标题： 微观测参数识别中的集成DIC及其在运动学边界条件准确性中的作用 显示英文标题

标题： On Micromechanical Parameter Identification With Integrated DIC and the Role of Accuracy in Kinematic Boundary Conditions

摘要： 集成数字图像相关（IDIC）如今是一种可靠的全场实验方法，用于准确识别材料参数。 它基于在力学实验过程中捕获的一系列图像的相关性，这些图像通过从底层力学模型导出的位移场进行匹配。 在最近的研究中，已经表明当施加的边界条件超出所使用的视场时，IDIC会受到不准确的影响。 一个典型的例子是在微观结构体积单元（MVE）内部进行微机械参数识别，其中图像通常通过电子显微镜或其他显微技术获得，但载荷是在更大的尺度上施加的。 对于任何IDIC模型，仍需要指定MVE的边界条件，这些边界条件的任何偏差或波动都可能显著影响识别的质量。 规定适当的边界条件通常是一项具有挑战性的任务，因为MVE没有自由边界，且由于底层的微观结构，边界位移通常是高度不均匀的。 因此，本文的目的是首先以系统的方式量化预定边界条件中的误差对识别准确性的影响。 为此，通过虚拟实验进行了三种类型的力学测试，每种测试针对不同的材料对比率水平和图像噪声水平。 为了简化，采用了一种在平面应变假设下的弹性可压缩Neo-Hookean本构模型。 结果表明，施加的边界条件需要很高的细节水平。 这促使了一种改进的边界条件应用方法，该方法将整个MVE边界的本构材料参数以及运动学变量作为自由度。 显示英文摘要

摘要： Integrated Digital Image Correlation (IDIC) is nowadays a well established full-field experimental procedure for reliable and accurate identification of material parameters. It is based on the correlation of a series of images captured during a mechanical experiment, that are matched by displacement fields derived from an underlying mechanical model. In recent studies, it has been shown that when the applied boundary conditions lie outside the employed field of view, IDIC suffers from inaccuracies. A typical example is a micromechanical parameter identification inside a Microstructural Volume Element (MVE), whereby images are usually obtained by electron microscopy or other microscopy techniques but the loads are applied at a much larger scale. For any IDIC model, MVE boundary conditions still need to be specified, and any deviation or fluctuation in these boundary conditions may significantly influence the quality of identification. Prescribing proper boundary conditions is generally a challenging task, because the MVE has no free boundary, and the boundary displacements are typically highly heterogeneous due to the underlying microstructure. The aim of this paper is therefore first to quantify the effects of errors in the prescribed boundary conditions on the accuracy of the identification in a systematic way. To this end, three kinds of mechanical tests, each for various levels of material contrast ratios and levels of image noise, are carried out by means of virtual experiments. For simplicity, an elastic compressible Neo-Hookean constitutive model under plane strain assumption is adopted. It is shown that a high level of detail is required in the applied boundary conditions. This motivates an improved boundary condition application approach, which considers constitutive material parameters as well as kinematic variables at the boundary of the entire MVE as degrees of freedom in...