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Identification of Gurson's Material Constants by Using Finite Deformation/Elastic Plastic Finite Element Method and Kalman Filter

利用有限变形/弹塑性有限元法和卡尔曼滤波器辨识古尔森材料常数

基本信息

批准号：
08455054
负责人：
AOKI Shigeru
金额：
$ 5.5万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

A new approach based on the inverse analysis is proposed for estimating material parameters of nonlinear constitutive equations. Using the measurable response of experimental specimens, the inverse analysis is carried out to predict most suitable values of unknown material constants. In general, the accuracy of prediction depends on types of specimens in tensile loading tests. In order to identify optimal specimen configurations, we have employed the Kalman filter technique in this approach. We have chosen the Gurson's model for porous elastic-plastic materials as the material model and its two parameters as the unknown constants. The Gurson's constitutive model has been widely used for studying ductile fracture as well as shear localization of various metals. Detailed finite element simulations are performed to demonstrate the effectiveness of the proposed method in determination of the two parameters relating to void nucleation in the Gurson's model. In the Kalman filter procedure, i … More t is found that the rate of convergence to the correct solutions depends on the shape of test specimen, initial estimates of the unknown parameters, and the accuracy of measured data as well as computed reference data. The analysis predicts that when two differently shaped specimens under tension are used (i.e., a rectangular plate with a center hole and the other plate with double side notches), a drastic improvement occurs in the rate of convergence.A new simple method for identifying the parameters in the constit utive equation for an elastic/visco-plastic meterial is proposed. In the propose d method, the time-histories of the input and output stresses in the split Hopkinson's bar test are measured, and a finite element calculation is performed using the measured time-history of the input stress. The identification employing the Kalman filter is carried out by comparing the calculated results with the meas ured time-history of the output stress. To demonstrate the usefulness of the proposed method, a split Hopkinson's bar test is performed using copper specimens, and two parameters characterizing the visco-plasticity are identified.In order to apply this method to impact problems, the researches on the inverse analysis in this field are reviewed. It is found that there exists a variety of problems which are suitable for this method. Less

提出了一种基于反分析的非线性本构方程材料参数估计方法。利用实验试样的可测响应，进行反分析以预测未知材料常数的最合适值。一般来说，预测的准确性取决于拉伸加载试验中的试样类型。为了确定最佳的标本配置，我们采用了卡尔曼滤波技术在这种方法。我们选择了多孔弹塑性材料的Gurson模型作为材料模型，它的两个参数作为未知常数。Gurson本构模型已被广泛用于研究各种金属的韧性断裂以及剪切局部化。进行详细的有限元模拟，以证明所提出的方法的有效性，在确定的两个参数有关的空洞成核的Gurson的模型。在卡尔曼滤波程序中， ...更多信息结果表明，收敛到正确解的速度取决于试件的形状、未知参数的初始估计值、测量数据和计算参考数据的精度。分析预测，当使用两个不同形状的拉伸试样时（即，本文提出了一种识别弹粘塑性材料本构方程参数的新方法。在提出的d方法中，在分离式霍普金森杆试验中的输入和输出应力的时间历程进行了测量，并使用所测量的输入应力的时间历程进行有限元计算。通过将计算结果与实测的输出应力时程进行比较，采用卡尔曼滤波进行了识别。为了验证该方法的有效性，利用分离式Hopkinson杆对铜试件进行了实验，确定了表征粘塑性的两个参数，并对该方法在冲击问题中的应用进行了综述。研究发现，存在着各种各样的问题，这些问题都适用于这种方法。少