Summary:When designing the core foam plastic, the main factor consid...
When designing the core foam plastic, the main factor considered for the panel is the strength and stiffness of the material, and for the core material, the main factor considered is the substantial weight reduction. Aluminum honeycombs, foams or NOMEX® honeycombs are commonly used as core materials in aircraft structures. Aluminium honeycombs or NOMEX® honeycombs have the advantage of high compressive modulus and light weight, they are widely used sandwich materials in aircraft structures, usually with carbon/glass fiber prepregs.
Common structures include wing leading edges, rudders, landing gear doors, wing bodies and wingtip fairings. Although the honeycomb sandwich structure has outstanding performance advantages over the metal sheet metal structure, airlines are still actively looking for its alternative materials, because the honeycomb sandwich material requires high maintenance and repair costs during use.
In some cases water and moisture can easily enter the honeycomb when cracks and pores appear in the panel. At low temperature, the water entering the honeycomb cells will expand after being frozen, which will destroy the bonding of adjacent honeycomb cells, which reduces the performance of the sandwich structure and must be repaired. The maintenance cost of the honeycomb sandwich structure makes the original light-weight advantage no longer exists compared with the foam sandwich structure.
Since the rigid foam core is closed-cell, water and moisture cannot enter the core, reducing the cost of maintenance and inspection, so the life cost of the foam core structure is more economical, although the weight of the foam to achieve the same shear capacity is higher Slightly heavier than honeycomb. With a series of problems in the use of composite honeycomb sandwich structures, researchers in the aerospace industry at home and abroad have turned their attention to high-performance polymer foam core materials, mainly PMI foam materials.
The use of foam cores in sandwich structural members can both reduce manufacturing costs and serve as a structural material. If only considered as a structural material, the design of the foam core sandwich structure and the honeycomb core sandwich structure is mainly at a disadvantage in terms of weight.