Biaxial low cycle fatigue characteristics of 4130X steel under asymmetric and non-proportional loading
In order to study the stress-strain state and fatigue damage behavior of 4130X steel under biaxial fatigue loading,fatigue test of 4130X steel under biaxial asymmetric,proportional and non-proportional cyclic loading was studied.The low cycle fatigue and ratcheting behavior of 4130X steel were systematically analyzed under different biaxial loading conditions from aspects of biaxial cyclic strain amplitude,biaxial ratcheting strain,fracture morphology and fatigue life.The results show that with the decrease of biaxial load ratio or the increase of phase difference,the both axes show significant cyclic softening phenomenon,and the biaxial ratcheting effect is more obvious,leading to the decrease of its fatigue life.The effect of load phase difference on fatigue life and equivalent strain is more significant for equal biaxial load ratios than that for other loading cases,and fatigue life decreases by 90%when the biaxial phase difference ΔФ changes from 0°to 90°.Fracture characteristics show that with the increase of biaxial non-proportionality degree,the number of dimples increases significantly as the dimples gradually change from isometric dimples to shear dimples.
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维普
