Isaac, Eccott, Pittman, Farah
Additional Information - Posters # 1995 Edinburgh
This study has sought to characterise the variations in mechanical properties and residual stresses that develop as a result of the differential cooling rates that occur through the thickness of commercially produced polyethylene pipes. The mechanical behaviour has been studied through measurement of tensile properties and creep performance. Significant differences in these properties have been recorded for samples taken from different regions of the pipe wall. As well as having the best tensile properties, samples from the inner regions of the pipe wall (with the slowest cooling rate) exhibited the lowest creep rates. In addition, residual strains have been measured using strain gauges, attached with a recently developed adhesive. The procedure involved machining pits to a series of different depths in commercial pipes, attaching strain gauges and then removing the bulk material from around the pit. This technique has allowed measurement of the variation in strains that develop through the thickness of pipe walls during processing.