Prediction of Strain Fatigue Life of HRB400 Steel Based on Meso-Deformation Inhomogeneity

Abstract

The relationship between strain fatigue life and evolution of meso-deformation inhomogeneity was studied, through the cyclic process of numerical simulation of crystal plasticity compared with the fatigue test of steel hot-rolled ribbed-steel bar 400 (HRB400). The statistical characterization parameters at grain level, including the standard deviation of the dot product of longitudinal stress and strain, the product of the macro stress and the standard deviation of the longitudinal strain, and the product of the macro stress ratio and the standard deviation of the longitudinal strain, were proposed and respectively applied to measure the meso-deformation inhomogeneity of materials. These parameters take the effect of peak stress into account, distinct from the pure strain statistical parameters. The numerical results demonstrate that the low-cycle fatigue life curves of materials are predictable using the new parameters as FIPs (fatigue indicator parameters), and the predictions are more rational than by utilizing the FIPs without considering the peak stress effect.

Fatigue Damage Evaluation of Aviation Aluminum Alloy Based on Strain Monitoring

“…Realizing the correlation between fine-scale deformation mechanisms and macroscopic mechanical behavior is crucial in the field of crystal plasticity mechanics, particularly in the study of fatigue in polycrystalline alloys [17][18][19][20][21][22][23][24][25][26]. For instance, Takayuki Shiraiwa [17] incorporated computed local plastic strain into the quasi-measurement of crack initiation to predict the fatigue life of 7075 aluminum alloy.…”

“…Sun [21] investigated the influence of grain orientation and hardened particles on the fatigue performance of friction stir welded (FSW) joints in aluminum alloys. In these studies [18][19][20][23][24][25], the prediction of metal fatigue life primarily involved exploring new fatigue indicating factors (FIPS). FIPS is a fatigue life prediction method based on crystal plasticity finite elements, which attributes the plastic deformation of crystalline materials to the slip of dislocations on the slip surface.…”

Torsional Fatigue Life Prediction of 30CrMnSiNi2A Based on Meso-Inhomogeneous Deformation

“…Hence, the mechanics analysis should consider of the materials’ structure. In order to investigate the correlation between deformation inhomogeneity evolution and fatigue life, the fatigue life of a superalloy and a pure copper under constant amplitude of tension-compression are studied by using the model of polycrystalline aggregate as the RVE with crystal plasticity [ 23 , 24 ]. Their investigation results show that the material deformation inhomogeneity at grain scale grows monotonically under cyclic loading.…”

“…If the critical value is used to estimate the fatigue failure of the material, the result is approximately close to the test. In literature [ 23 , 24 ], the method is also used to predict the tension–compression fatigue life curves of a superalloy GH4169 and a steel HRB400, and the estimated errors between the prediction and test are found all to be within the acceptable range. However, the materials used in the above studies are all displaying approximate Masing behavior and, moreover, the shear strain fatigue is not researched.…”