Resistance of PVC-U and PVC-M to cyclic fatigue

ISSN： 1743-2898

Source： Plastics, Rubber and Composites, Vol.34, Iss.1, 2005-02, pp. : 40-46

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Abstract

PVC pipes may be used in applications where they are subjected to cyclic pressures generated by the operation of pumps and valves. It is therefore important that the material's response to cyclic loading is quantified and incorporated into pipeline design when appropriate. Using rotational bending, PVC-U and PVC-M have been shown to exhibit very similar resistance to crack growth. Further, both materials exhibited a similar increase in fatigue crack growth rate as the test temperature increased. The rotational bending method was also used to investigate the presence of a fatigue threshold for PVC-M and PVC-U. It is concluded that the same cyclic fatigue design principles should be applied to both PVC-U and PVC-M pipes. Moreover, the existence of a threshold value should be taken into account so that derating for fatigue is not required if the amplitude of the stress intensity factor is below the threshold.