| The aero-engine working environment is harsh and the working condition is complex,which puts forward extremely high requirements for its accessories.As a typical high-integration aero-engine accessory,fuel pump regulator plays an significant role in the control system,and its undependability endangers the flight safety of the aircraft at first hand.Under the flight circumstance,the fuel pump regulator is subject to the vibration,friction,etc.caused by engine casing and internal components,which is easy to cause failure.In order to ensure the dependability of the fuel pump regulator,it is imperative to analyze its dynamic characteristics,the experimental analysis ability is improved and the simulation model is revised and updated to obtain the required engineering data.Meanwhile,based on the acoustic-structure coupling method and the virtual transfer path analysis,the dynamic characteristics are deeply explored.Main contents of this thesis include:(1)The modeling of the fuel pump regulator was carried out,and the simplification method of the complex structure model was summarized to improve the modeling efficiency.Meanwhile,the mesh quality of parts is evaluated to ensure the modeling quality.Then,according to the coupling characteristics of parts,the main connection modes,such as screw connection,sliding fit and tight fit,are simplified.At last,in order to confirm the feasibility of the modeling method,verification is conducted.(2)The hierarchical modal experiment was carried out.The main connection mode modeling was modified based on the key substructure modal experiment.The constraints.Material properties,size and position of the model were modified based on the overall machine modal experiment.The accuracy of the modified model is substantially improved.Utilizing the modified model combined with the large mass method to further solve the vibration response of the device,the result shows that the average error of the first-order response amplitude of each measuring point meets the engineering requirements.(3)The influence of fuel on the dynamic characteristics of the structure is analyzed.Based on the acoustic-structure coupling method,the modal,vibration and acoustic analysis models under the fluid-structure coupling state were established,respectively,from the frequency mode,key point response and field point acoustic radiation to carry out dynamic characteristics research.It is known that the fuel has almost no effect on the vibration shape,and the influence on the modal frequency declines as the frequency goes up.The fuel exhibits a strong vibration absorption effect at lower frequency.The overall acoustic radiation of the coupling system decreases,but the radiation efficiency increases.(4)According to the coupling characteristics of the installation surface of small airborne equipment such as fuel pump regulator,the finite load node is used to represent the distributed dynamic load.Based on the load inversion technology of transfer relation matrix,the equivalent load of path point is reconstructed,and the infinite transfer path is simplified to the finite path,and the virtual transfer path analysis model is constructed.Then,the best virtual analysis model is determined by comparing the response synthesis results of each model with the conventional forced response analysis results.Finally,the vibration model is modified according to the contribution analysis conclusion,and the vibration response level of key points is reduced. |
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