Evaluation of the Impact of Winding Density on the Strength of Composite Hybrid Tanks

When designing aerospace structures, there is always the challenge of meeting conflicting requirements. On one hand, the structure must comply with strength and stability demands, while on the other, it must have minimal weight. A review of existing materials and structures [1] shows that composite constructions are the most promising [2–4]. However, when designing tanks, inflatable shells, or any type of container, in addition to meeting operational criteria, airtightness is always a mandatory requirement. Hybrid tanks utilizing a metallic liner successfully fulfill this requirement. When using the filament winding technology with composite tape, it is not always necessary to cover the entire surface of the shell, which raises the question of winding density. This paper aims to determine the impact of winding density in a hybrid tank. It is focused on implementing a simplified modeling method that can be used for preliminary tank structure design. The method allows for analyzing the influence of winding geometric parameters and the mechanical properties of the composite reinforcement tape on the overall mass of the hybrid tank. The study is based on constructing a simplified orthotropic model of the composite reinforcement. The numerical experiment conducted revealed the relationship between stresses and strains under varying winding densities and established a performance criterion for the composite. It is recommended that the composite’s performance assessment be based on the strain-based strength theory. The study is limited to analyzing the influence of winding density through refined physical and mechanical properties of the composite, based on different spacing between reinforcement tapes, and does not address the optimization of structural parameters. The work is intended for using first-approximation results in building a model for finite element analysis. Future research may focus on applying the method for parametric shell modeling using finite element analysis and conducting numerical experiments to determine a viable minimum-mass design.