L. P. Borrego  F. V. Antunes  J. D. Costa  J. M. Ferreira     

Anales de la Mecánica de la Fractura, nº 22 . 2005 . Pág. -
Ver (.pdf): 62

Resumen: Fatigue crack propagation tests in compact mixed-mode specimens were carried out for several stress intensity ratios of mode I and mode II, KI/KII, in AlMgSi1-T6 aluminium alloy with 3 mm thickness. The tests were performed in a standard servo-hydraulic machine. A linkage system was developed in order to permit the variation of the KI/KII ratio by changing the loading angle. Crack closure loads were obtained through the compliance technique. A finite element analysis was also done in order to obtain the KI and KII values for the different loading angles. Crack closure increases under mixed-mode loading conditions in comparison to mode-I loading due the friction between the crack tip surfaces. Moreover, the crack closure level increases with the KI/KII ratio decrease. Correlations of the equivalent values of the effective stress intensity factor with the crack growth rates are also performed.

Localización: Almagro

Departamento de Engenharia Mecânica, Instituto Superior de Engenharia de Coimbra, Instituto Politécnico de Coimbra, Portugal.
Departamento de Engenharia Mecânica, Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Portugal.
Departamento de Engenharia Mecânica, Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Portugal.
Departamento de Engenharia Mecânica, Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Portugal.