Stifness operator for boundary problems of structural analysis and several new variational formulations

So-called "stiffness operator" for boundary problems of structural analysis is introduced in the distinctive paper. There is a direct analogy between this stiffness operator and corresponding stiffness matrix of the considering structure in terms of finite element method. Namely we can consider stiffness operator as a limiting (continual) generalization of stiffness matrix. The explicit formulation of stiffness operator is presented. Several new variational formulations are discussed as well.