本研究是利用有限元素分析軟體ANSYS Workbench 2021 R1來模擬不同外徑/壁厚比與不同圓孔直徑的6061-T6鋁合金圓孔管在不同曲率比(最小曲率/最大曲率)循環彎曲負載下的力學行為，相關的力學行為有彎矩-曲率與橢圓化-曲率的關係。其中所探討三種不同外徑/壁厚比分別為:16.5、31.0及60.0，五種不同圓孔直徑分別為:2、4、6、8及10mm，而四種不同的曲率比分別為: -1、-0.5、0及+0.5。本研究外徑/壁厚比16.5與31.0的6061-T6鋁合金圓孔管，最大曲率控制為+0.5m^(-1)，至於外徑/壁厚比60.0的6061-T6鋁合金圓孔管，由於管壁較薄，所以最大曲率控制為+0.4m^(-1)。由蘇揮凱[19]的實驗與ANSYS分析的結果顯示，在固定外徑/壁厚比與曲率比的情況下，圓孔直徑大小對彎矩-曲率的關係沒有太大的影響，但對橢圓化-曲率的關係有強烈的影響，且圓孔直徑愈大橢圓化增加就愈快。在三種外徑/壁厚比的6061-T6鋁合金圓孔管皆發現，當曲率比為-1時，循環彎矩-曲率的關係從第一圈開始便呈現一個彈-塑性的穩定迴圈，而橢圓化-曲率關係則呈現不對稱、棘齒與蝴蝶狀的增加趨勢。另外，當曲率比為-0.5、0與+0.5時，循環彎矩-曲率關係從第二圈開始即呈現一彈性的線性重疊路徑，且隨著循環圈數的增加，路徑會有些許鬆弛後接著呈現一個穩定的線性重疊路徑，因變形幅度皆在彈性的範圍內，因此橢圓化-曲率關係趨勢呈非常緩慢的增加。最後，有限元素ANSYS分析結果與實驗結果相互比較後可發現，有限元素ANSYS分析可以合理的描述實驗結果。

In this study, the finite element software ANSYS workbench 2021 R1 is used to analyze the response of 6061-T6 aluminum alloy round-hole tubes with different diameter-to-thickness ratios subjected to cyclic bending with different curvature ratios. Before analyzing, we need to substitute the parameters into the ANSYS software such as material properties, model of the round-hole tube, size of meshes, boundary and loading conditions of the model. The five different hole diameters are 2, 4, 6, 8 and 10 mm. Three different diameter-to-thickness ratios are 16.5, 31.0 and 60.0. To highlight the influence of mean curvature effect, four different curvature ratios (minimum curvature/maximum curvature) are used in this study. The curvature ratios are -1, -0.5, 0 and +0.5. The response includes the moment-curvature and ovalization-curvature relationships. For the diameter-to-thickness ratios of 16.5 and 31.0, the curvature controls between -0.5m^(-1)to +0.5 m^(-1). When the curvature ratio is -1, the curvature controls at -0.5~+0.5 m^(-1). When the curvature ratio is -0.5, the curvature controls at-0.25~+0.5〖 m〗^(-1). When the curvature ratio is 0, the curvature controls at 0~+0.5 m^(-1). When the curvature ratio is +0.5, the curvature controls at +0.25~+0.5 m^(-1). In addition, for the diameter-to-thickness ratio of 60.0, the curvature controls between -0.4 m^(-1) to +0.4 m^(-1). When the curvature ratio is -1, the curvature controls at -0.4~+0.4 m^(-1). When the curvature ratio is -0.5, the curvature controls at-0.2~+0.4 m^(-1). When the curvature ratio is 0, the curvature controls at 0~+0.4〖 m〗^(-1). When the curvature ratio is +0.5, the curvature controls at +0.2~+0.4〖 m〗^(-1). According to the experimental and analysis results, the hole diameter has almost no influence on the moment-curvature relationship but has strong influence on the ovalizaton-curvature relationship. Moreover, the larger the hole diameter is, the faster the ovalizaton increases. When the curvature ratio = -1, the moment-curvature relationship shows a stable loop from the first bending cycle. As for the ovalization-curvature relationships, it shows an increasing asymmetrical, ratchetting and bow-shape trend. However, when the curvature ratio = -0.5, 0 or +0.5, moment-curvature relationship presents an elastic linear overlapping path from the second bending cycle. And the ovalization-curvature relationship increases slowly because the deformation range is all within the elastic range.

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