A method to analyze the axially symmetric problem of composite thick tubes with arbitrary angles

A method was proposed to analysis the axisymmetric problem of composite tubes made up of winding layers with arbitrary angles. The traditional Lekhnitskii theory can obtain the exact elastic solution of the thick composite tubes with common winding layers. However, when there are 0° winding layers or isotropic layers in the thick walled tubes, singular parameters will appear in the both special layers. And the discontinuity condition between the special layer and the common layer could not be satisfied. Therefore, the reasons for the existence of singular parameters in special layers were discussed. Then, the continuity analysis and limit calculation of these parameters were carried out, so that the problem of parameter singularity was solved and the application of Lekhnitskii theory was extended to composite thick tubes with arbitrary angles. Finally, the mechanical responses of different composite tubes were analyzed by ABAQUS, and the results of finite element calculation were basically consistent with the developed theoretical results.