A Refined One‐Slit‐Ring Method to Quantify Residual Hoop Stress in Chlorinated Polyvinyl Chloride Pipe—Application to Specimens After Immersion in Primer

Abstract

A refined one‐slit‐ring method is presented to characterize residual hoop stress distribution in pipe ring specimens of inhomogeneous cross section. Although the original one‐slit‐ring method enables determination of residual hoop stress distribution through slitting single ring specimen in the axial direction, its use is limited to specimens of uniform material properties. This work is to extend applicability of the method to ring specimens with a cross section of core–shell structure. Chlorinated polyvinyl chloride (CPVC) pipe is used in the study, and core–shell structure in its ring specimens is introduced through immersion in primer for 30 min. Analytical expression for the residual hoop stress distribution in these specimens is derived, and verified using finite element (FE) simulation which uses a temperature gradient field to generate stress so that diametrical change by the slitting is same as that measured experimentally. Results from the analytical expression agree well with those from the FE simulation, showing decrease of the residual hoop stress by the exposure to primer, and the extent of decrease depends on the drying time after the immersion in primer, to about half of its original value after 30 days of drying, and then remains relatively constant afterwards. POLYM. ENG. SCI., 59:E296–E309, 2019. © 2019 Society of Plastics Engineers