本文選題：風(fēng)荷載　切入點(diǎn)：FLUENT　出處：《鄭州大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：風(fēng)荷載會(huì)對(duì)橋梁結(jié)構(gòu)的安全性和穩(wěn)定性造成重要的影響。渦激振動(dòng)是一種常見(jiàn)的風(fēng)致振動(dòng)現(xiàn)象，非常容易出現(xiàn)在阻尼小且細(xì)長(zhǎng)的結(jié)構(gòu)上，可能會(huì)引起結(jié)構(gòu)的疲勞損傷，并對(duì)交通安全造成一定的影響。目前結(jié)構(gòu)的發(fā)展方向是長(zhǎng)、細(xì)、柔和弱阻尼，因此需要研究結(jié)構(gòu)的渦激振動(dòng)問(wèn)題。 南京大勝關(guān)長(zhǎng)江大橋吊桿的長(zhǎng)度超過(guò)了50m，柔度很大，出現(xiàn)渦激振動(dòng)的可能性非常大。本文的主要工作是利用大型流體計(jì)算力學(xué)軟件FLUENT對(duì)該橋吊桿的氣動(dòng)性能進(jìn)行數(shù)值模擬，從而為渦激振動(dòng)的研究提供基礎(chǔ)。通過(guò)對(duì)升力系數(shù)、阻力系數(shù)和旋渦脫落圖的對(duì)比分析，，從長(zhǎng)方形、切角長(zhǎng)方形和圓角長(zhǎng)方形這三種參考截面中選擇出氣動(dòng)性能最優(yōu)的吊桿截面，從而達(dá)到減小風(fēng)致振動(dòng)影響的目的。 結(jié)合以上所做的工作并考慮實(shí)際工程情況，對(duì)單根和雙根切角長(zhǎng)方形截面吊桿的氣動(dòng)性能分別進(jìn)行數(shù)值模擬，并將兩種情況下得到結(jié)果進(jìn)行對(duì)比分析，找出最不利風(fēng)攻角的范圍和兩根桿件脫離相互干擾時(shí)的風(fēng)攻角值。本文通過(guò)以上工作得到以下結(jié)論： (1)隨著風(fēng)速的不斷增加，各截面吊桿所對(duì)應(yīng)的斯特羅哈數(shù)近似為一常數(shù)。 (2)隨著風(fēng)速的不斷增加，各截面吊桿的升力和阻力也是不斷增大的。 (3)從長(zhǎng)方形截面到切角長(zhǎng)方形截面再到圓角長(zhǎng)方形截面，發(fā)生渦激振動(dòng)時(shí)的起振風(fēng)速是在不斷減小的。 (4)在同一風(fēng)速情況下，從長(zhǎng)方形截面到切角長(zhǎng)方形截面再到圓角長(zhǎng)方形截面，升力系數(shù)、升力、阻力系數(shù)、阻力是不斷減小的。 (5)在有風(fēng)攻角情況下對(duì)單根切角長(zhǎng)方形截面桿件的氣動(dòng)性能進(jìn)行數(shù)值模擬，得到其最不利風(fēng)攻角出現(xiàn)在20°~25°之間。 (6)對(duì)雙根切角長(zhǎng)方形截面桿件的氣動(dòng)性能進(jìn)行數(shù)值模擬，并考慮風(fēng)攻角變化的影響，得到雙根桿件脫離相互干擾的風(fēng)攻角值大致為15°。
[Abstract]:Vortex-induced vibration is a common wind-induced vibration phenomenon, which is very easy to appear on the structure with small damping and slender length, which may cause fatigue damage of the bridge structure. At present, the development direction of the structure is long, fine, soft and weak damping, so it is necessary to study the vortex-induced vibration of the structure. The length of suspension rod of Nanjing Dashengguan Yangtze River Bridge is more than 50 m, the flexibility is very large, and the possibility of vortex-induced vibration is very high. The main work of this paper is to simulate the aerodynamic performance of suspension rod of the bridge by using the large-scale fluid computational mechanics software FLUENT. Through the comparative analysis of lift coefficient, drag coefficient and vortex shedding diagram, from the rectangle, In order to reduce the effect of wind-induced vibration, the optimal aerodynamic performance of suspender section is selected among the three reference cross-sections of tangent rectangle and circular rectangle. Combined with the above work and considering the actual engineering situation, the aerodynamic performance of single and double tangential rectangular section suspenders are numerically simulated, and the results obtained under the two conditions are compared and analyzed. Find out the range of the most unfavorable wind angle of attack and the wind angle of attack when the two bars are separated from each other. In this paper, the following conclusions are obtained from the above work:. 1) with the increasing of wind speed, the Sloan number corresponding to each section of the suspender is approximately a constant. 2) with the increasing of wind speed, the lifting force and resistance of each section of suspender are also increasing. (3) from rectangular section to tangent rectangle section to rounded rectangular section, the wind speed of starting vibration is decreasing when vortex-induced vibration occurs. 4) under the same wind speed, the lift coefficient, lift coefficient, resistance coefficient and resistance coefficient are decreasing continuously from rectangular section to tangent rectangle section to rounded rectangular section. 5) the aerodynamic performance of rectangular cross-section members with single tangent angle is numerically simulated under the condition of wind attack angle, and the most unfavorable wind attack angle appears between 20 擄and 25 擄. The aerodynamic performance of rectangular cross-section bar with double tangent angle is numerically simulated. Considering the influence of wind attack angle, the wind attack angle of double bar is about 15 擄.
【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：U441.3;U448.22

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本文編號(hào)：1569116