The effect of automated fiber placement process parameters on interlaminar shear strength of uncured prepreg bonded samples.

The effects of automated fiber placement (AFP) parameters on the inter-laminar bonding between the uncured thermoset prepreg tapes were investigated using a systematic series of experiments and FE analysis. The goal was to optimize inter-laminar bonding during the AFP lay-up process and provide a model for the interlayer bonding of uncured prepreg tapes during this process. The shear strength of the interfacial bonding plays a pivotal role in the formation of planar and non-planar deformations during the automated fiber placement (AFP) process. The quality of this bonding has a significant effect on the quality of the manufactured parts. Besides, the bonding strength is interconnected with various AFP process parameters including compaction roller, feed rate, temperature, and dwell time. Hence, a systematic series of experimental studies are conducted to investigate how changes in process parameters affect the shear strength of single lap joint (SLJ) specimens produced under various process conditions. To fabricate the single-lap joint samples under different conditions, an in-house setup was developed to simulate the AFP process allowing us to control compaction force, feed rate, temperature, and dwell time during the process. The experimental results of the single lap joints indicate that the shear strength of the bonded prepreg tows is significantly influenced by the interaction among the process parameters rather than by their individual, isolated effects. Moreover, the responses of prepreg SLJs are simulated using the FE method. Through the comparison of numerical and experimental results, it will be clearly shown that the developed FE framework can act as a reliable approach for modeling the bonding layer between prepreg tapes.