Combined Multiscale Creep Strain and Creep Rupture Modeling for Composite Materials

In this study, a novel multiscale combined creep strain and creep rupture model is proposed. By comparing to experimental data it was shown that the model provides accurate creep rupture predictions for unidirectional off-axis specimens. The creep strain model provides accurate predictions within the confines of the linear elastic restrictions used in its development. This creep strain and creep rupture model was incorporated into a progressive failure finite element simulation so that the effects of load redistribution could be considered, which tended to increase the life of the part. The finite element implementation also allowed for the consideration of realistic geometries resulting in complex stress states. By considering a perfectly flat specimen and one containing worst case thickness variation the experimental open hole creep rupture data was bounded. This suggests that by quantifying material defects realistic lifetime predictions can be made and an estimate of scatter can be acquired.