本文主要探討不同尖銳凹槽方向對於SUS304不鏽鋼管在循環彎曲負載下的力學行為及皺曲損壞的影響。本文共分為實驗與理論分析兩部分進行，並比對兩部分的分析結果。
由實驗彎矩-曲度曲線中顯示，在曲度控制循環彎曲負載時，SUS 304不鏽鋼管皆有循環硬化的現象，而經過一些循環圈數後迴圈會呈現較為穩定的狀態。其次，由實驗橢圓化－曲度曲線中發現，橢圓化值會隨著循環彎曲的圈數增加而呈棘齒狀的增加，且當橢圓化值增加到某一臨界值時，圓管便會發生皺曲損壞。此外，由實驗曲度－循環至皺曲圈數關係中可看出，控制的曲度越大時，循環圈數就越少；而當角度越大，則循環圈數就越多。若將上述實驗值置於雙對數座標中可發現，四個不同方向尖銳凹槽的試件其上述關係呈現四條不平行的直線。
最後，本文參考Shaw and Kyriakides【5】及Pan and Lee【12】論文中所提出的理論方程式，並適當的導入角度因子而提出一個方程式可以用來描述，不同方向尖銳凹槽圓管在循環彎曲負載時控制曲度與循環至皺曲圈數的關係。最後，理論方程式能合理的描述實驗結果。

In this thesis, the influence of the different notch directions on the mechanical behavior and buckling failure of SUS 304 stainless steel tubes subjected to cyclic bending. The material is divided into two parts, which includes experimental testing and theoretical analysis. And, the comparison between these two parts is also included.
It can be observed from the experimental moment-curvature curve that the SUS 304 stainless steel tube exhibits cyclic hardening and becomes steady after a few cycles for curvature-controlled cyclic bending. Next, From the experimental ovalization-curvature curve, the ovalization of the tube cross-section increases in a ratcheting manner with the number of cycles. The tube buckles when the ovalization reaches a critical value. In addition, from the experimental curvature-number of cycles to produce buckling relationship, the greater is the controlled curvature, the fewer of the number of cycles. However, the larger is the angle, the more the number of cycles. If the aforementioned experimental data are plotted in the log-log scale, four nonparallel straight lines corresponding to four different sharp-notched directions are found.
Finally, by referring the theoretical equations proposed by Shaw and Kyriakides【4】【5】and Pan and Lee【12】and importing the appropriate angle factor, a theoretical formulation is proposed to simulate the relationship between the curvature-number of cycles to produce buckling relationship for local sharp-notched circular tube subjected to cyclic bending. Through comparison with the experimental data, the theoretical equation can reasonably simulate the experimental results.

1. Brazier, L. G., 1927, “On the Flexure of Thin Cylindrical Shell and Other Thin Sections,” Proceedings of the Royal Society, Series A, Vol. 116, pp. 104-114.

2. Tuggu, P. and Schroeder, J., 1979, “Plastic Deformation and Stability of Pipes Exposed to External Couples,” International Journal of Solids and Structures, Vol. 15, Pp. 643-658.

3. Korol, R. M., 1979, “Critical Buckling Strains of Round Tubes In Flexure,” International Journal of Mechanics And Science, Vol. 21, pp719-730.

4. Shaw, P. K. and Kyriakides, S., 1985, “Inelastic Analysis of Thin-Walled Tubes under Cyclic Bending,” International Journal of Solids and Structures, Vol. 21, pp. 1073-1100.

5. Shaw, P. K. and Kyriakides, S. , 1987, “Inelastic Buckling of Tubes Under Cyclic Bending,” ASME, Journal of Pressure Vessel Technology, Vol. 109, pp. 169-178.

6. Corona, E. and Kyriakides, S., 1988, “On the Collapse of Inelastic Tubes under Combined Bending and Pressure,” International Journal of Solids and Structures, Vol. 24, pp. 505-535.

7. Corona, E. and Kyriakides, S., 1991, “An Experimental Investigation Degradation and Buckling of Circular Tubes under Cyclic Bending and External Pressure,” Thin-Walled Structures, Vol. 12, pp. 229-263.

8. Ju, G. T. and Kyriakides, S., 1992, “Bifurcation Buckling Versus Limit Load Instabilities of Elastic-Plastic Tubes under Bending and External Pressure,” Journal of Offshore Mechanics and Arctic Engineering, Vol. 113, pp. 43-52.

9. Pan, W. F., Wang, T. R. and Hsu, C. M., 1998, “A Curvature- Ovalization Measurement Apparatus for Circular Tubes under Cyclic Bending,” Experimental Mechanics, Vol. 38, No.2, pp. 99-102.

10. Pan, W. F., and Her Y. S., 1998, “Viscoplastic Collapse of Thin-Walled Tubes under Cyclic Bending,” ASME Journal of Engineering Materials and Technology, Vol. 120, pp. 001-004.

11. Lee, K. L., Pan, W. F. and Kuo, J. N., 2001, “The Influence of the Diameter-to-Thickness Ratio on the Stability of Circular Tubes under Cyclic Bending,” International Journal of Solids and Structures, Vol.38, pp. 2401-2413.

12. Lee, K. L. and Pan, W. F., 2002, “Pure Bending Creep of SUS 304 Stainless Steel Tuber,” Steel and Composite Structures - an International Journal, Vol. 2, No.6, pp. 461-474.

13. Lee, K. L., Pan, W. F. and Hsu, C. M., 2004, “Experimental and Theoretical Evaluations of the Effect between Diameter-to-Thickness Ratio and Curvature-Rate on the Stability of Circular Tubes under Cyclic Bending,” JSME International Journal, Series A, Vol. 47, No.2, pp. 212-222.

14. Lee, K. L., Shie, R. F. and Chang, K. H., 2005, “Experimental and
Theoretical Investigation of the Response and Collapse of 316L Stainless Steel Tubes Subjected to Cyclic Bending,” JSME International Journal, Series A, Vol. 48, No.3, pp. 155-162 .

15. Chang, K.H., Pan, W.F. and Lee, K.L., 2008, “Mean Moment Effect
on Circular Thin-walled Tubes under Cyclic Bending,” Structural
Engineering and Mechanics - an International Journal, Vol. 28, No.5,
pp. 495-514.

16. 廖信智，2009，「尖銳凹槽薄壁管在循環彎曲負載下黏塑性皺曲行為之研究」，國立成功大學工程科學研究所碩士論文。

17. 翁弘杰，2011，「尖銳凹槽圓管在循環彎曲負載下平均曲度對皺曲行為影響之實驗研究」，國立成功大學工程科學研究所碩士論文。

18. 張育生，2012， 「尖銳凹槽圓管在純彎曲負載下潛變行為之實驗研究」，國立成功大學工程科學研究所碩士論文。