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针对工程中常见的厚度方向变密度的闭孔铝泡沫材料,该文通过动态和静态压缩实验与模拟分析,探讨了大尺度变密度铝泡沫部件变形与吸能特性分析的有限元模型构建方法。对变密度铝泡沫大试样的准静态压缩和冲击压缩实验研究表明:厚度方向变密度铝泡沫材料的压缩过程呈现从低密度层开始的逐层屈服变形伴随整体变形的特性,与密度均匀的铝泡沫材料的变形特性显著不同。该文建立了变密度铝泡沫大试样的分层变密度变尺度有限元模型和近似的密度和尺度均匀的有限元模型,计算结果对比分析表明:分层变密度变尺度有限元模型能够模拟实际材料的逐层屈服变形特性,计算的试样准静态和冲击压缩变形与吸能特性等与实验结果相符;而基于均匀模型的计算结果则不能模拟逐层变形特性,与实验结果及理论特性明显不相符。分层变密度变尺度有限元模型的单元尺度会影响逐层屈服变形特性模拟结果,基于单元尺度接近实际铝泡沫材料胞元尺度的分层有限元模型的计算结果与实验结果一致性较好。这些研究结果对各种结构的铝泡沫材料应用研究具有重要意义。
Aimed at the closed-cell aluminum foam with variable density in the thickness direction, the finite element model construction method of deformation and energy absorption of large-scale variable-density aluminum foam components is discussed through dynamic and static compression experiments and simulation analysis. Experimental study on the quasi-static compression and impact compression of a large-density aluminum foam sample shows that the compression process of the variable-density aluminum foam in the thickness direction exhibits the layer-by-layer yield deformation accompanying with the overall deformation from the low density layer, The deformation behavior of aluminum foams is significantly different. In this paper, a variable-density variable-scale finite element model of stratified variable density and a uniform finite-element model of density and scale are established. The comparative analysis of the calculated results shows that the stratified variable density and variable-scale finite element model can simulate The layer-by-layer yield deformation characteristics of the actual material, the calculated quasi-static and impact compression deformation and energy absorption properties of the specimen are in good agreement with the experimental results. However, the calculation results based on the uniform model can not simulate the layer-by-layer deformation characteristics and the experimental results and theoretical characteristics Obviously does not match. The element scale of stratified variable density variable-scale finite element model will affect the simulation results of layer-by-layer yield deformation. The calculated results of stratified finite element model based on the cell-scale close to the actual cell size of aluminum foam are in good agreement with the experimental results. The results of these studies are of great importance to the research and application of various structural aluminum foams.