Prediction of the onset of strain localization in non-coaxial plasticity

摘要

A 3D non-coaxial elasto-plasticity model with a novel yield function is proposed and employed to study the onset of strain localization in plane strain and true triaxial tests. Bifurcation analysis under plane strain conditions shows that the proposed model is capable of giving an accurate prediction of the onset of shear band and producing a right trend of the band angle varying with the initial confining stress. Simulations of true triaxial tests show a good prediction of the influence of the intermediate stress ratio to the pre-bifurcation stress-strain relationships and the onsets of shear bands. Comparison with the predictions by the coaxial model indicates the introduction of the non-coaxial flow rule is critical to the prediction of strain localization.