Nonlinear vibration analysis of CFRR sandwich doubly-curved shallow shells with a porous microcapsule coating in hygrothermal environment

In this paper, the nonlinear vibration characteristics and response of laminated carbon fiber reinforced resin (CFRR) doubly-curved shallow shell with a porous microcapsule coating under hygrothermal environment is investigated. Based on the first-order shear deformation theory, the nonlinear equations of motion are obtained by using Hamilton's principle, which are solved by utilizing the direct integration method and Runge-Kutta method. The effect of temperature and moisture, geometric parameters of microcapsules, geometric parameters of the shell, laying angle for carbon fiber and porosity of coating matrix are considered. Through numerical examples, it is found that temperature, moisture, length of edges, laying angle for carbon fiber and porosity of coating matrix have a positive effect on the dimensionless nonlinear frequency ratio, but negative effect on the dimensionless linear and nonlinear natural frequency of the shell. In addition, temperature, moisture, length of edges, laying angle for carbon fiber and porosity of coating matrix are proportional to the dimensionless nonlinear amplitude of the shell.

Automated summary

This paper investigates the nonlinear vibration characteristics and response of laminated carbon fiber reinforced resin doubly-curved shallow shell with a porous microcapsule coating under hygrothermal environment. The nonlinear equations of motion are obtained using Hamilton's principle and solved by the direct integration method and Runge-Kutta method. The study considers the effects of temperature, moisture, microcapsule geometric parameters, shell geometric parameters, laying angle for carbon fiber, and porosity of the coating matrix. Numerical examples show that temperature, moisture, edge length, laying angle for carbon fiber, and porosity of the coating matrix have a positive effect on the dimensionless nonlinear frequency ratio, but a negative effect on the dimensionless linear and nonlinear natural frequency of the shell. Additionally, temperature, moisture, edge length, laying angle for carbon fiber, and porosity of the coating matrix are proportional to the dimensionless nonlinear amplitude of the shell.