Fracture mechanics analysis of arc shaped specimens for pipe grade polymers

Instrumented three-point bend impact fracture tests are widely used to evaluate pipe grade polymers. Often specimens cut from small-diameter pipe are used, and these are necessarily arc-shaped. Because the orientation and thermal history may differ between extruded pipe and compression moulded plaque material, this additional difference in geometry must be properly accounted for, or it may mask any effects on material properties. This paper modifies a previously published solution for the geometry-dependent energy correction factor for arc-shaped specimens, and extends it to a wider range of standard pipe geometries. When the results are properly corrected, the effects of processing on a commercial PE100 appear to be minor.