不完美界面是由一層厚度極薄的材料模擬等效而成，相較於完美界面，其特色是材料在界面上的位移或者應力不一定會連續。而透過改變界面的材料係數，可以使波傳經過界面時的相位差產生改變。本文主要透過調控等效後的界面參數的方式，來探討波傳在經過不完美界面後，如何能有最大的相位差範圍與其限制。首先，我們建立彈性波傳的運動方程，並接著介紹不完美界面的物理模型與其邊界條件的建立。再來，分析時間諧和的SH波與P波在經過兩種不完美界面時所產生的相位差。最後我們會根據得到的結論，簡述未來或可持續研究的方向。

In this thesis, the imperfect interface is assumed to be an extremely thin interphase interface between two materials. Boundary conditions on such interface including tractions and displacements are not required to be continuous. According to the stiffness of the interphase material, two different types of imperfect interface and their interface conditions are introduced which are HS (high stiffness) type and LS (low stiffness) type. By adjusting the parameter which also means the effective elastic moduli of the interphase material, we investigate the phase difference when two elastic plane waves, SH waves and P waves propagate through the imperfect interface of two types. The purpose of this research is to find the widest range of phase difference and to investigate its limitation so that it might be possible to design metasurface by using the concept of imperfect interface in the future.

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