Tabarrokian and Non-Tabarrokian systems in complementary formulations

Complementary formulations and mixed formulations are of importance for the finite element method. The two complementary formulations are the conventi onal formulation based on generalized displacements and the alternative for mulation based on generalized impulses. It is shown that so-called Tabarrok ian systems are those for which a complementary Lagrangian L* can be formed to advantage and a complementary Lagrange equation can be used. It is then shown that this is not the case for Non-Tabarrokian systems, for which an example is presented.