A reduced-order model for geometrically nonlinear curved beam structures with substructuring techniques

Modularization of complex structures allows for faster, higher quality, and more cost-effective design. However, sharing information about the geometry and materials of the modules presents a security risk when multiple companies are involved in the project. In such cases, an equivalent model can be developed for secure sharing purposes. The equivalent model should be able to predict the nonlinear geometrically behaviour of the module. This paper aims to develop a nonlinear equivalent model for substructures based on a combination of the Craig-Bampton technique and model order reduction. The paper provides explicit formulas for constructing the reduced-order matrices of the equivalent model based on third-order and fifth-order modal polynomial approximations. The ability of the equivalent models to simulate the geometrically nonlinear static displacements of structures is evaluated through two numerical examples of beam structures.