Composite core foam plastic refers to a new material formed by compounding two or more heterogeneous, special-shaped, and heterosexual materials. In addition to retaining the main characteristics of the original component materials, it can also obtain the original components through the composite effect. New excellent properties that the material does not have. According to their basic materials, composite materials can be divided into three categories: polymer (resin) matrix composite materials, metal matrix composite materials and inorganic non-metallic material matrix composite materials.


Aerospace and aeronautical engineering aircraft are very sensitive to structural quality and need to be made of lightweight and high-strength materials. In the nearly 100 years of aircraft development and more than 50 years of space engineering development, people have been looking for lightweight and high-strength materials. In the 1940s, people discovered glass fiber reinforced plastics, and later developed into advanced composite materials, which solved the problem of light weight and high strength of materials.


Almost at the same time, people discovered the sandwich structure, creating a structure with reasonable use of materials to meet the requirements of light weight and high strength. The basic structural foam of the sandwich structure currently used in engineering is composed of two upper and lower thin and strong panels and a lightweight core material that is filled in and firmly connected to the panels. There are many materials used for panels, such as aluminum, stainless steel, composite laminates, plywood, cardboard, etc.





There are foam sandwich structures, honeycomb sandwich structures and corrugated sandwich structures according to the form of the core material used. With the rapid development of polymer composite materials, the core materials used for foam sandwich structures are mainly polystyrene foam, polyurethane foam, and polyvinyl chloride foam. In recent years, polypropylene, chlorinated or sulfonated foams have appeared Polyethylene, polycarbonate, PTFE and other foamed plastics.


The sandwich panel can be regarded as a special form of laminate, that is, a layer of lightweight sandwich material is sandwiched between the two layers, and this layer of sandwich has a certain transverse shear stiffness. This structure has greater flexural rigidity because the material with greater strength and transverse weight is arranged at a position away from the centroid of the section, so it is mostly used as a flexural member for lateral loads. The bending analysis of the classical theory of thin plates or composite laminates is based on the assumption of Kerchhoff's straight normal. It is considered that the transverse shear modulus of the plate is infinite, so the transverse shear strain is zero when bending.