Crack‐tip plastic zones in glassy polymers under small‐scale yielding

摘要

AbstractTwo pressure‐modified von Mises yield criteria were used for the determination of the plastic zones developed around cracks subjected to opening‐mode loading conditions in glassy polymers. These criteria take into account the particular behavior of glassy polymers expressed by the dependence of their yield locus on the hydrostatic stress component and the difference in their tensile and compressive yield stresses. It was found that both criteria predict larger plastic zones than those obtained by the von Mises criterion which increase as the ratio of the compressive to tensile yield stress also increases. Furthermore, it was established that the differences in the predictions of plastic zones between the two criteria and the von Mises criterion increase with the Poisson's ratio of the material of the cracked pl