ABSTRACT

The term "model" frequently carries the connotation of a physical entity, such as a model of an airplane or a car. There are also sketches, drawings, block diagrams, electrical network diagrams, and mathematical models. This chapter look at these possibilities, and considers physical models in more detail. Sketches are important to the creative process. Typically, the making of a freehand sketch is the first act after an engineer conceives a new design concept. The modern tools of computer-aided design (CAD) have converted the tedious task of engineering drawing, carried out largely by engineering draftsmen, into a relatively easy task that can and should be incorporated into the decision-making activities of the designer. Designers use block diagrams to consider various alternatives as they strive for the best system to meet their specifications. Mathematical expressions relating the output of each block to its input are used in conjunction with these diagrams to determine whether a system will meet specifications.