Two New Three Field Generalized Variational Principles Applied to Thick Plate Bending

Based on a new proposition of the principle of minimum potential / complementary energy for the thick plate bending problem , a new three field generalized potential / complementary energy principle for such problems is established , applying the lagrange multiplier method , to release all the variational constraint conditions , including the relation between generalized stress and generalized strain, so as to provide more theoretical basis to approximate solutions to the problems .