Summary

Description

<p> We had two objectives in this task: 1. Develop effective single low-mass, low-power piezoelectric drive that can actuate rotary-hammer samplers through walls. 2. Determine design sensitivities and investigate Acoustic Mechanical Feed-throughs (AMF) using acoustic mode conversion with emphasis on extension to rotary. In our earlier studies, we were able to excite rotation from longitudinal vibrations but, without sufficient analytical foundations, it has been a challenge to get consistent results. Therefore, we focused our efforts on the modeling, analysis and optimization of configurations that effectively convert longitudinal forces to torque and rotation. The task consisted of conceiving drive configurations and optimizing them thru finite element and harmonic analysis, as well as producing and demonstrating the physical mechanism. The analytical task provided tools and data to select highly efficient mechanisms that use piezoelectric materials to generate elastic waves that wirelessly transmit power through a metallic wall. We produced a resonant breadboard system that converts high frequency micron-size displacements to macroscopic rotary and linear motions. The developed mechanism uses the converse piezoelectric effect as a means of generating elastic waves, which is transmitted in the form of elastic waves, was used to excite rotation through a wall and establish a basis for a systematic capability to design wireless actuation, manipulation, and deployment thru walls. Efforts were made to optimize the location of the nodal plane of the transducer and difficulties were encountered since the nodal location of the transducer is not necessarily a plane. Through our analytical studies, we were able to produce Acoustic Mechanical Feed-throughs (AMF) capability that consistently and efficiently induces rotation. We established sufficient data and analysis to allow submittal of a credible proposal for further development of the concept.</p>