同济大学学报（自然科学版）2017，Vol.45Issue(2)：180-187,8.DOI:10.11908/j.issn.0253-374x.2017.02.004
Q420钢材应变硬化与应变率效应的试验
Experimental Study on Strain Hardening and Strain Rate Effect of Q420 Steel
摘要
Abstract
Uni-axial tensile tests of Q420 steel at different strain rates (0.001-288 s-1) were carried out to study strain rate effect on mechanical properties by INSTRON and Zwick/ Roell HTM5020 testing machine.The experimental results show that Q420 steel is sensitive to strain rates,with strain hardening characteristic changing along strain rates.Finite element (FE) modeling of these tensile tests is developed to reversely extrapolate the true stress-strain relationship of Q420 steel beyond necking,using LS-DYNA of ANSYS.The simulation results show that the true stress-strain relationships of Q420 steel transform from power-law Ludwik model to exponential Voce model with the increasing strain rate.To get a fine dynamic constitutive model,a modified H/ V-R model is established by introducing a new strain rate sensitivity function into the H/V-R constitutive model,where Wagoner rate law is replaced by the dynamic increase factor of the Cowper-Symonds model.The results show that the modified H/V-R model fits the experimental data well and captures strain hardening at high strain accurately as well as the variation of strain hardening with strain rate.关键词
应变率/应变硬化/本构模型/Q420Key words
strain rate/strain hardening/constitutive model/Q420分类
建筑与水利引用本文复制引用
陈俊岭,李金威,李哲旭..Q420钢材应变硬化与应变率效应的试验[J].同济大学学报（自然科学版）,2017,45(2):180-187,8.基金项目
国家自然科学基金(No:51378381) （No:51378381）
