Residual Strength Tests on Fatigue-Cracked Multi-Fastener Specimens of Extruded L.65 Aluminium Alloy.

摘要

Static strength tests have been carried out on fatigue-cracked multi-fastener joint specimens of L.65 aluminium alloy to determine the influence of cracks of various shapes, sizes and locations on the residual strength. The residual static strengths were found to be considerably less than would have been expected on a simple percentage loss-of-area basis; whereas simple fracture mechanics analysis using models of a semi-elliptical surface crack and a semi-circular corner crack at a hole consistently predicted lower failing loads than those obtained experimentally. For the larger crack sizes, the percentage differences between actual and predicted failing loads were greater than for small crack sizes. Multiple fatigue cracking at different locations and the possibilities of interactions between cracks are complicating factors which introduce considerable uncertainties in extending simple fracture mechanics analyses methods to more complex practical cases. (Author)