Measuring the local mechanical properties of a floating elastic sheet

TL;DR

This paper introduces a novel non-invasive method to measure local mechanical properties, specifically the flexural modulus, of floating elastic sheets like sea ice, using deformation dynamics and laboratory experiments.

Contribution

The authors developed a new technique to extract local flexural modulus from deformation data, enabling high-resolution mapping of mechanical properties of floating elastic sheets.

Findings

Method accurately retrieves mechanical properties in lab tests.

Maps of sheet thickness achieved with sub-wavelength resolution.

Robustness confirmed across different membrane shapes and thicknesses.

Abstract

Polar regions are covered by sea ice, which can be seen as a thin solid elastic sheet with heterogeneous mechanical properties. The dynamics of deformation of a floating solid sheet are primarly governed by gravity, water density, and the flexural modulus, which depends on its mechanical properties, namely the thickness, the Young's Modulus and the Poisson ratio. Non-invasive methods from seismology can retrieve these three parameters from sheet deformation dynamics. In this article, we developed another method to extract locally the flexural modulus of a floating thin elastic sheet from the spatio-temporal deformations of the sheet. We perform laboratory experiment to test the accuracy and the robustness of this method on silicon membranes of controlled mechanical properties. Using patches of different thicknesses and shapes, we eventually draw maps of sheet thickness, with a sub-wavelength spatial resolution.