... by using the symplectic superposition method (SSM). Design/methodology/approach The original fourth-order partial differential equation is first rewritten into Hamiltonian system. The class of boundary value problems of the original equation is decomposed into three subproblems, and each subproblem...

... of the structure. Design/methodology/approach – By introducing dual variables and applying the variational principle, the canonical equations of Hamiltonian system are constructed. The precise integration algorithm and extended Wittrick-Williams algorithm are adopted to solve the equations and obtain...