Experimental investigation of the curing behaviour of fibre composite structures with snap-cure polymer systems

摘要

Purpose - Novel snap-cure polymers (SCPs), as matrix systems for high-performance fibre composite materials, provide high potential for manufacturing of component families with small batch sizes and high variability. Especially, the processing of powdered SCP is associated with relatively simple and inexpensive tools. In addition, because of their curing behaviour, they allow short tooling times so that the production of small batch size components is possible in relatively short cycle times. To enable an efficient manufacturing process, an understanding of the curing process is necessary. An adjustment of the process parameters for a uniform design of the temperature field in the material during the manufacturing process is essential. The paper aims to discuss this issue. Design/methodology/approach - For this, a powder SCP resin system was investigated under process-specific conditions. An experimental test approach for determination of various thermal and kinetic material properties was developed. For the adjustment of the process parameters and monitoring of the curing state during the manufacturing process, a kinetic material model was determined. In the end, the validation of the determined model was performed. For this, the temperature distribution under process- specific conditions was measured in order to monitor the curing state of the material. Findings - The experimental investigation showed an uneven temperature field in the material, which leads to an inhomogeneous curing process. This can lead to residual stresses in the structure, which have a critical impact on the material properties. Originality/value - The determined kinetic model allows a prediction of the curing reaction and adjustment of the process parameters which is essential, especially for thick-walled components with SCPs.