Guided elastic waves for soft elastomer characterization: an alternative to conventional rheometry

TL;DR

This paper presents a wave-based method using guided elastic waves in elastomer strips to characterize viscoelastic and hyperelastic properties over a broad frequency range, offering an alternative to traditional rheometry.

Contribution

The authors introduce a novel wave-guided elastomer characterization technique combining experimental measurements with theoretical modeling to extract rheological parameters.

Findings

Method yields parameters consistent with conventional rheometry.

Extends frequency range beyond traditional techniques.

Provides a simple, broadband approach to elastomer characterization.

Abstract

Elastic wave propagation is intrinsically sensitive to the mechanical properties of the medium through which it travels. In soft elastomers, this makes guided elastic waves natural probes of viscoelastic and acoustoelastic behavior over a broad frequency range. In this work, we introduce a wave-based mechanical characterization method in which a thin elastomer strip acts as a waveguide supporting multiple in-plane guided modes. By combining stroboscopic measurements of monochromatic wave fields with a theoretical framework that couples frequency-dependent viscoelasticity and elongation-dependent acoustoelasticity, we extract complex-valued dispersion relations for guided modes under controlled static elongation. A dedicated numerical implementation allows these experimental dispersion curves to be quantitatively matched to theory, enabling identification of the material's rheological and hyperelastic parameters. Applied to several commercial silicone elastomers, the method yields mechanical parameters that are consistent with conventional plate-plate rheometry, while extending the accessible frequency range beyond that of conventional techniques. By exploiting the richness of guided-wave dispersion and the sensitivity of waves to both frequency and pre-stress, this approach provides a unified, broadband, and experimentally simple route to the mechanical characterization of soft elastomers.