DAMPING, ELASTICITY, AND FATIGUE PROPERTIES OF TEMPERATURE-RESISTANT MATERIALS
SYRACUSE UNIV NY
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Rotating-cantilever beam fatigue-testing equipment was used to obtain the damping, elasticity, and fatigue properties of S816, TP-2-R, TP-2B, type 403, TP-1-2, TP-1-3, Inconel-X, and low-carbon N-155 alloys at room and various elevated temperatures and engineering stress levels. The data were utilized to investigate the changes in damping energy and dynamic modulus of elasticity with temperature in constant cyclic stress fatigue tests. Curves of the stresses vs the numbers of cycles are presented in addition to a series of new diagrams designed to show the effects of both stress magnitude and stress history on the damping and elasticity properties. Two methods for comparing the damping energies of a group of materials are discussed, and diagrams are presented to permit comparisons of the elasticity properties among materials tested at given temperatures. For all the materials and at all the temperatures investigated, the energy dissipated by damping increased rapidly with stress at values close to the fatigue strength of a material. During a constant reversed cyclic stress test, the damping energy decreased, remained the same, increased, or had a varying pattern as the number of stress cycles was increased. The changes in dynamic modulus of elasticity were generally reciprocal to the changes in damping energy.