The superior nature of long fiber reinforced thermoplastics (LFTs) in terms of properties such as specific modulus, strength, and excellent impact resistance, along with their lightweight properties, ease of processability and recyclability make them one of the most competitive materials leading to their growth in various fields of applications.
With the growing rise of LFTs, the research on their mechanical properties and their processing has grown as well. Injection molding method has been one of the most widely applied production method for LFTs processing. Research has shown that the mechanical edge offered by the LFT products obtained from injection molding is dependent on the lengths of the fibers in the final product. This makes it important to understand the breakage of fibers during processing.
This work addresses the breakage of fiber in injection molding by conducting a thorough review of the industrial, experimental and theoretical research done in the field. Following this, simulation approach has been undertaken to understand the fiber breakage in geometries which represent slightly complex shapes as compared to the conventionally used shapes. Based on the theoretical research, the state-of-the-art models have been reviewed and compared in their ability to produce reliable fiber breakage results.
The results showed the influence of rheology and geometry on fiber breakage in simulations, where shear rates led to higher fiber breakage and increasing viscosity led to a slight reduction in breakage. Further, the simulation study provided inconsistent results with variation in geometry, and a need for further fine tuning of simulation parameters was observed. The theoretical models applied in the study gave reliable results in terms of the trends of the fiber breakage, with a novel model, called Bechara model, showing acceptable and more time efficient results, in comparison with the currently applied commercial model, Phelps model.