Jeudi 6 novembre 2025 à 10h00 / Amphithéâtre F. Canac, LMA
Abstract: The aim of Damage Tolerance Approaches is to ensure that the existence of unavoidable defects does not compromise safety. This involves considering the most unfavorable case of brittle fracture and determining the propagation of a preexisting crack under cyclic loading until the Griffith energy fracture threshold is reached. Currently, this is done using simplified, smoothed-out crack geometries, relying either on tabulated values or Finite Element Methods. Since meshing of the entire structure is required, the latter currently struggles to accurately account for the small-scale tortuosity of the crack geometry.
In this presentation, I aim to show that asymptotic approaches are efficient alternatives to address this challenge. Asymptotic methods aim to provide analytical formulas for the variation of stress intensity factors caused by small-scale crack shape perturbations. In addition to supporting the reduction of safety margins, these approaches also help to ensure that small geometrical perturbations do not lead to unexpected catastrophic failure. I will present several applications including crack shape evolution, the influence of heterogeneities, and propagation in general mixed-mode I+II+III conditions.