2020/07/24 by Ryan Poling-Skutvik, Ryan Poling‐Skutvik, Eoin McEvoy +4
Engineering · Materials Science · Physics and Astronomy · #Advanced Materials and Mechanics #Advanced Sensor and Energy Harvesting Materials #Composite material #Condensed matter physics #Liquid Crystal Research Advancements #Materials science #Microstructure #Physics #Quantum entanglement #Quantum mechanics #Sigma #Statistical physics #Stress (linguistics) #Yield (engineering) #cond-mat.soft
paper · pdf · doi:10.1103/physrevmaterials.4.102601
published as Phys. Rev. Materials 4, 102601 (2020)
arxiv created 2020/07/24 · openalex publication_date 2020/10/28 · arxiv updated 2020/11/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Although phenomenologically simple to define, the yield stress is often difficult to quantify unambiguously in practice, especially for thixotropic materials with complex shear histories. Here, we identify a stress-controlled bifurcation in the yielding response of cellulose nanofibril gels, which we show can rigorously localize the yield stress in disordered materials with time-dependent behavior. After an initial yielding event, the fibrillar networks subsequently yield faster and at lower magnitudes of stress. For low stresses, the time to yielding increases with waiting time tw and diverges once the network has restored sufficient entanglement density to support the stress. For higher stresses, the yield time instead plateaus at a finite value because the developed network density is insufficient to support the applied stress. We quantitatively relate the yielding and aging behavior of the network to the competition between stress-induced disentanglement and dynamic fluctuations of the fibrils rebuilding the network. The critical stress \ensuremathσc that bifurcates the response of the material between these two states identifies the intrinsic yield stress in these disordered materials, independent of aging, thixotropic effects, or shear history.