膨脹接頭為一種能自由伸縮的彈性補償元件，在管線工程上是一項重要配件，本文應用板殻理論得之解析解分析法，分析盒形膨脹接頭之內側圓筒、外側圓筒及環狀圓板，在使用條件下的各項應力及伸縮剛性，然後由此深入探討幾何參數於力學行為上所扮演的角色，接著尋求盒形膨脹接頭各項尺寸間之相關特性，歸納出可供工程設計及製造者參考之資訊。
膨脹接頭經分析的結果，彎曲應力主控著應力，是各項應力最重要的。其最大應力一般位於環狀圓板的內緣或者外緣，當作用力是內壓或者拉伸時則最大應力在外緣處，反之，作用力是壓縮的話，其最大應力在內緣處，若兩同時作用時則視何者效應較強而定。在應力分佈之中，環狀圓板之應力分佈具重要角色。所以，環狀圓板對於膨脹接頭的應力評估上是非常重要。

Expansion joints used as a kind of flexible elastic compensating element, which are the most important component in the piping system. This paper is based on linear elastic thin-shell theory to conduct simplified equation to obtain different parameter of box type expansion joint. The structure of expansion joint has inner shell, outer shell and annular plates, each part has some special mechanism characters.
We investigated the various stress and axial stiffness of the box type expansion joint by means of analysis methods under various conditions. This is based on these analytical and studies the dimension rational evaluation. These are very useful for design rules and manufacture by adopting proper coefficients.
The stress results show that the bending stress are dominant factor, The maximum stress generally appear in the inner or outer of annular plat for both internal pressure and axial displacement. Therefore the stress distribution of the annular plates are very important for evaluating the stress of expansion joint.

[1] Wissler H., Festigkeitsberchnug Vor Ringflachenschaleh Diss Zurich, 1916.
[2] Clark R.A., On the Theory of Thin Elastic Toroidal Shell, Journal of Math. and Phy. Vol.26, No.3. 1950.
[3] Kopp S., and Sayre M. F., Expansion Joints for Heat Exchanger, ASME Winter Annual Meeting, New York, 1952.
[4] Wolf L.J. and Mains R.M., The Stress Analysis of Heat Exchanger Expansion Joints in the Elastic Range, Journal of Engineering for Industry, Trans. ASME, 1973.
[5] Yokell S., A Working Guide to Shell-and-Tube Heat Exchangers, pp.302-304, McGraw-Hill.
[6] Singh K.P. and Soler A.I., A Rational Procedure for Analyzing Expansion Joints, Advances in Design and Analysis in Pressure Vessel Technology ,PVP-Vol.130 ,pp.63~68 , ASME, 1987.
[7] Bednar H.H., Pressure Vessel Design Handbook, pp.217-226, KRIGER PUBLISHING COMPANY.
[8] 小林英男、柳田省三, 压力容器設計、解析,pp.244-246, 日本規格協会。
[9] JIS ,ハソドブックボイラ˙压力容器,日本規格協会, 1996.
[10] 型錄，東洋螺旋管工業株式会社。
[11] Standard of the Expansion Joint Manufacture Association, INC., eigth edition, 2003.
[12] Timoshenko S.P., Strength of Materials, Part II, P.205~214,Third Edition, Van Nostrand, New York, 1958.
[13] Ugural A.C., Stresses in Plates and Shells, 2nd edition, McGraw-Hill, 1999.