高速冲击载荷下AM80镁合金的力学本构及仿真模拟

发布时间：2018-10-14 11:40

【摘要】：采用霍普金森压杆技术对固溶态AM80镁合金进行大应变率范围下的高速冲击实验,应变速率分别为700、1100、2150、2750和3650 s~(-1)。结果表明:实验用AM80镁合金的流变应力随应变速率的增加而增加,表现出明显的正应变率敏感性;当载荷由准静态转为动态时,合金的流变应力显著增加。基于不同应变率下的应力—应变曲线确定实验用镁合金的Johnson-Cook(J-C)本构方程。采用ABAQUS有限元软件对合金的SHPB实验进行了数值模拟,根据模拟得到的入射波、反射波和透射波形计算得到各应变速率下的应力—应变曲线,并与实验及J-C本构拟合的应力—应变响应进行对比。结果表明:即使在本构拟合所选应变速率范围外,仿真分析结果也与实验及本构拟合结果基本吻合;但在较高应变时,由于本构未考虑温升效应,使得拟合结果与实验结果的差异较低应变时明显要大。
[Abstract]:The high speed impact test of solid solution AM80 magnesium alloy at large strain rate was carried out by using Hopkinson pressure bar technique. The strain rates were 700,1100,2150,2750 and 3650 s-1, respectively. The results show that the rheological stress of AM80 magnesium alloy increases with the increase of strain rate, and the rheological stress of AM80 magnesium alloy increases significantly when the load changes from quasi-static to dynamic. Based on the stress-strain curves at different strain rates, the Johnson-Cook (J-C) constitutive equations of magnesium alloys were determined. The ABAQUS finite element software was used to simulate the SHPB experiment of the alloy. The stress-strain curves at various strain rates were calculated according to the simulated incident wave, reflection wave and transmission wave. The stress-strain response is compared with the experimental and J-C constitutive fitting. The results show that even outside the range of strain rate selected by constitutive fitting, the simulation results are in good agreement with the experimental and constitutive fitting results, but when the strain is high, the temperature rise effect is not taken into account. The difference between the fitting results and the experimental results is larger than that at low strain.
【作者单位】：湖南大学汽车车身先进设计制造国家重点实验室;湖南大学机械与运载工程学院;
【基金】：国家自然科学基金资助项目(51475156) 国家科技重大专项(2014ZX04002071)~~
【分类号】：TG146.22

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