Finite element‐assisted analysis of experimental out‐of‐plane impregnation behavior of reinforcement textiles

Abstract The accurate characterization of out‐of‐plane permeability is crucial for the process design of composite parts involving through‐thickness resin impregnation. Through‐thickness permeability measurement of reinforcement textiles is however extremely challenging due to the dynamic interaction of fluid and reinforcement. In order to design the measurement equipment correctly and decide on correct processing parameters (in particular, injection pressure for different stiffness materials at different fiber volume fractions) complimentary finite‐element based simulations can be used to help analyze and understand the complex behavior of both fluid flow and textile compaction, which occurs during physical experiments. The simulation results, which can only be validated through outputs, such as flowrate, flow front development and to a limited extent textile displacement, available from the experiments, provide quantitative indications of the nonuniform through‐thickness fiber volume fraction distribution (not possible to measure via experiments) and therefore deviations from the measurement target fiber volume fraction. In this work, this methodology is used to analyze two reinforcement materials with significantly different compaction and permeability characteristics to provide possible insights into differences between saturated and unsaturated permeability measurements. Highlights Understanding hydrodynamic compaction by combining experiments and simulations. Simulation results validated by sensors integrated into the physical equipment. Out‐of‐plane fiber volume fraction distribution difficult to measure. Simulations provide visualization of fiber volume fraction distribution. Insights into causes of differences between saturated/unsaturated permeability.