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

在超声设备中，纵向（L）和扭转（T）振动运动组合是常见的。组合运动在设备的输出面或尖端传递LT振动。这类设备的示例是研究计划的基础，包括用于行星探索的超声钻，超声波活检的超声针头和超声波焊接设备。商业示例包括超声波手术剪切和触觉乳化装置。在这些示例中，传感器基于常规的langevin配置。然后有许多不同的方法激发LT运动。一个通过L波变性，通过切割和扭曲沿L波路径的多个插槽或螺旋来创建一个不均匀的截面，使波的一部分转化为T波，而其余部分则在整个部分中不变。第二种方法是通过调整两个模式以相同频率激发共振的两种模式来对l模式和t模式进行。另一种模式耦合方法还使用了两组压电元素，其中一组会产生L振动，而第二组产生了T振动。 LT设备也可以基于传递传感器本身中的LT运动，或者在模式变性设备的情况下，通过将几何特征引入连接到常规Langevin tendducer的输出面的超声角中的几何特征。如果LT运动在传感器本身中传递，则可以通过两组不同的螺旋压电环（一种令人兴奋的L，另一个令人兴奋的T运动），也可以通过在前质量中掺入螺旋或开槽结构。但是，在所有情况下，通常几乎没有控制设备的扭转（定义为切向尖端的轴向振动位移的比率）。还有一种商业化的乳化装置，仅依赖于尖端的T模式振动。当前产品中的差距是可开关模式传感器，其中L和T运动可以在同一共振频率的一个设备中独立激发。 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