Fatigue cracks initiation and propagation are major concerns for aircraft structural metallic components. When detected during in-service inspections, damaged parts of aircraft structure have to be replaced or repaired in order to guarantee life-extension. Fatigue cracks often appear at high stress locations and grow under cyclic loads. This is particularly the case around airframe holes where stress concentrations are observed. In many cases, initial hole shapes have been shown to be not optimized regarding stress level at hole boundary under inservice loads. In other words, it can be proved that larger holes allow lower peak stresses in function of airframe design and loads. Thus, a repair methodology can consist of material removal in order to eliminate the crack region. Such a rework can be driven to produce an improved hole shape regarding to peak stress levels and, then, minimize the risk of fatigue crack initiation. In this work, 2D elastic structures with an initial given hole are considered and submitted to tensile and shear loads. The peak value of a stress function linked to fatigue analysis criteria has to be evaluated on the hole boundary. The aim of the study is to find a new optimized hole shape with a minimum peak value. To do that, a finite element procedure has been developped. This iterative optimization procedure is of gradientless type and couples stress results of FEA software with a genetic algorithm which works in analogy with natural selection of species. To limit the computation time, improvements have been included. It concerns especially the parameters governing the hole shape.
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