Experimental Investigation of Process Induced Deformations of Automotive Composites with Focus on Fast Curing Epoxy Resins

Abstract

Due to the non-isotropic nature of carbon fibre reinforced plastics (CFRP) unavoidable deformations occur during part production. These deformations often lead to dissatisfaction of tolerances or result in cost and time intensive rework of the tooling. In a cost driven production environment, similar to the automotive industry, it is essential to predict the deformations beforehand in order to compensate the used tooling. In future applications Fast Curing Epoxy Resins (FCER), with curing times of less than 20 minutes, will play a key role in order to enable high rate CFRP-production at lower cost. Until now, minimal experimental data exists for FCER systems. The present paper reports on a comprehensive experimental study on different FCER systems. It includes the characterization of neat resin samples as well as the quantification of the spring-in deformation of different L-profiles. Additionally, a study of parameters such as lay-up, temperature, cooling rate and fibre volume fraction concerning their influence on the process induced deformations is performed. Finally, the results are compared to slower curing systems. The findings of the study are relevant for the future development of robust prediction methods for process induced deformations of FCER-based composites.