The Safety Factor: Case Studies in Engineering Judgment

Abstract

While the concept of the safety factor in mechanical analysis and design is introduced early and reinforced throughout the typical mechanical engineering curriculum, it is often misunderstood and misinterpreted by engineering students. This is especially evident in ‘capstone design’ experiences, when the safety factor ceases to be a ‘given’ and becomes yet another design variable that must be selected and justified by the student design team. This paper reviews the concept of the safety factor from a variety of viewpoints, each of which can provide some insight to the student of mechanical design, and addresses some of the classical misconceptions and misuses of the safety factor by undergraduate students. It also proposes teaching tools that can be used to highlight the concept of the safety factor as a design variable, whose specification requires analysis, insight, and engineering judgment.