The displacement solution of medium cylindrical shells bending problem;

Based on Timoshenko-Mindlin hypotheses and Hamilton’s principle,a systemof equations of nonlinear vibration is set up for laminated circular cylindrical thick shellswith parametric excitation.

The displacement fundamental equations of the thick shallow shells and thick cylindrical shallow shells concerning five independent variables,ie five middle surface displacements were established based on the displacement fundamental equations of the thick shells by transverse shearing deformation and basic hypothesis on shallow shells.