Some Study Of Model Updating Based On Sensitivity Analysis And Its Realization

Precise finite element model play a key role in modern structure design and it can be service for Model Updating of FEM is a new technology about structure dynamic design and plays an important role in prediction of dynamics response, etc. In this technology, model updating based on sensitivity analysis is more usable. In this thesis, this project is researched and the content is as follow:When an axis-symmetric structure is taken for correlation analysis, there may be a bad phenomenon named"phase error", why and how to solve this is discussed. Theory of model updating based on sensitivity analysis is analyzed and how to implementation is also shown. Meanwhile, the general method how to get the sensitivity coefficient and error of modal parameter is introduced.Some key questions of model updating are studied in this dissertation. Two method of updating parameter's definition, one is direct definition and another is indirect definition are investigated and the advantage and disadvantage of them are shown. A regularization method is discussed. Some methods of weighted function are studied to improve the condition of sensitivity matrix.One model updating software, N-Updating who is based on general software- Nastran and MatLab is developed. With the above theory study, this software makes use of Nastran function of FEM and sensitivity analysis, mathematics calculation of MatLab, to realize the technology of model updating. Meanwhile, this software also has the functions of correlation analysis and sensitivity analysis. With the use of N-Updating, an environmental vibration experiment clamp's finite element model is built and updated. The result shows that this study has engineering value...