Design of DAS fibres for elastic wave mode discrimination

Kristopher A. Innanen, Matthew Eaid

In 2016 a “Fibre Geometry and Sensing Model” was introduced in order to facilitate characterization of DAS fibres and their shapes as they respond to various types of elastic wave. The directionality of an arbitrary fibre and its capacity to enable multicomponent DAS sensing were both considered. The model grew considerably in 2017 and now contains the beginnings of a framework to analyze the characteristic response of a given fibre shape to a range of different elastic modes, P- and S-waves at a range of 3D obliquities, and Rayleigh waves for instance. The model can be set up to experience these waves in a useful form, “lighting up” in regions where the fibre response is above a given threshold. These responses are planned to be the basis for designing fibres which can optimally enhance certain wave modes (e.g., body waves) and suppress others (e.g., surface waves).