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

**Nils Meyer 1,\*, Oleg Saburow 1, Martin Hohberg 1, Andrew N. Hrymak 2, Frank Henning 1,3 and Luise Kärger 1**


Received: 29 May 2020; Accepted: 14 June 2020; Published: 22 June 2020

**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 agreemen<sup>t</sup> 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 agreemen<sup>t</sup> with literature data.

**Keywords:** short fiber reinforcement; process simulation; smoothed particle hydrodynamics
