A perspective on the structural integrity of notched components through the Effective Critical Plane approach

Fatigue-induced damage is a significant concern for components in various industries, often leading to unexpected failures during service. Multiaxial fatigue assessment methods, particularly Critical Plane (CP) methodologies, have been widely used to identify critical regions and predict crack initiation sites. However, traditional CP approaches require computational intensive plane scanning techniques, which becomes impractical for components with complex geometries or unknown critical areas. This study builds upon recent developments in CP factor efficient evaluation and, in particular, on the Effective Critical Plane (ECP) approach recently proposed by the authors, which prescribes a stress averaging over a small control volume centred on the critical location, before evaluating the CP factor. The radius of the control volume is a material parameter and the stress averaging is intended to introduce the original idea of the microstructural support of Neuber. The influence of stress averaging on the critical plane orientation is analysed in this work in order to show that the ECP approach not only reduces computational complexity, but also preserves the critical plane orientation and, as a result, the CP theoretical foundation. The work was carried out by several FE simulations, considering a structural steel and different notched components under complex loading scenarios. The control radius for the selected material was determined by a preliminary experimental investigation.