非結晶性PET材の降伏モードの遷移

抄録

In the previous paper, we showed in a constant strain rate shear test using an amorphous polyethylene terephthalate (PET) thin plate that 1. there were two kinds of yield mode, diffuse slip line (DSL) and localized shear band (LSB) modes and 2. the DSL mode appeared in a range of relatively high temperature and low strain rate and the LSB mode occurred in a range of relatively low temperature and high strain rate. In this paper, we investigated the condition of the yield mode transition in both tensile and shear tests and showed that 1. the yield mode transition occurred in tensile test as well as in shear test depending on test condition and 2. an example of a critical condition for the transition was given as a function of temperature T and strain rate S by T S^m = C where m and C were the constants.