鋁合金因具有質量輕、強度高與防蝕性佳等優點，因此已廣泛地應用於航太、船舶及國防工業等方面。通常將鋁合金製成蜂巢狀微結構，並應用於三明治層板結構之心材，如此可利用其質量輕之優點，以減輕整體結構重量。一般三明治結構除承受靜力載重作用下，亦承受機械運轉震動及自然之反覆載重，反覆載重作用下，可能因疲勞損傷之累積，最後導致結構之破壞。

　　本文改變鋁蜂巢材料中微觀桿件之形狀與分佈，進一步利用有限元素程式數值分析，以探討其對蜂巢材料疲勞壽命之影響。首先，考慮微觀桿件排列方式不同之效應，藉由Voronoi蜂巢材料於無限域概念之邊界設定，針對蜂巢材料之微觀桿件是否含微觀裂紋進行疲勞分析，結果顯示Voronoi蜂巢材料中微觀桿件最大應力較規則六邊形蜂巢材料高約40％至70％，因此，微結構桿件不規則排列將減短蜂巢材料疲勞壽命。另外，為探討微觀桿件幾何形狀之效應，令微觀桿件之剖面並非固定，結果發現蜂巢材料之數值分析具變剖面微觀構件之應力變化，同樣假設是否含微小裂紋，結果發現蜂巢材料之疲勞壽命於低相對密度條件下，主要受到微觀桿件中之變斷面區域比例的影響，而相對密度越大者，變斷面微觀桿件將可增長蜂巢材料之疲勞壽命。本研究成果除增進瞭解微觀結構缺陷對蜂巢材料疲勞壽命的影響外，亦提供結構工程設計上之參考。

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