Identification of material parameters in constitutive models for metal and metal/polymer composite sheets by elasto-plastic inverse analyzes

本研究的目的是提出一种新的弹塑性逆分析方法来识别金属或金属/聚合物复合材料板材各组份层的力学性能。(1)对于双金属板材，通过最小化实验数据(单向拉伸的拉伸载荷-应变曲线和循环弯曲的弯矩-曲率图)与相应的数值模拟结果之间的差异，成功地识别了单层循环塑性本构模型中的一组材料参数。通过将所识别的材料参数(每层8个参数，即各向同性/运动强化模型中的16个参数)的本构模型的模拟结果与不锈钢/铝复合材料薄板上的实验结果进行比较，验证了该方法的有效性。(2)为了确定聚合物层夹层铝板中聚合物的材料参数，还利用了V形弯曲实验中出现的聚合物层横向剪切变形的实验数据。此外，该方法还被用于确定聚合物层夹层铝板中聚合物的材料参数。值得注意的是：-该方法的优点是对整个复合板而不是对单个组件层使用实验数据(识别是可能的，而不需要执行从复合板去除层的耗时过程)。-识别过程不是基于传统的试错法，而是基于先进的优化技术。

The aim of the present research is to propose a new approach for the identification of the mechanical properties of individual component layers of metal or metal/polymer composite sheets by elasto-plastic inverse analyses. The present findings are summarizing as follows :(1) For a bimetallic sheet, a set of material parameters in a constitutive model of cyclic plasticity for individual layer was successfully identified by minimizing the difference between the experimental data (the tensile load vs strain curve in uniaxial tension and the bending moment vs curvature diagram in cyclic bending) and the corresponding results of numerical simulation. The method was verified by comparing the simulated results using the constitutive model incorporating the identified material parameters (eight parameters for each layer, i.e., totally sixteen parameters in an isotropic/kinematic haredening model) with the experimental results on a stainless steel/aluminirn composite sheet.(2) This method was also applied to determine the material parameters for a polymer in a polymer-layer sandwiched aluminium sheeL For that purpose, the experimental data of the transverse shear deformation of the polymer-layer appearing in V-bending experiments was used.Furtheremore, it is worth noting that :- this method has an advantage of using the experimental data for a whole composite sheet but not for individual component layers (the identificationis is possible without performing a time-consuming process of the removal of a layer from the composite sheet).- the identification procedure is based not on the conventional try-and-error approach but on an advanced optimization technique.