ABSTRACT
A successful design should take into account the function, material properties, and manufacturing processes. This chapter gives some guidelines for successful designs. For example, the stiffness of components under bending is a function of both the elastic constant of the material (E) and second moment of area (I). Fail-safe design allows defects to be detected before they develop to a dangerous size. For leak before burst in pressure vessels, the material toughness should be sufficiently high to tolerate a defect size that will allow the contents to leak out before it grows catastrophically. In designing for fatigue resistance, the material fatigue strength as well as surface finish and service environment should be considered. Safe-life, or finite-life, design assumes that fatigue-crack initiation is inevitable and the life of the component is estimated on the basis of the number of stress cycles that are necessary to initiate such a crack. The Larson–Miller parameter (LMP) is used for interpolation or extrapolation of creep data. Failure in hostile environments can be avoided by avoiding electrical contact between dissimilar metals, sealing crevices, drainage of liquids in containers, etc.
