One of the areas where composite materials are increasingly being used as replacements for conventional materials is in high temperature applications. Ceramic or metal Matrix Composites have become popular in applications that require high-temperature resistance. Their high costs of fabrication have limited their usage.
This research, however, focused on the needs of the aerospace industry in connection with the use of high temperature polymer matrix composites for structural components in the vicinity of power units.
In this project, the partners investigated the issues related to the processing of high temperature resin systems using the resin infusion process, especially the vacuum assisted resin infusion (VARI) system, a cost-effective method for manufacturing composite materials. Various initial trials helped to understand the polymeric resin systems (epoxy, cyanate ester, benzoxazine, bismaleimid, and their blends, etc.), dynamics of the used VARI and Quickstep (an out-of-autoclave, OoA) process and identify critical factors and key parameters. Based on the material selection and process screening, various laminates were tested for mechanical properties and thermal properties and the results will be compared with the requirements. Processing investigations for the eco-friendly manufacturing concepts and optimisation of polymeric resins and their cure kinetics led to the demonstration of liquid resin infusion-OoA methodology and manufactured a set component for further analysis.
This investigation ended with the recommendation on serial production and automation of the processes.
The objective of LRI-HiT was to primarily investigate and evaluate the producibility of composite laminates using a vacuum assisted process, a resin system that provides high thermo-mechanical properties, and Out-of Autoclave (OoA) QUICKSTEP curing. After the proven technological integration of processes, a part was manufactured to demonstrate the technological solution’s readiness at TRL 5-6.
For the combination of OoA process design, existing heated tool technologies and Quickstep’s flexible membrane concepts were evaluated. Considering the resin infusion and fast curing possibilities, the heated tool design and quickstep processing methods were modified. As an output, rigid heated mould tool that gives a final shape to the part and flexible membrane tool that exerts pressure and temperature during the processing is available. This helped to improve the temperature distribution over the entire tool surface as well as rapid heat transfer to reduce the processing time.
The integrated processes have been tested for their functionality and understood the process implications before manufacturing a demonstrator part. Upon successful initial tests, a 3D, T-stiffened representative part was manufactured which resembles the structure of the section-19 of an aircraft.
High temperature resistance resins operating temperature in the range of 200 °C were screened, tested for their performance and selected for the final demonstrator manufacturing. The goal of selection of a resin system that is less complicated and good for the infusion process has been achieved.
Process integration of rigid heated tool, matching, flexible Quickstep membrane, liquid resin infusion and fast heating concept has been successfully completed and the validation components are manufactured. A full-scale demonstrator has also been infused and cured using the newly developed technology. Materials and energy required for the demonstrator manufacturing were well tracked and documented for the purpose of assessing environmental impact and advantages over the state-of-the-art processing.
The developed curing technology is available for the further manufacturing trials as well as for the research activities at Quickstep GmbH.