Experimental Characterization of the Bearing Strength of Fiber Metal Laminates

Abstract

A novel experimental methodology extended from ASTM D953 was developed and implemented to conduct pin bearing experiments on GLARE3-5/4-0.3 and GLARE3-4/3-0.3 variants with the aim to examine a bearing load configuration from a local perspective as well as a global one. This was accomplished by introducing previously unconsidered testing fixtures and additional instrumentation, including bonded strain gages, as a means of measuring the local strain field generated by a bearing load. Load—displacement curves were produced as per the standard but were subject to numerous plateaus and significant statistical scatter, attributed to pin seating and global displacement measurement. Conventionally defined bearing yield strengths were calculated but lacked physical meaning, prompting the production of novel bearing strength vs. measured strain profiles. These new profiles, derived from the additionally acquired data, were void of the plateau anomalies and depicted a well defined trend, indicative of a more complete characterization of material response. Examination of these profiles resulted in a new, more intuitive definition of bearing yield strength that incorporated influence from the entire curve rather than idealizing it bilinearly. The phenomenological basis of the new definition suggests an analogous extension to additional methodologies such as standard tensile or compressive tests.