Vibration response analysis and parametric study of thin-walled box H-shaped composite beams considering local wall deformation

This article presents a novel vibration analysis model for thin-walled box H-shaped composite beam structures, specifically addressing the coupling effects between local wall deformation and three-dimensional global vibration. Developed within the framework of Timoshenko beam theory, the proposed model integrates governing equations for axial, transverse, and torsional vibrations and employs the transfer matrix method to obtain semi-analytical solutions for the system’s dynamic response. The accuracy and engineering applicability of the model are validated against classical Timoshenko beam theory and a homogenizedcomputer aided engineering(CAE) model, demonstrating excellent agreement in predicting first-order modal frequencies. A comprehensive parametric study investigates the influence of key geometric parameters—including wall thickness, cross-sectional dimensions, component lengths, and front/rear panel deflection angles—on the first-order modal response. Results reveal that variations in these parameters induce significant and highly nonlinear effects on both natural frequency and response amplitude, with varying degrees of influence observed across different structural components. This study provides valuable theoretical insights and a reliable analytical foundation for the dynamic design and optimization of thin-walled composite beam structures in practical engineering applications.