To reduce the wind-induced drag and improve the wind-resistance performance of a high-rise building, steady suction control is introduced into the building structure. Based on validation of the numerical methods by ex...To reduce the wind-induced drag and improve the wind-resistance performance of a high-rise building, steady suction control is introduced into the building structure. Based on validation of the numerical methods by experiment with suction control over the flow separation of a 3D backward-facing step, the Reynolds stress equation model is used to investigate the drag reduction (DR) properties of a high-rise building whose side faces are controlled by all-height suction. Effects of the orifice geometrical parameters and suction flux parameters on the DR and the separation control are analyzed, and the detailed flow fields are shown to clarify the mechanism of suction control. The results indicate that suction control is very effective in reducing the wind loads on the high-rise building model, and only the dimensionless suction flux dominates. Lastly, the power consumed and the counterforce induced by suction are discussed, the suction models become the "zero-drag" model under certain suction angles.展开更多
A bio-inspired suction cup actuated by shape memory alloy(SMA)for miniature wall climbing robots is developed based on studying characteristics of biological suction apparatus.Some fast control strategies are introduc...A bio-inspired suction cup actuated by shape memory alloy(SMA)for miniature wall climbing robots is developed based on studying characteristics of biological suction apparatus.Some fast control strategies are introduced to improve negative pressure response.Theoretic model of the suction cup is built,and simulation and experiments results indicate the effectiveness of the fast control strategies.The largest negative pressure of the suction cup can reach 14 000 Pa,and its generating and cancelling just need 5 s.Research results indicate the suction cup can be used as an adhesion mechanism for miniature wall climbing robots.展开更多
This paper presents a series of monotonically combined lateral loading tests to investigate the bearing capacity of the MSCs （modified suction caissons） in the saturated marine fine sand. The lateral loads were appl...This paper presents a series of monotonically combined lateral loading tests to investigate the bearing capacity of the MSCs （modified suction caissons） in the saturated marine fine sand. The lateral loads were applied under load- and displacement-controlled methods at the loading eccentricity ratios of 1.5, 2.0 and 2.5. Results show that, in the displacement-controlled test, the deflection-softening behavior of load-deflection curves for MSCs was observed, and the softening degree of the load-deflection response increased with the increasing external skirt length or the decreasing loading eccentricity. It was also found that the rotation center of the MSC at failure determined by the load-controlled method is slightly lower than that by the displacement-controlled method. The calculated MSC capacity based on the rotation center position in serviceability limit state is relatively conservative, compared with the calculated capacity based on the rotation center position in the ultimate limit state. In the limit state, the passive earth pressures opposite the loading direction under load- and displacement-controlled methods decrease by 46% and 74% corresponding to peak values, respectively; however, the passive earth pressures in the loading direction at failure only decrease by approximately 3% and 7%, compared with their peak values.展开更多
基金Project (No. 59895410) supported by the National Natural Science Foundation of China
文摘To reduce the wind-induced drag and improve the wind-resistance performance of a high-rise building, steady suction control is introduced into the building structure. Based on validation of the numerical methods by experiment with suction control over the flow separation of a 3D backward-facing step, the Reynolds stress equation model is used to investigate the drag reduction (DR) properties of a high-rise building whose side faces are controlled by all-height suction. Effects of the orifice geometrical parameters and suction flux parameters on the DR and the separation control are analyzed, and the detailed flow fields are shown to clarify the mechanism of suction control. The results indicate that suction control is very effective in reducing the wind loads on the high-rise building model, and only the dimensionless suction flux dominates. Lastly, the power consumed and the counterforce induced by suction are discussed, the suction models become the "zero-drag" model under certain suction angles.
基金National Science and Technology Foundations of China(No.61075086,No.60875058)the Hi-Tech Research and Development Programof China(863 Program)(No.2009AA04Z221)
文摘A bio-inspired suction cup actuated by shape memory alloy(SMA)for miniature wall climbing robots is developed based on studying characteristics of biological suction apparatus.Some fast control strategies are introduced to improve negative pressure response.Theoretic model of the suction cup is built,and simulation and experiments results indicate the effectiveness of the fast control strategies.The largest negative pressure of the suction cup can reach 14 000 Pa,and its generating and cancelling just need 5 s.Research results indicate the suction cup can be used as an adhesion mechanism for miniature wall climbing robots.
基金supported by the National Natural Science Foundation of China(Grant Nos.51379118 and 51639002)SDUST Scientific Found(Grant No.2015KYTD104)
文摘This paper presents a series of monotonically combined lateral loading tests to investigate the bearing capacity of the MSCs （modified suction caissons） in the saturated marine fine sand. The lateral loads were applied under load- and displacement-controlled methods at the loading eccentricity ratios of 1.5, 2.0 and 2.5. Results show that, in the displacement-controlled test, the deflection-softening behavior of load-deflection curves for MSCs was observed, and the softening degree of the load-deflection response increased with the increasing external skirt length or the decreasing loading eccentricity. It was also found that the rotation center of the MSC at failure determined by the load-controlled method is slightly lower than that by the displacement-controlled method. The calculated MSC capacity based on the rotation center position in serviceability limit state is relatively conservative, compared with the calculated capacity based on the rotation center position in the ultimate limit state. In the limit state, the passive earth pressures opposite the loading direction under load- and displacement-controlled methods decrease by 46% and 74% corresponding to peak values, respectively; however, the passive earth pressures in the loading direction at failure only decrease by approximately 3% and 7%, compared with their peak values.
