电流变液复合层的声波透射行为
Sound transmission behavior through a sandwiched electrorheological layer
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摘要: 对夹于两柔性电极间的淀粉硅油电流变液进行了声波透射实验研究。结果表明: 电流变液的声波透射有较强的频率选择性。淀粉体积分数为31 %时, 在100~160 Hz 频率范围内, 随电场强度E 增加, 相对透射率T出现增强峰, 其它频率段T 基本不随E 变化。当E = 2. 0 kV/ mm 时, 在130 Hz 处透射峰的相对透射率约为零电场时的7 倍。透射波相位随E 增大, 入射波频率为105 Hz 时, 李萨如图椭圆主轴随E 增加顺时针转动45°。电场强度加大, 增强峰的幅值和相位表现出可调节的特征。随颗粒体积分数从16 %增大到31 % , 电流变液中声波最大相对透射率( E = 2. 0 kV/ mm) 从1. 8 变为7 , 增强峰的响应频带向高频移动。分析认为, 电流变液中场致微结构与声波的相互作用可能是出现这些现象的原因。Abstract: The sound t ransmission behaviors through a thin elect rorheological ( ER) layer sandwiched between twosheet s of flexible elect rodes were investigated experimentally. The t ransmission spect rum of the ER layer shows frequency selective characters. The relative t ransmittance T of the ER layer with a particle volume fraction of 31 %exhibit s an enhanced hump within 100~160 Hz with the increase of the external elect ric field E , while T doesnptchange with E at other f requencies. The relative t ransmittance T at the hump peak of 130 Hz under E = 2. 0 kV/ mmis nearly 7 times that of zero elect ric field st rength. The phase angle of t ransmitted sound increases with E also. Atthe f requency of 105 Hz , the long axis of Lisajous ellipse figure rotates clockwise by 45°as E increases f rom 0 tO2. 0 kV/ mm. With the increase in E , the amplitude and phase of the t ransmission hump show tunable features. Asφincreases f rom 16 % to 31 % , the maximum T changes f rom 1. 8 to 7 ( E = 2. 0 kV/ mm) and the respondingf requency band of the enhanced hump moves towards the high f requency direction. The interaction between the fieldinduced microst ructures and the sound waves may be the cause of the phenomenon.