風機鋼管圓柱在彎矩與軸力作用下之行為:實驗與有限元素分析

Behavior of Wind Turbine Hollow Steel Round Columns under Bending Moment and Axial Load:Experiment and Finite Element Analysis

謝承翰(Cheng-Han Hsieh)

指導教授 ： 周中哲

國立臺灣大學/工學院/土木工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202102880

摘要

由於再生能源在國際間逐漸受到重視，其中風力發電為我國發展重點，作為風力發電機的主要結構，對於中空鋼管圓柱(Round-HSS)的研究就顯得十分重要，然而相關研究文獻較為缺乏，且主要聚焦於低斷面徑厚比的撓曲強度試驗，因此本研究共製造了1座試體，材料使用JIS SS400，試體斷面徑厚比為360，試體外直徑為1440 mm、試體總高度為5305 mm，進行單曲率反覆側推試驗，並會將郭泯辰 (2019)、劉琨耀 (2020)的研究結果納入本研究進行比較與討論。比較試驗結果可以發現，試體韌性μ隨著試體徑厚比D/t的增加而略微下降，但部分試體會由於初始局部挫屈較早發生，導致受壓側管壁支撐力不足，使得試體韌性μ略微上升介於1.28~1.95，並使試體強度上升幅度有限，產生正負迴圈試體強度不對稱。接著討論各國規範對於撓曲強度的預測，AISC (2016)會隨著試體徑厚比的增加偏向低估，ASME (2016)、ASCE (2011)皆為低估，EN1993-1-6 (2017)與試體結果趨勢較為一致，JRA (2002)與試體結果趨勢較為一致但較為高估。最後利用有限元素分析軟體ABAQUS建立模型，討論模型對於施加不同軸力的情況下，對鋼管圓柱模型撓曲強度的影響，其結果顯示，施加0.05Py軸力的模型最大強度下降5 %~6 %，施加0.20Py軸力的模型最大強度下降22 %~25 %，軸力比例小幅度影響彈性勁度與韌性，而各國規範對於折減後撓曲強度的預測，ASME (2016)、ASCE (2011)皆為低估，AISC (2016)、EN1993-1-6 (2017)、JRA (2002)相較準確，但皆隨著斷面徑厚比的增加偏向保守，並隨著模型軸壓比例的增加使低估現象逐漸明顯。

關鍵字

風機塔柱 ； 中空鋼管圓柱 ； 反覆測推試驗 ； 撓曲強度 ； 有限元素分析

並列摘要

As renewable energy is gradually valued internationally, wind turbines are becoming an important source of clean energy. Due to this, more research is being conducted on the round-hollow steel section (Round-HSS) as it serves as an important part of the wind turbine. The focus of past studies has been on the flexural strength test of Round-HSS tubes with a low cross-sectional diameter-to-thickness ratio (D/t). However, the relevant research literature on Round-HSS tubes with a large cross-sectional diameter-to-thickness ratio (D/t) is lacking. In this research, a Round-HSS steel tube specimen was manufactured and tested in this study made from JIS SS400 steel, of diameter-to-thickness ratio equal to 360, 1440 mm in diameter, and 5.305 m in total height, which was tested under increasing cyclic load. Research results from Guo (2019) and Liu (2020) are also included in this study for comparison and discussion with previous tests. The results showed that, if initial local buckling occurs near peak, then the ductility (μ) of the specimen decrease 5 % with the increase in diameter-to-thickness ratio (D/t) of the specimen. But, if the initial local buckling occurs earlier before peak, then the ductility (μ) of the specimen is increased slightly between 1.28~1.95, and the strength of the specimen is limited, also resulting in the asymmetry of the strength in the positive and negative loop of the specimen. A comparison of the prediction of flexural strength by national specifications is also done in this study. It was found that AISC (2016) tends to underestimate with the increase in diameter-to-thickness ratio of the specimens, ASME (2016) and ASCE (2011) underestimated its flexural strength, EN1993-1-6 (2017) tends to be more consistent, and JRA (2002) tends to overestimate the flexural strength with increase in the diameter-to-thickness ratio of the specimens. Finally, finite element analysis was conducted using ABAQUS in which a model of Round HSS tube was established, and the influence of the model on the flexural strength under different axial loads was discussed. The results showed that the maximum strength of the model with 0.05Py and 0.20Py axial load was reduced by 5%~6% and 22%~25% respectively. The amount of axial load ratio slightly affect the elastic stiffness and ductility of the tube. However, the prediction of flexural strength after reduction in national specifications from ASME (2016) and ASCE (2011) were too conservative, AISC (2016), EN1993-1-6 (2017), and JRA (2002) tend to be conservative with an increase in the diameter-to-thickness ratio of the section, and this underestimation becomes more severe with the increase in axial load ratio.

並列關鍵字

Wind turbine column ； Round-HSS section ； Cyclic test ； Flexural strength ； Finite element analysis

參考文獻

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