具非完美交界面多鐵層狀複合材料之等效材料性質

Effective Properties of Laminated Multiferroic Composites with Imperfect Interfaces

吳典融(Wu, Tien Jung)

指導教授 ： 郭心怡

國立交通大學/工學院/土木工程系所/碩士(2018年)

摘要

本研究以理論分析探討非完美交界面對多鐵層狀複合物等效材料性質之影響。多鐵複合材料具良好的磁電耦合效應，使其成為近代智能材料研究重點之一。以往理論研究常假設複合材料之交界面為完美結合，然而實際複合材料的交界面常因製造過程而產生裂縫或孔洞等瑕疵，形成非完美交界面，影響其整體等效行為。非完美交界面包括勢能連續但曳引力不連續之強非完美交界面(Interface Stress Type)，以及勢能不連續但曳引力連續之弱非完美交界面(Linear Spring Type)。本研究使用矩陣法求解具非完美交界面多鐵層狀複合物之等效材料性質，矩陣法為Qu和Cherkaoui在2006年所提出，用以求解具完美交界面彈性材料層狀複合物之等效材料性質，本研究將其推廣至多鐵複合物具非完美交界面問題，並以雙層法與Mori-Tanaka模型驗證其正確性，最後以等效磁電電壓係數 比較不同交界面條件下複合物磁電效應之強弱。
本研究使用BaTiO3-CoFe2O4進行數值模擬分析，結果顯示不論複合物具完美交界面、強非完美交界面或弱非完美交界面，使用矩陣法所得等效材料性質都與雙層法及Mori-Tanaka模型的預測結果一致。此外，數值結果顯示BaTiO3-CoFe2O4在具強非完美交界面或弱非完美交界面時，其 皆較完美交界面情形下降，可知BaTiO3-CoFe2O4層狀複合物之磁電效應在具完美交界面時較佳，在具非完美交界面時將減弱，此結果與BaTiO3-CoFe2O4之多鐵纖維狀複合物不同。本研究亦在附錄附上PVDF-(Terfenol-D)與(PZT-5A)-(Terfenol-D)之數值結果，其趨勢與BaTiO3-CoFe2O4相同。

關鍵字

非完美交界面 ； 多鐵層狀複合材料 ； 等效材料性質 ； 磁電耦合效應 ； 矩陣法

並列摘要

We propose a theoretical frameworks to study the effective properties of laminated mutiferroic composites with interface imperfections. Multiferroic composites have recently drawn ever-increasing interest due to their good performance in magnetoelectric effect. In the early research, the interfaces of composites were assumed to be perfectly bonded. In reality, however, the interfaces are imperfectly bonded with cracks, holes or flows due to the manufacturing process. In this work, both generalized interface stress type and generalized linear spring type imperfect interfaces are considered. The former presents the discontinuity in potential while the continuity in traction. The later presents the discontinuity in traction while the continuity in potential. We used the matrix method to solve the effective properties of laminated mutiferroic composites with imperfect interfaces. The matrix method was first proposed by Qu and Cherkaoui to investigate the effective property of laminated elastic composites in 2006. Mori-Tanaka method with two-level recursive scheme is employed to verify the results. Effective magnetoelectric voltage coefficient, , is presented to measure the efficiency of magnetoelectric effect.
Numerical calculations are demonstrated for BaTiO3-CoFe2O4 multilayer media, and are shown in good agreement with two-level recursive scheme. Furthermore, it is observed that the interface imperfection would reduce the magnitude of , comparing to the corresponding perfect interface case. This feature is opposite to that predicted and observed in the corresponding cylindrical composites.

並列關鍵字

Imperfect interface ； Laminated multiferroic composites ； Effective properties ； Matrix method

參考文獻

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