(南京航空航天大學(xué) 機(jī)電學(xué)院，南京210016)
摘 要: 對(duì)Al-Mg-Sc材料進(jìn)行靜態(tài)力學(xué)性能實(shí)驗(yàn)，采用微型SHPB(Split Hopkinson pressure bar)實(shí)驗(yàn)裝置對(duì)Al-Mg-Sc材料在應(yīng)變率為103~104范圍內(nèi)進(jìn)行動(dòng)態(tài)力學(xué)行為測(cè)試。結(jié)果表明：Mg-Sc合金材料隨應(yīng)變率的提高，真實(shí)應(yīng)力—應(yīng)變曲線(xiàn)略有升高，表明Al-Mg-Sc材料不是一種對(duì)應(yīng)變率敏感的材料；隨著應(yīng)變率的升高，材料發(fā)生的應(yīng)變?cè)龃螅?/SPAN>表現(xiàn)出在高應(yīng)變率下具有明顯的應(yīng)變強(qiáng)化效應(yīng)。通過(guò)分析，選用較為合理的Johnson—Cook本構(gòu)模型來(lái)構(gòu)建Al-Mg-Sc合金高應(yīng)變速率流變方程。根據(jù)遺傳算法確定J—C方程中的參數(shù)。擬合值與實(shí)驗(yàn)值較吻合，證明經(jīng)SHPB實(shí)驗(yàn)數(shù)據(jù)構(gòu)建的流變方程是合理的，這為Al-Mg-Sc板料高應(yīng)變速率下有限元分析需要的材料變形特性參數(shù)提供了重要的數(shù)據(jù)來(lái)源。
關(guān)鍵字: Al-Mg-Sc合金；高應(yīng)變速率；微型SHPB裝置；流變方程；遺傳算法
（College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics,Nanjing 210016, China）
Abstract:The static mechanics performance of the Al-Mg-Sc material was investigated, and then dynamic mechanics behavior of the Al-Mg-Sc material was measured at strain rate ranging from 1 000 to 10 000/s with the miniature split Hopkinson pressure bar (SHPB) apparatus. The results show that the Al-Mg-Sc material is not a kind of strain rate sensitive materials, but it has obvious strain strengthening effect under high strain rate. A more reasonable Johnson—Cook equation by comparing is chosen to analyze the dynamic mechanical properties of Al-Mg-Sc alloy after its relationship parameters are fitted by genetic algorithm with the experimental data. The comparison between data of experiment and fitted constitutive equation indicates that the constitutive equation is suitable for expressing the dynamic behavior of Al-Mg-Sc alloy, which provides important material characteristic parameter for mechanics numerical analysis further in the high strain rate.
Key words: Al-Mg-Sc alloy; high strain rate; miniature split Hopkinson pressure bar; constitutive relation; genetic algorithm
