Engineering (from Latin ingenium, meaning "cleverness" and ingeniare, meaning "to contrive, devise") is the application of scientific, economic, social, and practical knowledge in order to invent, design, build, maintain, and improve structures, machines, devices, systems, materials and processes. The discipline of engineering is extremely broad, and encompasses a range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied science, technology and types of application.
Engineering is defined 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 or safety to life and property.
One who practices engineering is called an engineer, and those licensed to do so may have more formal designations such as Professional Engineer, Designated Engineering Representative, Chartered Engineer, Incorporated Engineer, Ingenieur or European Engineer.
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 1300, when an engine'er (literally, one who
operates an engine) originally referred to "a constructor of
military engines."
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
examples 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."
Later, as the design of civilian
structures such as bridges and buildings matured as a technical discipline, the
term civil engineering
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.
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, the Brihadeeswarar Temple of Thanjavur and tombs of India, 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.
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.
Ancient Greece developed machines in both the civilian and military
domains. The Antikythera mechanism, the first known mechanical computer,
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.
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.,
the trireme, the ballista and the catapult. In the
Middle Ages, the trebuchet was developed.
Renaissance
era
The first electrical engineer is considered to be William
Gilbert, with his 1600 publication of De Magnete,
who coined the term "electricity".
The first steam engine
was built in 1698 by mechanical engineer Thomas Savery.
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 18th 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.
Modern
era
The early stages of electrical engineering included 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.
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.
John Smeaton was the first self-proclaimed civil engineer, and often
regarded as the "father" of civil engineering.
He was an English civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist.
Smeaton designed the third Eddystone Lighthouse (1755–59) where he pioneered the use of 'hydraulic lime'
(a form of mortar which will set under water) and developed a technique
involving dovetailed blocks of granite in the building of the lighthouse. His
lighthouse remained in use until 1877 and was dismantled and partially rebuilt
at Plymouth Hoe where it is known as Smeaton's Tower.
He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements
needed to obtain "hydraulicity" in lime; work which led ultimately to
the invention of Portland cement.
Chemical engineering, like its counterpart mechanical engineering, developed in
the nineteenth century during the Industrial Revolution.
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.
The role of the chemical engineer was the design of these chemical plants and
processes.
Aeronautical engineering deals with aircraft design
while aerospace engineering is a more modern term that expands the reach of the
discipline by including spacecraft design. Its origins can be traced back to the aviation pioneers
around the start of the 20th century 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.
The first PhD in engineering (technically, applied science and
engineering) awarded in the United States went to Josiah Willard Gibbs at Yale University
in 1863; it was also the second PhD awarded in science in the U.S.
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
Main branches of engineering
Engineering, 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:
- Chemical engineering – The application of physics, chemistry, biology, and engineering principles in order to carry out chemical processes on a commercial scale, such as petroleum refining, microfabrication, fermentation, and biomolecule production.
- 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 manufacturing
engineering, acoustical engineering, corrosion engineering, aerospace, automotive, computer, electronic, petroleum, systems, audio, software, architectural, biosystems, biomedical,
geological, textile, industrial, materials,
and nuclear
engineering. These and other branches of engineering are represented in the 36
institutions forming the membership of the UK Engineering Council.
New specialties sometimes combine
with the traditional fields and form new branches - for example Earth
Systems Engineering and Management
involves a wide range of subject areas including anthropology,
engineering, environmental science, ethics and philosophy. 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.
Methodology
Engineers apply mathematics and sciences such as physics 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 may 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.
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.
Computer use
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 design tools
in the profession is computer-aided design (CAD) software like Autodesk Inventor,
DSS SolidWorks,
or Pro Engineer 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.
There are also many tools to support
specific engineering tasks such as computer-aided
manufacturing (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).
Social context
Engineering as a subject 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 has
interconnections with society and human behavior. Every product or construction
used by modern society will have been influenced by engineering. Engineering 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.
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.
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:
- Engineers Without Borders
- Engineers Against Poverty
- Registered Engineers for Disaster Relief
- Engineers for a Sustainable World
- Engineering for Change
- Engineering Ministries International
Relationships
with other disciplines
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,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.
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."
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.
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.
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.
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.
The heart for example functions much
like a pump,
the skeleton is like a linked structure with levers,
the brain produces electrical
signals etc.
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.
Art
There are connections between
engineering and art;
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.
An exhibition about the art of NASA's aerospace design.
Robert Maillart's bridge design is perceived by some to have been
deliberately artistic.
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.
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.
Other
fields
In political science
the term engineering has been borrowed for the study of the subjects of social
engineering and political engineering, which deal with forming political and social structures
using engineering methodology coupled with political science
principles. Financial engineering has similarly borrowed the term.
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