ORDER-REDUCED MODAL ANALYSIS BASED ON THE POD TECHNIQUE FORSPATIAL STRUCTURES UNDER WIND LOADING

摘要

With the rapid development of building materials and structural technology, spatial structures are becoming morernand more large-span and flexible. For the structural design of such spatial structures, wind load may be veryrnimportant since this structural system are relatively light, and they may be sensitive to the external loadrndistribution and the stability is usually an important, even dominant, problem. In a modal analysis of thernwind-induced vibration of these spatial structures, it has been reported that the contributions of several modes,rnbut not always the first several modes, would give dominant contribution to the whole response, which indicatesrnthat a higher-order modal analysis is necessary in wind-induced vibration of the structural systems. In this paper,rnan order-reduced model analysis strategy was presented based on the Proper Orthogonal Decomposition (POD)rntechniques, and the efficiency of the presented strategy was established through comparative analysis with therntraditional modal analysis method. The results show that, with this presented order-reduced model analysisrnmethod, the order of the final structural modal equation group can be effectively reduced due to the goodrnconvergences of both the POD modes of wind field on the surface of the structures and the nature vibrationrnmodes of the structures themselves. Meanwhile, the so-called important vibration modes can be selected outrnconveniently by considering the correlation of the structural vibration modes and the proper orthogonal modesrnextracted by the POD method from the wind pressure field. Finally, with a k6-12 single-layer reticulatedrnspherical shell as an example, the characteristics of the POD modes of the wind field on the surface of thernstructure was investigated by wind tunnel test of the rigid spherical shell model with a scale of 1:400, andrnnumerical comparison was carried out to show the good efficiency of the presented method in comparison withrnthe conventional approach in model analysis for the spatial structures.