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On the Fatigue Crack Growth Analysis of Spliced Plates under Sequential Tensile and Shear Loads
Last modified: 2015-02-05
Abstract
The spliced plates on an aircraft with wing mounted power plant aresubject to sequentially applied tensile and shear load cycles, with far more tensilecycles than shear cycles. This paper aims to propose an approach to address the fatiguecrack growth under this scenario. Current understanding on fatigue crack growthbehaviours was reviewed, focusing on crack surface interferences and fatigue crackgrowth mechanisms under non-proportional mixed-mode loads. A generic spliced platewas analysed using non-linear finite element modelling. The analysis revealed shearinduced-bearing at fastener holes, and predicted both shear-induced- I K and shearinduced-II K at a 0° crack emanating from the fastener hole edge. When the crack isshort relative to the fastener hole radius, the shear-induced- I K is dominant therefore ithas the potential to cause shear-induced mode I overload. As the crack grows longer,the shear-induce- II K increases, and depending on the load level, this may lead to bothshort-range acceleration and long-range retardation. Through the above analysis, theengineering problem of fatigue crack growth in a spliced plate under sequential tensileand shear loads was converted into a more generally understood problem of fatiguecrack growth under cyclic mode I plus intermittent cyclic mixed-mode loads.
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