Brittle cracking was induced in a rigid thermoplastic polyurethane (R-TPU) and an acetal resin in an effort to develop an accelerated test method for studying the documented failures of pressurized plumbing components. Times to failure (on the order of 10 to 1000 hours) were recorded under a range of stress intensity factors (SIF). At a given SIF, time-to-failure for the R-TPU was nearly three orders of magnitude greater than that of the acetal resin. The presence of 50 ppm mono-chloramine in water accelerated the acetal resin crack growth approximately five fold, while leaving the R-TPU unaffected. Crack growth behavior of the R-TPU was found to be thermally activated.
展开▼
