A simple pseudo-Compact tension (pCT) test apparatus to determine the mode I fracture toughness

Abstract

[Abstract:] We introduce a simplified pseudo-compact tension (pCT) test apparatus, specifically designed to accurately determine the mode I fracture toughness (KIC) under direct tension conditions for rocks and other geomaterials. The device is compatible with conventional multipurpose loading frames typically available in many geomechanics laboratories. The mechanical behavior of the designed apparatus and the accuracy of the KIC determinations have been assessed through a 3D finite element model elaborated with ABAQUS and experimentally validated using aluminum and polymethyl methacrylate (PMMA) specimens under digital image correlation (DIC) examination technique. Results confirm the good performance of the new pCT apparatus, since it provides sufficient stiffness while yielding KIC values consistent with the reference pCT apparatus. Both devices measured an average KIC value of 1.80MPa m1/2 for PMMA specimens. This new device provides a cost-effective entry to the versatile pCT fracture toughness testing methodology, ensuring accurate and reproducible test results.