Causes of scatter in high rate fracture testing of polymers

A method based on the measurement of failure time is being developed by the European Structural Integrity Society to determine high rate fracture toughness of polymers. The test method appears reasonably straightforward but produced unacceptably high scatter, due to failure time data scatter. In this work an experimentally based sensitivity study was performed by fracture tests at 1ms-1 in order to determine the causes of scatter and to seek to improve the test protocol. No single cause of scatter was identified but the quality and repeatability of the notching technique was identified as a major contributor.