Stress distributions in soft particle glasses : Insights from a thermodynamic model

Minaspi Bantawa ; Paolo Edera ; Michel Cloitre ; Roger T. Bonnecaze
J. Rheol. 69, 2025, 611–620
https://doi.org/10.1122/8.0000921

Jammed suspensions of soft particle glasses (SPGs) exhibit intriguing rheological response under different shear flows, such as stress overshoot in start-up shear and Herschel–Bulkley behavior in steady shear. However, the fundamental link between microscopic processes and macroscopic (bulk) behavior remains elusive. To address this, we employ large-scale 3D simulations of model SPGs to study the impact of shear-induced microstructural rearrangements on particle stress distributions. These rearrangements cause significant changes in stress distribution, consequently influencing the overall stress and bulk rheology of the system. The characteristics of stress distribution, including its width and peak, are found to be influenced by factors such as particle volume fraction, applied shear rate, and system history. Building upon previous works, we introduce a thermodynamic model that offers insights into the particle stress distribution in SPGs, providing a microscopic basis for understanding bulk rheology. Furthermore, we present a self-consistent model based on the advection–diffusion equation, which describes the evolution of particle stress distribution in SPGs under steady shear. Our findings emphasize the importance of stress distributions in elucidating bulk rheology and highlight the utility of thermodynamics as a valuable tool for modeling these complex materials.