Crack tip shielding in elastic particulate composites undergoing damage

A simple rate-independent phenomenological constitutive model is used to model fracture behavior in elastic particulate composites undergoing damage. The constitutive model consists of two damage functions that govern the degradation of the bulk and the shear moduli. The elastic modulus is assumed to reach a saturation level under uniaxial conditions. Using the path independence of the J-integral and the concept of cracktip shielding, the remote or the applied stress intensity K_∞ is related to the cracktip stress intensity factor K_t. The results from the model are used to predict the cracktip conditions in particulate composites undergoing damage. The model compares well with experimental results in predicting the crack opening profile as well as the displacement field in the vicinity of a cracktip.