Nonlinear elastic effects in the ultrasonic assessment of cumulative internal damage in filled polymers

摘要

Dewetting and cumulative internal damage in filled polymers are being studied by means of a new ultrasonic technique. Previously, a theoretical model was formulated which relates ultrasonic measurements made on a polymer to vacuole formation and growth. In this model, the effect on soundwave propagation of higher‐order (nonlinear) elastic phenomena in the material was neglected in comparison with that of the vacuoles. The nonlinear elastic effects are the subject of the present analysis. The theory developed here is combined with the previous analytical treatment to obtain a quantitative model for ultrasonic assessment of polymer damage which is valid for nondewetted as well as dewetted material. Computations made according to the comprehensive theoretical model are found to be in close agreement with ultrasonic data taken on typical specimens of a filled polymer undergoing uniaxial strain.