Study On Vibration Characteristics Of Bulkhead Structure And Optimization Of Vibration And Noise Reduction

With its superior mechanical properties and lightweight characteristics,sandwich panels have been widely used in the field of shipbuilding.As an important part of the sandwich panel system,the core of SPS is made of special materials,which can dissipate energy,reduce vibration amplitude,and block and absorb noise.Therefore,it can be used in vibration reduction and noise reductionThis article aims at achieving lightweight and vibration reduction and noise reduction,adopts SPS bulkhead to replace the steel bulkhead,forms the design plan and conducts static calculations to ensure that the structure has sufficient rigidity and strength;then,the vibration performance of the two bulkhead structures is analyzed;next,the response surface method of Box-Behnken Design is used to obtain the optimized design plan;finally,the application of polyurethane sandwich bulkheads in noise control is explored,and the conclusions obtained can reduce ships vibration and noise reduction design plays a reference role.The main research contents of this thesis are as follows:(1)Taking the ship bulkhead structure as the research object,based on the original steel bulkhead,an SPS bulkhead with equal mass and equal stiffness was designed.Numerical simulation is used for statics analysis and comparison to ensure that the stiffness of the SPS bulkhead is not lower than that of the steel bulkhead and the strength meets the design specifications.(2)Calculate the vibration characteristics of steel bulkheads and SPS bulkheads to obtain their natural frequencies and modal shapes.Then,based on the modal simulation results,simulate their vibration responses in the frequency domain and time domain to obtain the response The results of the comparison verify the application of polyurethane sandwich panels in vibration control.(3)Parameterized analysis of the vibration characteristics and vibration response of the SPS bulkhead is carried out,and the influence of geometric parameters and material parameter changes on the vibration characteristics and vibration response of the structure is obtained.(4)According to the results of parametric analysis,six design variables suitable for the optimization scheme are determined;the amplitude-frequency response value is taken as the optimization target,and the lightweight of the bulkhead structure is fully considered;54 sets of test schemes are obtained through the Box-Behnken test design,and Perform finite element simulation calculations for each set of experimental design schemes;build an optimized model by fitting the experimental data and verify its reliability,and finally use the optimized model to obtain the optimal combination of design variables.(5)Based on random incident plane waves,a finite element model of sound transmission loss of the bulkhead structure under reverberant sound field excitation is established.First,the reliability of the finite element model is verified by comparing and analyzing the experimental data and theoretical values of literature;then the COMSOL Multiphysics software is used for equivalent quality The sound transmission loss of steel stiffened bulkhead and SPS bulkhead under the conditions is calculated,and the change law of sound transmission loss is studied and evaluated.