Generation and analysis of digital twins for CoDiCoFRP accounting for fiber length and orientation distribution

We present an adaption of the Orientation Corrected Shaking (OCS) method, originally developed for discontinuous short fiber-reinforced polymers, for generating continuous discontinuous fiberreinforced polymers. Due to the combination of continuous and discontinuous reinforced phases, the interface between the two layers needs to be accounted for in a realistic way. The material flow during compression molding of CoDiCoFRP leads to ply migration at the interface resulting in an interlinked region between the layers, which is observable in 3D imaging. To account for this type of interface, we adapt the OCS method to enforce soft constraints for the fibers, i.e., a fiber’s midpoint but not the entire fiber is constrained to its respective layer. Hence, at the interface fibers may penetrate the opposite phase, providing a link between the phases. In a computational study, we generate CoDiCoFRP with the OCS method and investigate whether the selection of the fiber length distribution type for given volumeweighted mean 𝑚 and standard deviation 𝑠 influences the effective stiffness of the generated microstructures. For Weibull, Gamma and log-normal distribution the results almost coincide, with differences smaller than 0.5%, revealing that for these cases the statistical quantities 𝑚 and 𝑠 are the only important descriptors to model the fiber length distribution.