Modeling And Simulation Research Of Vibration Tests On An Electrodynamic Vibration Generator

Finite element modeling and numerical calculations were carried out and the simulation technology of the sine-scan vibration test was investigated on a certain electrodynamic vibration generator, together with the clamp and the plate specimen designed by ourselves. Woks in this dissertation are shown as following.Firstly, the research progress of dynamics simulation technology was reviewed, and the background and significance of simulation technology on the vibration test were described. The development as well as the basic process of vibration generator simulation technology was introduced. According to the shortage of prevenient studies, the subject of this dissertation was determined.Secondly, the basic theory of vibration and numerical calculation methods frequently used in the finite element dynamic analysis were introduced. Lanczos method for computing large real-symmetric eigenvalue problems in a modal analysis was described in detail. The calculation methods for frequency response in MSC.Nastran were also introduced.Thirdly, the main structure of the electrodynamic vibration generator and its main working property were described. Based on the software MSC.Patran and MSC.Nastran, finite element modeling was carried out on the electrodynamic vibration generator itself. Method of modeling and the boundary conditions set were introduced. Then the model was updated repeatedly according to the modal test data of the vibration generator. The finally updated result shows that: the material parameters of each group of the vibration generator can reflect its real material properties, the total mass of each group is equal to its real mass, and moreover, the calculated mode results of the vibration generator are close to its modal test results that the maximum relative error is below 4 percent. The main modes of vibration were also analyzed according to the calculated mode results. The influence of structural damping coefficients on the peak value of the response of the vibration generator was investigated to determine the damping parameter according to the calculations of frequency response on the vibration generator. In the end, based on linear assumption, the simulation algorithm of the sine-scan vibration test was presented and the simulation was carried out on the updated modal of vibration generator. The results indicate that the simulation results are close to the experimental ones that the modal can be used for simulation of vibration test with attached structural members on it.Fourthly, the finite element modeling methods and experimental simulation technology were discussed and studied on the whole entity including the electrodynamic vibrationgenerator, the designed clamp and the designed plate specimen. The simulation procedures are that: (1) Finite element models of the clamp and the plate specimen were created and then updated according to their modal tests. (2) By proper boundary conditions and equivalence of nodes, the models of the electrodynamic vibration generator, the clamp and the plate specimen were joined together to form a new model, whose accuracy was verified by its modal test. (3) Calculation of frequency response on condition of constant amplitude sine-drive force was carried out on the whole new model. The sine-scan vibration test simulation on the whole model was accomplished by using the algorithm presented previously. (4) A real sine-scan vibration test was performed to verify the simulation results. The comparison shows that the simulation results is in accordance with the experimental results within lOOOHz, the simulation results provide favorable prediction to the dynamic property of the whole structure.Lastly, the dissertation was summarized and the research to be continued was put forward.