Invited Speaker

Abstract: The combination of continuous fiber reinforced thermoplastic composites (CFRTPCs) and continuous fiber 3D printing (CF3DP) technique enables the rapid production of complex structural composites. To address the quality control challenges in 3D printing of continuous fiber-reinforced thermoplastic composites (CFRTPCs), it is crucial to thoroughly investigate the material behaviours across multiple scales and establish a relationship between processing parameters, microstructure evolution, and the quality of the final product. This can be achieved by employing advanced multi-scale simulation methods. In this work, molecular dynamics (MD) methods were utilized to investigate the interfacial mechanical and thermal properties of CFRTPCs at the microscale level. We found that the interfacial properties were improved with higher forming temperatures, and this was due to the diffusion of polymer atoms within the interface. Furthermore, it was observed that as the loading temperature increased, a notable shift in the failure mode could be also observed. At the mesoscale level, a phase field model was developed to investigate the issue of polymer crystallization within the composites, considering the effects of fibre surface properties, nucleating sites, and cooling temperature. Through our research, we aim to provide valuable insights into the fundamental principles governing the interplay of processing temperature, material type, and material microstructure evolution. These factors collectively influence the interfacial properties and transcrystalline growth of composite materials. The findings could benefit the multiscale modelling of composite manufacturing and the micro-structure design of composites with consideration of thermal management.

Keywords: Fiber-reinforced composite, thermoplastic, MD simulation, phase filed modelling