Multi-Scale Modeling of the Impact Response of a Strain-Rate Sensitive High-Manganese Austenitic Steel

Orkun Onal,Demircan Canadinc,Cemre Ozmenci

doi:10.3389/fmats.2014.00016

Abstract

A multi-scale modeling approach was applied to predict the impact response of a strain rate sensitive high-manganese austenitic steel. The roles of texture, geometry and strain rate sensitivity were successfully taken into account all at once by coupling crystal plasticity and finite element (FE) analysis. Specifically, crystal plasticity was utilized to obtain the multi-axial flow rule at different strain rates based on the experimental deformation response under uniaxial tensile loading. The equivalent stress – equivalent strain response was then incorporated into the FE model for the sake of a more representative hardening rule under impact loading. The current results demonstrate that reliable predictions can be obtained by proper coupling of crystal plasticity and FE analysis even if the experimental flow rule of the material is acquired under uniaxial loading and at moderate strain rates that are significantly slower than those attained during impact loading. Furthermore, the current findings also demonstrate the need for an experiment-based multi-scale modeling approach for the sake of reliable predictions of the impact response.

Highlights

Austenitic high-manganese (Mn) steels, a class of high strength steels, have received considerable attention since they offer a rare combination of exceptional work hardening capacity, high wear and abrasion resistance, high strength, and significant ductility (Owen and Grujicic, 1999; Bayraktar et al, 2004; Bouaziz et al, 2011)
Finite element (FE) simulations of the impact experiments were carried out, where the roles of texture, geometry, and strain rate sensitivity (SRS) were successfully taken into account all at once by incorporating the proper multi-axial material flow rule obtained from crystal plasticity simulations into the finite element (FE) analysis
Crystal plasticity was utilized to obtain the multi-axial flow rule at different strain rates based on the experimental deformation response under uniaxial tensile loading, and the equivalent stress – equivalent strain response was incorporated into the FE model for the sake of a more representative hardening rule under impact loading

Summary

Introduction

Austenitic high-manganese (Mn) steels, a class of high strength steels, have received considerable attention since they offer a rare combination of exceptional work hardening capacity, high wear and abrasion resistance, high strength, and significant ductility (Owen and Grujicic, 1999; Bayraktar et al, 2004; Bouaziz et al, 2011) These extraordinary mechanical properties have been subject to several studies (Karaman et al, 2000, 2001; Bayraktar et al, 2004; Hutchinson and Ridley, 2006; Ueji et al, 2008; Niendorf et al, 2009, 2010), many of which revealed that the main mechanism underlying the observed mechanical behavior is the presence of twins in the microstructure accompanied by additional microstructural features, such as stacking faults, dynamic strain aging (DSA), and interaction of twins with dislocations (Karaman et al, 2000, 2001; Hutchinson and Ridley, 2006; Ueji et al, 2008). Dislocations are prevented from gliding not by twin boundaries or HDDWs only, and by carbon (C), which can diffuse within the matrix throughout the deformation, as it becomes excited by the energy provided by the applied stresses (Canadinc et al, 2008a)

Methods

Results

Conclusion