(1. 大連理工大學(xué) 運(yùn)載工程與力學(xué)學(xué)部 工業(yè)裝備結(jié)構(gòu)分析國(guó)家重點(diǎn)實(shí)驗(yàn)室，大連 116024;
2. 沈陽(yáng)工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽(yáng) 110870)
摘 要: 使用霍普金森壓桿技術(shù)對(duì)擠壓AZ91D鎂合金進(jìn)行3種應(yīng)變速率下的動(dòng)態(tài)壓縮實(shí)驗(yàn)，基于實(shí)驗(yàn)數(shù)據(jù)的擬合確定了其動(dòng)態(tài)壓縮的Johnson-Cook (J-C)本構(gòu)方程。采用擬合的J-C本構(gòu)參數(shù)和LS-DYNA有限元軟件對(duì)擠壓AZ91D鎂合金在3種應(yīng)變速率下的SHPB實(shí)驗(yàn)進(jìn)行了數(shù)值模擬，根據(jù)模擬得到的入射波、反射波和透射波形計(jì)算得到各應(yīng)變速率下完整的應(yīng)力-應(yīng)變曲線(xiàn)，并與實(shí)驗(yàn)及擬合的應(yīng)力-應(yīng)變響應(yīng)進(jìn)行了對(duì)比。結(jié)果表明：當(dāng)應(yīng)變速率在400~1000 s-1之間變化時(shí)，AZ91D鎂合金的應(yīng)變速率敏感性隨應(yīng)變率增大而增大；基于J-C材料模型描述的AZ91D 鎂合金應(yīng)變速率相關(guān)的應(yīng)力-應(yīng)變本構(gòu)模型，其數(shù)值模擬結(jié)果與擬合結(jié)果及實(shí)驗(yàn)結(jié)果基本吻合。
關(guān)鍵字: 擠壓AZ91D鎂合金；動(dòng)態(tài)壓縮實(shí)驗(yàn)；本構(gòu)行為；數(shù)值模擬
（1. State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics,
Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, China;
2. School of Materials Science and Technology, Shenyang University of Technology,
Shenyang 110870, China）
Abstract:Dynamic compression experiments of extruded AZ91D magnesium alloy at three different strain rates were carried out based on split Hopkinson pressure bar (SHPB) technique, and a Johnson-Cook dynamic constitutive equation was obtained by fitting the experimental data. The SHPB dynamic compression of the material was simulated by using LS-DYNA software with the fitted Johnson-Cook constitutive parameters. Calculated incident, reflected, and transmitted waves were correlated with the stress-strain response of the extruded AZ91D sample using two-wave analytical method; the stress-strain curves at different strain rates obtained in the simulations were compared with the experimental and fitted stress-strain responses. The results show that the strain rate sensitivity of the extruded AZ91D Mg alloy increases with increasing the strain rate from 400 s-1 to 1000 s-1. The numerical simulation results and fitted results based on the Johnson-Cook strain-rate dependent constitutive model for the extruded AZ91D Mg alloy are basically in agreement with the experimental results.
Key words: extruded AZ91D Mg alloy; dynamic compression experiment; constitutive behavior; numerical simulation
