抄録
The environmental delayed fracture process in high polymeric solids consists of three stages, which are crack initiation, crack growth and final fracture. Unfortunately, there have been few systematic studies theoretical and experimental about each stage, although they are important to clarify the delayed fracture mechanism of high polymeric solids.
The present work was carried out to investigate the crack initiation and growth behaviours by using specimens with and without a notch. The results obtained are summarized as follows:
(1) The existence of a critical notch root radius ρcrit. may be suggested from the observation of the fracture mode transition.
(2) The environmental crack growth process consists of three stages. At the first stage of initial crack growth, the crack growth curve may be expressed as a function of loading time and initial stress intensity factor. At the second stage of stable crack growth, the crack growth rate is normalized by stress intensity factor.
