AbstractThe tearing energy theory developed to describe the failure properties of vulcanized rubbers is shown to be applicable to the cut growth and fatigue properties of cellular polyurethanes. The effective inherent flaw size to initiate cut growth in the cellular polyurethane predicted from fatigue results has been found to be similar to the measured size of the largest pore in the material. The cut growth properties of the cellular polyurethane have been compared with solid polyurethane of the same type, crosslinked polyurethanes, and vulcanized rubbers. It is found that the minimum value of tearing energy (T0) under which no fatigue failure occurs in the absence of chemical effects is far higher in polyurethanes than vulcanized rubbers. It is thought that this is due to the segmented structure of the polyurethane which has highly hysteresial tensile properties.
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