Abstract
The specimen fractures appearances are analyzed to investigate the effects of mean tensile stress on the fatigue crack initiation and early propagation plane orientation under axial-torsion fatigue loading for 2A12T4 aluminum alloy. The fatigue crack initiation and early propagation plane orientations are measured by optical microscope, the results of macro-analysis show that both the maximum shear stress amplitude and normal mean stress have effects on the orientations of crack initiation and propagation plane orientation, which are close to the plane of the maximum shear stress amplitude plane. With increasing the mean tensile stress, more cracks are inclined to initial and propagate on or near the maximum shear stress amplitude plane with larger normal mean stress, and the angle of deviation from the plane of maximum shear stress amplitude increases. The predicted plane orientations based on critical plane methods are compared with experimental measured results.
Highlights
I n practice many engineering structures are subjected to fatigue loading, especially multiaxial fatigue loading, and that many of the structures undergo tensile mean stress due to external static load, weight or residual stress [1].So many multiaxial fatigue failure criteria based on critical plane approach have been proposed and applied to determine theS
The specimen fractures appearances are analyzed to investigate the effects of mean tensile stress on the fatigue crack initiation and early propagation plane orientation under axial-torsion fatigue loading for 2A12T4 aluminum alloy
The fatigue crack initiation and early propagation plane orientations are measured by optical microscope, the results of macro-analysis show that both the maximum shear stress amplitude and normal mean stress have effects on the orientations of crack initiation and propagation plane orientation, which are close to the plane of the maximum shear stress amplitude plane
Summary
I n practice many engineering structures are subjected to fatigue loading, especially multiaxial fatigue loading, and that many of the structures undergo tensile mean stress due to external static load, weight or residual stress [1].So many multiaxial fatigue failure criteria based on critical plane approach have been proposed and applied to determine the. The research on multiaxial fatigue crack initiation and propagation plane orientation contributes to the selecting of critical plane and determining the fatigue failure mode. Fatigue crack initiation and propagation are affected by material type, structure, size and load paths [3]. The effects of mean stress and multiaxial loading paths on fatigue life are considered by many criteria, the study of mean stress on the crack initiation and propagation plane orientation in middle and high cycle fatigue is fewer. Experiment had been carried out in order to study the effect of mean tensile stress on crack initiation and early propagation plane orientation. Optical microscope is used to measure crack initiation and early propagation plane orientation (stage I) on specimen fracture. The predicted plane orientations based on critical plane models are compared with experimental measured angles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
