本研究探討具曲度及變剖面微構件蜂巢材料於多軸應力作用下之破裂行為，其中包括第一型與第二型兩種不同類型之破壞模式。首先，利用有限元素套裝軟體ABAQUS，建立一預存巨觀裂紋之含雙缺陷蜂巢材料數值分析模型，然後分別進行不同破壞模式之應力分析，由數值結果顯示蜂巢材料第一型與第二型破裂韌性受微結構幾何形狀參數所影響。此外，本研究亦提供含雙缺陷蜂巢材料之第一型與第二型破裂韌性數值結果表示式，可藉由已知蜂巢材料相對密度及微結構幾何參數 與 ，直接代入數值結果表示式中計算獲得無因次化第一型與第二型破裂韌性。最後，利用線彈性疊加原理，求得含雙缺陷蜂巢材料之混合型破壞準則，並建立含雙缺陷蜂巢材料之多軸破壞面，以利工程設計或實際運用之依據與參考。

Aim of this study is to investigate the multiaxial fracture of hexagonal honeycombs with dual imperfections of curved cell edges and plateau borders, including mode I and mode II fracture toughnesses. The effects of dual imperfections on the mode I and mode II fracture toughnesses of hexagonal honeycombs are numerically evaluated by conucting a series of finite element analyses. Numerical results indicate that the mode I and mode II fracture toughnesses are significantly affected by the dual imperfections of curved cell edges and plateau borders. In addition, numerical expressions for describing the normalized mode I and mode II fracture toughnesses of hexagonal honeycombs with dual imperfections are provided. Furthermore, using the linear superposition principle the mixed mode fracture criterion is developed and the failure surfaces of honeycombs with dual imperfections arethus generated.

[1] L. J. Gibson and M. F. Ashby,“Cellular Solids：Structure & Properties,”2nd edition, Pergamon Press, Oxford, 1997.

[2] 沈振鵬,“具曲度及變剖面微構件之蜂巢材料力學性質,”國立成功大學土木工程研究所碩士論文, 2004.

[3] C. H. Chuang and J. S. Huang,“Elastic moduli and plastic collapse strength of hexagonal honeycombs with plateau border,”International Journal of Mechanical Sciences, Vol.44, pp.1827-1844, 2002.

[4] J. S. Huang and S. Y. Liu,“Fatigue of honeycombs under in-plane multiaxial loads,”Material Science and Engineering, Vol.308, pp.45-52, 2001.

[5] S. K. Maiti, M. F. Ashby and L. J. Gibson,“Fracture Toughness of Brittle Cellular Solids,”Scripta Metallurgica, Vol.18, pp.213-217, 1984.

[6] J. S. Huang and L. J. Gibson,“Fracture toughness of brittle honeycombs,”Acta Metall. Mater., Vol.39, No.7, pp.1617-1626, 1991.

[7] J. S. Huang and L. J. Gibson, “Fracture toughness of brittle foams,”Acta Metall. Mater., Vol.39, No.7, pp.1627-1636, 1991.

[8] J. S. Huang and J. Y. Lin,“Mixed-mode fracture of brittle cellular materials,”Journal of Materials Science, Vol.31, pp.2647-2652, 1996.

[9] T. L. Anderson,“Fracture Mechanics,”second edition, CRC press, U.S.A., 1995.