Damage Development Analysis Based on Strain Energy Release Rate for 3-d Woven Composite

Methods of damage development analyses for various types of composite materials such as 3-D woven composite have not been established sufficiently because it is quite difficult to simulate the failure propagation. A FEM simulation of failure process of 3-D composite was executed by Mibayashi including the thermal residual stresses after the curing process, and the deformations and stresses calculated by the homogeneous method . Tsai-Wu criterion was utilized as a failure law to judge if the elements are failed or not. The simulation of the failure process was carried out until the rupture of the fiber while considering the occurrence of the transverse cracks and finally the failure mechanism could be grasped. Also a FEM simulation of woven CF/Epoxy laminates was executed in the same manner furthermore including the delaminations between the fiber tows by Tanaka . However, it is well known that the energy criterion should be adopted to predict crack propagation from the view of the fracture mechanism except for the crack’s initiation. Therefore, in this study damage development analysis for 3-D composite is carried out with Tsai-Wu and Hashin criterion adopted to estimate the onset of the transverse cracks. The energy criterion and crack closure method are applied to predict the crack propagation. Then the result from this simulation is compared with that of the simulation executed by Mibayashi . The present simulation will be indicated its significant effectively as one of methods of the damage development simulations.