試驗模態(tài)分析系統(tǒng)的設計與開發(fā).pdf

1、華中科技大學碩士學位論文試驗模態(tài)分析系統(tǒng)的設計與開發(fā)姓名：陳川申請學位級別：碩士專業(yè)：機械電子工程指導教師：軒建平20090521華 中 科 技 大 學 碩 士 學 位 論 文 華 中 科 技 大 學 碩 士 學 位 論 文 IIAbstract Experiment modal analysis is a process to establish mathematic model of describing structure

2、9;s vibration characteristic based on experiment. It provides a method to find out the dynamic's characteristics of mechanical structure. And it plays an important role in mechanical structural designing and modifyin

3、g. From the basis of the theories of modal analysis, the paper has done some research on the frequency-domain modal parameter identification methods, and focuses on the parameter identification method of orthogonal polyn

4、omial curve fitting based on the frequency response function. In order to improve the accuracy of parameter identification, the paper analyses the influence of the noise on the calculation of frequency response function.

5、 Through the creation of simulation models the paper has verified the accuracy of the algorithm, at the same time, has compared the accuracy of the overall curve fitting with the accuracy of the sub-band curve fitting, i

6、n order to provide algorithms for the software development. Based on the principles and steps of the experiment modal analysis, the experiment modal analysis system is designed and developed by object-oriented programmin

7、g language Visual C ++. The software is divided into four modules: data acquisition module, database module, frequency response function calculation module, parameter identification module. Data acquisition module contro

8、ls NI-9233 data acquisition card to acquire data simultaneously and displays the real-time data. Database module saves the data using the ACCESS database. Frequency response function calculation module and parameter iden

9、tification module provide the orthogonal polynomial curve fitting algorithm for parameter identification using C++ and Matlab mixed programming method. In the industrial field and laboratory structure modal the effective

10、ness of the experimental modal analysis system is verified. In order to verify the accuracy of the experiment modal analysis system, the paper identifies modal parameters using the test data of the water injection pipeli

11、ne in Tuha Oil Province of China National Petroleum Corporation, compares with the analysis results of the professional software-ME'scopeVES, and proves that they are basically agreed. Finally, the cracked beam modal

12、 testing has been done to acquire natural frequency, damping ratio and residue of the cracked beam. Key words: experimental modal analysis, frequency response function, orthogonal polynomial method, data acquisition, C++