摘要
　　以變形動力學(DK)和J2理論之純剪本構方程式依Darveaux等人在溫度299K、353K以及407K時之剪應力與穩態潛變剪應變率實驗數據進行材料參數之決定後，發現兩理論之預測值與實驗值都有良好之結果，但在299K時變形動力學比J2理論預測值大約10倍。兩理論對單軸潛變應力時之潛變率預測值則大為不同；在各溫度下，高於DK工程截取應力之潛變率皆比J2理論之值高，並有背離之現象。以97.5Pb/2.5Sn之薄壁圓管進行彎扭耦合作用潛變分析得知在定溫定扭下，變動彎矩使得變形動力學之 受到彎扭耦合影響程度比J2理論小，而兩理論之 受到彎扭耦合影響程度則相反；若改以定溫定彎矩之方式，變動扭矩則發現變形動力學之 受到彎扭耦合影響程度比J2理論小，而兩理論之 受到彎扭耦合影響程度雖然相反，但沒有太大差異。本文對彎扭耦合下潛變分析理論及分析方法，可作為設計及研發參考之準則，進行估算。

Abstract
　Material parameters in the deformation kinetics (DK) and the J2 theory are determined from Darveaux and Banerji shear creep data of 97.5Pb/2.5Sn at 299K, 353K and 407K. The theoretical predictions of two different theories are in very well agreement with the experimental data, but at 299K the theoretical predictions by DK is about 10 times larger than those of J2 theory. However, the predictions of creep strain rate under uniaxial tensile stress of the two theories are not very alike. At various temperatures, the predictions of DK in the stress range higher than the engineering cut-off stress are larger than the predictions of J2, and their tendencies are deviated each other. From Bending/Torsion steady creep analysis of 97.5Pb/2.5Sn thin-walled tubes via DK and J2 theories, the analysis show that (1) under constant temperatures and constant torque with changing bending moment, the coupling effect of bending and twisting of DK on twist rates, are smaller than J2 theory, while the curvature rates of two theories are on the contrary. (2) under constant temperatures and constant bending moment with changing torque, the plot of torsion vs. curvature rate illustrates the coupling effect by bending and twisting of DK on curvature rate , are smaller than J2 theory, while the coupling effect of twist rates are opposite. The methodology of Bending/Torsion steady creep employed in this paper can be used for engineering design.

[1]Frost, H. J., Howard, R. T., Lavery, P. R., and Lutender, S. D., ”Creep and Tensile Behavior of Lead-Rich Lead-Tin Solder Alloys”, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 11, No 4, pp.371-379, 1988.
[2]Darveaux R., and Banerji, K., ”Constitutive Relations for Tin-Based Solder Joints”, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 15, No 6, pp.1013-1024, 1992.
[3]Lau, J. H. ”Torsion of Hollow Circular Cylinders with Creep”, Journal of the Engineering Mechanics Division, ASCE, 108 , pp.185-190, 1982.
[4]Lau J. H. and Lau, T. T., ”Creep of Pipes under Axial Force and Twisting Moment”, Journal of the Engineering Mechanics Division, ASCE, 108 ,pp.174-179. 1982.
[5]Lau, J. H. ”Bending of Thin-Walled Circular Cylinder with Creep”, Journal of the Engineering Mechanics Division, ASCE, 107 , pp.185-190, 1981.
[6]Lau J. H. and Lau, T. T., ”Creep of Pipes under Axial Force and Bending Moment”, Journal of the Engineering Mechanics Division, ASCE, 108 , pp.190-195, 1982.
[7]Lau, J. H. ”Bending and Twisting of 96.5Pb/3.5Ag and 97.5Pb/2.5Sn Solder Interconnects with Creep”. IEEE Electronic Components and Technology Conference Proceedings, pp.1108-1114. 1994.

[8]Shames, I. H., and Cozzarelli F. A., ”Elastic and Inelastic Stress Analysis”. Taylor and Francis. 1997.
[9]Valanis, K. C., and Lee, C. F., ” Deformation Kinetics of Steady-State Creep in Metals”, Internal Journal of Solids and Structures, 17, pp.589-604, 1981
[10]Valanis, K. C., ”Deformation Kinetics in Three Dimensions”, Internal Journal of Engineering Science, 22, 8-10, pp. 979-988, 1984.
[11]Lee, C.F. Chang, M.K. and Chung, W.K.,“Deformation Kinetics of Steady Creep in Sn/Pb Solder Alloys with Application”, Journal of Mechanics, Vol.20, NO.2, pp.85-93, 2004.
[12]張明凱,”變形動力學之銲錫材料的穩態潛變行為”.成功大學工程科學系碩士畢業論文,2001年.