for 8/10/05
Mechanical Engineering—The Ever-Evolving Profession
by Avram
Bar-Cohen
Recent waves of "obsolescence angst"
washing over the mechanical engineering community [e.g. the
Mechanical Engineering magazine feature story "The End of
the M.E.?" May 2005] appear to ignore the strength of
the discipline's scientific foundation and its evolutionary transformation
over the millennia. An informed view of the current frontiers of science
and technology and recognition of the world's unslaked thirst for new
products suggest that reports of mechanical engineering's demise are premature
and grossly exaggerated (to paraphrase Mark Twain). Mechanical engineering
is not only alive and well: it is critical to the competitiveness of the
United States in the 21st century.
The discipline originated in the early machines—inclined planes,
levers, screws, pulleys, and springs—which provided a means (the
so-called mechanical advantage) to enhance the limited strength of the
human body. Animal power was harnessed next, followed by the exploitation
of swift rivers and strong winds. During these early years, kinematics,
dynamics, strength of materials, and the innovative design of mechanisms
and transmissions, as well as agricultural and production tools, were
at the heart of the discipline. But with the introduction of steam power
as the prime mover and the enabler of large-scale manufacturing and long-distance
transportation, the mechanical engineer's vocabulary grew to include thermodynamics,
heat transfer, and fluid mechanics.
With the advent of the reciprocating internal combustion engine and then
the gas turbine, which expanded land and sea transportation and made long-range
air travel possible, the mechanical engineer again mastered, and successfully
applied, the new sciences of combustion and aerodynamics. The electric
generator, electrical grid, and the electric motor brought cheap power
to every corner of the civilized world, relying on mechanical engineers
to help design and build the power stations, switches, and controllers,
and to link the means of production and transportation to this new prime
mover. The availability of a compact, high-power prime mover for compressing
an evaporated refrigerant enabled the creation of mechanical refrigeration
and air conditioning, undeniably among humankind's greatest inventions.
The microelectronic revolution and the beginning of space exploration
in the latter half of the 20th century introduced miniaturization into
the practice of mechanical engineering. While bigger, faster, stronger
continued to apply to many ME domains, for important sectors of the profession
small was beautiful. After an initial monopoly by electrical engineers
and materials scientists, by the early 1970s large numbers of mechanical
engineers were developing fabrication, assembly, and packaging processes
for millimeter- and then micron-scale electronic components, combining
their knowledge of mechanics, dynamics, and heat transfer with new bonding
and joining technologies to create miniature, thermally stabilized, and
highly reliable electronic components and systems.
Curiously, with electrical engineers leading the digital revolution, more
and more of the electrical power distribution and control, particularly
for electromechanical products, was taken over by MEs. Stepper motors,
along with electrical clutches, were used commonly to replace mechanical
transmissions. The launch weight constraints encountered by the U.S. space
program stimulated the use of engineered composite materials and legitimized
the design and optimization of minimum mass solutions. In the latter part
of the 20th century, use of the growing capability in engineered materials,
microelectronics, and microcontrollers to create artificial organs and
prosthetic limbs gave birth to a new, biomedical domain in mechanical
engineering practice and research.
In parallel with the profession's contributions to the solution of space,
microelectronics, and biomedical "mega challenges," the vast
post-World War II expansion of scientific research and the perceived socioeconomic
benefit of rapid, and frequent, commercial product introduction brought
to the fore the mechanical engineer's unique role in "product realization."
The broad science and engineering base, as well as experiential learning
of product design, characteristic of ME education in the latter decades
of the past century, has defined the mechanical engineer as a system and
product integrator, well positioned to harness a diverse set of emerging,
scale-spanning technologies to produce a constant stream of innovative
products.
The scales of design and fabrication are continuing to shrink. Minimization
of mass and required energy are now a common expectation in product development.
"Smart" materials with embedded controllers are no longer a
novelty. And the application of mechanical engineering principles to biological
systems is being pursued by a greater and greater number of new graduates.
Rather than signaling the end of mechanical engineering, these developments
portend the continued, and perhaps even more rapid, evolution of the profession
in the decades ahead.
The viability and potential impact of mechanical engineering in the 21st
century is clearly in evidence in the commercialization of the scientific
trilogy—information, biomedicine and nanotechnology—defining
the frontiers of science in the early years of the 21st century. Thermal
management and mechanics are crucial to the successful packaging and exploitation
of nanoscale electronic circuits and photonic devices emerging from research
laboratories. Kinematicians are leading the efforts to unravel the secrets
of protein folding, essential to genomics, proteomics and DNA scaffolding.
Thermodynamics underpins the application of polymerase chain reaction
and self-assembly processes, key techniques in miniaturized bio-assaying
and in nano fabrication, respectively. The integration of smart materials
and micro-controllers, along with the application of rapid prototyping
and advanced manufacturing techniques, is transforming—and personalizing—the
biomedical industry.
If the growing body of new science is to yield a significant number of
near-term products, the product realization process—integral to the
practice of mechanical engineering—must be used to address the gulf
between discovery and commercial success. In the absence of modeling techniques,
failure analysis, reliability prediction, established design tools, and
cost-effective manufacturing processes, the incalculable promise of info,
bio, and nano technologies for improving the human condition will remain
largely unrealized.
For humankind to successfully meet the burgeoning challenges to its dominion
on this earth—breathable air, potable water, plentiful energy and
safety from the elements—the knowledge embodied in three millennia
of mechanical engineering practice must be reapplied in the context of
the 21st century. While these components of mechanical engineering knowledge
can and should be integrated into the toolkits of the other branches of
engineering, it is the MEs who are best able to place this knowledge at
the service of society and product development organizations.
So, although the mechanical engineers of 2005 may be working very different
applications with very different tools from those of 1955, 1905, and 1005,
today's practitioners of the mechanical arts are the evolved descendants
of earlier engineers. Moreover, in the decades and centuries ahead, when
solid mechanics, fluid mechanics, kinematics, heat transfer, dynamics,
and manufacturing issues arise, mechanical engineers will be there to
respond. The depth of mechanical engineering knowledge, the strength of
its foundations, the significance of its contributions to mankind, and
the resilience of its practitioners bespeak a future rich in opportunities
and a profession that will—and must—continue to play a critical
role in the creation of innovative solution to society's unmet needs.
Avram Bar-Cohen, an ASME Fellow, is a mechanical
engineering professor and department chair at the University of Maryland
in College Park.
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