Determination of Mechanical Design Properties of Materials

Abstract

Abstract The design of most structural and mechanical parts is based on the modulus of elasticity and a permissible stress level for the materials. Traditionally, these properties are determined from the information obtained by means of tension tests. An alternate method of determining the necessary design parameters has been developed. It is based on the dynamic determination of the elastic energy at maximum amplitude and the energy dissipation per cycle of a test sample. The method is particularly useful for bending or torsional tests. It allows the accurate determination of the elastic moduli of materials and determines stress values which cause a permanent strain smaller or equal to a predetermined value. Several materials have been tested in bending in this manner. The elastic moduli and stresses causing permanent strains smaller than a specified amount have been measured. The results have been compared with those obtained by means of tension tests. Excellent agreement has been obtained.