Dynamic Analysis And Optimization Of A Knapsack Spray Vibrator Vibration Isolation System

As a small farm implement,the spray duster has been widely used in China.This paper aims at the engineering research problem of vibration isolation design and structure optimization of a knapsack spray duster.The theoretical modeling calculation and vibration modal test are used to analyze the dynamic characteristics,and the parameters of the system's force transmission rate are optimized for the spray duster.Vibration and noise reduction design provides a reference.First,consult the literature and carry out on-site investigations to understand the research status and development trend at home and abroad.Use 3D mapping software to draw the 3D solid model of the whole machine.According to its actual characteristics,establish and simplify the vibration isolation model,and list the vibration equations of the vibration isolation system.Find the first six natural frequencies.Using the admittance transfer matrix method and the generalized four-terminal parameter method to establish the relationship between the parameters of the knapsack sprayer vibration isolation system lay the foundation for the followingSecondly,based on the dynamic model,the power flow analysis is performed to analyze the influence of the parameters of the vibration isolation system on the basic transmission power flow.Based on the stiffness and damping of the vibration isolation system as optimization variables,optimization was carried out using the MATLAB optimization toolbox.After optimization,the power flow transmitted to the foundation was significantly reduced,the resonance peak was also significantly reduced,and the amplitude at the power frequency was reduced from-108.2 dB to-115.3dB decreased by 6.5%,which shows that the optimized vibration isolation system has greatly improved its energy absorption capability.Thirdly,The finite element modal analysis of the whole machine was performed by ANSYS Workbench,and the whole machine experimental modal analysis was performed using LMS Test.Lab.The relative errors of the first two natural frequencies obtained by the theoretical modeling calculations and the modal tests are less than 5%within the allowable range,which proves the reliability of the theoretical modeling and also proves the validity of the parameter optimization performed in this way;The error of the first six natural frequencies of the two modal analyses is less than 5%within the allowable range,and the first six modes are consistent,which proves the accuracy of the finite element model and provides the results for the next harmonic response analysis and verification optimization.A good foundation.In addition,the fourth-order natural frequency is close to the operating frequency of 142Hz and should be reinforced at the engine cover.Finally,harmonic response analysis was used to verify the effect of vibration reduction and noise reduction after optimization.The vibration curve after optimization was significantly reduced compared with the whole before optimization.The amplitude at the frequency of 142Hz was reduced from 4.1056e-4m to 1.0233e-4m,a decrease of 75%,and the damping effect was obvious,indicating that the parameter optimization result based on the theoretical model was effective.The optimized noise curve is significantly lower than before optimization.After optimization at 142Hz,the sound pressure level is reduced from 86.5dB to 62.1dB,and the sound pressure level is reduced by 28.2%.This shows that the noise reduction effect is obvious and the optimization result is effective.