Stress and fracture analysis of circular arc blends for repair of cracked metallic components

摘要

This paper presents compact functions for peak stresses and stress decay distributions due to circular arc blend repairs, on circular holes in uniaxially loaded plates. Key geometric parameters are varied, focusing on relatively shallow blends, consistent with the in-service repair of fatigue cracking in ageing airframes. The highly accurate stress results are obtained using adaptive p–version finite element analyses. In the 2D cases, both single and double sided repairs are considered, where the blend consists of either a single or multi-arcs. For the 3D analyses, the focus is on blends to repair corner cracks at the hole edge. It is found that in all cases, the peak stress can be significantly reduced by maximising the ratio of blend radius to hole radius, thereby lowering the possibility of recracking. The multi-arc case offers the greatest stress reduction. The stress decay functions presented can be used to obtain stress intensity factors for the fatigue analysis of cracks which may re-initiate at the blends.