本文主要係實驗分析五種不同尖銳凹槽深度 (0.2、0.4、0.6、0.8 及1.0 mm)的304 不銹鋼管在三種不同加載曲度率 (0.0035、0.035 及0.35 m−1s−1) 循環彎曲負載下的力學行為與皺曲損壞 (黏塑性行為)。實驗係透過彎管試驗機與曲度－橢圓化量測器來進行實驗數據的控制、量測及蒐集。實驗結果顯示，不論任何凹槽深度，304 不銹鋼管的彎矩－曲度關係會呈現循環硬化的現象，且最後彎矩－曲度曲線會形成一穩定的迴圈。而橢圓化－曲度關係則呈現不對稱棘齒狀的變化，且凹槽深度越深，曲線的不對稱現象會越明顯。由雙對數座標中曲度－循環彎曲至皺曲圈數的實驗關係中發現，在個別的加載曲度率循環彎曲負載下，五個不同尖銳凹槽深度的試件可近似為五條幾乎平行的直線。最後，本文參考Shaw 和Kyriakides [1]及 Pan 和Her [2]論文中的理論方程式後，提出一個可以描述不同尖銳凹槽深度的304 不銹鋼管在不同加載曲度率循環彎曲負載時，控制曲度與循環彎曲至皺曲圈數關係的理論方程式。在與實驗值做比較後發現，理論分析能合理的描述實驗結果。

This paper presents an experimental investigation of the mechanical
behavior and buckling failure (viscoplastic behavior) of 304 stainless steel tubes with five different sharp-notched depths (0.2, 0.4, 0.6, 0.8 and 1.0mm) subjected to cyclic bending with three different curvature-rates(0.0035, 0.035 and 0.35 m−1s−1). A tube bending machine and curvature-ovalization measurement apparatus were used to control, measure and collect experimental data. It can be observed from the experiment data
that the 304 stainless steel tube with any notch depth exhibits a cyclic
hardening phenomenon from the moment and curvature relationship, and
a steady-state loop of the moment-curvature curve is found after a few
loading cycles. It can also be observed that the relationship between the
ovalization and curvature demonstrates a nonsymmetric, ratcheting
phenomenon. Higher notch depth leads to further nonsymmetry of the
curve. It can be observed from the experimental curvature-number of
cycles to produce buckling curves that five almost parallel straight lines
can be found for five different sharp-notched depths at each curvature-rate in a log-log scale. Finally, by referring to the theoretical formulations proposed by Shaw and Kyriakides [1], and Pan and Her [2], a theoretical formulation was proposed to simulate the relationship between the controlled curvature and the number of cycles to produce buckling for 304 stainless steel tubes with different sharp-notched depths at different
curvature-rates. By comparing theoretical analysis with experimental data,
it is shown that the theoretical formulation can properly represent the
experimental results.