The relationship between installation stiffness and the natural characteristics of reinforced cylindrical shells and its application to structural vibration mitigation design

The study primarily focuses on the impact of the installation stiffness at the bottom of the reinforced cylindrical shell on its natural characteristics. Using the finite element modal analysis method, it systematically investigates the effects of three installation stiffness forms—rigid base, rubber pad-supported base and isolator-supported base on the natural frequencies and mode shapes of the stiffened cylindrical shell. Additionally, the influence of key parameters such as rubber pad thickness and elastic modulus on the natural characteristics of the stiffened cylindrical shell is examined. The results show that as installation stiffness increases, the natural frequencies of the stiffened cylindrical shell significantly rise, with a more pronounced effect on lower-order modes. The rubber pad-supported base maintains vibration characteristics close to those of the free state, particularly above 50 Hz. Furthermore, increasing the rubber pad thickness and decreasing the elastic modulus both lead to a reduction in natural frequency, particularly for lower-order modes, which are more sensitive to these parameter changes. These findings provide important guidance for optimizing the vibration characteristics and isolation design of stiffened cylindrical shell structures.