Measurement And Analysis Of Vibration Characteristics Of Hard-Coating Thin Plate Under Random Excitation

Plate structure has been most widely used in the field of aerospace,such as aero-engine blades,aircraft skin and cabinets for astronauts to store items.These plate structures often affect the performance of the whole structure and even cause vibration fatigue damage due to excessive vibration.In the actual engineering environment,hard coating material can effectively restrain the vibration of structural parts to a certain extent,so as to achieve the effect of vibration reduction.In order to effectively implement the hard coating damping on the plate structure,it is necessary to create the corresponding dynamic analysis model to reliably predict the hard coating damping effect.In view of the working environment of the dynamic equipment of the above-mentioned plate structures,they are usually subjected to random loads.Therefore,it is necessary to study the modeling and analysis method of the vibration characteristics of the hard-coating plate under random excitation loads.In this paper,the vibration test,dynamic analysis and optimization design of partiallycovered hard-coating thin plate under random excitation are studied by taking hard-coating thin plate as research object.The specific research contents are as follows:(1)The vibration characteristics of the hard-coating thin plate were tested under the random excitation of the electromagnetic vibration shaker,an autocorrelation function is used to obtain the power spectral density of vibration response acceleration under stationary random excitation.Based on the detailed description of the random vibration test process of the hardcoating thin plate,the actual test of the cantilever thin plate before and after coating was carried out,and the test results were verified by the LabVIEW module.The results show that the described method has better repeatability compared with the test module of LMS.Meanwhile,the test results show that,the hard coating has better damping effect on the thin plate.(2)Based on ANSYS software,modeling and vibration characteristics analysis of doublecovered hard-coating thin plate under random excitation were carried out.Based on the finite element model of the hard-coating thin plate structure,a method to obtain the power spectral density of the vibration response acceleration of the plate structure under random excitation is presented.A case study was carried out on a double-covered NiCrAl hard-coating thin plate.The inherent characteristics and vibration responses of the thin plate before and after coating were solved.The vibration characteristics obtained from the calculation were compared with the experimental results to verify the rationality of the modeling solution method.(3)A dynamic finite element model of a thin plate with double-covered hard coating Material was established based on the equivalent monolayer theory,and a Pseudo Excitation method(PEM)was described to solve the random vibration response of the hard-coating thin plate.The material characteristics of hard-coating are described in the form of complex modulus,the stiffness and mass matrix of double-covered hard-coating thin plate structure are derived,and the motion equation of the hard-coating thin plate structure is established.The vibration response of hard-coating thin plate structure is solved by PEM,and a specific formula is given.The vibration characteristics of double-covered NiCrAl hard-coating thin plate were also solved and compared with the experimental results,which proved the rationality.On this basis,the influence of hard coating material parameters(thickness,energy storage modulus,loss factor)on the vibration damping ability of the coating was analyzed.(4)A finite element model of a partially-covered hard-coating thin plate structure was established and its vibration characteristics under random excitation were solved.Taking the position of the hard coating as the design variable and obtaining the Root Mean Square(RMS)value of the acceleration power spectral density as the optimization objective,an optimization model for vibration reduction of the partially-covered hard-coating thin plate was established.Particle Swarm Optimization(PSO)algorithm was used to solve the optimization model,and the specific solution process was given.Taking a thin plate partially deposited with NiCrAl material as an example,the optimization of the hard coating position is realized.In the practical application of power equipment engineering,it is necessary to study the vibration characteristics and vibration reduction of plate structures under random excitation.The research contents and results of this paper can provide reference for the vibration characteristics analysis and vibration reduction optimization design of hard-coating structures under random excitation.