EXTENDED FAILURE MODELS FOR GLOBAL AND LOCAL ANALYSES OF COMPOSITE AEROSTRUCTURES

This work presents the implementation of an advanced phenomenological failure model to perform "hot-spot” failure analysis and predict the onset of intralaminar damage of fiber-reinforced polymers in large-scale models. The selected failure criteria identify the critical failure mode, accounting for general three-dimensional stress states, which is essential for the design and analysis of composite laminates under higher levels of triaxiality. Then, to represent the quasi-brittle behavior of composite materials up to ultimate strength, these failure criteria are coupled with a smeared crack model for transverse cracking and continuum damage mechanics models for fibre-dominated damage, which together account for the kinematics of matrix cracking and fibre tensile or compressive fracture during damage propagation. Furthermore, cohesive elements are used to predict delamination. A test case involving a stringer runout loaded in tension was selected for the validation of “hot-spot” analysis, while a series of scaled tests on unnotched specimens was used for the validation of the mesoscale model.