(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: 為研究軋制態(tài)AZ31鎂合金在高應(yīng)變率變形條件下的各向異性，沿鎂合金板材的法向(ND)、45°方向和軋制方向(RD)分別進(jìn)行應(yīng)變速率700 s-1、1000 s-1、1300 s-1和1600 s-1的分離式霍普金森壓桿(SHPB)實(shí)驗(yàn)。根據(jù)實(shí)驗(yàn)結(jié)果擬合得出不同加載方向下的Johnson-Cook本構(gòu)方程。應(yīng)用有限元分析專(zhuān)用前處理軟件Hypermesh與顯式動(dòng)力學(xué)仿真軟件LS-DYNA對(duì)SHPB實(shí)驗(yàn)過(guò)程進(jìn)行數(shù)值模擬。實(shí)驗(yàn)與數(shù)值模擬結(jié)果表明：軋制態(tài)AZ31鎂合金在高應(yīng)變率條件下沿軋制方向加載時(shí)具有更強(qiáng)的變形能力且真應(yīng)力-真應(yīng)變曲線存在明顯的屈服階段；沿法向加載時(shí)表現(xiàn)出更明顯的正應(yīng)變速率強(qiáng)化效應(yīng)和應(yīng)變速率敏感性。數(shù)值模擬后處理所得真應(yīng)變-時(shí)間曲線和真應(yīng)力-真應(yīng)變曲線與SHPB實(shí)驗(yàn)結(jié)果吻合度較高。不同加載方向下AZ31鎂合金的Johnson-Cook本構(gòu)方程參數(shù)均具有較高的擬合精度。
關(guān)鍵字: AZ31鎂合金；高速變形；各向異性行為；Johnson-Cook本構(gòu)方程；數(shù)值模擬
（School of Materials Science and Technology, Shenyang University of Technology, Shenyang 110870, China）
Abstract:In order to investigate the isotropic behavior of rolled AZ31 magnesium alloy sheet under high strain rate deformation, the Split Hopkinson Pressure Bar (SHPB) experiments were carried out along normal direction(ND), 45°and rolling direction(RD) at an average strain rate of 700 s-1, 1000 s-1, 1300 s-1 and 1600 s-1, respectively. Based on the experiment results of SHPB, Johnson-Cook constitutive equations of different deformation directions were established. The numerical simulation of SHPB was carried out by jointly using of preprocessing software Hypermesh and explicit dynamics simulation software LS-DYNA. Both experimental and simulation results showed that the rolled AZ31 magnesium alloy along RD has higher deformation ability and the yield stage in true stress-strain curves is more obvious than the other two directions. While ND shows obvious positive strain rate hardening effect and strain rate sensitivity. True strain-time curves and true stress-strain curves obtained by post-processing of numerical simulation are well agreement with the SHPB experimental results. Johnson-Cook constitutive equation parameters of rolled AZ31 magnesium alloy along different loading directions have high precision.
Key words: AZ31 magnesium alloy; high strain rate deformation; isotropic behavior; Johnson-Cook constitutive equation; numerical simulation
