On the interaction between a full craze and a near-by circular inclusion in glassy polymers

Crazing is the common reason in polymer composites to cause failure. So far research work on craze phenomenon has been done only in homogenous polymer materials. The first time in our current study, the stress analysis has been carried out on the interaction between a circular inclusion and a full craze in polymer composites. A craze can be treated as a crack with fibrils bridging the two crack surfaces. The forces applied by the bridging fibrils to the crack surfaces (pulling the two surfaces closer) depend on the crack opening displacement, while the crack opening displacement is directly related on the forces applied by the bridging fibrils. To solve this dilemma, an iterative procedure is created and introduced to solve the formulated singular integral equations. The influences of the inclusion's elastic properties on the craze thickness profile and the stress intensity factors are investigated in details. It is found that the case with a “stiffer” inclusion produces smaller craze thickness. Also, the craze thickness profile is strongly affected by the inclusion size and the craze-inclusion distance. The shielding effect of a stiffer inclusion on the craze is discussed by evaluating the stress intensity factors at both craze tips.