Analytic solutions describing the stresses and displacements of beams on a
Pasternak elastic foundation are presented using a symplectic method based on
classical two-dimensional elasticity theory. Hamilton’s principle with a Legendre
transformation is employed to derive the Hamiltonian dual equation, and separation
of variables reduces the dual equation to an eigenequation that differs from the
conventional eigenvalue problems involved in vibration and buckling analysis.
Using adjoint symplectic orthonormality, a group of eigensolutions of zero
eigenvalue, corresponding to the Saint-Venant problem, are derived. This approach
differs from the traditional semi-inverse analysis, which requires stress or
deformation trial functions in the Lagrangian system. The final solutions,
which account for the effects of an elastic foundation and applied lateral
loads, are approximated by an eigenfunction expansion. Comparisons with
existing numerical solutions are conducted to validate the efficiency of this new
approach.
Keywords
Saint-Venant problem, elastic foundation, symplectic,
Hamilton principle, Legendre transformation
State Key Laboratory of Structural
Analysis for Industrial Equipment and Department of Engineering
Mechanics
Dalian University of Technology
Dalian 116024
China