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RISS 인기검색어
- 검색키워드
- 저자 : Shouke Li (검색결과 4 건)
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Numerical study on the mitigation of rain-wind induced vibrations of stay cables with dampers
Li, Shouying,Wu, Teng,Li, Shouke,Gu, Ming Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.6
Although the underlying mechanism of rain-wind induced vibrations (RWIVs) of stay cables has not been fully understood, some countermeasures have been successfully applied to mitigating this kind of vibration. Among these, installing dampers near the bridge deck was widely adopted, and several field observations have shown its effectiveness. In this study, the effectiveness of dampers to RWIVs of stay cables is numerically investigated comprehensively by means of finite difference method (FDM). Based on the free vibration analysis of a taut string, it is found that the 3-points triangle scheme, which can be easily implemented in FDM, can offer an excellent approximation of the concentrated damping coefficient (expressed as a Dirac delta function) at the location where the damper is installed. Then, free vibration analysis of a 3-D continuous stay cable attached with two dampers is carried out to study the relationship of modal damping ratio and damping coefficient of the dampers. The effects of orientation of the dampers and cable sag on the modal damping ratio are investigated in detail. Finally, the RWIV response of a 3-D continuous stay cable attached with two dampers is examined. The results indicate that 0.5% of damping ratio is sufficient to reduce the RWIV vibration of the Cable A20 on the No.2 Nanjing Bridge over Yangtze River.
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Li, Shouying,Chen, Zhengqing,Li, Shouke Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5
A new theoretical model on rain-wind induced vibration (RWIV) of a continuous stay cable is developed in this paper. Different from the existing theoretical analyses in which the cable was modeled as a segmental rigid element, the proposed scheme focuses on the in-plane and out-of-plane responses of a continuous stay cable, which is identical with the prototype cable on cable-stayed bridge. In order to simplify the complexities, the motion law of the rivulet on the cable surface is assumed as a sinusoidal way according to some results obtained from wind tunnel tests. Quasi-steady theory is utilized to determine the aerodynamic forces on the cable. Equations of motion of the cable are derived in a Cartesian Coordinate System and solved by using finite difference method to obtain the in-plane and out-of-plane responses of the cable. The results show that limited cable amplitudes are achieved within a limited range of wind velocity, which is a unique characteristic of RWIV of stay cable. It appears that the in-plane cable amplitude is much larger than the out-of-plane cable amplitude. Rivulet frequency, rivulet distribution along cable axis, and mean wind velocity profile, all have significant effects on the RWIV responses of the prototype stay cable. The effects of damping ratio on RWIVs of stay cables are carefully investigated, which suggests that damping ratio of 1% is needed to well mitigate RWIVs of prototype stay cables.
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Numerical study on the mitigation of rain-wind induced vibrations of stay cables with dampers
Shouying Li,Teng Wu,Shouke Li,Ming Gu 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.6
Although the underlying mechanism of rain-wind induced vibrations (RWIVs) of stay cables has not been fully understood, some countermeasures have been successfully applied to mitigating this kind of vibration. Among these, installing dampers near the bridge deck was widely adopted, and several field observations have shown its effectiveness. In this study, the effectiveness of dampers to RWIVs of stay cables is numerically investigated comprehensively by means of finite difference method (FDM). Based on the free vibration analysis of a taut string, it is found that the 3-points triangle scheme, which can be easily implemented in FDM, can offer an excellent approximation of the concentrated damping coefficient (expressed as a Dirac delta function) at the location where the damper is installed. Then, free vibration analysis of a 3-D continuous stay cable attached with two dampers is carried out to study the relationship of modal damping ratio and damping coefficient of the dampers. The effects of orientation of the dampers and cable sag on the modal damping ratio are investigated in detail. Finally, the RWIV response of a 3-D continuous stay cable attached with two dampers is examined. The results indicate that 0.5% of damping ratio is sufficient to reduce the RWIV vibration of the Cable A20 on the No.2 Nanjing Bridge over Yangtze River.
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Kang Yang,Ying Tang,Huayu Xue,Xiaoyue Ji,Fu-Liang Cao,Shouke Li,Li Xu 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.1
Yellow horn (Xanthoceras sorbifolia Bunge) contained abundant linoleic acid (LA), accounting for about 44% of its lipid. Here, LA was enriched by low temperature crystallization followed by urea complexation, and the optimal enrichment conditions were optimized with response surface methods (3:1 ratio of EtOH/FFA, crystallization at − 25 °C for 24.5 h; 2:1 ratio of urea/FFA1, 6.6:1 ratio of EtOH/urea, crystallization at − 10 °C for 22.4 h). Under these conditions, the final LA content and recovery were 97.10% and 62.09%, respectively. In vitro hypoglycemic studies suggested that the LA extract with stronger inhibition on α-glucosidase and lower one on α-amylase than acarbose exhibited a positive control for carbohydrate digestion with lower adverse effects. The enzyme kinetics and Lineweaver–Burk plots analyses revealed a reversible competitive inhibition on α-amylase and α-glucosidase. The findings of this research provided insights for the development of the LA extract as the functional component of health food.
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