Forms, fibres honeycomb

Aramid fibre dipped in liquid phenolic, polyester or polyamide resin to form a paper can be used to form a honeycomb (NOMEX). Properties are dependent on paper thickness, cell geometry and size. Advantages of non-metallic honeycomb cores are absence of internal corrosion and impact resilience. 

In the vacuum infusion process, the fibre sheets are placed in a dry state with a plastic sheet laid over the entire form to create a vacuum. Resin is introduced at one end. The vacuum enables the flow of the resin and an even distribution of the matrix through the fibres. In comparison with the hand laminating process, a higher volume of fibre can be achieved in the composite material. However, it is difficult to control the flow of the resin along edges, comers, etc. It is also not possible to vacuum-infuse honeycomb materials for a sandwich structure. 

Marissen, R., Duurkoop, D., Hoefnagels, H., Bergsma, O. K. Creep forming of high strength polyethylene fibre prepregs for the production of ballistic protection helmets. Composites Science and Technology 2010 70(7) 1184-8 (Special issue on Chiral Smart Honeycombs). 

Fibrelam board skins coasist of unidirectional glass-fibre/epoxide resin. The skins are pre-made in the form of sheets for subsequent bonding to the honeycomb core. 

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