Page 27 - Analysis and Design of Machine Elements

An Overview of Machine Design
information, professional judgement and ingenuity in solving practical problems, but 5
also cultivate a strong sense of responsibility and professional work ethic. Mechanical
design involves almost all the disciplines of mechanical engineering [8–10]. The exten-
sive knowledge and skills required for a mechanical designer are briefly summarized as:
– Competence in mathematics, statics, dynamics, mechanics of materials, kinemat-
ics and mechanisms to facilitate load, stress and strength analyses; an advanced
CAD/CAE (computer-aided design or engineering) or FEM (finite element method)
techniqueispreferred;
– Familiar with engineering materials and their properties, materials processing, heat
treatments and manufacturing processes;
– Knowledge of tribology, fluid mechanics, heat transfer, electrical and information
technology and controls;
– Creativity, complex problem-solving capability and project management skills;
– Competence in graphical representation by sketches, engineering drawing, CAD
tools and 3D visualization to convert mental design concepts into technical drawings;
– Both verbal and written communication skills and presentation skills to articulate
design projects, describe constraints and limitations and present proposals and tech-
nical reports;
– Teamwork and collaboration capability, and a sense of social and ethical responsibil-
ities.
Students are expected to appreciate that machine design is an integration of physical
and engineering considerations with social concerns, with an aim to design machines

with satisfactory lives and high reliabilities. With the globalization of business world,
future design engineers are expected to feel comfortable to work in a vibrant and multi-
cultural environment, learn to satisfy the needs of customers in a competent, responsi-
ble, ethical and professional manner and able to communicate complex aspects of design
verbally and graphically to other members in both national and international concurrent
design teams.

1.2 Machine Design

1.2.1 Machine Design Considerations

An important assessment of design quality is machine’s safe and reliable performance of
its intended function for the prescribed design life without serious breakdown. Besides,
machine design involves a multitude of considerations, as summarized in Table 1.1. It
is unrealistic to satisfy all these considerations, as some are seemingly incompatible.
Designers are challenged to recognize incongruities and find compromises between
these discrepancies. During the design process, the total life cycle of a product, from
initial ideation, design, manufacturing, assembly to service and final disposal, should be
reviewed, and situations that may practically occur during manufacturing, transport-
ing, storing, installing, servicing and disposal be evaluated. The main concerns selected
from Table 1.1 are discussed next and will be addressed throughout the book.
Apart from proper functioning, successful design of competitive machines must pre-
vent premature failures to ensure safe and reliable operation throughout design life-
time. Traditional safety considerations for an element include strength, deflection and