数字图像相关技术在多孔气凝胶基复合材料弹性力学常数识别中的应用

Using digital image correlation technology (DIC) and finite element model correction technique (FEMU), multiple mechanical engineering constants in the two-dimensional woven high aluminum fiber reinforced porous aerogel matrix composites were identified through on-axis and off-axis tensile tests. The effects of objective function construction, optimization method, initial value of parameter and random error in the measured displacement field on the identifying results and efficiency were investigated by mechanical experiments and finite-element-based numerical virtual experiments. The results show that, for two-dimensional woven porous aerogel matrix composites, when the variance of the DIC measured displacement and finite element calculated displacement is chosen as the objective function and the L-M nonlinear least-square optimization method is used to calculate the sensitivity matrix, the multiple mechanical properties in the loading surface can be identified simultaneously with high efficiency. The proposed method is insensitive to the differences in initial values of material constitutive parameters and random error in the DIC displacement measurement and has strong robustness.