Numerical and experimental analyses in composites processing: impregnation, heat transfer, resin cure and residual stresses

This is a literature review of the published scientific results by the authors on numerical modelling and experimental characterization of composites processing with a focus on the resin injection pultrusion (RIP) process. Differential scanning calorimetry is used to obtain cure kinetic parameters for an epoxy resin system. The cure kinetic parameters are used for thermo-chemical simulations of the RIP process which are subsequently validated by temperature measurements. Scanning Electron Microscopy (SEM) and X-ray Computed Tomography (XCT) are used to characterize the microstructure of a glass fiber reinforced polyurethane profile. SEM was used to obtain the variation in cross-sectional fiber volume fraction and subsequently relating this variation to permeability. XCT was used to obtain individual fiber inclination and relating these inclinations to the observed reduction in longitudinal stiffness as proposed in literature by Herbert Krenchel. Considering multi-physics modelling of the RIP process two new state-of-the-art approaches are summarized in this work: i) a coupled flow-thermo-chemical model necessary for thick-section profiles, and ii) a steady state 3D-Eulerian approach for thermo-chemical-mechanical simulations showing a significant increase in computational performance compared with the traditional Lagrangian approach. Finally a study by Mortensen et al., on how to minimize residual stresses by minimizing the gelation temperature is reviewed.