Coupled vibration analysis of bolted variable angle tow plates under combined nonlinear effects

To establish a dynamical modal of variable angle tow (VAT) plate accurately, the fiber path and fiber orientation of the VAT plate are described by high-order polynomials. Then, a simplified nonlinear joint model with interface dynamic partitioning is proposed to simulate the interface mechanical behavior of bolted joints. Based on these, a nonlinear semi-analytic dynamic model of the bolted VAT plate is built, which considers both material and joint nonlinearity and can accurately predict nonlinear vibration response. After verifying the proposed modeling method, a special bolted VAT plate is used as the analysis object for free vibration and forced vibration analysis. Firstly, the frequency veering behavior of the VAT plate caused by variations in boundary stiffness, connection stiffness, and fiber orientation is studied. Then, by analyzing the forced vibration response of the bolted VAT plate, it is found that under the combined effect of the modal interaction, material nonlinearity, and joint nonlinearity, the bolted VAT plate exhibited complex but rule-based nonlinear dynamic behavior. More importantly, the research work done in this paper has certain guiding significance for the optimization design of vibration resistance of a bolted VAT thin-walled structure with variable stiffness parameters and joint parameters as design variables.