一种振动颗粒康复仪的噪声分析与降噪设计

Noise Analysis and Vibration Control of Vibrated Particles Rehabilitation Device

对新开发的振动颗粒康复仪的振动噪声控制策略进行了研究。首先,通过对原样机的声强测试分析,确认实施按摩作业的薄壁圆柱桶与颗粒层为主要噪声源;其次,基于有限元方法,对圆柱桶进行了模态分析与振动响应分析,得到了圆柱桶场点处声压级频率响应曲线,构建了对圆柱桶噪声分析的数值仿真模型;最后,进行了试验验证。对现有不锈钢材质圆柱桶的振动传递路径进行了隔振处理分析,变桶底连接为法兰连接,并在法兰与振动平台间增加隔振层。数值仿真结果表明,与原样机相比,场点处声压级降低了约16.7dB。若当筒体材料选用阻尼大、比重小、壁厚大的有机玻璃材料时,基频的提高使结构的固有频率更远离激振频率,仿真发现与原样机相比,场点处声压级有望降低约28.2dB。搭建了改为有机玻璃桶且增加隔振层的试验样机,噪声试验表明:与原样机相比,空桶工作时,噪声降低了约15.2dB(A);加入按摩颗粒后,噪声降低约3.5dB(A)。

The vibration and noise control strategy of the new developed particle vibration rehabilitation device is proposed.Firstly,the sound intensity of the prototype is tested,and it is confirmed that the thinwalled cylindrical barrel and particle layer are the main noise sources.Then,by finite element method(FEM),the vibration response of cylindrical barrel are calculated.After that,the frequency response curve of sound pressure level at cylindrical barrel field point is obtained,and the numerical simulation model of cylindrical barrel noise analysis is constructed and conformed by rig experiments.The vibration transmission path of the stainless steel cylinder barrel is improved by replacing the connection of the bottom of the barrel with a flange and rubber layer between the flange and the vibration platform.It is shown by simulation that the sound pressure level at the field point is reduced about 16.7 dB compared with the original prototype.And when the cylinder barrel material is changed to polymethyl methacrylate which is more damping and thicker,the field point sound pressure level will be expected to reduce about 28.2 dB,partly because the increase of the natural frequencies of the structure help to avoid resonance to take place.Finally,a test prototype with a polymethyl methacrylate barrel and a vibration isolation layer is set up.It is shown that the noise is reduced by about 15.2 dB(A)compared with the original prototype;and the noise is reduced about 3.5 dB(A)if the barrel is filed with massage particles.