A simple pseudo-compact tension (pCT) test apparatus to measure pure tension mode I fracture toughness

Abstract

[Abstract] The pseudo-compact tension (pCT) test has been proposed as a reliable method for meas-uring the mode I fracture toughness (KIC) in rocks under pure tensile conditions, but its original implementation requires a specially designed, large-size testing device, limiting its practical applicability. Here we present a simplified and compact apparatus for pCT testing that can be easily installed in any conventional loading frame operating in compression. Its mechanical behavior was assessed numerically with the finite element method and exper-imentally with an aluminum specimen. In addition, the digital image correlation (DIC) technique was employed to observe the mechanical performance of the most stressed el-ements of this fixture. The operation of the device was checked by testing polymethyl methacrylate (PMMA) specimens having different starter notch lengths. Results show that the new pCT testing system has sufficient stiffness and provides KIC values comparable to those of the originally developed device.