A Comprehensive Review of the Physics Involved in Modelling Transport Phenomena Associated with Extrusion-Deposition Additive Manufacturing Process

The dilemma of most upcoming researchers in the field of fiber reinforced polymer (FRP) composite processing is not the lack or accessibility to relevant background literature but rather their comprehensive nature, or their applicability to the specific needs of the researcher. Most existing literature either target just a specific modeling aspect or present high-level overview of the overall FRP process which lacks necessary underlying physics, coupling across hierarchical physics scales and computational techniques needed to improve on existing process simulation tools without necessarily reinventing the wheel. The current review article presents detailed understanding of the overall FRP composite process, the relevant transport phenomena and underlying physics across various scales and current trends in computational solution techniques used to predict FRP composite melt-flow phenomena in order to develop well equipped process-structure-property (PSP) maps for improved process monitoring and optimized print properties and performance. The overall position of potential research opportunities from survey of existing simulation efforts includes (i) the refinement of existing and development of new quantitative and qualitative multiscale models for predicting transport phenomena, (ii) development of new closed-form tensor evolution equations and constitutive relations with new information of the bulk fiber and melt-flow field states, and (iii) proper model benchmarking with experimental observation from in-situ process monitoring, and development of machine learning tools for the creation of a robust PSP map.