Numerical modelling strategies using implicit and explicit methods to simulate quasi-static and dynamic three-points bend fracture tests of a ductile steel

Frédéric Nozères,Jérôme Limido,Yann Quirion,Patrice Bailly,Hervé Couque,Rémi Boulanger,F Gálvez Díaz-Rubio,D.A Cendón Franco

doi:10.1051/epjconf/202125002033

Abstract

Three-point bend fracture tests have been conducted at different loading rates with a quadratic martensitic steel. The failure energy has been found to increase with loading rate. To get insights in this increase a numerical investigation has been undertaken with different strategies using ABAQUS and IMPETUS softwares in order to address quasi-static and dynamic loading conditions. Simulations were conducted with the ABAQUS software in order to carry out a comparative analysis of both implicit and explicit approaches. In addition to standard Finite Element Method (FEM) applied to quasi-static and dynamic conditions, the eXtended-Finite Element Method (X-FEM) was applied to quasistatic conditions. In both approaches, implicit and explicit, crack initiation and propagation were governed by a critical plastic strain threshold combined with a displacement-based damage evolution criterion. Simulations conducted with the IMPETUS software use an explicit approach and second order elements for both quasi-static and dynamic loading conditions. A node-splitting method using an energy-based damage criterion was employed to simulate the crack initiation and propagation. Experimental data and numerical results have been compared, allowing to determine the ability of these two softwares to simulate accurately three-point bend fracture tests.

Highlights

The influence of loading rate on the fracture strength of a quadratic martensitic steel has been investigated with threepoints bend fracture tests
The failure energy of three-point bend fracture specimens made of a quadratic martensitic steel was found to increase with the increase of the applied displacement rate, from quasi-static loading conditions, 0.002 m/s, to dynamic conditions 82 m/s
To get insights in this failure energy increase, a numerical investigation was undertaken with different strategies using the ABAQUS and IMPETUS softwares in order to address quasi-static and dynamic loading conditions

Summary

Introduction

The influence of loading rate on the fracture strength of a quadratic martensitic steel has been investigated with threepoints bend fracture tests. To interpret the experimental data, a numerical investigation has been undertaken with different computational approaches in order to deal with quasi-static and dynamic loading conditions. A special attention was given to the influence of numerical methods on the results, considering that standard constitutive laws and “off-the-shelf” fracture criteria have been retained for the studied ductile martensitic steel. The objective of this work is to investigate the incidence of implicit and explicit approaches on the computational result in order to implement tailor-made physical models to represent the studied material. As a matter of fact, further additions to this analysis should be considered in a future

Objectives

Results

Conclusion