Research On Dynamic Model Updating Technology For Complex Structures Based On Response Surface Methodology

Due to the difficulty of prototype test or model test for complex structures during the period of design, construction and maintenance, anaylysis based on computing model is a common alternate method to achieve the mechanical properties of the complex structures. But differences are offen found between the initial computing model, which is built based on the specifications and the experiences of the engineers, and the prototype because of the suppositions in the modeling process. The differences may lead to analysis errors. It indicates that the initial computing model must be modified or updated to fit the analysis request, or make the computing model corresponding to the real conditions.Based on the review on the development and current research of structure dynamic model updating technology, the paper points out that traditional model based on numerical correction method did not take into account the complexity of the problem, limited solved method just in classical mechanics principle and finally entrapped in trouble of numerical calculation. Model updating based on statistical analysis has made a rapid progress in recent years. Although it has given into consideration the complexity of problem, obtained typical samples by means of experiment and employed analysis results as sample in order to make agreement between calculated results and actual ones, it did not make full use of prior infor-mation and excessively depended on analysis technology which leads to indefinite physical meaning of the modified model.This paper argues that not only basic classical mechanics but also complexity play roles in solving complicated structure issue. Complexity hidden in the stream of data, which makes model updating technology face to. The authentic, reliable update results can be achieved only if the relationship between mathematical and physical principles, the laws of statistics and the prior (posterior) information should be given into account during the process of modification model for complicated structure.(1) Put forward that dynamic correction for complex structures should be aimed at spe-cific structure rather than modification techniques which meet all structures, so as to make full use of prior information of this structure to reach and ensure solutions’feasibility and stability and ensure solution.(2) Propose that complex structure should be established on an equivalent fast runnig parameter model for dynamic model modification and use response surface method rather than base on finite element model of the mass matrix, stiffness matrix.(3) Come up with response surface methodology based on structure mechanics equa-tions and dimensional analysis principle to improve the application of traditional response surface method in model modification for complex structure and attempt to make the re-sponse surface function form closer to the real structure of the mechanism model.(4) Propose that complex structure model modification method based on statistical learn- ing theory. Apply the latest results-support vector machine (SVM) model into parameter calculation in the process of complex structure modification and avoid numerical calculation difficulty in traditional model and the dimension disasters and over-fitting problems in neural network method as well.(5) Explore the feasibility and approaches of support vector machine (SVM) in com-plex structure model modification. Apply and implement the theory into the model modifi-cation process of an actual complicated structure-an underground powerhouse structure in a pumped storage power station.