短纤维悬浮体系的流变性质

本文介绍了Dinh-Armstrong流变本构方程,并由此导出了中等浓度纤维悬浮体的粘度、第一法向应力差、第二法向应力差以及拉伸粘度的解析表达式,在简单剪切流时,导出的解析式与Dinh-Armstrong方程的数值解是一致的.在拉伸流时,尽管起始时和稳定态的粘度一致,但在过渡阶段存在一些定量的差异.

RHEOLOGICAL PROPERTIES OF SHORT-FIBERSUSPENSIONS

The Dinh-Armstrong constitutive equation is used to derive analytic expressionsfor the viscosity and the normal stress difference in shear and elongational deformation ofnondilute, short-fiber suspensions in Newtonian media. This is achieved by approximatingthe fourth order orientation tensor of the integral constitutive equation with the componentsof the Finger strain tensor according to Currie's expressions that relate the strain tensor toflow kinematics,The derived analytic expressions are in agreement with the numericalresults given by Dinh-Armstrong in simple shear flow. In elongation, although themagnitudes of dimensionless viscosity at start-up and steady state are identical,there isquantitative disagreement in the values in-between.