ENGINEERING DESIGN

 

Engineering design is a purposeful activity directed toward the goal of fulfilling human needs, particularly those which can be met by the technological factors of our culture. It is brought to bear, when necessary, when the appropriate technology is complex and its application not obvious and when prediction and optimization of the outcome requires analytical procedures.

Its philosophy consists of three major parts, namely, a set of consistent principles and their logical derivatives, an operational discipline which leads to action, and finally a critical feedback system which measures the advantages, detects the shortcomings, and illuminates the directions of improvement.

Generally, engineering design is product oriented and these products enter and must be compatible with the four processes in the production-consumption cycle, namely; production, distribution, consumption, and recovery or disposal. The designer is obliged to take account, in proper measure, of these differing viewpoints and to synthesize their separate objectives into a coherent design.

The design project can generally be broken down into three phases:

  • Feasibility study
  • Preliminary design
  • Detailed design

A feasibility study is undertaken to achieve a set of useful solutions. It consists of such work as follows:

  1. Determine the validity of need.
  2. Identify design parameters, constraints, and major design criteria.
  3. Develop a list of plausible solutions.
  4. Sort plausible solutions for useful solutions based on physical realizability, economic worthwhileness, and financial feasibility.

A substantial amount of interaction with the permanent staff is essential here, since a great deal of creative thought has usually occurred prior to engaging engineering design services from Topsfield Engineering Service.

With a set of useful solutions, preliminary design is undertaken to establish the best design concept. Typically this effort contains the following:

  1. Compare alternatives against major design criteria and constraints until a superior design surfaces.
  2. Analyze the superior design for sensitivity, compatibility, stability, life behavior, and obsolescence.
  3. Build and evaluate an experimental design.
  4. Simplify the design.

The final phase, detailed design, begins with the concept evolved in the preliminary design. Its purpose is to furnish the engineering description of a tested and producable design.

This is decision time. With a series of alternatives looked at and one solution looked at rather carefully, it is time to decide to move forward with a particular design or to abandon the design as infeasible.

With a decision to proceed, an overall, but provisional, synthesis is accomplished. It is developed as a master layout. With this as a basis, the detailed design or specification of components is carried forward. From time to time, exigencies in the detailed work at the component level may dictate changes in the master layout; therefore it has provisional status. As the paper design progresses, experimental design is appropriately initiated. Experimental models are constructed to checkout untried ideas which are not suitable to final disposition by analysis. Components, partial prototypes, and finally complete prototypes are tested as the need for information arises. This information accruing from the testing programs, provides a basis for redesign and refinement until an engineering description of a proven design is accomplished.

In summary, the design process describes the gathering, handling, and creative organizing of information relevant to the problem situation; it prescribes the derivation of decisions which are optimized, communicated, and tested or otherwise evaluated; it has an iterative character, for often in the doing, new information becomes available or new insights are gained which require the repetition of earlier operations. It resembles the general process of problem solving in the main features, but it uses sharper, and for the most part, more analytical tools, which have been especially shaped and sharpened for the problems of engineering design. It carries the process through analysis, synthesis, and evaluation & decision, and extends it into the realms of optimization, revision, and implementation.