Thixotropic spectra and Ashby-style charts for thixotropy

TL;DR

This paper introduces a universal, model-insensitive framework using thixotropic spectra and Ashby-style charts to compare and visualize thixotropic properties across different fluids and microstructures.

Contribution

It presents a novel generalized framework based on thixotropic spectra for comparing thixotropic effects, independent of specific models, and visualizes properties using Ashby-style diagrams.

Findings

Effective characterization of thixotropic timescales and mode strengths.

Visualization of average thixotropic properties on Ashby-style diagrams.

Framework applicable to diverse microstructures and experimental data.

Abstract

There is no universal model for thixotropy, and comparing thixotropic effects between different fluids is a subtle yet challenging problem. We introduce a generalized (model-insensitive) framework for comparing thixotropic properties based on thixotropic spectra. A superposition of exponential stress modes distributed over thixotropic timescales is used to quantify buildup and breakdown times and mode strengths in response to step-change input. This mathematical framework is tested with several experimental step-shear rate data on colloidal suspensions. Low-dimensional metrics based on moments of the distribution reveal characteristic average thixotropic properties which are visualized on Ashby-style diagrams. This method outlines a framework for describing thixotropy across a diverse range of microstructures, supporting scientific studies as well as material selection for engineering design applications.