本文主要針對五種不同孔徑的圓孔於6061-T6鋁合金管做循環彎曲負載實驗，探討其相關力學行為及現象，由實驗後所得到的實驗數據繪出彎矩-曲度關係圖、橢圓化-曲度關係圖、控制曲度-循環至損壞圈數關係圖，從彎矩-曲度關係圖可發現，對稱循環彎曲負載下，鋁合金管產生硬化現象，隨著循環次數增加，迴圈趨於穩定，從橢圓化-曲度關係圖，孔徑愈大，橢圓化增長的速度愈快、其迴圈形成的∞形愈明顯，控制曲度-循環至損換圈數關係圖，孔徑愈大時循環至損壞損壞圈數愈少，最後，本文描述不同孔徑大小的鋁合金圓管在循環彎曲負載下，控制曲度與循環至損壞圈數的理論方程式，與實驗值相較後發現，理論與實驗直相互擬和。

This paper mainly discusses the behavior of round-hole 6061-T6 aluminum alloy tubes with five different hole diameters under cyclic bending. During the symmetrical cyclic bending, it can be observed the mechanical behavior and phenomenon. The experimental data can be obtained the moment-curvature, ovalization-curvature curves and controlled curvature-number of bending cycles required to ignite failure relationships. It can be seen from the moment-curvature curve that the loops display a little cyclic hardening and become stable after a few bending cycles. Next, from ovalization-curvature curves, the larger the diameter of 6061-T6 aluminum alloy round-hole tube is, the faster the ovalization grows and the more obvious the shape of ∞ for the loop is. It is shown from controlled curvature-number of bending cycles required to ignite failure relationship that the larger the diameter, the less the number of bending cycles required to ignite failure is. Finally, a theoretical formulation was proposed in this paper to simulate the relationship between the controlled curvature and the number of bending cycles required to ignite failure. By comparing the theoretical analysis with the experimental data, theoretical formulation properly simulates the experimental results.

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