A method to analyze the axisymmetric problem of FRP laminated tubes based on singularity correction

Abstract

In order to solve the problem of singularity in the stress and strain calculation process of FRP laminated tubes with arbitrary layer angles under axisymmetric thermomechanical loading, a three-dimensional elasticity theory analysis method based on singularity correction by modifying the stiffness matrix coefficients is proposed. Firstly, the basic three-dimensional elasticity theory model for FRP laminated tubes under axisymmetric thermomechanical loading is established through the displacement method. Then, the singularity plies in the laminate are determined, and the stiffness matrix coefficients of the singularity plies are modified respectively. Modifications to the displacement function coefficients, stiffness coefficients, boundary condition, and interlayer continuous condition equilibrium equations are also conducted subsequently. Verifications of the present approach are conducted by comparing the stress distributions calculated by the singularity correction method with those extracted by traditional isotropic elasticity models and then with numerical results provided by finite element analysis. Good consistency was obtained; thus, the correctness of the theory is proved from both theoretical and numerical aspects.