【摘要】 为确定钛合金材料的Johnson-Cook模型中5个待定本构参数,克服传统单因素分析法的弊端并提高参数识别效率和精度,采用拉丁超立方抽样、Spearman秩相关分析的参数敏感度整体分析方法,并在参数敏感度分析结果和基本遗传算法的基础上,建立了一种基于改进小生境算法、可疑峰值点判断策略和局域精确搜索技术的改进遗传算法,基于实验数据建立了精细的钛合金Johnson-Cook本构模型。采用隐式应力积分法将该模型嵌入到ABAQUS用户材料子程序UMAT中,并通过隐函数求导方法推导出一致切线刚度矩阵。通过ABAQUS有限元软件对钛合金材料的动态响应进行数值模拟分析,计算结果与已有的实验数据吻合良好,UMAT子程序的准确性得到验证,可用于钛合金材料的动态响应预测分析中。更多还原

【Abstract】 A global analysis method of parameter sensitivity based on the Latin hypercube sampling(LHS)method and Spearman rank correlation method was applied to determine 5material parameters of Johnson-Cook classical constitutive model of titanium alloy and improve the efficiency and precision of parameters identification.Furthermore,on the fundamental of the analytic result of parameter sensitivity and basic genetic algorithm(GA),an advanced genetic algorithm based on the advanced niche genetic algorithm,global peak value determination strategy and local accurate searching techniques was developed.By this algorithm,a finer Johnson-Cook constitutive model was established based on experimental data.A user-defined material(UMAT)subroutine for the optimized model was written into ABAQUS software,with the implicit stress update algorithm achieved.And consistent tangent stiffness matrix was deduced by adopting implicit function derivative method.Then numerical simulation of the dynamic response of titanium alloy material by ABAQUS software was performed and the results indicate that the simulation data is in good agreement with the experimental data.The UMAT subroutine can be applied to dynamic response prediction of titanium alloy.更多还原