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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。
To determine the five constitutive parameters to be determined in the Johnson-Cook model of titanium alloy, overcome the shortcomings of the traditional single factor analysis and improve the efficiency and accuracy of parameter identification, using Latin hypercube sampling, Spearman rank correlation analysis of parameter sensitivity analysis Based on the results of parameter sensitivity analysis and basic genetic algorithm, an improved genetic algorithm based on improved niche algorithm, suspicious peak point decision strategy and local accurate search technique was established. Based on the experimental data, a refined Johnson-Cook titanium alloy constitutive model. The implicit stress integration method was used to embed the model into ABAQUS user material subroutine UMAT. The consistent tangent stiffness matrix was deduced by the implicit function derivation method. The dynamic response of titanium alloy is simulated by ABAQUS finite element software. The calculated results are in good agreement with the existing experimental data. The accuracy of UMAT subroutine is verified and it can be used in the dynamic response prediction analysis of titanium alloy.