Probing local nonlinear viscoelastic properties in soft materials
Name
2007.11090.pdf
Description
Accepted version
Size
6.07 MB
Format
Adobe PDF
Checksum (MD5)
9e42477c5063d1d72351d6e1bbcecf06
Author(s)
Chockalingam, S
Roth, C
Henzel, T
Cohen, T
Date Issued
2021
Journal
Journal of the Mechanics and Physics of Solids
Publisher
Elsevier BV
Citation
S. Chockalingam, C. Roth, T. Henzel, T. Cohen, Probing local nonlinear viscoelastic properties in soft materials, Journal of the Mechanics and Physics of Solids, Volume 146, 2021
Version
Author's final manuscript
Abstract
© 2020 Elsevier Ltd Minimally invasive experimental methods that can measure local rate dependent mechanical properties are essential in understanding the behaviour of soft and biological materials in a wide range of applications. Needle based measurement techniques such as Cavitation Rheology (Zimberlin et al., 2007) and Volume Controlled Cavity Expansion (VCCE, Raayai-Ardakani et al. (2019a)), allow for minimally invasive local mechanical testing, but have been limited to measuring the elastic material properties. Here, we propose several enhancements to the VCCE technique to adapt it for characterisation of viscoelastic response at low to medium stretch rates (10−2 - 1 s−1). Through a carefully designed loading protocol, the proposed technique performs several cycles of expansion–relaxation at controlled stretch rates in a cavity expansion setting and then employs a large deformation viscoelastic model to capture the measured material response. Application of the technique to soft PDMS rubber reveals significant rate dependent material response with high precision and repeatability, while isolating equilibrated states that are used to directly infer the quasistatic elastic modulus. The technique is further established by demonstrating its ability to capture changes in the rate dependent material response of a tuneable PDMS system. The measured viscoelastic properties of soft PDMS samples are used to explain earlier reports of rate insensitive material response by needle based methods: it is demonstrated that the conventional use of constant volumetric rate cavity expansion can induce high stretch rates that lead to viscoelastic stiffening and an illusion of rate insensitive material response. We thus conclude with a cautionary note on possible overestimation of the quasistatic elastic modulus in previous studies and suggest that the stretch rate controlled expansion protocol, proposed in this work, is essential for accurate estimation of both quasistatic and dynamic material parameters.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/J.JMPS.2020.104172
