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新方法，用于估计非线性本构股票的材料参数。使用实验标本的可测量响应，进行反分析以预测最合适的材料常数值。通常，预测的准确性取决于拉伸载荷测试中标本的类型。为了识别最佳标本配置，我们在这种方法中使用了Kalman滤波器技术。我们选择了Gurson的多孔弹塑料材料的模型作为材料模型及其两个参数作为未知常数。 Gurson的本构模型已被广泛用于研究延性裂缝以及各种金属的剪切定位。进行详细的有限元模拟，以证明所提出的方法在确定古尔森模型中与空隙核的两个参数中的有效性。在Kalman滤波器程序中，i ...更多T，发现与正确解决方案的收敛速率取决于测试样品的形状，未知参数的初始估计以及测量数据的准确性以及计算的参考数据。分析预测，当使用两个不同形状的标本在张力下（即具有中心孔的矩形板，另一个带有双侧凹口的板），会在收敛速率上进行急剧改善。一种新的简单方法，用于识别弹性/粘胶仪的组成方程中的参数。在提案D方法中，测量了霍普金森杆测试中输入应力和输出应力的时间历史，并使用测量的输入应力时间历史进行有限元计算。使用Kalman滤波器的识别是通过将计算结果与测量的输出应力时间历史进行比较来进行的。证明该方法的有用性，使用铜样本进行霍普金森分裂的棒测试，并确定了两个表征Visco塑性性的参数。在将此方法应用于影响问题的情况下，审查了该领域的反向分析的研究。发现存在适合此方法的各种问题。较少的