The American Heritage Dictionary (4th Edition) defines engineering as the application of scientific principles to practical ends for the design, manufacture and operation of structures and machines (1). Whereas science deals with basic knowledge, engineering uses that knowledge for the solutions of problems to improve the quality of life. In the process of solving problems engineering encounters new challenges that require new knowledge. These challenges provide feedback to science for the acquisition of new knowledge.
Engineering has been a very prominent aspect of life right from the beginning of human existence. The Holy Scriptures recorded in Genesis 26:4 that “God said, let us make man… and let them have dominion…over all the earth…”(2). By that command, engineering was established as the core profession for man. It is therefore no wonder that apart from the things that God directly created every other thing that is in existence came to be through engineering. Engineering principles had been used in such accomplishments as the building of the pyramids of Egypt between 2700-2500 BC, the works of Archimedes between 287-212 BC and the Great Wall of China about 220 BC
Most of the early engineering developments which produced such elementary “machines” as the inclined plane, the wheel, the lever and the sail had to do with simple physical phenomena such as overcoming friction, lifting, hauling and fastening. At the centre of these developments were measurements of distances, angles, weights, heights and time. With time, phenomena as magnetism, static electricity, properties of materials, combustion and thermal processes and chemical processes followed. Modern era of engineering may be said to begin about 1750 because the term “Civil Engineering” was first used in that year (3, 4, 5).
Engineering principles were first taught in an organised form in “Military Academics”. The first organised academic discipline of engineering was therefore Military Engineering. In the United States of America, the first schools to offer engineering education was the United States Military Academy in 1817, Norwich University in 1819 and Rensselaer Polytechnic Institute in 1825(6). The academic training of those days was devoted mostly to warfare. Later, the term Civil Engineering was coined to take care of all things civilian as opposed to Military Engineering (6). Military Engineering later had a change in name effectively to Mechanical Engineering when industrialization became the main focus rather than warfare in the affairs man.
2.0 THE ENGINEERING PROFESSION AND MECHANICAL ENGINEERING
In his book, Engineering As a Career, Smith (5) lists six vocations as professions namely Medicine, Teaching, Architecture, Law, Ministry and Engineering. These vocations have four common characteristics which quality them as professions:
- A significant body of special knowledge.
- An internship training period following the formal education
- A code of ethics of practice for those practicing the profession
- Recognition of his responsibilities to society over and above responsibilities to his clients or other members of the profession by practitioners.
It is also expected that members of the profession must engage in continuous development of themselves to keep abreast with current trends and requirements of the profession. Kemper (4) in his book, The Engineer and His Profession, cautions that it does not follow that every engineer is a professional just because engineering is a profession. To be qualified to be a “Professional Engineer” every individual must meet the responsibility on a personal basis.
From the definition of engineering earlier stated, the body of special knowledge the engineer is expected to have is that which will enable him design, manufacture and operate structures and machines. From the same American Heritage Dictionary earlier referred to, a structure is something made up of parts that are put together in a particular way while a machine is a device or system consisting of fixed and moving parts that alters, directs or modifies mechanical energy and transmits it to accomplish a specific objective.
On the other hand, Mechanical Engineering is defined as a discipline of engineering that applies the principles of physical and material science for analysis, design, manufacture and maintenance of mechanical systems. A cursory look at the definitions of engineering and mechanical engineering shows a synonymy. The only difference in the definitions is that for engineering structures and machines are referred to but for mechanical engineering, it is mechanical systems.
Mechanical systems are systems that relate to machines/tools or operated/produced by machines. It does then appear that engineering is much about mechanical engineering.
For structures to be put in place analyses of forces is key. The branch of physics that is concerned with the analyses of the action of forces is known as mechanics.
Sub-discipline of mechanics includes the following:
- Statics: is the study of how forces affect stationary bodies.
- Dynamics: (also known as kinetics) is the study of how forces affect moving bodies.
- Kinematics: is the study of motion of bodies or collection of bodies (systems) without considering the forces that cause the motion.
- Fluid Mechanics: is the study of how fluids react to the action of forces.
- Thermodynamics: is the study of how fluids react to the action of forces due to heat.
- Mechanics of Materials: is the study of how different materials deform under forces (also known as loads or stresses for solids and pressure for fluids).
- Continum Mechanics: is the study of the action of forces on bodies when the bodies are considered to be continuous rather than discrete.
Mechanical engineering derives its name from mechanics and mechanics is central to engineering. And this is shown by the fact that that almost all the foundation engineering subjects except electro-technology and electronics are studies about mechanics and hence mechanical engineering. Mechanical engineering is therefore the hub of engineering.
3.0 THE DEVELOPMENT OF ENGINEERING
The emergence of Military Engineering, Civil Engineering and Mechanical Engineering has been discussed earlier. All through the ages, the problem has been to perform tasks with minimum physical demand on man. Animals were tried. The horse which was shown to be intelligent and at the same time full of energy, was used. The horse power was the measure of the rate at which a “standard horse” could perform a task. Humans, as slaves, were also tried. Each of these had its problems. A breakthrough in the foundation of engineering occurred in the 17th century when Sir Isaac Newton formulated the three Newton’s Laws of Motion but perhaps the most important advancement in Mechanical Engineering occurred when the steam engine that could perform useful work was developed about 1700. That was the beginning of what was regarded as the Industrial Revolution of the 18th century in Europe. With the steam engine, many mechanical devices were developed that could be driven by the engine. These efforts marked the clear emergence of Mechanical Engineering.
