Finite element model updating for space truss structure by fuzzy pattern identification

Taking the roof space truss structure of Shenzhen Citizen Center as the engineering background, a novel finite element model updating method for the large space steel truss structure is proposed in the paper. Among all the components, the numerical model's accuracy depends on the joint rigidity of the nodes. Thus the main purpose of updating is to determine the proper joint rigidity of all nodes. The process is conducted as following: Firstly, nodes are classified according to their size and rigidity, and then by changing joint rigidity parameters of different types of nodes and utilizing finite element method, the database which reflects the relationship between joint rigidity parameters and natural vibration frequencies of model is established. Secondly, structural natural vibration frequencies are selected as the input, and joint rigidity parameters of classified nodes are the output data, the fuzzy pattern system is obtained. Finally, the measured natural vibration frequencies of the roof structure of Shenzhen Citizen Center are inputted into the fuzzy pattern identification system, and then rigidity parameters of three categories of joint are determined. Thus, accurate finite element model of the roof space truss structure of Shenzhen Citizen Center is achieved.