Multi-scale simulation and analysis of process-induced thermo-chemical phenomena during the curing of thick-walled thermoset fibre composite laminates

• Applicant: Professor Dr.-Ing. Christian Hopmann
• Subject Area: Plastics Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 530751617

In the proposed research project, the process-dependent material behaviour of thick-walled thermoset fibre-reinforced plastics (FRPs) with continuous fibre reinforcement is to be analysed for the first time during the curing and cooling process, taking into account time- and spatially-resolved changes in the degree of cure. The applicant pursues the approach of describing the thermo-chemical phenomena that occur and the temperature equalisation processes inside the FRP in their entirety to develop an appropriate and efficient modelling and homogenisation strategy based on this for transferability to laminate and multilayer composites. The project's overall objective is the realistic and cross-scale prediction of the temperature equalisation processes occurring during the processing of thick-walled thermoset FRPs, taking complete account of cross-linking and temperature-dependent material characteristics. The time and spatially resolved temperature and curing degree distribution in a thick-walled FRP laminate are simulated, starting immediately after the fibre impregnation process up to the complete cooling process. Based on validation tests, it is to be shown that the developed macro-model can be used to precisely describe the temperature and curing degree distribution in thick-walled laminates. Furthermore, by linking the developed thermo-chemical model with an existing cross-link-dependent thermo-viscoelastic material model, a mechanistic model for FRP will be developed, which precisely describes the residual stress development on RVE level. By linking temperature compensation processes with thermo-chemical phenomena during the curing and cooling process, the understanding of the process can substantially be increased and provides a basis for further advanced process design and optimisation. For this purpose, the current state of research will be used and extended in the cross-link-dependent modelling of material behaviour. In particular, the thermo-chemical properties of the epoxy resin (EP) will be consistently characterised and modelled as a function of temperature and cross-linking. Our research on EP suggests that if heat conduction and heat of reaction are neglected, deviations from the expected material behaviour (e.g. non-linear shrinkage) and influencing the reaction kinetics can occur.

• DFG Programme: Research Grants