Establishing Mechanical Property Allowables for Metals

Abstract Allowable mechanical property development for structural design of metallic aerospace vehicles requires an approved method for statistically analyzing empirical test data. When sufficient test data have been analyzed, the resulting allowables are presented to members of the metal-producing industry, airframers, and regulatory agencies for approval. Upon approval, these properties are published by the government for unrestricted use. However, even though sufficient data are made available, the analysis process is not always straightforward. When data do not conform to acceptable distributions, the process cannot be completed: The purpose of this paper is to promote a better understanding of this type of problem, and a possible rationale to overcome such events without increasing the amount of test data.