A Study of Residual Stress and Property Mismatch on SIF Distributions for Cracks Parallel to and Within Bondlines

Abstract

As a result of the need to extend the storage life of rocket motors, new emphasis has been placed upon the effect of cracks developed during storage and transport on the integrity of motor performance. In addressing this need, the authors have developed a three specimen test procedure for evaluating the stress intensity factor (SIF) distribution for cracks through the thickness of rubberlike materials near to and within simulated bond lines between the motor grain and its liner. A refined frozen stress method is employed for making measurements, and preliminary studies have shown that, for cracks in the bond line under both Mode I and Mixed Mode loads, the stress intensity factors are elevated primarily due to bond line residual stresses and may not be affected by modulus mismatch.