This page has only limited features, please log in for full access.
In this study, a practical method is proposed to predict the two-degree-of-freedom (2DOF) post-flutter behavior of a 5:1 rectangular section. For this method, a hybrid strategy in the time–frequency domain is introduced to obtain the time-history solution of the nonlinear coupled oscillator, and the nonlinear unsteady aerodynamic forces, described by the amplitude-dependent flutter derivatives, are considered as well as the other nonlinearities of the section model system, i.e., damping and stiffness. Moreover, wind tunnel tests are performed to validate the effectiveness of the proposed method. The numerical results show that the system may exhibit limit cycle oscillation (LCO) due to the aerodynamic and/or damping nonlinearities. Finally, this method is applied to predict the aeroelasticity of a continuum model and to analyse the parameter sensitivity.
Ruilin Zhang; Zhiwen Liu; Lianhua Wang; Zhengqing Chen. A practical method for predicting post-flutter behavior of a rectangular section. Journal of Wind Engineering and Industrial Aerodynamics 2021, 216, 104707 .
AMA StyleRuilin Zhang, Zhiwen Liu, Lianhua Wang, Zhengqing Chen. A practical method for predicting post-flutter behavior of a rectangular section. Journal of Wind Engineering and Industrial Aerodynamics. 2021; 216 ():104707.
Chicago/Turabian StyleRuilin Zhang; Zhiwen Liu; Lianhua Wang; Zhengqing Chen. 2021. "A practical method for predicting post-flutter behavior of a rectangular section." Journal of Wind Engineering and Industrial Aerodynamics 216, no. : 104707.
In recent years, stay cables on cable-stayed bridges have been equipped with various kinds of lamps to lighten the cables at night. Large amplitude vibration of the stay cables of the Kuimen Bridge was observed after some rectangular lamps were installed. The mechanism and countermeasure of the cable vibration of this bridge were investigated in this paper. First, wind-induced responses of six stay cables were extracted from a video observed in the field. Second, according to Den Hartog's theory, a series of force measurement wind tunnel tests on stay cable attached with a rectangular box were carried out to test the possibility of galloping. Third, a series of vibration measurement wind tunnel tests based on 2-dimensional and 3-dimensional test models were carried out to reproduce the vibration of the cable-lamp test model. In the test, the features of wind-induced vibration were studied at the damping level of 0.1%, 0.3%, 0.6% and the inclination angles of the stay cable include 25°, 35°, 40°, and 45°. The results show that the rectangular aluminum alloy box of the lamp on stay cables can result in the unstable galloping vibration at a very low wind velocity. The critical wind velocity of the cable-lamp test model can be as low as 6.3 m/s (damping ratio ζ = 0.1%), which is a wind velocity often encountered. It appears that the critical wind velocity increases with the increase of the structural damping ratio, but is only 9–11 m/s when the damping ratio is 0.6%. It seems that increasing the damping ratio has little effect on suppressing the galloping of the stay cable. Finally, the rectangular aluminum alloy box of the lamp was removed and only an electrical wire was attached on the cable surface. The vibration measurement wind tunnel tests based on the 3-dimensional cable-wire test model indicate that the stay cable attached with an electrical wire is aerodynamically stable if the position angle of the wire is 0°, which is consistent with the actual situation.
An Miao; Li Shouying; Liu Zhiwen; Yan Banfu; Li Longan; Chen Zhengqing. Galloping vibration of stay cable installed with a rectangular lamp: Field observations and wind tunnel tests. Journal of Wind Engineering and Industrial Aerodynamics 2021, 215, 104685 .
AMA StyleAn Miao, Li Shouying, Liu Zhiwen, Yan Banfu, Li Longan, Chen Zhengqing. Galloping vibration of stay cable installed with a rectangular lamp: Field observations and wind tunnel tests. Journal of Wind Engineering and Industrial Aerodynamics. 2021; 215 ():104685.
Chicago/Turabian StyleAn Miao; Li Shouying; Liu Zhiwen; Yan Banfu; Li Longan; Chen Zhengqing. 2021. "Galloping vibration of stay cable installed with a rectangular lamp: Field observations and wind tunnel tests." Journal of Wind Engineering and Industrial Aerodynamics 215, no. : 104685.
In recent years, high-mode vortex-induced vibration (VIV) of stay cables has been observed in some cable-stayed bridges. It can cause undue stress and fatigue in the anchorages at the deck and/or pylons and in the cables themselves. In this study, experimental investigations were performed to characterise and control the high-mode VIV of stay cables by using horizontal- and inclined-rigid-stay-cable models. First, wind tunnel tests using the horizontal-rigid-dimpled-stay-cable model were performed to investigate the VIV characteristics of dimpled stay cables and effective VIV suppression measures. Wind tunnel tests were then conducted on an inclined rigid dimpled cylinder with and without helical fillets to investigate further the VIV characteristics of dimpled stay cables and effective suppression measures. Finally, stay-cable field measurements were made for comparison with the experimental results of the stay-cable model. The results show that stay-cable VIV can occur in cases of low damping, and the VIV of the stay cable can be effectively suppressed by increasing the damping ratio of the stay cable. Moreover, helical fillets with a diameter of d = 2.0 or 3.5 mm, which are usually used to control rain–wind induced vibration of stay cables in cable-stayed bridges, cannot effectively suppress the high-mode VIV responses of stay cables. The inclined-dimpled-stay-cable model with a damping ratio of 0.2 % at inclination angles of 25° and 40° exhibits significant VIV for the cases of wind yaw angles of 0°, 15°, -15°, and -30°. However, helical fillets with d = 10 mm (d = 0.07D, where D is the diameter of the stay cable) and pitch of 12D can effectively suppress the VIV responses of the stay cables.
