An Efficient Approach for Identifying Constitutive Parameters of the Modified Oyane Ductile Fracture Criterion at High Temperature

Abstract

The paper presents the theoretical part of a method for identifying constitutive parameters involved in the modified Oyane ductile fracture criterion at high temperature. Quite a general rigid viscoplastic model is adopted to describe material behavior. The ductile fracture criterion is in general path-dependent and involves stresses. Therefore, the identification of constitutive parameters of this criterion is a difficult task which usually includes experimental research and numerical simulation. The latter requires a precisely specified material model and boundary conditions. It is shown in the present paper that for a wide class of material models usually used to describe the behavior of materials at high temperatures, the criterion is significantly simplified when the site of fracture initiation is located on traction free surfaces. In particular, this reduced criterion does not involve stresses. Since there are well established experimental procedures to determine the input data for the reduced criterion, the result obtained can be considered as a theoretical basis for the efficient method for identifying constitutive parameters of the modified Oyane ductile fracture criterion at high temperature. The final expression can also be used in computational models to increase the accuracy of predictions.

Hot tensile deformation behaviors and constitutive model of an Al–Zn–Mg–Cu alloy

“…Generally, the hot compressive and tensile experiments are carried out to discuss the effects of deformation parameters on the material flow behaviors and microstructural evolution during hot forming. In order to obtain the high performance components, the damage degree inside the workpiece should be strictly controlled [20]. Therefore, it is significant to understand the hot tensile deformation behaviors and fracture characteristics of alloys for the optimal processing parameters.…”

Prediction of Ductile Fracture Behaviors for 42CrMo Steel at Elevated Temperatures

“…In fact, the effects of deformation temperature and strain rate on the ductile fracture are significant, which should be considered when the ductile fracture criterion is established. Considering the combined effects of deformation temperature and strain rate on the ductile fracture behaviors, the suitable ductile fracture criteria have been established for 3Cr20Ni10W2 alloy (Ref 7), Ti40 alloy (Ref 8,9), 30Cr2Ni4-MoV ultra-super-critical rotor steel (Ref 10), and magnesium alloys (Ref 11). Yoon and Lee (Ref 12) found that the fracture mechanism changes from brittle to ductile with increase of the forming temperature for AZ31 magnesium alloy sheet.…”