The effect of material model in describing mechanism of plasticity-induced crack closure under variable cyclic loading

Abstract

Three-dimensional finite element method is utilized to analyze the plasticity-induced crack closure (PICC) phenomenon in a cracked plate under variable amplitude loading conditions: the effect of a single spike tensile overload, and also the case of a single compressive overload (underload). To accurately capture the PICC process the choice of material model employed is of significant importance, therefore this paper considers a relatively new model, the Ellyin-Xia model, and the more widely employed kinematic hardening model. The study shows significant difference in the results obtained while employing the two models.

Finite element simulation of plasticity induced crack closure with different material constitutive models

“…As soon as crack propagation moves this initial plastic wedge away, crack tip plastic deformation starts stabilizing. The application of an overload produces a similar effect [8].…”

“…In fact, mechanical modelling of metals elastoplastic behaviour requires the definition of a flow rule, a yield surface and hardening laws that determine the evolution of the yield surface with plastic deformation [6][7][8]. For the specific case of cracks growing under cyclic loading, modelling of cyclic plasticity inside the crack tip area implies a correct description of both isotropic and kinematic hardening mechanisms, which makes mixed hardening constitutive models necessary.…”

“…Jiang et al [1] also discussed the inability of the elastic-perfectly plastic model, with the pure kinematic hardening rule of Prager-Ziegler, and of the bilinear model to describe stress ratcheting and stress relaxation during cyclic loading. Elliyn and Ozah [8] also published a study concerning the effect of material model in describing PICC under variable amplitude cyclic loading. The authors compared numerical results from a pure kinematic hardening model with that from a multi-surface yield model, the Ellyin-Xia model [39], and found significant differences in the results.…”

Study of Crack Closure Effect of Hull Plate under Low Cycle Fatigue

“…Based on the above, many scholars have studied crack closure behavior [9][10][11][12][13] under overload. Ding [14] used the FEM to numerically simulate standard CT specimens of ni Q345R steel, and analyzed in detail the crack surface contact behavior under a single overload.…”

Influence of Material Parameters on Plasticity Induced Crack Closure

“…The elastic-plastic behaviour of the metallic materials is determined by its yield stress and subsequent hardening behaviour, and for this reason, phenomenological modelling of plastic deformation processes implies the definition of a flow rule, a yield surface and hardening laws that determine the evolution of the yield surface with plastic deformation. Considering the relevant importance of the elastic-plastic materials behaviour on PICC, numerical simulation studies comparing the PICC results obtained with different mechanical models were already published [1][2][3][4][5]. However, numerical studies with a systematic analysis of the influence of different elasticplastic material parameters on PICC are still rare.…”