Flexible Fiber Motion in Fiber-Reinforced Composite Material Processing

Abstract

Simulation of a single flexible fiber suspension solved using partitioned fluid structure interaction (FSI) strategy is presented in this paper. The study of fiber motion during injection modeling process in composite material manufacturing is the motivation of this research. Fluid field is solved by mixed finite element method (FEM). Stokes equation is used as governing equation due to low Reynolds number characteristics. Total Lagrangian (TL) incremental FEM is used for calculating flexible fiber translation, rotation and deformation. Bathe time integration method is used for solving fiber dynamics. The interaction between the fiber (solid) and fluid results from forces on the surface of fiber, which are extracted from fluid solver and are exerted on fiber, solved as the natural boundary condition. After solid solver running forward a certain time step, new positions and velocities of each node on fiber surface are obtained which can be used for updating fluid mesh domain and served as essential boundary condition of fluid field. The process continues until the motion and deformation of fiber are obtained. Example of rigid and flexible fiber motion in a simple shear flow and a Poiseuille flow are presented in this paper. The simulation of rigid fiber are very close to the result of Jeffery’s theory. Snake rotation can be observed when the flexible fiber was tested in Poiseuille flow.