Experimental and numerical investigations on the influence of center-hung scoreboard on dynamic characteristics of suspend-dome structure

Abstract

The LED display, i.e., the center-hung scoreboard, nowadays has become an indispensable display device in large stadiums, and some of which with weight is more than 30t. To investigate the influence of center-hung scoreboard load on the dynamic characteristics of the suspend-dome structure, a 1:20 dynamically scaled model of the Lanzhou Olympic Sports Complex was designed, considering different lifting-lowering heights of the center-hung scoreboard by changing the sling length. Shaking table dynamic characteristics experiment was conducted by using the white noise excitation method for the suspend-dome structure with the sling lengths of 200 mm, 400 mm, and 600 mm individually. The change rule of dynamic characteristic parameters such as natural frequencies and damping ratios was concluded by the Hilbert-Huang Transformation method for modal identification and the transfer function method for checking. With the increase of sling length, the natural frequencies of the center-hung scoreboard become smaller, and the damping ratios become more extensive. Compared with the results of the scaled model without a center-hung scoreboard, the high-order natural frequencies and damping ratios of the overall structure with the center-hung scoreboard are significantly increased, and the coupling effect between the center-hung scoreboard and the structure should not be ignored in the dynamic analysis. The test values were compared with the simulation results of Abaqus as well. It is shown that the test values of the scaled model are essentially consistent with the simulation results, which indicates that the test points are reasonably arranged, the test method is correct, and the finite element modeling method is accurate. The effects of sling stiffness and sling length on the dynamic characteristics of the suspend-dome structure were studied by Abaqus software. The results show that the sling stiffness hardly affect the dynamic characteristics of the overall model. When the sling length is less than 300 mm, the lifting-lowering of the center-hung scoreboard influences the distribution of the natural frequency and the vibration mode of the overall structure. In this range, the lifting-lowering of the center-hung scoreboard should be focused on actual engineering.