Free vibration and global sensitivity analysis of perforated composite skew shallow shells on elastic foundations

Abstract

This paper deals with the development of a finite element model for the free vibration analysis of laminated composite skew shallow shells resting on a two-parameter elastic foundation and containing cutouts. The first-order shear deformation theory, including rotatory inertia effects, has been employed to model the shell deformations. A nine-node isoparametric finite element formulation with five degrees of freedom that achieves C⁰ continuity of the displacement and rotation fields across inter-element boundaries has been developed. Numerical examples show excellent accuracy and convergence characteristics of the present formulation for shallow shells having a planform length to shell curvature ratio of up to 0.5. A sensitivity analysis of the skew shell parameters with cutouts and elastic foundations using a Gaussian process machine learning based surrogate modelling technique has been proposed. New results of free vibration analysis of skew shallow shells with cutouts are presented, and the combined effects of skew geometry, cutouts, and elastic foundation on the frequency response of curved shells are discussed. The proposed methodology provides a computationally efficient and accurate framework for the dynamic analysis of complex laminated composite skew shallow shell structures.