Mixed-Mode I/II/III Fracture Grip Interface

Abstract

This paper describes the design and manufacture of a pair of novel and patented grips for experimental study of cracked specimens made of industrial materials and subjected to the mixed-mode I, II and III fracture loading the details of which have not been made public prior to the patent date of 13 Feb 2009. The innovation patent number: 2008101040 entitled, “Mixed mode I/II/III fracture grip interface” and was granted in Australia. The mixed-mode fracture studies are vital for integrity assessment of components used in various industries including aerospace, automobile, railway, power plants, refineries, military industries, etc. Commercially the grips may be attractive to companies manufacturing mechanical testing equipment such as INSTRON and National Instruments and Tektronix. At UNSW, the grips are currently being applied to measure the critical crack-tip opening displacements at fracture (a measure of the fracture toughness) of PMMA and aluminium 7075-T6 alloy under various loading conditions. To demonstrate the application of the grips, the paper describes typical results concerning mixed-mode I, II and loading. Keywords: Mixed-mode fracture, crack-tip opening displacement, fracture toughness, mechanical design