Research On Dynamic Response Of Typical Aerostructure Under Noise Load

The mechanics environment of high-speed vehicles during launch,atmospheric flight and reentry phase is more complicated,and the noise and vibration environment are extremely harsh.This kind of noise environment is mainly caused by the engine propulsion system and its jet noise and unsteady aerodynamic forces on the surface of the aircraft.It will seriously jeopardize the safety and reliability of the missile structure and the equipment on the missile.This type of vibration is also commonly referred to as “sonic vibration”.The sound and vibration mechanics environment is characterized by large randomness and wide frequency band.It not only includes low-frequency excitation,but also includes mid-high frequency excitation.Among them,medium-low frequency excitation will not only aggravate structural damage,but also cause bad pressure in the cabin to generate high sound pressure levels.Learning the environment,thereby greatly reducing the reliability of the entire system,is one of the main reasons why the aircraft instrumentation does not work properly and the aircraft structure is destroyed.In this paper,starting from the mutual conversion of frequency domain-time domain noise load,the method of obtaining and loading random noise in time domain is studied.The dynamic response of thin plate structure in time and frequency domain under noise loading is studied,and the typical structure of thin plate is studied.The acoustic vibration experiment under the noise load verified the correctness of the noise conversion method and the loading method.Using the traditional Fourier transform method combined with the periodic diagram method,the method of mutual conversion of noise in the frequency domain and time domain is studied.The random phase information is added to the noise load signal in the frequency domain to obtain the random noise in the time domain.Purpose,and use Matlab software for programming.Under the effect of random noise load,the transient and frequency response of the thin plate was analyzed.In the research,the noise response analysis is divided into two categories:(1)Without considering the propagation of noise in the gas medium,the noise is directly loaded on the surface of the thin plate to obtain the acceleration and stress response of the key nodes of the sheet;(2)The noise is considered in the gas medium,the noise acts on the surface of the thin plate through the gas medium,and the distribution of sound pressure in the gas is calculated and the stress response of the key nodes of the thin plate is calculated.Based on the analysis of the acoustic vibration response of thin plates,the acoustic vibration experiments were performed on the thin plates to obtain the natural frequency and mode shape of the thin plate,as well as the acceleration and strain response data of the key points.The simulation results were compared with the experiment results to verify the finite element model,the noise load conversion method and the correctness of the loading method.The dynamics simulation of the wing structure of a certain type of hypersonic aircraft is carried out.The first ten-order mode of the wing structure is obtained,and the position where the vibration of the wing structure is the most severe and the stress is the largest is obtained.This analysis provides an analytical basis for the design of the wing structure.