本文主要是研究不同凹槽深度的環圓周尖銳凹槽C2700黃銅圓管在對稱曲率循環彎曲負載下的力學行為以及失效損壞，其中不同凹槽深度分別為: 0.2、0.4、0.6、0.8與1.0 mm，圓管的壁厚皆為1.5 mm，透過彎管實驗機進行曲率控制循環彎曲至失效損壞的實驗，並根據實驗收集到的數據，整理並統整出彎矩-曲率、橢圓化-曲率與控制曲率-循環至損壞圈數的關係圖。
從實驗彎矩-曲率關係中發現，從第一圈開始，該關係即呈現一個穩定迴圈的狀態，而凹槽深度越大時，管壁就越薄，彎曲到指定的曲率就不需要較大的彎矩。從實驗橢圓化-曲率的關係中發現，曲線呈現對稱、棘齒與增加的趨勢，而在曲率的峰值處會產生較大的橢圓化值。此外，凹槽深度越大時，橢圓化增加就越快，反之亦然。從實驗控制曲率-循環至損壞圈數的關係中發現，當控制曲率越大或凹槽深度越大時，循環至損壞的圈數就越少。若將控制曲率和循環至損壞圈數之間的關係繪製於雙對數座標中，則五種不同凹槽深度會對應出五條幾乎平行的直線。最後，本研究使用2010年Lee提出的理論方程式來描述環圓周尖銳凹槽C2700黃銅圓管在對稱曲率循環彎曲負載下的控制曲率和循環至損壞圈數關係，並經與實驗數據比對後發現，該理論能夠合理描述實驗結果。

The study investigates the mechanical behavior and buckling failure of circumferential sharp-notched C2700 brass tubes with five different notch depths subjected to cyclic bending. The different notch depths are 0.2, 0.4, 0.6, 0.8 and 1.0 mm, with tube thickness of 1.5 mm. Using the bending test machine, experiments were conducted to control curvature cyclic bending until failure, and data collected were organized to establish relationships between moment-curvature, ovalization-curvature, and controlled curvature-the number of cycles needed to initiate failure.
From the experimental moment-curvature relationship, a stable loop was observed from the first cycle, with thinner tube thickness requiring less moment to bend to the specified curvature, especially for larger notched depths. The ovalization-curvature relationship exhibited symmetrical, serrated, and increasing trends, with larger notched depths leading to faster ovalization increase. Additionally, in the controlled curvature-the number of cycles needed to initiate failure relationship, higher controlled curvature or larger notched depths resulted in fewer number of cycles needed to initiate failure. When plotted on a double logarithmic coordinate system, the five different notched depths corresponded to nearly parallel lines. Finally, this study uses the theoretical equations proposed by Lee in 2010 to describe the relationship between control curvature and number of cycles needed to initiate failure for circumferential sharp-notched C2700 brass tubes under cyclic bending. Comparison with experimental data revealed that the theory reasonably describes the experimental results.

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