Particle simulation for predicting fiber motion in injection molding of short-fiber-reinforced composites

Abstract

This study proposes a numerical analysis for predicting fiber motion during injection molding of short-fiber-reinforced composites using the moving particle semi-implicit (MPS) method. Its meshless and Lagrangian nature enables us to track individual fibers and to easily represent free surfaces. In this study, the mechanism of fiber orientation in a T-shaped bifurcation was investigated experimentally and numerically. The fiber orientation of injection-molded glass-fiber/polypropylene composite was observed by X-ray CT. Despite the symmetric mold shape, there was asymmetric fiber orientation due to the mold filling process.Fiber motion in the bifurcation was then analyzed by the proposed simulation, and the fiber orientation was quantitatively evaluated in each small region. The prediction agreed well with the experiment, and the associated mechanism of fiber orientation is discussed. Furthermore, this approach explicitly demonstrates the interaction between fibers, which is an advantage of the proposed approach.

Smoothed particle hydrodynamics simulation for injection molding flow of short fiber-reinforced polymer composites

“…The distance between the particles was 0.15 mm; the single fiber was modeled as a rigid body composed of 10 particles (fiber aspect ratio was 10), and the initial position of the fiber was vertical to the plates. 20 The densities of the fluid and fiber were 900 kg/m 3 and 1500 kg/m 3 , respectively.

Figure 3.The SPH analytical model of a single fiber in the simple shear flow.

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“…Consequently, the important influences of the heterogeneous distribution and fiber accumulation during the injection molding process may not take into consideration. To address these ignored influences, Yashiro et al 19,20 have predicted the injection molding process of SFRP composites using a meshless method called moving particle semi-implicit (MPS). Several injection molding models with different geography were analyzed, and the motion of individual fibers can be followed since the specific fibers were modeled.…”

Kriging‐based orthotropic closure for flow‐induced fiber orientation and the part stiffness predictions with experimental investigation

“…Londoño‐Hurtado et al found that the Folgar–Tucker model can predict the fiber orientation, and presented a mathematical model to model orientation distribution in the processing of fiber‐reinforced composites. Yashiro et al developed a numerical method for predicting fiber motion during injection molding of short fiber‐reinforced composites by the moving particle semi‐implicit method. And they numerically investigated the fiber orientation mechanism of the T‐shaped bifurcation with the meshless and Lagrangian nature of the method.…”

Sequential kriging‐based closure approximations for flow‐induced fiber orientation and prediction of composite stiffness

“…As a result, knowing the flow induced fiber orientation is of great importance because the fiber orientation state significantly affects the composite mechanical properties. Accordingly, accurate and efficient predictions of the fiber orientation are challenging tasks and have been investigated for many years owing to their industrial applications .…”