A New Complementary Energy Computational Method for Large Deformation of Rods

Equilibrium equations on nodes are taken as constraint conditions, and Lagrange multipliers are substituted into complementary functionals expressed with base forces, and derivatives of displacement with respect to coordinates.Then a conditional stationary problem is transformed into an unconditional stationary problem.Based on this complementary energy principle, internal forces and displacements are obtained when a rod system is in large deformation.Thus it is feasible for the complementary energy principle to apply to large deformations in rods systems.