Layup and curing Wing component (wing test)

The component is produced with wet layup in a similar fashion as the molds  The difficulty with wet layup is that the low resin viscosity and low tack makes it hard to preform and assemble. The plies were cut using paper templates created directly from CATIA v5. A drappability analysis was conducted on each layer to define the cutting kits.

Standard 2x2T 200 gsm was used with 5 layers on each wall. The spars have 4 layers each of the same material. Resin is Axson Epolam 2022, and was cured at 60ºC. This cure cycle was selected since this is a test wing to validate the processing, not the structural performance of the wing itself. The Epolam 2022 resin system can be postcured at 100ºC to obtain a higher Tg.

To create the assembly, the material is layup on each upper and lower moulds, including cores. After that, the spar preforms are layup on the mandrels and foam cores. Each preform is bagged and debulked separatelly before being assembled.

The end result was quite good and showed that wet layup could be used for the entire car. However, weight is such a big concern that it will have to be studied a bit further with different parts and perhaps compare that with a prepreg-alike made. For a wet layup I expect a 20% more RW than for the prepreg, but on the other hand is so much cheaper.

I am planning on making a simple sample test plan to obtain material characteristics for the FEA. Even though I do not have FEA software to compute dedicated composite elements, a shell analysis with a definition of the orthotropic properties for each type of laminate area would do. I will use the rule of mixtures to combine the different layups and materials.