Assessing Progressive Failure of Large-Scale Composite Structures using a Damage-Based Multi-Scale Model

Abstract

A damage-based multi-scale model was developed for predicting progressive failure of large-scale laminated composite structures subjected to practical multiaxial loading. Computational micromechanics was coupled with a continuum damage mechanics constitutive law in order to predict stiffness degradation of multidirectional laminates containing ply cracks in multiple orientations. An energy based technique based on linear elastic fracture mechanics concepts was used to simulate the evolution of ply cracks. The model was then implemented within commercial finite element software through a user-defined subroutine for evaluating subcritical damage evolution and stiffness degradation of wind turbine blades. The study is the first step in developing an accurate prediction model that accounts for the multi-scale nature of damage, which can be used for predicting progressive failure of large-scale composite structures. The results for a long wind turbine blade illustrated the capabilities of the developed simulation model to predict subcritical damage evolution. This is an important contribution since the developed model accounts for the early stages of progressive structural failure, which is vital for increasing the accuracy of damage tolerance analysis of structures and for structural health monitoring.