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arXiv · 2110.05127

The Elastic Spiral Phase Pipe

Gregory J. Chaplain·Jacopo M. De Ponti
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Abstract

We design a device for the passive mode conversion of guided, axisymmetric, ultrasonic waves in hollow elastic pipes into arbitrary non-axisymmetric flexural waves that have a constant angular profile along the pipe axis. To achieve this we create an elastic analogue to optical spiral phase plates - the elastic spiral phase pipe. Three possible configurations of the elastic spiral phase pipe are presented which allow the efficient generation of non-axisymmetric flexural waves from an axisymmetric, longitudinal forcing. The theory leverages the dispersive nature of the guided elastic waves that are supported in pipes through a defined relative refractive index. As such we include a spectral collocation method used to aid the design of the elastic spiral phase pipe that is corroborated with numerical simulations and then experimentally verified.

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Gregory J. Chaplain, Jacopo M. De Ponti. 2021-10-11. The Elastic Spiral Phase Pipe. https://doi.org/10.1016/j.jsv.2021.116718

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