The steam engine, revolutionary as it was as a prime mover, had its drawbacks. Water which is the working fluid was corrosive, has a high density compared with most fluids, and has a high specific heat which means that it requires a high supply of heat to bring it to boil among other disadvantages. For the engine to operate on a closed cycle, a condenser which is a bulky equipment is necessary. On the other hand, if it has to be operated on an open cycle, then water has to be constantly supplied to replenish the steam ejected to the atmosphere. No matter the cycle though, the boiler is indispensable. The steam engine therefore had a low thermal efficiency as well as inherent operational difficulties.
The search for a better source of energy to drive the many mechanical devices that had been developed culminated in the discovery of electricity and hence Electrical Engineering. Benjamin Franklin pioneered the understanding of magnetism and static electricity, while Samuel Morse was noted for telegraph and Thomas Edison the carbon filament lamp. Soon it was discovered that electricity could be generated when a steel shift rotates in a magnetic field.
Along with the developments in mechanical and electrical technology came a better understanding of the properties of matter. Soon, air was introduced as the “energy carrier” and that gave rise to internal combustion engines as opposed to the steam engines in which combustion for the generation of heat has to take place external to the engine. Fuels were needed for the internal combustion engines, lubricants were needed to oil the mechanical devices and protective coatings in the form of pigments and paints to preserve the machines from corrosion and wear. All these substances were chemicals. The engineering discipline that took care of the production of these chemicals naturally became known as Chemical Engineering.
Other engineering disciplines emerged as a consequence of the World War II namely Nuclear Engineering, Aeronautical Engineering, Computer Engineering and others in that category. With the space age came Astronautical Engineering, marine transportation and oil and gas development came Marine Engineering and Petroleum Engineering. The need for large-scale production of food brought about Agricultural Engineering. Lately, a concern for the environment has led to the emergence of Environmental Engineering and Bioengineering. There appears to be no end to the expansion of new frontiers of engineering. It can however be said that with the exception of perhaps Civil Engineering all the other disciplines emerged as a result of developments in Mechanical Engineering. It can also be said that with the exception of Civil Engineering and Electrical Engineering, the other disciplines may be considered as specialties within Mechanical Engineering or originated as a result of advances in Mechanical Engineering.
4.0 THE POSITION OF MECHANICAL ENGINEERS
From all that have been stated it is easy to deduce what the position of the Mechanical Engineer is in the Engineering Profession. The presence of the Mechanical Engineer is required in aerospace, chemical, civil, electrical, manufacturing, metallurgical, agricultural, marine, petroleum and other engineering disciplines to varying degrees. Most of the equipment required by all these disciplines for their jobs are designed, manufactured and maintained by Mechanical Engineers. The generation of electricity which is vital in engineering is basically the prerogative of the Mechanical Engineer. The Electrical Engineer’s work is more in the transmission and distribution of the electricity so generated.
Broadly, the activities of engineering may be classified within four areas namely (a) Industry (b) Transportation (c) Housing and (d) Communication. Civil Engineering practice is mainly in (b) and (c), Electrical Engineering practice is predominantly in (a), (b) and (d); Chemical engineering is predominantly in (a) Marine Engineering, predominantly in (b); Agricultural Engineering in (a); Petroleum Engineering in (a) and Mechanical Engineering in all four. Mechanical Engineers and Electrical Engineers are the core movers of industry. Mechanical Engineers are also the main movers in the design, manufacture and maintenance of transportation facilities on the roads, rails, air, water and space. In housing, beside the structures which are basically the preserve of Civil Engineers, the other facilities are catered for mainly by Mechanical Engineers and Electrical Engineers. Mechatronics is the combination of mechanics and electronics. It is an interdisciplinary branch of Mechanical Engineering, Electrical Engineering and Software Engineering. Mechatronics is key in Communication.
CONCLUDING REMARKS
Mechanical engineering is one of the oldest and broadest engineering disciplines. It is central to industrialization and development. There is hardly an engineering endeavor where the Mechanical Engineer is not required. All other engineering disciplines revolve around mechanical engineering, just the way the planets rotate and derive their sustenance from the sun. So the Mechanical Engineer is the sun of the engineering profession.
REFERENCES
- The American Heritage Dictionary of English Language, 4th ed., 2001
- The Holy Bible, Authorized King James Version, Cornerstone Bible Publishers, Nashville, Tennessee, 1998.
- L.S. de Camp, the Ancient Engineers (Cambridge Mass: MIT Press, 1963).
- T.D. Kemper, The Engineer and His Profession, 2nd ed (New York: Holt, Rinehart and Winston, 1975).
- R.J. Smith, Engineering as a Career (New York)
- Colombia Encyclopedia, 6th ed, 2001-2007
Source: NIMechE
