To develop guidelines for the processing of discontinuous thermoplastic composite material in order to achieve a robust manufacturing process for advanced parts with predictable and consistent material properties
Keywords: discontinuous, chopped, woven, flakes, integrated features, consolidation
The conventional production processes of continuously reinforced thermoplastic composites provide an excellent way to manufacture shell-shaped parts with high quality, but with limited geometrical complexity. And, significant amounts of high-value scrap are generated during prepreg cutting and laminate nesting operations for, respectively, autoclave consolidation and press forming. Currently, this waste is down cycled to particulate fillers or even incinerated. Even though the nesting and trimming processes can be optimized, the scrap generation is inevitable.
This project aims to develop guidelines for producing near net-shaped parts with complex geometries using chopped woven prepreg material. Potential applications include semi-structural and non-load bearing structures. Additionally, it enables to reclaim the virgin woven prepreg scrap from the conventional production process and thereby close one part of the manufacturing value chain.
The performance of a discontinuously reinforced composite part depends on the form of the discontinuous material, design of the part and the process used. In terms of processing, atypical flow mechanisms of chopped woven prepreg flakes were identified and explained with analytical models developed from the fundamentals of fluid mechanics. On the other end, the ability of the material to fill intricate design features such as integrated ribs were assessed with scaled molding experiments. A method to assess the variability of mechanical properties, such as tensile properties, and to arrive at the material allowable was established based on phenomenological models and statistical principles.
Finally, the processing strategy developed from the results was successfully put to test in molding a full-scale, net-shaped demonstrator part with complex features such as integrated ribs, as-molded holes with boss, joggles, thickness transitions, cut-outs and embossed logo.
- Interested in application of the developed knowledge? Please contact Sebastiaan Wijskamp.
- Interested in the underlying scientific background? Please contact Iqbal Rasheed.
- New thermoplastic composites materials
- Resin Systems
- Fiber Placement
- Tailored Blanks
- Press Forming
- Welding Technologies
- Metal composite joints