Structural Performance Perception Methods Based On Monitoring Data And Multi-Scale Simulation

Main means of structural performance perception include theoretical method,laboratory test,model analysis and structural health monitoring.However,theoretical method is difficult to achieve the understanding of large and complex structure;laboratory test is difficult to grasp the behavior of structure in real conditions;model analysis has the problems of simulation accuracy and analysis error.In view of the above technical difficulties,structural health monitoring directly and truly reflects the stress state and workin g performance of the real structure through measured response,but limited number and location of sensors limit the completeness of the acquisition of response,and the understanding of the details of the key parts.Simutaneously,structural multi-scale model can fully obtain all kinds of responses,and grasp the performance of whole structure and key parts.Therefore,it is necessary to take the advantages of structural health monitoring and multi-scale model to develop structural performance perception methods.In this dissertation,the mixed-dimensional coupling method and updating method of structural multi-scale model are studied firstly,and then the structural performance is percepted based on the updated structural multi-scale model;on the other hand,based on the monitoring data,the separation method of measured response and the state perception method of structural component are studied,respectively.The main research works of the dissertation are as follow:Considering that the simplified stress distribution will reduce the calculation accuracy and reliability of the structural multi-scale model,mixed-dimensional coupling method based on the refined stress distribution pattern is proposed.The establishing method of the stress distribution calculation model is given,the determination method of the mapping relationship between the nodal stresses and coordinates on the intermediate section is proposed;and then,the coefficient of determination is used as the evaluation index of goodness of fit,the mapping relationship is optimized by iterative calculation,the refined stress distribution pattern is given;combined with the element shape function,the coupling between different dimensional elements at the connected interface is realized.By the numerical simulation tests on the member level and structural level,the effectiveness of the proposed method is verified.The finite element model used for performance perception should have the ability to accurately reflect the multi-type responses on global scale and local scale of the structure.To this end,structural multi-scale model updating based on multi-objective and multi-parameters is propsed.Based on orthogonal test and joint hypothesis test,a global sensitivity analysis method of parameters is given to screen the significant parameters.Defining the structural multi-type responses as the objectives,the approximate model between each objective and its significant parameters is established based on Kriging spatial interpolation technique,and the simulation values of responses are obtained;according to the error function between the simulated response and measured response,sub-objectives that reflect the global and local characteristics of the structure are constructed;simultaneously,the value ranges of parameters are limited,multi-scale model updating is equivalent to a multi-objective optimization problem with constraints;the NSGA-II is used to determine the optimal solution of parameters,and then the multi-scale updated model for performance perception is obtained.The effectiveness of the proposed method is verified by updating the multi-scale model of the warren truss structure.Combined with the simulation of the structural operational loads,the method of performance perception based on multi-scale updated model is proposed.Taking the actual project of the Zhuhai Opera House as an example,the performance perception of the large shell structure is carried out.By considering the stress measuring points arrangement,the local refined model of the related structural components is established,the global simplified model of the remaining components is established;for the different box section,the corresponding refined stress distribution patterns are given,then the mixed-dimensional coupling of the local and global models is realized,the initial multi-scale model is established.The natural frequency and stress response are used as the global scale and local scale updating objectives,the multi-scale updated model is obtained by updating the initial model.Based on it,combined with the actual load conditions,the response of the position that is not installed sensor is perceived,the complete acquisition of various types of response is realized.Considering the variable environmental loads during the operation period,the change of force state and stress level of the structure are perceived.In order to understand the influence of different loads on the structural response,a separation method of measured response based on the Variatio nal Mode Decomposition is proposed.According to the multi-time scale characteristics of the measured response,the boundary frequency of the slow-varying temperature response and transient load response is determined;using the estimated bandwidth of each response component function,a constrained variational model based on the sum of which is established;combined with the alternating direction multiplier method,the synchronous solving of each response component function is realized,the optimal solution corresponding to the minimization of the constrained variational model is obtained,and then the synchronous and nonlinear separation of the temperature effect and wind effect are completed.Furthermore,the feasibility of the proposed method is verified by separating the measured stress under typhoon.In order to effectively identify the early deterioration and local small damage of the structure,and to clarify the effect of temperature on assessment index,a state perception method of structural component based on the separation of measured stress response is proposed.The expression of strain response based on the unit impulse response function and external excitation function is derived,and then the expression of cross-correlation function of any two strain measuring points is obtained;one strain measuring point is selected as reference point,the cross-correlation functions between the other points and reference point are calculated,the vector based on the absolute amplitude of which is constructed.Considering the fixed modulus between stress and strain monitoring data,and the unit impulse response function is only related to the structural natural characteristics,a state perception index based on the residual error of amplitude vector is given.Finally,based on the separated wind effect,the state changes of component during the operation period is accurately perceived;based on the raw measured stress,the effect of temperature on assessment result is clarified.