封閉式泡沫鋁材料之受壓力學響應與變形演進

Abstract

本研究目標在以實驗與數值模擬方式，探討ALPORAS封閉式泡沫鋁材料之受壓力學響應與其在受壓過程中之變形演進。實驗方面，本研究進行受壓力學實驗，並利用微電腦斷層掃描觀察記錄泡沫材料微觀結構於受壓過程中之變形機制與演進。 數值模擬方面，首先根據實際泡沬材料細胞面數與邊數特徵，建立一簡單而具代表性之細胞尺寸雙分布理想數值模型。然而考慮到理想模型與真實微觀結構差異，另建立一系列修正數值模型，以探討曲邊、曲面等各幾何特徵對泡沫材料機械性質之影響。數值模擬結果發現，理想數值模型系統性地高估了相對楊氏模數等機械參數，而修正數值模型所得結果則較接近實驗值。另一方面，泡沫材料各機械參數均隨幾何特徵參數增大而降低。最後本研究亦進行了封閉式泡抹鋁材料完整受壓力學響應之數值模擬。包含整體應力－位移曲線、變形演進等方面，修正數值模型均較理想數值模型更接近實驗結果。

The present study aims to investigate the compressive mechanical properties of closed-cell aluminum foam under uniaxial compression by means of both experimental and numerical efforts. Crushing experiments were first conducted along two mutually perpendicular directions during which the deformation patterns and their evolutions were recorded using the micro-CT technique. In an effort to reproduce the experimental findings numerically, an ideal and several modified numerical models, both having a bi-dispersed cell size distribution and based on realistic geometric features of the cellular microstructure, were subsequently developed. The ideal model overestimated the compressive response by a large margin as compared to the experimental results whereas the modified models lead to numerical results which are much closer to experimental ones. In addition, the mechanical constants such as the Young’s modulus decreased as the geometric characteristic factors increased. Numerical simulations on the complete compressive response were also performed using the numerical models developed. Similar to the case of mechanical constants, the modified models outperformed the ideal model in terms of the complete response, the deformation patterns as well as the deformation evolutions.