Three‐dimensional Numerical Simulation on Fiber Orientation of Short‐glass‐fiber‐reinforced Polypropylene Composite Thin‐wall Injection‐molded Parts Simultaneously Accounting for Wall Slip Effect and Pressure Dependence of Viscosity

On account of the inherent features of the thin-wall injection molding process, a three-dimensional numerical model, which accounts for wall slip effect and pressure dependence of viscosity (PDoV), was proposed for a more accurate simulation of the fiber orientation in thin-wall injection-molded parts of short-glass-fiber-reinforced polymer composites (SGFRPC). First, the fiber orientation was simulated using the three-dimensional and mid-plane models, respectively. The comparison between the simulated and experimental results verifies that the three-dimensional numerical results were in better agreement with the experimental measurements. Secondly, the influences of wall slip effect and PDoV on fiber orientation in thin-wall injection-molded parts of SGFRPC were analyzed based on the three-dimensional numerical model. The results show that the three-dimensional numerical simulation simultaneously accounting for wall slip effect and PDoV can better predict the fiber orientation in thin-wall injection-molded parts of SGFRPC, suggesting the validation of the proposed model. Finally, five main processing parameters, that is, injection rate, melt temperature, mold temperature, packing pressure, and packing time, were also studied in terms of their influences on the fiber orientation in thin-wall injection-molded parts of SGFRPC.