Brittle and ductile yielding in soft materials

• 成果类型: Article
• 署名作者: Kamani, Krutarth M.; Rogers, Simon A.
• 署名单位: University of Illinois System; University of Illinois Urbana-Champaign
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13948
• DOI: 10.1073/pnas.2401409121
• 发表日期: 2024-05-28
• 关键词: amplitude oscillatory shear; nonlinear rheology; stress; BEHAVIOR; hard; suspensions; TRANSITION; DYNAMICS; fracture; glasses

摘要

Many soft materials yield under mechanical loading, but how this transition solid -like behavior to liquid -like behavior occurs can vary significantly. Understanding the physics of yielding is of great interest for the behavior of biological, environmental, and industrial materials, including those used as inks in additive manufacturing muds and soils. For some materials, the yielding transition is gradual, while others abruptly. We refer to these behaviors as being ductile and brittle. The key rheological signatures of brittle yielding include a stress overshoot in steady -shear -startup tests a steep increase in the loss modulus during oscillatory amplitude sweeps. In this work, we show how this spectrum of yielding behaviors may be accounted for in a continuum model for yield stress materials by introducing a parameter we call the brittility factor. Physically, an increased brittility decreases the contribution of recoverable deformation to plastic deformation, which impacts the rate at which yielding occurs. The model predictions are successfully compared to results of different rheological protocols a number of real yield stress fluids with different microstructures, indicating the general applicability of the phenomenon of brittility. Our study shows that the brittility soft materials plays a critical role in determining the rate of the yielding transition provides a simple tool for understanding its effects under various loading conditions.