Notchology-the effect of the notching method on the slow crack growth failure in a tough polyethylene

Abstract

The effect of various notching methods on the life time of slow crack failure at 80 °C for a tough gas pipe grade of polyethylene was investigated. The standard notching procedure involved pressing an ordinary razor blade into the single-edge notched tensile specimen at a rate of 50 μm min-1 at room temperature. The other notching methods involved using a sharper razor blade, cooling in liquid nitrogen, pre-cracking by fatigue, slicing with a scalpel, or using a rotary cutter. The standard procedure gave a life time of 28000 min under a stress of 2.4 MPa; the sharper blade, cooling in liquid nitrogen, and pre-cracking by fatigue gave an equivalent life time. Slicing with a scalpel or a rotary cutter provided a much longer life time. © 1990 Chapman and Hall Ltd.