許多產品為了功能性或成本上之需求，須將各種不同材料組合在一起。當其結構受到機械應力或熱應力時，易造成材料界面發生剝離（debounding）的現象，而使得相異材料的界面失效。一般為了描述界面裂紋的成長，採用大量的實驗數據來建立經驗公式模型，耗費大量的時間與成本。為了解決這個問題，本論文採用有限元素法配合內聚力模型（cohesive zone model, CZM）來描述界面裂紋的成長。
本研究是利用雙線性型式之內聚力模型配合有限元素方法，模擬相異材料界面受到機械應力或熱應力作用時，界面之張開量以判斷是否有裂紋生成；並模擬相異材料受到週期性加卸載時，界面裂紋的成長速率。本研究利用耦合模型減少模擬所需元素數量，並且以較細密之網格分析楔形角處或裂紋尖端，以有效率的分析雙材料之界面。
根據研究結果發現，全域-局部耦合有限元素模型在受到單調機械或熱應力作用時，其結果均與單一有限元素模型結果吻合，且當受週期性負載時，結果仍與單一模型近似。因此可利用耦合模型取代單一模型分析複雜之結構，以減少分析之時間。

From the perspectives of capabilities and manufacturing costs, a lot of structures and assembled using distinct materials. Under either thermal or mechanical stresses during fabrication or in-use conditions, debonding is likely to occur on the interface of materials. The conventional approach for studying the interface crack growth and related failure is by suing experimental tests to obtain empirical estimations. The required cost is high and the time duration is lengthy. To overcome this difficulty, the cohesive zone model (CZM) approach may be used to study the interface crack problem.
In this study, finite element analysis using a bilinear CZM is used to simulate interface debonding under either thermal or mechanical loads. The model is applied to study the interface crack formation and growth from bimaterial wedge corner under bending loads. The effect of corner wedge angle on crack growth rate is also investigated. The modeling results agree to those typical fracture mechanics approach.
In addition, as an interface to reduce the complexity of finite element model, global-and-local finite element approaches were also examined. The global-and local model with coupled displacement condition is shown to the same results as that obtained from the single model.

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