Investigation of mechanisms to control the longitudinal and torsional mode vibration response of an ultrasonic transducer

研究控制超声换能器纵向和扭转模式振动响应的机制

• 批准号: 2744576
• 金额: --
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2744576
• 关键词: Investigation; mechanisms; control; longitudinal; torsional

Combining longitudinal (L) and torsional (T) vibration motion is common in ultrasonic devices. The combined motion deliver LT vibrations at the output face or tip of the device. Examples of such devices that have been the basis of research programmes include ultrasonic drills for planetary exploration, ultrasonic needles for bone biopsy, and ultrasonic welding devices. Commercial examples include ultrasonic surgical shears and phacoemulsification devices. In these examples, the transducer is based on a conventional Langevin configuration. There are then a number of different approaches to exciting the LT motion. One is through L-wave degeneration that creates a non-uniform section, by cutting and twisting a number of slots or a helix along the path of the L-wave such that part of the wave converts into a T wave whilst the remaining part propagates unchanged through the section. A second approach is to couple the L mode and a T mode by tuning the two modes to be excited in resonance at the same frequency. Another mode coupling approach additionally uses two set of piezoelectric elements, where one set generates L vibration whilst the second set generates T vibration. LT devices can also be based on delivering LT motion in the transducer itself or, in the case of mode degeneration devices, by introducing the geometrical features in an ultrasonic horn attached to the output face of a conventional Langevin transducer. Where LT motion is delivered in the transducer itself, this can be via two sets of differently poled piezoelectric rings (one exciting L and the other exciting T motion) or by incorporating a helical or slotted structure in the front mass. In all cases, however, there is often little control of the torsionality of the device (defined as the ratio of tangential to axial vibrational displacement of the tip). There is also a commercialised phacoemulsification device that relies only on T mode vibrations of the tip. A gap in current offerings is a switchable-mode transducer, where L and T motions can be excited independently in one device at the same resonance frequency. This PhD will explore a range of configurations that can deliver such a switchable-mode ultrasonic transducer, including through the incorporation of differently poled piezoceramic elements.The main tasks to be carried out include:1) A review of the currently available LT devices developed commercially or published in the literature2) Research the potential applications of a switchable-mode ultrasonic transducer3) Support the design and testing of torsional piezoelectric rings and investigate their incorporation into designs for a switchable-mode transducer4) Develop FEA models in OnScale to design potential configurations of a switchable-mode ultrasonic transducer and to simulate their performance5) Design, prototype, characterise and test a number of configurations with potential for controlled switchable responses, and validate the FEA models6) Establish a range of performance tests to indicate the most promising transducer

组合纵向（L）和扭转（T）振动运动在超声装置中是常见的。组合运动在设备的输出面或尖端传递LT振动。作为研究方案基础的这类装置的例子包括用于行星探测的超声波钻、用于骨活检的超声波针和超声波焊接装置。商业实例包括超声手术剪和超声乳化装置。在这些示例中，传感器基于传统的朗之万配置。然后，有许多不同的方法来激励LT运动。一种是通过L波退化，其通过沿着L波的路径切割和扭曲多个槽或螺旋沿着，使得波的一部分转换成T波，而其余部分不变地传播通过截面，从而产生不均匀的截面。第二种方法是通过调谐L模式和T模式以在相同频率下谐振来耦合这两种模式。另一模式耦合方法另外使用两组压电元件，其中一组产生L振动，而第二组产生T振动。LT装置还可以基于在换能器本身中传递LT运动，或者在模式退化装置的情况下，通过在附接到常规朗之万换能器的输出面的超声变幅杆中引入几何特征。在换能器本身中传递LT运动的情况下，这可以通过两组不同极化的压电环（一个激励L运动，另一个激励T运动）或通过在前质量中结合螺旋或开槽结构来实现。然而，在所有情况下，通常很少控制器械的扭转度（定义为尖端的切向与轴向振动位移之比）。还有一种商业化的超声乳化装置，其仅依赖于尖端的T模式振动。当前产品中的一个差距是可切换模式换能器，其中L和T运动可以在同一个设备中以相同的谐振频率独立地激励。该博士将探索一系列可以提供这种可切换模式超声换能器的配置，包括通过纳入不同极化的压电陶瓷元件。要执行的主要任务包括：1）对目前商业上开发或文献中发表的LT设备进行综述2）研究可切换模式超声换能器的潜在应用3）支持扭转压电环的设计和测试，并研究将其纳入可切换模式换能器的设计4）在OnScale中开发FEA模型，以设计可切换模式超声换能器的潜在配置并模拟其性能5）设计、原型制作、验证和测试许多具有受控可切换响应潜力的配置，并验证有限元模型6）建立一系列性能测试，以表明最有前途的换能器