Heterogeneous materials are widely applied in many fields. Owing to the spatial variation of its constitutive parameters, the mechanical characterization of heterogeneous materials is very important. The virtual fields method has been used to identify the constitutive parameters of materials. However, there is a limitation: constitutive parameters of one material have to be a priori; then, constitutive parameters of the other one can be identified. Aiming at this limitation, this article presents a method to identify the constitutive parameters of heterogeneous orthotropic bimaterials under the condition that constitutive parameters of both materials are all unknown from a single test. A constitutive parameter identification method of orthotropic bimaterials based on optimized virtual field and digital image correlation is proposed. The feasibility of this method is verified by simulating the deformation fields of a two-layer material under three-point bending load. The results of numerical experiments with FEM simulations show that the weighted relative error of the constitutive parameter is less than 1%. The results suggest that the variation coefficient-to-noise ratio can perform a priori evaluation of a confidence interval on the identified stiffness components. The results of numerical experiments with DIC simulations show that the weighted relative error is 1.44%, which is due to the noise in the strain data calculated by DIC method.

中文翻译：

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正交异性双材料本构参数的优化多项式虚场法

异质材料广泛应用于许多领域。由于其本构参数的空间变化，异质材料的机械表征非常重要。虚拟场方法已用于识别材料的本构参数。但是，存在一个局限性：一种材料的本构参数必须是先验的；然后，可以确定另一个的本构参数。针对这一局限性，本文提出了一种在两种材料的本构参数都无法通过一次测试确定的情况下，识别非均质正交各向异性双材料本构参数的方法。提出了一种基于优化虚拟场和数字图像相关性的正交异性双材料本构参数识别方法。通过模拟两层材料在三点弯曲载荷下的变形场，验证了该方法的可行性。有限元模拟的数值实验结果表明，本构参数的加权相对误差小于1％。结果表明，变异系数与噪声比可以对确定的刚度分量执行置信区间的先验评估。DIC模拟的数值实验结果表明，加权相对误差为1.44％，这是由于DIC方法计算出的应变数据中存在噪声。有限元模拟的数值实验结果表明，本构参数的加权相对误差小于1％。结果表明，变异系数与噪声比可以对识别出的刚度分量执行置信区间的先验评估。DIC模拟的数值实验结果表明，加权相对误差为1.44％，这是由于DIC方法计算出的应变数据中存在噪声。有限元模拟的数值实验结果表明，本构参数的加权相对误差小于1％。结果表明，变异系数与噪声比可以对确定的刚度分量执行置信区间的先验评估。DIC模拟的数值实验结果表明，加权相对误差为1.44％，这是由于DIC方法计算出的应变数据中存在噪声。