Research On Noise Reduction Of Magnetic Resonance Therapy Module Based On Dynamic Vibration Absorption Technology

Magnetic resonance instrument(MRI)is an advanced tissue imaging tool.However,due to the working principle of MRI,it will generate vibration and noise.The transmission of vibration to the treatment table will affect the quality of imaging.In order to solve this problem,this paper adopts a method of vibration reduction and noise reduction by periodically arranging dynamic vibration absorbers on the cylindrical casing of the MRI gradient coil.This idea comes from the application of the band gap characteristics of phononic crystals in vibration reduction.Firstly,this paper uses COMSOL Multiphysics to build a finite element model of MRI.The model is built by shell elements,which results in a small number of meshes and high computational efficiency.Secondly,according to the MRI standard test method,the noise level of the existing MRI structure is analyzed,including the frequency of the maximum noise,the spatial location where the maximum noise occurs,and the maximum value of the steady-state sound field in the MRI treatment cabin under the trapezoidal wave excitation of the maximum noise frequency.Noise sound pressure level.Using standard test methods for finite element simulation can provide a reference for experimental analysis.At the same time,the experimental results also help to calibrate the finite element model.Finally,the dynamic vibration absorber is distributed on the MRI,and the mass,stiffness and damping of the vibration absorber are optimized with Comsol optimization module.The minimum sound pressure level on the central axis of the MRI treatment cabin is the design goal.Optimal design of the filter to obtain a set of optimal parameters of the shock absorber.The analysis results show that the vibration reduction and noise reduction method in this paper has a good vibration reduction and noise reduction effect.Compared with the existing MRI structure,the optimized MRI structure has a maximum sound pressure level reduced by 3.3%on the center axis of the treatment cabin,and the average sound pressure level was reduced by 5%.