Interactions and orientation in concentrated suspensions of rigid rods: Theory and experiment

Engineering, Mechanical

Sandstrom, Chad Richard

关键词: Engineering, Mechanical;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/20445/9329153.pdf?sequence=2&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

A theory for the processing-induced fiber orientation and stress in fiber reinforced-polymer composites is presented. Short-fiber-reinforced polymer composites are represented by concentrated suspensions of rigid rods. In concentrated suspensions, fiber-fiber contact is likely and affects the fiber orientation state and suspension rheology. Fiber orientation is given as a function of the strain in the continuum and the probable effects of physical inter-fiber contact. Continuum stress is calculated from the stress in the fluid and fibers, where fiber stress is a result of the local disturbance in the fluid velocity field and of the inter-fiber contact forces. Fiber orientation is described via probability density function whose transport equation has the form of a generalized advection-diffusion equation with a orientation dependent diffusion. This equation is solved using a finite difference scheme and the results are presented versus experiments with suspensions with planar orientation in planar stretching flow. Experiments and simulation agree that increasing concentrations result in increased interaction-based diffusion.