Equivalent Structural Modeling Using Laminated Composite Shell Analysis for the Nozzle Component of a Launch Vehicle Engine

In this study, an equivalent structural modeling and structural analysis are proposed for the engine nozzle of a launch vehicle. A specific shell element that combines an optimal triangle (OPT) membrane element and a discrete Kirchhoff triangle (DKT) plate-bending element is developed. Equivalent structural modeling is performed for a complex three-dimensional component and especially for the launch vehicle engine nozzle by considering the outer/inner surfaces and cooling channel of an engine nozzle. Shell element and an optimization approach are used for the relevant orthotropic material properties. Laminated composite material and curved geometry are considered in the shell analysis to consider a realistic engine nozzle component. The accuracy and efficiency of the present structural analysis are validated by performing a relevant modal analysis. The results indicate that the equivalent structural modeling procedure is correlated with the prediction that accounts for the original solid element assemblage. The efficiency of the equivalent structural modeling is ascertained by the reduction in the number of degrees of freedom and computational cost. The application of the present equivalent structural modeling for a more complex component, i.e., multiple-clustered engine nozzles facilitates large-size fluid-structure interaction analysis.