Estudo da influência da topologia dos furos na taxa de propagação de trincas

Abstract

The drilling process for bolted or riveted joints of components is very common in the naval, aeronautical, mechanical and civil industries. In this context, the present work aims to study, through computer simulation, the influence of hole geometry (through, chamfered and rounded) on crack propagation when submitted to static and dynamic loads. For the static crack evaluation, failure was considered when the stress intensity factor (FIT) exceeds the fracture toughness of the material (KIc). In the case of fatigue, the condition of small crack tip plastification zone and the Paris Law were considered for determining region II of the dadN x DeltaK curve. Initially, a parametric analysis of the hole geometry was performed to obtain a topology that would result in less discontinuity of the stress field and consequently less influence on static crack growth. The best performing topology was then used to study the fatigue crack growth rate considering the Paris Law. The numerical tests were performed on a 7075-T6 aluminum specimen resulting in dadN x DeltaK curves with good agreement with the literature.