Barés Jonathan, Cárdenas-Barrantes Manuel, Pinzón Gustavo, Andò Edward, Renouf Mathieu, Viggiani Gioacchino, Azéma Emilien
LMGC, Université de Montpellier, CNRS, Montpellier, France.
CFTC, Universidade de Lisboa, 1749-016 Lisbonne, Portugal.
Phys Rev E. 2023 Oct;108(4-1):044901. doi: 10.1103/PhysRevE.108.044901.
Very soft grain assemblies have unique shape-changing capabilities that allow them to be compressed far beyond the rigid jammed state by filling void spaces more effectively. However, accurately following the formation of these systems by monitoring the creation of new contacts, monitoring the changes in grain shape, and measuring grain-scale stresses is challenging. We developed an experimental method that overcomes these challenges and connects their microscale behavior to their macroscopic response. By tracking the local strain energy during compression, we reveal a transition from granular-like to continuous-like material. Mean contact geometry is shown to vary linearly with the packing fraction, which is supported by a mean field approximation. We also validate a theoretical framework which describes the compaction from a local view. Our experimental framework provides insights into the granular micromechanisms and opens perspectives for rheological analysis of highly deformable grain assemblies in various fields ranging from biology to engineering.
非常柔软的颗粒集合体具有独特的形状改变能力，通过更有效地填充空隙，使其能够被压缩到远远超过刚性堵塞状态。然而，通过监测新接触的形成、监测颗粒形状的变化以及测量颗粒尺度的应力来准确跟踪这些系统的形成具有挑战性。我们开发了一种实验方法，克服了这些挑战，并将其微观行为与宏观响应联系起来。通过在压缩过程中跟踪局部应变能，我们揭示了从颗粒状到连续状材料的转变。平均接触几何形状显示出与堆积分数呈线性变化，这得到了平均场近似的支持。我们还验证了一个从局部观点描述压实的理论框架。我们的实验框架为颗粒微观机制提供了见解，并为从生物学到工程学等各个领域中高度可变形颗粒集合体的流变学分析开辟了前景。
