| 柴海伟,李海洋,范端,黄俊宇*.基于同步辐射原位CT的聚氨酯泡沫微观变形机理研究[J].实验力学,2020,35(2):225~233 |
| 基于同步辐射原位CT的聚氨酯泡沫微观变形机理研究 |
| Investigations on the micro deformation mechanisms of polyurethane foams with the in-situ, synchrotron-based tomography |
| 投稿时间：2018-12-03 修订日期：2019-01-17 |
| DOI：10.7520/1001-4888-18-263 |
| 中文关键词: 硬质聚氨酯泡沫； 闭孔泡沫； 原位CT 数字体图像相关 |
| 英文关键词:rigid polyurethane foam closed-cell foam in-situ CT digital volume image correlation |
| 基金项目:国家自然科学基金(No.11802252)资助 |
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| 中文摘要: |
| 为揭示聚氨酯泡沫的微观结构性能关系，本文依靠自主研发的微型材料试验机，在美国APS光源2BM线站上搭建了原位CT系统，对闭孔硬质聚氨酯泡沫在准静态压缩加载下的变形损伤行为进行了三维实时表征，分辨率可达0.87μm。通过原位CT试验获取了硬质聚氨酯泡沫的应力应变关系，以及三个变形阶段(弹性、平台、压实)的三维结构演化过程。三维图像显示，在平台段会观察到局部压缩带从样品两端向中间传播的过程，且压缩带传播速度会超过压头速度。同时，利用数字体图像相关技术精确计算了聚氨酯泡沫的三维变形场，表明压缩变形主要集中在变形带内部。通过追踪胞元变形过程并利用表面曲率场来量化胞壁变形，发现胞元坍塌主要源于包壁屈曲形成的褶皱。 |
| 英文摘要: |
| In order to reveal the relationship between the microstructures and properties of polyurethane foam, an in-situ CT system is built on the 2BM line of APS light source in the US. The deformation and damage of a closed-cell rigid polyurethane foam under quasi-static compression loading is characterized in a three-dimensional (3D), real-time manner, with a resolution of 0.87μm. The stress-strain curve of the rigid polyurethane foam and the evolution of 3D structures in three deformation stages (elastic, platform and densification) are obtained via the in-situ CT test. 3D images show that the local compression bands are observed to propagate from the ends of sample to the center in the platform stage, and the band propagation velocity exceeds the platern velocity. The axial deformation fields of polyurethane foam are calculated accurately using the digital volume image correlation technique, showing that the compression deformation is mainly concentrated in the deformation bands. The deformation process of cells is tracked and the micro deformation of cell walls is quantified with the curvedness index. It is found that the collapse of cells is mainly originated from the folds formed by the buckling of cell walls. |
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