有限元素耦合力場實例探討

The Study of Finite Element Coupled Field Analysis with Practical Examples

周志宜(Chih-Yi Chou)

指導教授 ： 康淵

中原大學/工學院/機械工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400108

摘要

摘要
多領域的耦合現象在日常生活、科學與工程問題中非常普遍。隨著科技的進步,耦合分析的能力也不斷的發展,耦合現象的探討與應用也越來越重要。近年微機電系統的發展,使耦合分析受到更大的關注。
本文介紹了耦合分析的涵義與應用,並對耦合分析之相關技術與問題作一番的說明,也扼要的介紹一些現有之耦合分析軟體。期使讀者能體認耦合分析之重要性,並了解耦合分析之方法,進而善用之,對工程之發展當有很大的助益。
本文主要在探討分析單一溫度場與固力場及耦合溫度場與固力場,求解之結果的差異。由本文得知分析單一溫度場所使用之元素型態2D 必須為Thermal Plane55,才能成功的將溫度分佈轉換至固力場變成Structural Plane42求解其應力分佈及變形量。3D則必須為Thermal Solid70,才能成功的將溫度分佈轉換至固力場變成Solid45求解其應力分佈及變形量。
耦合溫度場與固力場求解時,元素型態2D必須使用Coupled Field Plane13。3D必須使用Coupled Field Solid 5才能求解。
由本文分析結果得知,利用此二種分析方法求解其變形量與應力集中的位置相同。
應用3D順序耦合分析法,求解一因流場所產生之壓力分佈造成結構之變形及應力。由本文得知解析單一流場所使用之元素型態3D 必須為Fluid142,才能成功的將壓力分佈轉換至固力場變成Structural Solid45求解其應力分佈。另外分析流場所使用之Fluid142元素,因無法與其他元素一起求解,所以當分析流場時,如物體為流體,使用Fluid142元素時,流體之材料特性必須輸入在編號1號之欄位。物體為固體,使用Fluid142元素時,固體之材料特性必須輸入在編號2號以上之欄位。Fluid142元素利用此種方法來詮釋單一元素,同時解析多種不同之材料特性。

關鍵字

多領域 ； 耦合分析 ； 電腦輔助工程分析模擬 ； 誇領域

並列摘要

Abstract

The multi-physics coupling phenomena are quite common in daily life, scientific and engineering problems. Due to the progress of technology, the capability of coupled-field analysis is also under intensive development. The study and application of coupled-field events are attracting much attention. In recent years, due to the development of MEMS systems, coupled-field analysis is more emphasized then ever.
This paper introduces the meaning and application of coupled field analysis. The related techniques and problems are explained, and some of the existing software in this field is also briefly discussed. The purpose is to make clear the importance of coupled-field analysis to the reader, and further more realize the methodologies behind the picture. It should be quite beneficial to the progress of the engineering research and development.
The main focus of this paper is to analyze the difference between the sequential coupling approach of solid mechanics and heat transfer, and the direct coupling approach. It was shown that for in the 2D sequential coupling problems, the thermal plane element 55 and the structural plane element 42 must be utilized associatively in order to successfully transfer the temperature distribution result into the thermal load of structural analysis for calculation of stress and deformation. For 3D problems, the Thermal Solid 70 and the Structural Solid 45 must be used.
For the direct coupling approach, Coupled Field Plane13 for 2D and Coupled Field Solid 5 for 3D should be used.
From the examples of this paper, it can be seen that both approaches result in the same deformation and the same location of stress concentration.
Examples were shown using the sequential coupling approach to solve the deformation of a structure due to the pressure from a flow field. It was shown that for 3D flow field (only) analysis, Fluid 142 must be used to successfully transfer the pressure distribution onto Structural Solid45 for stress analysis. In addition to that, Fluid 142 can not be included in the model simultaneously with other types of elements. Also, when using Fluid 142, the material properties of the fluid must be assigned with material ID 1. For solid material with Fluid 142 elements, the material ID must be assigned as 2 or larger. Fluid142 elements use this material numbering approach to distinguish between fluid and solid.

並列關鍵字

computer-aided engineering analysis and simulation. ； coupled-field analysis ； multi-discipline

參考文獻

1. Kiefling, L. and Feng, G. C.,“Fluid-Structure Finite Element Vibrational Analysis,” AIAA Journal , Vol. 14, NO. 2, pp. 199-203, 1976.

2. Zienkiewicz, O. C. and Bettess, P.,“Fluid-Structure Dynamic Interaction and Wave Forces. An Interoduction to Numerical Treatment,” International Journal For Numerical Methods in Engineering, Vol. 13, pp. 1-16, 1978.

3. Morand, H. and Ohayon, R.,“Substructure Variational Anslysis of the Vibrations of Coupled Fluid-Structure Systems. Finite Element Results,” International Journal For Numerical Methods in Engineering, Vol. 14, pp. 741-755, 1979.

4. Wilson, E. L. and Khalvati, M.,“Finite Elements For the Dynamic Analysis of Fluid-Solid Systems,” International Journal For Numerical Methods in Engineering, Vol. 19, pp. 1657-1668, 1983.

5. Chen, H. C. and Taylor, R. L.,“Vibration Analysis of Fluid-Solid Systems Using a Finite Elements Displacement Formulation,” International Journal For Numerical Methods in Engineering, Vol. 29, pp. 683-698, 1990.