Analysis of a Failure in a Polyethylene Gas Pipe Caused by Squeeze off Resulting in an Explosion

A failure caused by squeezing off a polyethylene (PE) gas pipe was investigated. The failure mechanisms were analyzed. Two modes of fracture were found: brittle and slow crack growth (SCG). The formation of the brittle fracture was particularly interesting because its origin was not produced by a defect in the material, but by the compressive stress fields produced by squeezing and enhanced by the visco-elastic behavior of PE. The micro deformation, which was associated with the nucleation of brittle fracture, was analyzed. The time for the SCG was predicted based on the size of the brittle fracture. It is most likely that the failure would not have occurred if the squeeze and release rates had been controlled.