# 1998 Gothenburg
In previous work on the impact behaviour of pipe grade polyethylene (PE), the 'thermal decohesion model' was proposed by Leevers [ l ] to explain the embrittlement of PE under impact and at low temperatures. One of the initial assumptions of the model was that the crack tip craze could be represented by a Dugdale model, although it was later modelled more accurately using the Hayes method . However, in both models, the craze stress was taken to be the yield stress of the material. It will be shown here that, following recent research, it is more appropriate, under impact conditions, to represent the craze stress by the high rate draw stress of the material, which can be found from tensile draw tests.