DESIGN STRESSES IN PROBABILISTIC FORM FOR ELLIPSOIDAL AND TOROIDAL PRESSURE VESSELS.

Design has customarily been based on applied loading, geometry, and handbook values for strength to give a deterministic solution. The engineering profession, however, has become increasingly concerned with the adequacy of design calculations. Appropriate illustrations of application of these equations are provided. The difficulty of relying on a factor of safety is demonstrated. As an example, consider a torus of circular cross-section with internal pressure. In one configuration with a given set of parameters using mean values and deterministic equations, the factor of safety is 1. 70. The probabilistic equations indicate 2 probable failures in 100,000 vessels.