Numerical model for compression molding process of hybridly laminated thermoplastic composites based on anisotropic rheology

In this work, a numerical model is developed for simulating the compression molding process of a hybrid composite material, alternately laminated with continuous and discontinuous fiber-reinforced layers. Although various process simulation models are already available for plastic materials embedding each type of the reinforcements, they are incapable of simultaneously dealing with the continuity and discontinuity. Here, thermomechanical behavior of the continuous fiber-reinforced layer and rheological behavior of the discontinuous fiber-reinforced layer are separately modeled and eventually integrated assuming perfectly bonded interfaces. The unified process model is applied to the simulation of compression molding of a full-scale battery pack structure of an electric vehicle. A simple yet robust rheology test is utilized to measure rheological properties necessary for the numerical simulation. In the full-scale simulation, thermoforming process of the hybrid charge is successfully simulated and fiber direction changes due to the suspension flow are also predicted. It is found that the reoriented fibers significantly affect stress distributions at the final stage of the process. The process model developed in the present study can be implemented into either the Lagrangian or Eulerian framework.

Automated summary

In this study, a numerical model was developed to simulate the compression molding process of a hybrid composite material with alternating layers of continuous and discontinuous fiber reinforcement. The model successfully integrated the separate modeling of the thermomechanical behavior of the continuous fiber-reinforced layer and the rheological behavior of the discontinuous fiber-reinforced layer. The developed process model was applied to the full-scale simulation of a battery pack structure in an electric vehicle, accurately predicting the thermoforming process and fiber direction changes. The reoriented fibers were found to significantly affect the stress distributions at the final stage of the process. The process model can be implemented in either the Lagrangian or Eulerian framework.