Low Cycle Fatigue Behaviour of DP Steels: Micromechanical Modelling vs. Validation

Ghazal Moeini,Carsten Könke,Sebastian Myslicki,Ali Ramazani,Veera Sundararaghavan

doi:10.3390/met7070265

Ghazal Moeini, Carsten Könke + Show 3 more

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https://doi.org/10.3390/met7070265

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Abstract

This study aims to simulate the stabilised stress-strain hysteresis loop of dual phase (DP) steel using micromechanical modelling. For this purpose, the investigation was conducted both experimentally and numerically. In the experimental part, the microstructure characterisation, monotonic tensile tests and low cycle fatigue tests were performed. In the numerical part, the representative volume element (RVE) was employed to study the effect of the DP steel microstructure of the low cycle fatigue behavior of DP steel. A dislocation-density based model was utilised to identify the tensile behavior of ferrite and martensite. Then, by establishing a correlation between the monotonic and cyclic behavior of ferrite and martensite phases, the cyclic deformation properties of single phases were estimated. Accordingly, Chaboche kinematic hardening parameters were identified from the predicted cyclic curve of individual phases in DP steel. Finally, the predicted hysteresis loop from low cycle fatigue modelling was in very good agreement with the experimental one. The stabilised hysteresis loop of DP steel can be successfully predicted using the developed approach.

Highlights

Dual phase (DP) steels, as a popular type of high strength low alloy steels, offer desirable mechanical properties such as high strength and good formability [1]
For ferrite as a soft material, the cyclic stress-strain curve is the curve liesThe below thehardening/softening cyclic curve, and cyclic softening if thecan tensile stress-strain curve lies above cyclic behavior of a material be explained by differences between above the tensile curve, showing the cyclic hardening behavior
We have investigated the behavior of dual phase (DP) steel during low cycle fatigue using micormechanical modelling and validated our results with the experimental ones

Summary

Introduction

Dual phase (DP) steels, as a popular type of high strength low alloy steels, offer desirable mechanical properties such as high strength and good formability [1]. DP steel has a unique microstructure consisting of a soft ferrite matrix and varied volume fraction of metastable hard martensite, which result in a combination of high work hardening and high ductility [3,4]. These favourable mechanical properties have led to the extensive use of DP steels in the construction of different automobile parts [5,6]. Shen et al [12] performed the in situ

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