压缩速度对电流变液抗压强度影响的实验研究

Experimental investigation of compression speed influence on the compressive resistance of electrorheological fluids

在挤压型电流变器件应用中,压缩速度是一个重要设计参数。如果不清楚压缩速度对抗压强度的影响,会造成应用中设计和控制的失准。该文实验表明,在相同外加电压下,随压缩速度升高,电流变液的压缩强度有较大降低,与剪切速率对电流变液的剪切强度的影响类似。在压缩过程中同步测试得到的电流密度曲线与压缩应力曲线的变化趋势基本一致。电流密度的测试结果表明随压缩速度的增加,链结构被压溃更严重,同时由于电场力与粘性力的比值降低,不利于被破坏的链结构的恢复,颗粒间局部平均电场强度降低,从而导致抗压强度降低。

The compression speed is a very important parameter in applications of electrorheological （ER） fluids based on their compression resistance. The design and control of ER devices will fail without consideration of the influence of the compression speed, Experiments showed that with the same external applied voltage, the compressive resistance of ER fluids decreased significantly with increasing compression speed, which is similar to the influence of shear rate on the shear strength of ER fluids. The current intensity flowing through the ER fluid during compression varies in a similar trend as the compression stress, which indicates that the destruction of the chain structures in the fluid become more severe with increasing compression speed. The decrease of the compression resistance is ascribed to the decrease of the ratio of the polarization to the viscous forces, which prevents reconstruction of the chain structure and reduces the average local electric field strength between particles.