Multi-beam Radiation Force Generator for Selective Excitation of Vibrational Modes in Objects

Reference #:

2004-245

Inventors/Contributors

James F. Greenleaf, Ph.D., Mostafa Fatemi, Ph.D., Thomas Huber, Ph.D.

Description

The method developed allows selective excitation of an object using the interference of sonic beams. As an example, this method can be implemented using two ultrasound beams. This is a refinement of earlier methods for noncontact excitation using ultrasound (Greenleaf and Fatemi), in that it enables certain modes of vibration to be enhanced relative to other vibrational modes. The present invention includes two or more diverging or converging ultrasound beams, each generating an amplitude modulated ultrasound field. The beams are modulated with similar modulation frequency but with different phases. By varying the phase of two or more ultrasound beams by the user can cause changes in the relative amplitude of different vibrational modes. Advantages over conventional methods for modal testing: (1) non-contact, suitable for small objects such as MEMS, (3) wide frequency bandwidth. Advantage over using a single ultrasound beam as described by previous disclosure. This method can use two diverging beams to selectively excite a particular mode.

Patent Status

Pending