Dear, Brown, Mason
# 1995 Edinburgh
The threshold load to just maintain crack propagation and conditions for catastrophic failure, should the material be loaded above this threshold, are two key evaluation requirements when assessing polymers for pipe applications. Often these assessments need to be made during material research and development and before trial manufacture of pipes. This is when material samples are in the form of compression moulded sheets of small size. Charpy type experiments do not provide the above assessment data under simulated steady pipe pressure load conditions, so a different method to achieve these data has been devised. This method provides for obtaining the required data when the material has been loaded and allowed to stress relax, to represent the conditions of a pressurised pipe, before a crack is initiated.