3D crack propagation testing and modeling in thick Aluminum 2024 T351

摘要

DGA is continuously enhancing its capability to provide through-life support with the Air Forces for aircraft life extension and life management. Ageing fleet concerns and application of damage tolerance requires studying the propagation of elliptical cracks in thick structures. Those cracks have no direction of invariance and are 3D cracks. Lack of knowledge on those shapes causes usage of overly conservative propagation laws, and therefore to non optimise inspection programs which increase the maintenance costs. Most of the times, as soon as the geometry run out the classical library, cracks are modelled by "through cracks" which is highly conservative, and critical crack size is underestimated due to a lack of precise residual strength criteria when the stress intensity factor is not uniform all along the crack front.