Zhiwen Liu; Jingsi Shen; Shuqiong Li; Zhengqing Chen; Qingbao Ou; Dabo Xin. Experimental study on high-mode vortex-induced vibration of stay cable and its aerodynamic countermeasures. Journal of Fluids and Structures 2020, 100, 103195 .
AMA StyleZhiwen Liu, Jingsi Shen, Shuqiong Li, Zhengqing Chen, Qingbao Ou, Dabo Xin. Experimental study on high-mode vortex-induced vibration of stay cable and its aerodynamic countermeasures. Journal of Fluids and Structures. 2020; 100 ():103195.
Chicago/Turabian StyleZhiwen Liu; Jingsi Shen; Shuqiong Li; Zhengqing Chen; Qingbao Ou; Dabo Xin. 2020. "Experimental study on high-mode vortex-induced vibration of stay cable and its aerodynamic countermeasures." Journal of Fluids and Structures 100, no. : 103195.
The present wind tunnel study focuses on the effects of the steady-suction-based flow control method on the flutter performance of a 2DOF bridge deck section model. The suction applied to the bridge model was released from slots located at the girder bottom. The suction rates of all slots along the span were equal and constant. A series of test cases with different combinations of suction slot positions, suction intervals, and suction rates were studied in detail for the bridge deck model. The experimental results showed that the steady-suction-based flow control method could improve the flutter characteristics of the bridge deck with a maximal increase in the critical flutter speed of up to 10.5%. In addition, the flutter derivatives (FDs) of the bridge deck with or without control were compared to investigate the fundamental mechanisms of the steady-suction-based control method. According to the results, installing a suction control device helps to strengthen aerodynamic damping, which is the primary cause for enhanced flutter performance of bridge decks.
Jian Zhan; Hongfu Zhang; Zhiwen Liu; Huan Liu; Dabo Xin; Jinping Ou. Steady-Suction-Based Flow Control of Flutter of Long-Span Bridge. Applied Sciences 2020, 10, 1372 .
AMA StyleJian Zhan, Hongfu Zhang, Zhiwen Liu, Huan Liu, Dabo Xin, Jinping Ou. Steady-Suction-Based Flow Control of Flutter of Long-Span Bridge. Applied Sciences. 2020; 10 (4):1372.
Chicago/Turabian StyleJian Zhan; Hongfu Zhang; Zhiwen Liu; Huan Liu; Dabo Xin; Jinping Ou. 2020. "Steady-Suction-Based Flow Control of Flutter of Long-Span Bridge." Applied Sciences 10, no. 4: 1372.
To study wind characteristics over mountainous terrain, the Xiangjiang Bridge site was employed in this paper. The improved boundary transition sections (BTS) were adopted to reduce the influence of “artificial cliffs” of the terrain model on the wind characteristics at the bridge site over the mountainous terrain. Numerical simulation and experimental investigations on wind characteristics over mountainous terrain with/without BTS were conducted for different cases, respectively. The research results show that the cross-bridge wind speed ratios and wind attack angles at the main deck level vary greatly along the bridge axis, which can be roughly divided into three parts, namely the mountain (I, III) and central canyon areas (II). The cross-bridge wind speed ratios at the main deck level with BTS is generally larger than that without BTS in the central canyon area (II) for most cases, while the opposite trend can be found in wind attack angles. The longitudinal wind speed ratios of the terrain model with BTS at L/4, L/2, and 3L/4 of the bridge length are larger than that of the terrain model without BTS for most cases. In general, the maximum relative error between numerical results and experimental results is about 30% for most cases.
Xiangyan Chen; Zhiwen Liu; Xinguo Wang; Zhengqing Chen; Han Xiao; Ji Zhou; Chen. Experimental and Numerical Investigation of Wind Characteristics over Mountainous Valley Bridge Site Considering Improved Boundary Transition Sections. Applied Sciences 2020, 10, 751 .
AMA StyleXiangyan Chen, Zhiwen Liu, Xinguo Wang, Zhengqing Chen, Han Xiao, Ji Zhou, Chen. Experimental and Numerical Investigation of Wind Characteristics over Mountainous Valley Bridge Site Considering Improved Boundary Transition Sections. Applied Sciences. 2020; 10 (3):751.
Chicago/Turabian StyleXiangyan Chen; Zhiwen Liu; Xinguo Wang; Zhengqing Chen; Han Xiao; Ji Zhou; Chen. 2020. "Experimental and Numerical Investigation of Wind Characteristics over Mountainous Valley Bridge Site Considering Improved Boundary Transition Sections." Applied Sciences 10, no. 3: 751.