An engineering approach for Prepreg characterization

Abstract

Characterizing prepregs for process-simulation purposes is expensive. The present paper reports on a novel approach for thermoset prepreg characterization. It focusses on determining key-parameters which allow for comparing prepregs from a process-induced distortion (PID) perspective. The approach uses conventional thermomechanical-analysis (TMA) devices for data generation. It analyzes through-thickness strains along the whole curing process, which are the dominant driver for spring-in distortions. The measured data is utilized in a parameter-fitting scenario, allowing for characterizing compaction, chemical shrinkage and thermal dilation. Aside from magnitudes, the approach also provides information when chemical-shrinkage occurs during the process. The approach is applied here for quasi-isotropic carbon-fiber-epoxy-resin samples made from (QI) 8552/AS4 while selected comparisons with a corresponding M21E/IMA sample are provided for sake of capability demonstration.