AN EQUILIBRIAL PROCESS ZONE IN POLYMERIC MATERIALS

A process zone at the tip of a fatigue crack grown in polymeric materials has been widely reported. A new method that treats the process zone as an allotropically transformed material is employed for the prediction of the process-zone size. A specific energy of material transformation as well as transformation stress and draw ratio are determined from an independent test on polymer drawing. The prediction of the model with no adjustable parameters appears to be in a good agreement with the experimentally observed process zone for various polyethylenes and polycarbonate.