Types and characteristics of sandwich structure manufacturing technology in FRP production process

Sandwich structures are generally composites made of three layers of material. The upper and lower layers of the sandwich composite material are high-strength and high-modulus materials, and the middle layer is a thicker lightweight material. The FRP sandwich structure is actually a recombination of composite materials and other lightweight materials. The sandwich structure is used to improve the effective utilization of materials and reduce the weight of the structure. Taking beam-slab components as an example, in the process of use, it is necessary to meet the requirements of strength and rigidity. The characteristics of glass fiber reinforced plastics are high strength, Modulus is low. Therefore, when a single glass fiber reinforced plastic material is used to make beams and slabs to meet the strength requirements, the deflection is often very large. If the design is based on the allowable deflection, the strength will be greatly exceeded, resulting in waste. Only by adopting the design of the sandwich structure can this contradiction be solved reasonably. This is also the main reason for the development of the sandwich structure.

Due to the high strength, light weight, high rigidity, corrosion resistance, electrical insulation and microwave transmission of the FRP sandwich structure, it has been widely used in aircraft, missiles, spacecraft and models, roof panels in the aviation industry and aerospace industry. Reduce the weight of the building and improve the use function. The transparent glass fiber reinforced plastic sandwich panel has been widely used in the lighting roofs of industrial plants, large public buildings and greenhouses in cold regions. In the field of shipbuilding and transportation, FRP sandwich structures are widely used in many components in FRP submarines, minesweepers, and yachts. The FRP pedestrian bridges, highway bridges, automobiles and trains, etc. designed and manufactured in my country all adopt the FRP sandwich structure, which meets the multi-performance requirements of light weight, high strength, high rigidity, heat insulation and heat preservation. In the lightning cover that requires microwave transmission, the FRP sandwich structure has become a special material that other materials cannot compare with.

Types and characteristics of FRP sandwich structures

According to the different types and forms of core materials used in the sandwich structure, the FRP sandwich structure is divided into: foam sandwich structure, honeycomb sandwich structure, trapezoidal plate sandwich structure, rectangular sandwich structure and circular sandwich structure.

(1) Foam plastic sandwich structure The foam plastic sandwich structure uses glass fiber reinforced plastic sheet as the skin (panel) and foam as the core layer. Components with little force and high thermal insulation performance requirements, such as aircraft tails, thermal insulation ventilation ducts and templates.

(2) Honeycomb sandwich structure The honeycomb sandwich structure uses glass fiber reinforced plastic sheet as the skin, and honeycomb material (glass cloth honeycomb, paper honeycomb or other cotton cloth and aluminum honeycomb, etc.) as the core layer. The honeycomb sandwich structure is light in weight, high in strength and high in rigidity, and is mostly used for structural parts with large structural dimensions and high strength requirements, such as load-bearing plates of FRP bridges, spherical roof structures, radomes, reflective surfaces, refrigerated truck floors and box structures Wait.

(3) Trapezoidal and rectangular lead-action layer structure The panel (skin) of this lead-action layer structure is a glass fiber reinforced plastic sheet, and the sandwich layer is a glass fiber reinforced plastic trapezoidal plate or a rectangular plate. This sandwich structure has strong directionality and is only suitable for high-strength flat plates, not for products with curved shapes.

(4) Ring-shaped sandwich structure It uses a glass fiber reinforced plastic sheet as the skin and a glass fiber reinforced plastic ring as the core layer. The characteristics of this sandwich structure are that the core material consumption is low, the strength is relatively high, and the force of the plate has no directionality. It is the most suitable transparent glass fiber reinforced plastic sandwich structure plate for lighting.

Post time: Mar-02-2022

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