An Approach for Predicting Fiber Orientation Distribution in Plastic Injection Molding of Composites

Aims: This paper presents an approach for predicting the fiber orientation distribution in plastic injection composites.
Methodology: By introducing fiber orientation tensor, the average distribution of fibers in the composite is acquired through injection molding simulation with Autodesk Moldflow Simulation Insight version 2014. Quantitative fiber orientation distribution along thickness at specific spot is obtained by image analysis on microscopic photos of samples. The proposed approach is demonstrated by a car instrument panel made from injection molding of thermoplastics with glass fibers. Tensile test samples are cut from the instrument panel with an angle of 0º, 45º, 90º to the fiber orientation at sites where fibers are highly aligned for measuring tensile modulus. The fiber orientation distribution and its effect on the tensile modulus are investigated.
Results: It is shown that the car instrument panel is heterogeneous in mechanical properties. The fibers are roughly distributed into three layers along the thickness with each layer having roughly aligned fibers.
Conclusion: It is necessary to consider the effect of fiber orientation and thickness layer distribution on the mechanical properties during numerical analysis of plastic injection composites.