RUI: Excitation of Macro and Micro Cantilevers Using Ultrasound Radiation Force

本师生合作计画的目标是利用超音波辐射力，对宏观与微观杠杆的振动模式激发进行综合研究。超声辐射力激励方法是一种非接触技术，其依赖于入射在物体上的两个或更多个超声频率之间的干涉。这种干涉在差频处产生辐射力，这可以在物体中引起振动。超声辐射力将用于振动尺寸跨越两个数量级的杠杆，共振频率从小于100 Hz到超过200 kHz。特别感兴趣的将是一种方法的研究，其中一对超声换能器可以选择性地激发不同的振动模式，这取决于换能器是以相同的相位还是不同的相位驱动。将开发超声激发过程的计算模型，以更好地理解潜在的激发机制，并促进未来的研究。该项目将导致对超声辐射力的能力的更基本的理解，用于宏观和微观杠杆和类似物体的非接触激励。该项目将产生广泛的影响，因为微观杠杆的振动在越来越多的应用中起着重要的作用。通过监测微悬臂梁振动状态的变化，当单个细胞、病毒或某些分子附着在微悬臂梁上时，可以检测到质量的微小变化。同样，在材料科学领域，研究人员通常使用原子力显微镜来研究表面。这些重要的技术可以受益于超声辐射力的非接触性质。与传统的激发方法相比，微悬臂梁的选择性激发能力可能会提高这些技术的灵敏度。参与该项目的本科生将有机会在校园内进行尖端研究，并与其他机构的知名研究小组合作。学生将获得广泛领域的经验，包括声学，光学，计算机控制的数据采集，信号处理，模态分析和计算机建模;这对物理或工程职业生涯都是有价值的培训。他们还将开发演示，以更好地向公众宣传这一研究领域，并加强古斯塔夫斯完善的K-12推广计划。

The goal of this faculty-student project is a comprehensive study of excitation of vibrational modes of macro and micro cantilevers using the ultrasound radiation force. The ultrasound radiation force excitation method is a non-contact technique that relies on the interference between two or more ultrasound frequencies incident on an object. This interference produces a radiation force at the difference frequency, which can induce vibrations in the object. The ultrasound radiation force will be used to vibrate cantilevers spanning over two orders of magnitude in size and with resonance frequencies from less than 100 Hz to over 200 kHz. Of particular interest will be the study of a method whereby a pair of ultrasound transducers can selectively excite different vibrational modes, depending on whether the transducers are driven with the same phase or differing phases. A computational model of the ultrasound excitation process will be developed, both to better understand the underlying excitation mechanism, and also to facilitate future research. This project will result in a more fundamental understanding of the capabilities of ultrasound radiation force for noncontact excitation of macro and microcantilevers and similar objects.This project will have a broad impact, because of the important role that the vibration of microcantilevers plays in an ever increasing number of applications. By monitoring changes in the vibrational state of a microcantilever, it is possible to detect the minute change in mass when single cells, viruses or certain molecules attach to the microcantilever. Similarly, in the realm of materials science, researchers routinely use atomic force microscopy to study surfaces. These important techniques may benefit from the noncontact nature of the ultrasound radiation force. The capability of selective excitation of microcantilevers may enhance the sensitivity of these techniques as compared with conventional excitation methods.The undergraduate students involved in this project will get the extraordinary opportunity to perform cutting-edge on-campus research and also collaborate with well-known research groups at other institutions. The students will gain experience in a wide range of fields, including acoustics, optics, computer-controlled data acquisition, signal processing, modal analysis and computer modeling; this is valuable training for careers in either physics or engineering. They will also develop demonstrations to better communicate this research area to the public and to enhance Gustavus' well-established K-12 outreach programs.