A NUMERICAL STUDY OF FATIGUE CRACK CLOSURE INDUCED BY PLASTICITY

L.F.P. Borrego  F.V. Antones  J.D. Costa**  J.M. Ferreira     

Anales de la Mecánica de la Fractura, nº 19 . 2002 . Pág. 439 -444
Ver (.pdf): Anales19-071

Resumen: Crack closure delays the intrinsic mechanisms responsible for crack growth (cyclic plastic deformation, clivage, etc.), therefore it must be considered in the modelling offatigue crack growth. The objective ofthis work is to develop a numerical procedure to obtain crack closure induced by plasticity. First the crack closure was experimentally measured on M{T) specimens with 3 mm thickness made of 6082-T6 aluminium alloy. A pin rnicrogauge was used along with the compliance technique. Different load conditions were studied, namely constant amplitude load and single tensile overloads. Then different aspects ofthe numerical procedure were analysed namely the finite element mesh and the node release scheme. A good agreement was found between experimental and numerical crack closure results, if the finite elements have a size lla==rp,c near the crack tip, being rp,c the size of cyclic plastic zone.

LocalizaciónGerona

Department of Mechanical Eng., ISEC, 3030 Coimbra - Portugal
Department of Mechanical Eng., University of Coimbra, Pinhal de Marrocos
Department of Mechanical Eng., University of Coimbra, Pinhal de Marrocos
Department of Mechanical Eng., University of Coimbra, Pinhal de Marrocos