Research Of Transmission Towers-lines System Model Updating

With the progress of science and technology,finite element model updating methods also has been developed rapidly.Because of the error of finite element model geometry,material properties and boundary conditions,many large projects require to use the technology of finite element model updating.Accurate finite element model which are obtained through model updating technology,can play a crucial role in design optimization,dynamic modification,damage detection,reliability analysis and other projects.Since the 1970 s,the finite element methods can be divided into three categories: a matrix type,parametric and model updating method based on neural network.The method based on parametric and sensitivity analysis has used most widely.In this paper,the method of Bayesian principle and sensitivity analysis are using to studied the finite element model updating technical.Taking a major transmission tower-line project as the background,to model the finite element model of an transmission tower-line system,and then the structural dynamic properties are computed.Doing sensitivity analysis for different parameters of bars,select the EA as a model updating parameter considering engineering experience.This paper develops a procedure for model updating based on Bayesian principles and sensitivity analysis,selecting frequency as the objective function,setting the initial target error,and modifying the finite element model.Study process is divided into two parts,one is the model updating for transmission Towers,and the other is the model updating for tower-line system.And set a mean of 5% and 10% of two target error and introduced CCABS value as convergence criteria for calculated.For the results of model updating,a method which limits the maximum range of change for correction parameter has been put forward.It can avoids some parameters change too much after updating,which leaves the model loses physical meaning.In the course of the study,the changing of parameters are limited to ±2%,±5%,±6%,±7%,±8%,±9%,±10% and ±20%,comparing the differences between different parameters limit of the correction result,and analyzing the reasons for these differences which combined with engineering experience.Finally,from the results of analysis,the achievement of this paper has a certain degree of value in engineering applications,however,this paper also explains there is a lot of follow-up work to finish and improvement in the last chapter.