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为了建立更加真实的闭孔泡沫铝三维细观分析模型,提出了一种基于CT(Computed Tomography)的有限元模型构建新方法。首先,对CT扫描得到的泡沫铝试件的扫描图像进行Otsu算法分析,确定了区分基体材料和空气的灰度最佳阈值,并基于映射网格思想直接从扫描图像生成了试件的有限元分析模型,实现了泡沫金属三维细观分析模型的重建。在此基础上,进行了泡沫铝试件准静态压缩和动态冲击试验的数值模拟,结果表明,准静态下泡沫铝的内部变形随机分布于整个试件,且与其三维结构密切相关;而动态冲击下变形在冲击端附近首先发生,体现出显著的局部化效应。本方法能真实地描述了泡沫金属内部的细观结构,实现了泡沫铝试件在准静态压缩和冲击作用下的受力、变形与破坏过程更加详细地模拟分析。
In order to establish a more realistic three-dimensional closed-cell foam aluminum microscopic analysis model, a new method based on CT (Computed Tomography) finite element model was proposed. Firstly, Otsu algorithm was used to analyze the scanned images of aluminum foam samples obtained by CT scanning, and the optimal thresholds for grayscale discrimination between substrate and air were determined. Based on the mapping grid, the finite element Analyze the model and realize the reconstruction of the three-dimensional mesoscopic analysis model of foam metal. On this basis, the numerical simulation of quasi-static compression and dynamic impact test of aluminum foam specimens is carried out. The results show that the internal deformation of aluminum foam is randomly distributed throughout the specimen and closely related to its three-dimensional structure. The dynamic impact The lower deformation occurs first in the vicinity of the impact end, demonstrating a significant localized effect. The method can truly describe the mesostructure of the foam metal and realize the stress analysis, deformation and failure process of the aluminum foam specimen in quasi-static compression and impact.