Nonlinear vibration characteristics of elastically supported FRP cylindrical shells under temperature gradient conditions: Theoretical and experimental studies

The nonlinear free vibrations of elastically supported fiber-reinforced polymer cylindrical shells (FRPCSs) under temperature gradient conditions are investigated using both theoretical and tested techniques. A dynamic model of the FRPCSs with consideration of such complex thermal conditions is firstly established based on the first-order shear deformation theory in conjunction with Hamilton's principle, the Galerkin method, the artificial spring technique, etc. Numerical results at room temperature and in a uniform thermal environment with classical or arbitrary boundary conditions are utilized to give a rough validation of this model. Subsequently, a thermal-vibration system is set up to measure the nonlinear natural frequencies of two FRPCS specimens subjected to four different temperature gradient conditions in free-free boundary constraints, and iterative calculations are performed to identify the temperature-dependent material properties. Finally, the detailed comparisons of calculated and experimental results provide a solid validation of the proposed model. This study offers a practical model tool to forecast the nonlinear free vibrations of the FRPCSs in a complex thermal environment, which can be readily adjusted and extended to other forms of composite shells. Also, the predicted and measured results can help assess the structural thermal-vibration behaviors when the temperature gradient effect needs to be considered.Communicated by Makoto Ohsaki.