A damage model based on the introduction of a crack direction parameter for FRP composites under quasi-static load

Continuum damage mechanics model with consideration of crack direction is developed for the prediction of fracture behavior in fiber reinforced polymer (FRP) composites under quasi-static load. Traditional continuum damage mechanics (CDM) models cannot well predict the crack propagation path in the development state of discrete crack. The crack direction parameter is introduced as a major factor with damage variable for damage propagation and failure analysis. The CDM model, which has the capability to reliably predict the initiation and direction of crack propagation while analysing the multi failure of FRP composites, is proposed by introducing crack direction parameter to material property degradation method. Failure criteria is set up according to the behavior of FRP composites for damage initiation, and fracture-mechanics-based energy release rate criteria is employed for damage evolution. APDL is used to simulate crack propagation, ultimate strength and complex failure behavior of FRP composite structure for this model. Results from the previous researches, when compared with those of this model, showed good agreement, thus demonstrating that proposed methodology can be used for simulation of FRP composite damage failure and strength prediction.