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Investigation of Parametric Model Updating

Author: LiJian
Tutor: HongJiaZhen
School: Shanghai Jiaotong University
Course: General Mechanics
Keywords: Model Updating Finite Element Laser vibrometer Modal
CLC: O342
Type: Master's thesis
Year: 2007
Downloads: 502
Quote: 8
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Abstract

Based on the experimental data, the method of the finite element model updating. Since the 70s of the last century, the finite element model updating technology has been developing rapidly, and are widely used in the engineering field to improve the finite element model with experimental data, to improve the accuracy and reliability of the analysis of the finite element model. Model updating method can be divided according to the modified object matrix correction method and parameter correction method. Matrix-type correction correction object facing the cryptic physical problems in the correction for the finite element model of the system matrix; parameter Amendment Act mostly dependent on the results of the sensitivity analysis, sensitivity analysis is often making the wrong position modeling errors judge to modify the parameters of reasonable doubtful. Therefore, the finite element model updating methods still need further study. Currently, most of the parameters modify the law is mainly exposed to the following three issues: 1 unmeasured high-end part of the experiment, the correlation between the modified finite element model and experiment can not guarantee improved; 2, modify the physical parameters are not necessarily in line with the physical characteristics of the test object; 3, less efficient iterative calculation and divergence problem exists. Typically, the evaluation of the effects of the finite element model updating method is to analyze the frequency of the finite element calculation the modal correlation with experimental data, according to the model of the amendment to the above problems, that in the course of the study need to add two validation criteria: (1) with After the correction of low-level experimental data, not only relatively low-level data on the correlation, but also to compare the correlation in the \Modifying whether the physical characteristics of the correction target. In 2006, Hu et al proposed a parameter type to modify the new method: the orthogonal model - orthogonal modes (CMCM) method, the method without the need for sensitivity analysis and does not need to iterate better modeling error judgment a higher computational efficiency. This study found that there is a good correlation of the method in the finite element model with experimental data exist for solving difficult if not impossible to complete the correction calculation. In this regard, the paper proposes an improved method the (ICMCM Act). Through a number of typical numerical experiments to compare the the the CMCM method, ICMCM Act, the matrix correction method and business correction software FEMtools correction results verify the validity of the ICMCM. This article uses state-of-the-art laser vibrometer system vibration experiments on beam, board structure, to obtain a high accuracy of the experimental data, and use to compare ICMCM Act and FEMtools of software correction effect and correction results. The analysis shows that, the proposed ICMCM in this article can effectively improve the accuracy of the calculation of the dynamic characteristics of the finite element model, to modify the parameters of the physical characteristics of the actual objects. The first chapter describes the background and significance of the model updating engineering, developments in the field of domestic and international model updating so far, the objectives and content of this study. The second chapter describes the analysis of finite element model of reliability analysis methods, as well as the degrees of freedom to match the finite element model with experimental data. Comparison and preliminary study carried out by a numerical example. The third chapter describes several methods of model updating, including the the the CMCM law, FEMtools software, research CMCM method of defects and proposes an improved ICMCM law. Verified through numerical experiments law's validity ICMCM. The fourth chapter describes the amendment procedure of advanced laser vibrometer system as well as developed in this paper. Ready for model updating based on the experimental data. Chapter of the beam, board structure vibration testing laboratories and experimental data obtained correction ICMCM the law and FEMtools software effect. The results show that proposed in this paper ICMCM method can effectively improve the correlation of the finite element model with experimental data, reasonable and reliable parameter correction, in line with the physical characteristics of the test object.

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