Manuel de Freitas  Luis Reis  Bin Li      

Anales de la Mecánica de la Fractura, nº 22 . 2005 . Pág. -
Ver (.pdf): 57

Resumen: In this paper the uniaxial/biaxial low-cycle fatigue behaviour of three structural steels (CK45 normalized steel, 42CrMo4 quenched and tempered steel and stainless steel AISI 303) are studied, evaluated and compared. Two fatigue parameters are evaluated for estimating non-proportional fatigue lives: the additional hardening and the factor of non-proportionality. A series of tests of uniaxial/biaxial low-cycle fatigue composed of tension/compression with static or cyclic torsion were carried out on a biaxial servo-hydraulic testing machine Instron 8088. Different loading paths were carried out, including proportional and non-proportional loading paths in order to verify the additional hardening caused by different loading paths. The experiments showed that the three materials studied have very different additional hardening behaviour. Generally, the transient process from the initial loading cycle to stabilized loading cycle has only a few cycles, the stabilized cyclic stress/strain parameters are controlling parameters for fatigue damages. A factor of non-proportionality of the loading paths is evaluated based on the Minimum Circumscribed Ellipse approach. Application of the factor of non-proportionality and the additional hardening coefficient to the ASME methodology for multiaxial loading fatigue, allows a good correlation between the predicted and the experiments results.

Localización: Almagro

Department of Mechanical Engineering, Instituto Superior Técnico, Portugal
Department of Mechanical Engineering, Instituto Superior Técnico, Portugal
Department of Mechanical Engineering, Instituto Superior Técnico, Portugal