For the manipulation of microparticles, ultrasonic devices, which employ acoustophoretic forces, have become an essential tool. There exists a widely used analytical expression in the literature which does not account for the effect of the geometry and acoustic properties of the chip material to calculate the acoustophoretic force and resonance frequencies. In this study, we propose an analytical relationship that includes the effect of the chip material on the resonance frequencies of an acoustophoretic chip. Similar to the analytical equation in the literature, this approach also assumes plane wave propagation. The relationship is simplified to a form which introduces a correction term to the acoustophoretic force equation for the presence of the chip material. The proposed equations reveal that the effect of the chip material on the resonance frequency is significant—and is called the device resonance—for acoustically soft materials. The relationship between the actuation modes of the piezoelectric actuator(s) and position of the nodal lines inside the channel are discussed. Finite element simulations are performed to verify the proposed equations. Simulations showed that even if some of the assumptions in the derivations are removed, the general conclusions about the motion of the microparticles are still valid.

中文翻译：

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声流体粒子处理的扩展视图：体声波设备的致动模式和设备共振现象的场景

为了操纵微粒，利用声电泳力的超声装置已经成为必不可少的工具。文献中存在一种广泛使用的分析表达式，该表达式不考虑芯片材料的几何形状和声学特性对计算声电泳力和共振频率的影响。在这项研究中，我们提出了一种分析关系，其中包括芯片材料对声电泳芯片共振频率的影响。类似于文献中的解析方程，该方法还假设了平面波传播。该关系被简化为一种形式，该形式针对芯片材料的存在将校正项引入到声泳力方程中。设备共振—用于声学柔软的材料。讨论了压电致动器的致动模式与通道内节点线位置之间的关系。进行有限元模拟以验证所提出的方程。模拟表明，即使删除了推导中的某些假设，有关微粒运动的一般结论仍然有效。