McKetta Department of Chemical Engineering and Texas Materials Institute, University of Texas at Austin, Austin, TX 78712, USA.
Soft Matter. 2018 Aug 29;14(34):7064-7074. doi: 10.1039/c8sm01153b.
We identify the minimal interparticle interactions necessary for a particle dynamics simulation to predict the structure and flow behaviour of soft particle glasses (SPGs). Generally, two kinds of forces between the particles must be accounted for in simulations of SPGs: viscous or frictional drag forces and elastic contact forces. Far field drag forces are required to dissipate energy in the simulations and capture the effect of the rheology of the suspending fluid. Elastic forces are found to be dominant compared to near-field drag or other forms of friction forces and are the most important component to compute the rheology. The shear stress, the first and second normal stress differences for different interparticle force laws collapse onto universal master curves of the Herschel-Bulkley form by non-dimensionalizing the stress with the yield stress and the shear rate with the viscosity of the suspending fluid divided by the low-frequency shear modulus. The Herschel-Bulkley exponents are close to 0.5 with a slight dependence on the repulsive pairwise elastic forces.
我们确定了粒子动力学模拟预测软粒子玻璃（SPG）结构和流动行为所需的最小粒子间相互作用。通常，SPG 模拟中必须考虑两种粒子间的力：粘性或摩擦阻力和弹性接触力。远场阻力用于在模拟中耗散能量，并捕捉悬浮液流变性的影响。与近场阻力或其他形式的摩擦力相比，弹性力占主导地位，是计算流变学的最重要组成部分。通过用屈服应力对应力进行无量纲化，用悬浮液的粘度除以低频剪切模量对剪切率进行无量纲化，不同粒子间力律的剪切应力、第一和第二法向应力差都可以归结为赫谢尔-布尔克利（Herschel-Bulkley）形式的通用主曲线。赫谢尔-布尔克利指数接近 0.5，与排斥成对弹性力有轻微的依赖关系。
