Composite multi-closed-chamber thick-walled box beam and integral moulding method

Abstract

The invention brings forward a composite multi-closed-chamber thick-walled box beam and an integral moulding method. The box beam comprises a multi-closed-chamber box framework and an external skin. The multi-closed-chamber box framework adopts a fiber reinforced material / prepreg resin system, and the external skin adopts a fiber reinforced material fabric / liquid molding resin system. The multi-closed-chamber box framework and the external skin are integrally formed. A layer of fibrofelt reinforced resin film is also included between the multi-closed-chamber box framework and the external skin. The fibrofelt reinforced resin film has a consistent resin system with the external skin. By inserting a layer of the fibrofelt reinforced resin film with lower surface density between the internal framework and the external skin, the resin film has good compatibility with the prepreg resin system and the liquid molding resin system in the curing mechanism. In addition, the influence on flow of the liquid molding resin is little, interface connection quality between the internal framework and the external skin is improved, and internal quality and integrity of the product are improved.

Description

technical field [0001] The invention relates to a composite material multi-closed thick-walled (referring to the case where the ratio of the wall thickness to the maximum dimension of the section is greater than 0.05) box-shaped beam and an integral forming method, belonging to the technical field of composite materials. Background technique [0002] Compared with simple cross-section beams, multi-closed box beams have good resistance to bending, transverse shearing and torsion. As an important engineering structural element in advanced equipment, they are widely used in aerospace, ground transportation, Marine ships and other fields. With the continuous improvement of advanced equipment's demand for lightweight structures, resin-based composite materials have gradually become one of the preferred alternatives to traditional metal materials due to their high specific strength and high specific modulus. [0003] The multi-closed box beam is generally composed of a "foam core...

AI Technical Summary

Problems solved by technology

If the autoclave forming method is adopted, the internal closed-chamber structure and the skin structure need to be prepared separately first, and then combined into a whole structure through secondary cementation and curing. On the one hand, this method needs to use expensive autoclave and other equipment, and also requires Multi-step curing leads to longer product preparation cycle and higher cost; while using the traditional RTM molding method, when the length of the multi-closed box beam is longer and the wall thickness is larger, the resin flow is longer and it is not easy in the direction of wall thickness. Sufficient infiltration resulting in quality defects such as dry spots, delamination or porosity

At present, multi-process compounding is a direction of research on composite material molding methods, such as RTM and compression molding composite molding of various products with relatively complex structures; however, due to the differences in curing mechanism, viscosity, etc. between the prepreg resin system and the liquid molding resin system During the molding process, the prepreg resin system will be in a very viscous state at the interface between the two resin systems, which will hinder the flow and consolidation of the liquid molding resin system, and easily form pores at the interface. Defects such as delamination, which in turn affect the internal quality of the final part

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