Dynamic constitutive relation of 5083P-O aluminium alloy and its influence on energy-absorbing structure

Yue Feng,Bing Yang,Tao Zhu,Guangwu Yang,Shoune Xiao,Zhiwu Zhu

doi:10.1177/1687814018807334

Yue Feng, Bing Yang + Show 4 more

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https://doi.org/10.1177/1687814018807334

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Abstract

Dynamic and quasi-static tensile tests of 5083P-O aluminium alloy were carried out using RPL100 electronic creep/fatigue testing machine and the split Hopkinson tension bar, respectively. The dynamic constitutive relation of the material at high strain rates was studied, and the constitutive model in accordance with Cowper–Symonds form was established. At the same time, a method to describe the constitutive relation of material using the strain rate interpolation method which is included in LS-DYNA software was proposed. The advantages and accuracy of this method were verified by comparing the results of the finite element simulation with the fitting results of the Cowper-Symonds model. The influence of material strain rate effect on squeezing force, energy absorption and deformation mode of the squeezing energy-absorbing structure based on the constitutive models of 5083P-O were studied by means of finite element simulation. The results show that when the strain rate of the structure deformation is low, the material strain rate strengthening effect has little influence on the structure. However, with the increase of the strain rate, the strengthening effect of the material will improve the squeezing force and the energy absorption of the structure, and will also influence the deformation mode, that is, the decrease of the deformation with high strain rates while the increase of the deformation with low strain rates.

Highlights

With the increase of train collision accidents, people pay more and more attention to the passive safety of train operation besides the active safety control
Numerous studies on the dynamic constitutive relations of aluminium alloys have been carried out and it can be seen that the strain rate sensitivity is quite different for aluminium alloys with different chemical components and different heat treatment methods
Most of the aluminium alloys have positive strain rate sensitivity, that is, the stress will increase with the increase of the strain rate at the same plastic strain level

Summary

Introduction

With the increase of train collision accidents, people pay more and more attention to the passive safety of train operation besides the active safety control. When collision of trains happens, the cab and the energyabsorbing structure at the front of the train are the main areas of deformation and energy absorption. These structures suffer different strain rates during the deforming process.[1] At present, the material model is usually simplified when the finite element simulation of train collision is performed, and the strain rate effect of the material is generally ignored.[2,3,4,5,6] relevant studies on the collision behaviours of ship and automobile showed that the difference of strain rates had different influences on the structure, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, China. The sensitivity of 2024 and 7050 aluminium alloys is relatively low, and the experimental results showed that both the alloys had no strain rate sensitivity at largescale strain rate of 1024 ; 104 s21.14

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