Book Description

Prediction of hysteretic specific damping energy of structural materials under combined dynamic stresses knowing the damping under uniaxial stresses is discussed. Consideration is limited to biaxial states of stress. Bounds for biaxial stress damping are proposed to be the values predicted by assuming purely dilatational damping and purely distortional damping. Available published data show qualitative agreement with the predicted bounds. New experiments for this report involving vibration decay tests on mild steel beams and circular plates are discussed with emphasis on accuracy. Data for beams are used to predict bounds for plate damping. Plate damping data are bracketed by these bounds which lends confidence in the theory for this sort of stresses. It is concluded that the theory will give satisfactory results for isotropic, homogeneous materials provided the biaxially-stressed part and the specimens for the uniaxial-stress damping experiments are from the same stock and the uniaxial tests match the temperature and frequency of the application. (Author).