Parameter Identification of Fiber Orientation Models Based on Direct Fiber Simulation with Smoothed Particle Hydrodynamics

Abstract

The behavior of fiber suspensions during flow is of fundamental importance to the process simulation of discontinuous fiber reinforced plastics. However, the direct simulation of flexible fibers and fluid poses a challenging two-way coupled fluid-structure interaction problem. Smoothed Particle Hydrodynamics (SPH) offers a natural way to treat such interactions. Hence, this work utilizes SPH and a bead chain model to compute a shear flow of fiber suspensions. The introduction of a novel viscous surface traction term is key to achieve full agreement with Jeffery’s equation. Careful modelling of contact interactions between fibers is introduced to model suspensions in the non-dilute regime. Finally, parameters of the Reduced-Strain Closure (RSC) orientation model are identified using ensemble averages of multiple SPH simulations implemented in PySPH and show good agreement with literature data.

Variety of fiber orientation tensors

“…holds. Equation (7) implies that ψ (n) is symmetric with respect to all rotations S which are contained in the symmetry group of the microstructure S RV being a subset of SO (3). Following [30], eight different material symmetries exist and tensor representations of Hooke tensors following these symmetries are given in, e.g., [31].…”

“…Multiple kinds of orientation tensors exist [1]. Practical applications related to fiber orientations include both identification of the fiber orientation information by experimental methods [2] or process simulation [3] and usage of the orientation information in fullfield [4], meanfield [5,6], or damage simulations [7]. Both groups of applications, identification and usage of orientation information, benefit from damage simulations [7].…”

Assessment of Analytical Orientation Prediction Models for Suspensions Containing Fibers and Spheres

“…Despite the importance of the FT parameter, there exist contradicting trends and ideas about the FT parameter that is reported to range over at least five orders of magnitude. For example, Bay [24] and Mezher et al [25] assume that C I should decrease with φ f a r ; while Phan Thien et al [26], Folgar and Tucker [17], Meyer et al [7], and Fan et al [27] report it to increase. A different dependency is published by Ranganathan and Advani [28], who suggest that when the model parameter is describing the particle-particle interactions, then it must depend on the local particle orientation and therefore change over time (decreasing from 0.6 to 0.05 in their work).…”

“…On the one hand, Direct Numerical Simulations (DNS) can be applied on a particle scale, which means that the particles and the flow around them is fully resolved. Methods on this scale mainly differ in the choice whether the momentum of the particle phase is mapped back onto the fluid phase [6,7] (so called two-way coupling (TWC)), or not [2,8] (so called one-way coupling (OWC)), but they all provide the advantage that the orientation of particles can be measured. On this scale, it is also possible to include complex interactions such as surface chemistry [9], magnetism [10], or drying [11].…”

Editorial for the Special Issue on Discontinuous Fiber Composites, Volume II

“…Chang et al [12] apply the detailed fiber simulation to validate fiber breakage experiments inside a simple shear flow. Meyer et al [13] applied a direct fiber simulation approach to successfully identify fitting parameters for phenomenological fiber orientation models. Morais et al [14] present their research on carbon nanotube (CNTs) composites and investigate the influence of local nanofiber microstructure on electrical conductivity.…”