Crack growth in a pipe grade PVC material under static and cyclic loading conditions

Abstract

The creep crack growth (CCG) and the fatigue crack growth (FCG) behavior of a commercial pipe grade PVC material was studied based on a linear elastic fracture mechanics (LEFM) methodology. The FCG tests were performed under sinusoidal load control at a frequency of 5 Hz and at R-ratios (F min /F max ) of 0.1, 0.3 and 0.5; the test temperatures were 23 °C and 60 °C. The creep crack growth behavior (corresponding to R = 1) was studied at a test temperature of 60 °C. The results of the FCG tests revealed that fatigue crack propagation is primarily controlled by the cyclic component of the crack tip stress field rather than by the mean stress level. Comparing FCG and CCG data in terms of K Imax and K I , respectively, also confirmed the deteriorating effect of the fatigue loading on the crack growth resistance. Fracture surface investigations for both fatigue and static loading were performed to gain insight into the micromechanisms of crack advance.