https://scholars.lib.ntu.edu.tw/handle/123456789/80697
Title: | 麻田散鐵薄膜或薄膜於基材上具平面法向異向性之微結構模擬 Microstructure Simulation of Martensitic Thin Film/Substrate Accounting for the out-of-plane Inhomogeneity |
Authors: | 林昇旺 Lin, Sheng-Wang |
Keywords: | 麻田散鐵材料快速傅立葉轉換;新式相場法;微結構;Martensitic Material;Fast Fourier Transform;Novel Phase-Field Method;Microstructure | Issue Date: | 2009 | Abstract: | 麻田散鐵材料由於擁有形狀記憶效應,在智能材料中受到格外的重視,近年來已被大量應用在感測器以及致動器元件上。這些特殊的性質其實源自於這些材料擁有的顯微結構,內部秩序性的顯微結構排列與演化導致了巨觀非線性反應的產生。所以,如何有效且正確的使用這些材料,分析與模擬材料顯微結構,進而取得外界刺激、材料顯微結構、非線性反應之間的關連性,是最為重要的課題。本文以過去研究團隊所發展之理論模型為根基,發展出一套能夠描述二維麻田散鐵材料薄膜系統以及薄膜基材系統微結構演化的新式相場模型並且進行數值分析模擬。文藉由能量極小原理搭配變分法推導其個別演化方程式,並且利用快速傅立葉建立計算材料內應力之快速演算法。對於薄膜系統之數值模擬,(1) 我們首先驗證其計算應力場演算法之正確性,(2) 接著為過去研究團隊在法線方向之壁接觸角度所建立之假設,證明其可信度,(3) 最後系統性的改變模擬參數,觀察與分析其個別能量最低時的微結構排列圖形。對於薄膜基材系統,我們重複步驟(1)與(3),同樣得到了許多令人滿意且與實驗結果相符合的結果。在未來可為進行相關實驗或者進行類似模擬的研究員,提供相當有幫助的資訊與概念。 Martensitic materials play an important role of smart materials because of shape memory effect, and they are applied extensively to produce sensors and actuators. The microstructures make those materials have special property and the regular arrangement and evolution of microstructures can induce significant nonlinear behaviors. Therefore, it’s an important topic to use the materials in a right way, to analyze and simulate the microstructure and to get the relationship between external stimuli, microstructure and nonlinear behaviors. We develop a novel phase-field model to describe 2-D Martensitic film system and film with substrate system base on the theory our group developed in the past so that we could operate microstructure simulation and govern the formation and evolution.n the article, each case we get the evolution equation by energy limited method and construct the fast mathematical calculations to calculate the stress field in the materials by Fourier transform. Film system, we first confirm the credibility of the mathematical calculations to calculate the stress field. Second, we prove the credibility of the assumption our group make to the out-of-plane inhomogeneity. Finally, we change the parameters systematically to observe and analyze the microstructure patterns. Film with substrate system, we repeat the first step and final step in film system, and we also get many satisfied results which are consistent to experiments. In the future, those results will offer much helpful information and idea to researchers who operate analogous simulations or experiments. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/183558 |
Appears in Collections: | 應用力學研究所 |
File | Description | Size | Format | |
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ntu-98-R96543039-1.pdf | 23.53 kB | Adobe PDF | View/Open |
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