CDM MODEL FOR INTRALAMINAR PROGRESSIVE DAMAGE ANALYSIS OF COMPOSITE LAMINATES

Based on continuum damage mechanics (CDM), a model was proposed for predicting intralaminar progressive damage of composite laminates, including damage description, damage model judgment and damage evolution. Four different damage modes existent within lamina, namely, fiber tension fracture (FFT), fiber compression fracture (FFC), inter fiber tension fracture (IFFT) and inter fiber compression fracture (IFFC), were considered, and damage state variables corresponding to these four modes were also defined. Material constitutive relationship being in the damaged states in the material principal axes was derived compared to that of undamaged states. The onset of the damage was estimated with Puck's criteria and the evolution of the damage was controlled by the strain energy release density within the characteristic length. Assuming that the material was exhibited linear strain-softening behavior, a new damage evolution law associating damage state variables with equivalent strain on fracture plane was established in this paper. The proposed model can predict damage initiation, damage evolution and final failure of composite laminates. Failure analyses of 45/0/-45/90_2S notched laminates under tension and compression were performed with the present model and showed that it is capable to predict the strength of the composite laminate and analyze the failure process.