在破壞力學中應力強度因子為重要的參數。然而若想藉由界面裂縫的定義式求得應力強度因子並非容易之事，因為在裂縫尖端會有奇異性的行為，難以獲得穩定的物理量。因此在破壞力學中，與路徑無關的積分式極為重要，因為可以透過遠離尖端的路徑，減少裂縫尖端奇異行為的影響，而取得準確的應力強度因子，包含H積分亦是如此，而且H積分比其他積分式更能處理較為複雜的破壞問題，例如界面角或是界面裂縫。除此之外，若是選擇沿著材料體邊界為積分路徑，在邊界元素法的運算中，該路徑上的部分高斯點，有可能因為太靠近邊界節點而產生奇異積分的問題，因此將透過內插法規避奇異積分的運算，進而獲得準確的物理量。
本文將脫層視為界面裂縫問題，將利用界面特殊邊界元素模擬，而界面特殊邊界元素從一般邊界元素延伸而成，其對於相異材料交界處，已經自動滿足完美接觸的連續條件，在模擬界面裂縫問題時，不需對界面劃分元素，只需針對裂縫表面劃分元素即可。另外，考慮多層纖維排向相異的疊層板發生脫層問題時，可以利用等效混合理論，將多層疊層問題轉換成雙材料問題，以滿足界面特殊邊界元素的材料數量，即可對該問題進行模擬，之後搭配上H積分即可計算出應力強度因子。
透過不同的問題進行測試，包含雙材料界面裂縫、四層複材疊層板脫層問題或是十層複材疊層板脫層問題，而測試時使用圓形路徑與多邊形路徑進行H積分計算，最後所得結果也皆符合與路徑無關之特性。

In fracture mechanics, the stress intensity factors are an important parameter that can help us to know whether the material will fail. However, it is difficult to obtain the stress intensity factors through its definition because the crack tip has singular behavior that makes us cannot get the stable value of the stress near the tip. Therefore, there have many path-independent integrals in the fracture mechanics, H-integral included. H-integral is better than others to deal with complex problems, including interface wedge and interface crack. In addition to choosing the integral path that is along the material boundary, some gaussian points on the path will be close to the boundary nodes that make us encounter the singular integral. For the singular integral, we use the interpolation method to circumvent it and get the accurate displacement and stress.
The interface special boundary element extends from the normal boundary element and it satisfies the perfect bond condition for the interface between two dissimilar materials. It will reduce the time for simulating the problem because it only meshes the elements for the crack surface and needs not to mesh elements for the interface. Additionally, when considering an interface crack in the multilayer composite that each layer has different fiber orientations, we can equivalent the composite to two dissimilar materials by the equivalent theory which is used widely in composite mechanics. After equivalent, it can also calculate the stress intensity factors through the interface special boundary element and H-integral.

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