The corresponding generalized stiffness matrix depends on both the stiffness characteristics and the geometrical constraint characteristics of the system.

Then, the generalized stiffness matrix and load vector in the equilibrium equations are formulated by using the virtual work principle, and the numerical integration method is discussed.

Then, those useful generalized nodes are selected, and the generalized stiffness matrix is enlarged. A more accurate numerical solution can be obtained after the new equilibrium equations are solved.