本文利用彎管試驗機將不同外徑/壁厚比(30、40、50及60)以及不同圓孔直徑(2、4、6、8及10 mm)的6061-T6鋁合金圓孔管進行純彎曲潛變的實驗，並觀察潛變曲率、橢圓化與時間之間的相互關係，而純彎曲潛變的負載是指將圓孔管彎曲至某個固定彎矩後，維持該彎矩一段長時間。當純彎曲潛變實驗開始時，圓孔管的彎曲曲率會隨著時間先是會迅速增加，之後趨於平緩的增加直至失效損壞，至於純彎曲潛變負載也會使得橢圓化持續的增加，當橢圓化到達一臨界值時，圓孔管會發生失效損壞。
根據實驗純彎曲潛變的潛變曲率與時間的關係圖顯示，在相同的潛變彎曲力矩時，外徑/壁厚比越大或是圓孔直徑越大的圓孔管在純彎曲潛變負載下，潛變曲率增加的也就越快。最後，本文使用2014年Lee et al.【7】所提出描述純彎曲潛變負載下潛變曲率與時間的關係式，並根據實驗數據加入不同外徑/壁厚比及不同圓孔直徑的變數，則理論公式可以用來描述不同外徑/壁厚比及不同圓孔直徑的6061-T6鋁合金圓孔管在純彎曲潛變負載下的潛變曲率與時間關係，並與實驗結果相互比較後可發現，理論可以合理的描述實驗結果。

In this paper, the response of 6061-T6 aluminum alloy round-hole tubes with different diameter-to-thickness ratios (30、40、50、60) and different round-hole diameters (2、4、6、8 and 10 mm) under pure bending creep is studied. The relationship among the creep curvature, ovalization and time are observed. It can be seen that when the pure bending creep experiment starts, the curvature of the round-hole tube increases rapidly with time, subsequently, it increases gently until failure. The ovalization also increases, and the round-hole tube failure when the ovalization reaches a critical value.
According to the experimental result of the creep curvature-time relationship under pure bending creep, it is shown that under the same bending moment, the larger the diameter-to-thickness ratio or the round-hole diameter leads to faster increase of the creep curvature. Finally, the formulation proposed by Lee et al. in 2014 is modified to describe the relationship between creep curvature and time under pure bending creep. Based on the experimental data, material parameters related to diameter-to-thickness ratios and round-hole diameters are included. Therefore, the theoretical formula can be used to describe the relationship between creep curvature and time of round-hole 6061-T6 aluminum alloy tubes with different diameter-to-thickness ratios and different round-hole diameters under pure bending creep. Theoretical analysis is compared with the experimental finding, it is shown that the theoretical formulation can simulate the experimental results reasonably.

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