关键词: 复合材料壳体, 纤维缠绕, 层合板, 板壳理论, 封头应力分析

Abstract: Generally, inconsistent radial displacement at the equatorial circle is caused by the calculation of stress field based on the cylindrical shell and Laplace film theory for the cylinder body and the head respectively, and this inconsistency arises the phenomenon of theoretical structural separation which is incompatible with the actual deformation during the overall loading process. Due to the variation of angle, thickness and curvature of the fiber-wound composite shell head, the calculation of stress field is very complicated. Taking the inconsistency of radial displacement and deformation at the equator as starting point, the method of theoretical analysis of complex force field of fiber-wound composite head not only considers the sudden change of the structure curvature at the equatorial circle, but also considers that of the stiffness of material on the structure at the same time. And by making the metal connector end face pressure load to be the equivalent load of contact part of the composite, the radial film displacement under the equivalent load of pole hole is used as the boundary condition of the control equation. Based on the plate and shell theory, this paper discussed the calculation method of the moment stress field of the fiber-wound composite case head, and established a theoretical model of composite rocket case with bending moment, explored the reason why pole hole always swell damage. A standard pressure test of a ø150 dry winding composite case was carried out, the comparison of analytical and numerical solutions show that the method has good approximation accuracy to describe the stress field distribution of the fiber winding composite material layers. According to the theoretical calculation results, reveals internal mechanism from the aspects of structural mutation and material stiffness mutation, as well as the law of shell stress under different winding schemes. This calculation method has the potential to lay a theoretical foundation for a reasonable structural design, which is of great significance to quickly understand the overall strain state of the case at the beginning of design.

Key words: composite materials shell, filament winding, laminate, plate and shell theory, stress analysis of dome