Force Network Analysis using Complementary Energy

The method presented solves statically indeterminate force networks, which are graphical representations of forces (force polygons) of a structure, by using complementary energy. Statically indeterminate force networks, which have nodes where four or more members come together, have for each node multiple possible force polygons that make equilibrium. This holds for force networks of structures in one plane, such as trusses, as for geometric three-dimensional structures, such as shells. In the case of the latter the surface of thrust of the shell is discretized into a network of forces (equivalent to the thrust line of an arch), with discrete loads at its vertices.