Forensic engineering uses the concepts of mechanical, chemical, civil, and electrical engineering as tools in the reconstruction of crimes and accidents and the determination of their cause. A major component of that work involves traffic accident reconstruction. To determine what may have caused the accident, forensic engineers use evidence such as skid marks; damage to cars and their positions after the accident; road and environmental conditions; injuries to drivers, passengers, and pedestrians; and witness accounts. In developing their explanations, engineers may work in concert with forensic pathologists, toxicologists, criminalists, and other engineers. Some forensic engineers specialize in marine incidents or aircraft crashes.
Another major area of forensic engineering is failure analysis. Mechanical, chemical, civil, and structural engineers all bring their skills to bear on problems involving how and why buildings or other structures deteriorate or fail prematurely. An example of such work was the collapse of a walkway high above the lobby of the Kansas City Hyatt Regency Hotel in 1981, which killed and injured many people. Forensic engineers were called in to determine why the balcony collapsed.
A somewhat unusual application of forensic engineering involves animals on farms where high-voltage power lines or communication transmission lines pass overhead. For many years, there have been suggestions by farmers that transient currents from these power lines affect the health of their animals, including cows’ ability to give milk. Many electrical engineers have studied this problem and cases have ended up in court.
Forensic engineers are usually educated engineers who have earned a doctorate and who develop expertise in one or more of the forensically important disciplines. There are no university graduate programs in forensic engineering; most of the expertise is developed on the job, perhaps working with more-experienced practitioners.
Mechanical engineering, the branch of engineering concerned with the design, manufacture, installation, and operation of engines and machines and with manufacturing processes. It is particularly concerned with forces and motion.
The invention of the steam engine in the latter part of the 18th century, providing a key source of power for the Industrial Revolution, gave an enormous impetus to the development of machinery of all types. As a result, a new major classification of engineering dealing with tools and machines developed, receiving formal recognition in 1847 in the founding of the Institution of Mechanical Engineers in Birmingham, Eng.
Mechanical engineering has evolved from the practice by the mechanic of an art based largely on trial and error to the application by the professional engineer of the scientific method in research, design, and production. The demand for increased efficiency is continually raising the quality of work expected from a mechanical engineer and requiring a higher degree of education and training.
Four functions of the mechanical engineer, common to all branches of mechanical engineering, can be cited. The first is the understanding of and dealing with the bases of mechanical science. These include dynamics, concerning the relation between forces and motion, such as in vibration; automatic control; thermodynamics, dealing with the relations among the various forms of heat, energy, and power; fluid flow; heat transfer; lubrication; and properties of materials.
Second is the sequence of research, design, and development. This function attempts to bring about the changes necessary to meet present and future needs. Such work requires a clear understanding of mechanical science, an ability to analyze a complex system into its basic factors, and the originality to synthesize and invent.
Third is production of products and power, which embraces planning, operation, and maintenance. The goal is to produce the maximum value with the minimum investment and cost while maintaining or enhancing longer term viability and reputation of the enterprise or the institution.
Fourth is the coordinating function of the mechanical engineer, including management, consulting, and, in some cases, marketing.
In these functions there is a long continuing trend toward the use of scientific instead of traditional or intuitive methods. Operations research, value engineering, and PABLA (problem analysis by logical approach) are typical titles of such rationalized approaches. Creativity, however, cannot be rationalized. The ability to take the important and unexpected step that opens up new solutions remains in mechanical engineering, as elsewhere, largely a personal and spontaneous characteristic.