ANALYTICAL AND EXPERIMENTAL STUDIES ON FATIGUE CRACK PATH UNDER COMPLEX MULTIAXIAL LOADING

M. de Freitas  B. Li e L. Reis       

Anales de la Mecánica de la Fractura, nº 21 . 2004 . Pág. -
Ver (.pdf): 6-08

Resumen: In real engineering components and structures, many accidental failures were due to unexpected or additional loadings, such as additional bending or torsion, etc. Fractographical analyses of the failure surface and the crack orientation are helpful for identifying the effects of the non-proportional multiaxial loading. There are many factors influencing the fatigue crack paths, such as the material type, structural shape and loading path, etc. This paper studies the effects of multiaxial loading path on the crack path. Experiments were conducted on a biaxial testing machine, on the specimen made of steel 42CrMo4, with six different biaxial loading paths. Fractographical analyses of the plane of crack initiation and propagation were carried out. Theoretical predictions of the damage plane were conducted using the Brown-Miller, the Findley, the Wang-Brown, the Fatemi-Socie, the SWT and the Liu´s criteria. Comparisons of the predicted orientation of the damage plane with the experimental observations show that the shear-based multiaxial fatigue models give very good predictions.

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Department of Mechanical Engineering Instituto Superior Técnico, Av. Rovisco Pais, 1049-001, Portugal
Department of Mechanical Engineering Instituto Superior Técnico, Av. Rovisco Pais, 1049-001, Portugal