Failure Modeling for QP980 Steel by a Shear Ductile Fracture Criterion

Abstract

The wide application of advanced high strength steels with high specific strength in the automotive industry can significantly reduce energy consumption and contribute to carbon neutrality. Accurate prediction of the ductile fracture behavior of advanced high strength steels under complex stress states is of great significance for its application in automobile industry. In this study, the ductile fracture behavior of QP980 under complex stress states, covering shear, uniaxial tension, and plane strain tension, is investigated by conducting the hybrid experiment and simulation. The pressure-coupled Drucker yield function is chosen to characterize the effect of stress states on yielding for QP980, considering its high accuracy compared with the von Mises yield function. Failure limit of the stress states is modelled by five uncoupled ductile fracture criteria (Brozzo, Oh, Rice-Tracey, Ko-Huh, and DF2012). To improve the numerical prediction accuracy, the parameters of the constitutive model are optimized by using the inverse engineering approach. The numerical predicted results are compared with the experimental load-stroke curves with the onset of fracture. The comparison indicates that the prediction error of the DF2012 criterion is significantly lower than those of the other four criteria. In addition, the prediction accuracy is greatly improved with the parameters of the constitutive model optimized by the inverse engineering.

Thermal Stress Compensation for an Aircraft Engine Duct System Based on a Structural Redesign of Tie Rods

“…Since the above-established model involves elastic-plastic deformation and contact problems, Static Structural and its built-in Newton-Raphson method [31][32][33][34][35][36][37] were used to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”

“…to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”

“…Meanwhile, since the tee is located in the middle of the duct system, the effects produced by the three branches were superimposed, leading to a very obvious concentration of secondary stress. Moreover, as shown in Figures 10-12, with the temperature changing from 315.56 °C to 537.78 °C, the stress concentration phenomenon became more to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”

A Review of Sheet Metal Forming Evaluation of Advanced High-Strength Steels (AHSS)

“…In this context, mesh sensitivity analysis aims to obtain a close match of the simulated load-stroke curves between different element size meshes. Wang et al [224] adopted this approach. Only then, can one move to the next step of calibrating the constitutive material model parameters.…”

Boundary condition effect on the evaluation of stress triaxiality fields

“…The stress fields may be used to evaluate stress triaxiality fields (written as the ratio between hydrostatic and von Mises equivalent stresses). Stress triaxiality plays an important role in damage and 2 fracture mechanics for predicting the type of failure (i.e., ductile or brittle [15,16,17,18,19]). Combinations of DIC and X-ray diffraction (XRD) techniques may be used to measure both total and elastic strain fields [20,21,22,23,23].…”