Optimization Design Of Axial Vibration Isolation Performance Of Cylindrical Structures

The effective control of low-frequency pipeline vibration has long been an urgent application demand and a significant problem in the field of engineering.Phononic crystals,which prohibit the propagation of sound and vibration within their band gap range,offer an opportunity for artificially tunable solutions.Therefore,by introducing the concept of phononic crystals into pipeline structure design,it is possible to create pipeline structures with desired band gap characteristics,which can provide an effective solution for the control of low-frequency pipeline vibration.This presents a novel approach for reducing pipeline system vibration and noise,which is of great significance for the engineering community.In this paper,the low-frequency vibration control of the circular tube structure is the research goal,and two circular tube structures are designed by using the band gap characteristics of the phononic crystal.The following researches are carried out on these two structures:(1)This paper takes the pyramid lattice cylinder structure as the object,The parametric model is determined by independent structural parameters such as width,height and number of arrays,etc.and commercial finite element software was used to calculate the axial vibration characteristics of lattice structure.The influence of key parameters such as cell width,cell height and rod diameter on the damping effect was studied by the dimensionless parameters of normalized frequency and relative bandwidth.Through parameter analysis,a pyramid lattice cylinder structure with low frequency and broadband vibration damping performance has been designed.Then a sample is made by additive manufacturing.The vibration test results show that the experimental results are consistent with the finite element simulation.In the range of 500 Hz to 1500 Hz,the structure shows obvious vibration reduction effect,and the average attenuation strength reaches about 50 d B.(2)Using the concept of local resonant phononic crystals,a three-component circular tube periodic structure is designed through parametric modeling.Then based on the finite element method,an automatic energy band structure calculation software platform was established,combined with the ISIGHT optimization analysis software,different optimization objectives were set to optimize the structure design,and the key parameters affecting the vibration reduction effect of the pipeline were analyzed.On this basis,the test sample was prepared by pouring polyurethane elastomer,and the vibration test experiment was completed and compared with the finite element simulation results.The results show that the experimental results are basically consistent with the finite element simulation results,and it has excellent vibration reduction performance below 1000 Hz.(3)The vibration damping performance of the three-component circular tube structure was evaluated when it was subjected to axial displacement loads and internal pressure loads on the tube wall,the structural configuration and band gap change trend of the circular tube under axial tension,compression and inner wall compression are analyzed.The results show that in the range of tensile strain of 0.1,the band gap of the structure is very stable,which is basically the same as before deformation;when the compressive strain is applied,the band gap changes significantly,the entire bandwidth becomes narrower,and the initial frequency of the band gap shifts to high frequency;When the inner wall is under pressure,the pressure is within 3MPa,and the structure and band gap are very stable.