Plumier, André[Université de Liège - ULg > Département Argenco : Secteur SE > Ingéniérie sismique >]
Habraken, Anne[Université de Liège - ULg > Département ArGEnCo > Département ArGEnCo >]
Proceedings of the 4th International Conference on Fracture and Damage Mechanics
Aliabadi, M. H.
Nishida, S. I.
4th International Conference on Fracture and Damage Mechanics
du 12 au 14 juillet 2005
[en] Fatigue Cracks ; Fatigue Continuum Damage Model ; residual stress in welding
[fr] Cohesive Zone Model
[en] Fatigue cracks in welded connections of steel moment frame buildings submitted to earthquakes are studied. The connections of beams with thick flanges designed to resist to seismic phenomena by plastic dissipation are presented. The structural components, the materials and the crack mechanics are described. To predict the crack initiation, the knowledge of residual internal stresses, generated by the welding process, is required. So these stresses are assessed by a FEM thermo-mechanical analysis. The potential sites of crack locations are detected by using an FEM model of the connection with the continuum damage model of Lemaître and Chaboche. After these FEM analyses, new meshes with specific elements located at the potential crack locations are defined. A cohesive zone law is used to model the crack propagation. This model describes the crack growth by analyzing the energy released by the generation of the new surfaces and damage micro-phenomena behind the crack tip. A constitutive tension-separation law computes this energy. In these cases of low cycle fatigue, the damage and the cyclic loading conditions are taken into account.