechanics:
"Engineering is quite different from science. Scientists try to understand nature. Engineers try to make things that do not exist in nature. Engineers stress invention. To embody an invention the engineer must put his idea in concrete terms, and design something that people can use. That something can be a device, a gadget, a material, a method, a computing program, an innovative experiment, a new solution to a problem, or an improvement on what is existing. Since a design has to be concrete, it must have its geometry, dimensions, and characteristic numbers. Almost all engineers working on new designs find that they do not have all the needed information. Most often, they are limited by insufficient scientific knowledge. Thus they study mathematics, physics, chemistry, biology and mechanics. Often they have to add to the sciences relevant to their profession. Thus engineering sciences are born."[29]
Although engineering solutions make use of scientific principles, engineers must also take into account safety, efficiency, economy, reliability and constructability or ease of fabrication, as well as legal considerations such as patent infringement or liability in the case of failure of the solution.
[edit] Medicine and biology
The study of the human body, albeit from different directions and for different purposes, is an important common link between medicine and some engineering disciplines.
Medicine aims to sustain, enhance and even replace functions of the
human body, if necessary, through the use of
technology.
Modern medicine can replace several of the body's functions through the use of artificial organs and can significantly alter the function of the human body through artificial devices such as, for example,
brain implants and
pacemakers.
[31][32] The fields of
Bionics and medical Bionics are dedicated to the study of synthetic implants pertaining to natural systems.
Conversely, some engineering disciplines view the human body as a biological machine worth studying, and are dedicated to emulating many of its functions by replacing
biology with technology. This has led to fields such as
artificial intelligence,
neural networks,
fuzzy logic, and
robotics. There are also substantial interdisciplinary interactions between engineering and medicine.
[33][34]
Both fields provide solutions to real world problems. This often requires moving forward before phenomena are completely understood in a more rigorous scientific sense and therefore experimentation and
empirical knowledge is an integral part of both.
Medicine, in part, studies the function of the human body. The human body, as a biological machine, has many functions that can be modeled using Engineering methods.
[35]
The heart for example functions much like a pump,
[36] the skeleton is like a linked structure with levers,
[37] the brain produces
electrical signals etc.
[38] These similarities as well as the increasing importance and application of Engineering principles in Medicine, led to the development of the field of
biomedical engineering that uses concepts developed in both disciplines.
Newly emerging branches of science, such as
Systems biology, are adapting analytical tools traditionally used for engineering, such as systems modeling and computational analysis, to the description of biological systems.
[35]
A drawing for a booster engine for
steam locomotives. Engineering is applied to
design, with emphasis on function and the utilization of mathematics and science.
There are connections between engineering and art;
[39] they are direct in some fields, for example,
architecture,
landscape architecture and
industrial design (even to the extent that these disciplines may sometimes be included in a University's
Faculty of Engineering); and indirect in others.
[39][40][41][42]
The
Art Institute of Chicago, for instance, held an exhibition about the art of
NASA's aerospace design.
[43] Robert Maillart's bridge design is perceived by some to have been deliberately artistic.
[44] At the
University of South Florida, an engineering professor, through a grant with the
National Science Foundation, has developed a course that connects art and engineering.
[40][45]
Among famous historical figures
Leonardo Da Vinci is a well known
Renaissance artist and engineer, and a prime example of the nexus between art and engineering.
[30][46]
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