Hybrid Finite Elements

At finite element formulations employing the PvD the equilibrium condition is satisfied in a weak sense, whereas the other governing equations are fulfilled exactly by introducing these equations into the work equation of the PvD, cf. Section 2.1. As a consequence, the displacements persist as primary variables, whereas the stresses or stress resultants, which are the more important state variables for the structural design, are only computed by the subsequent stress analysis. Since the displacements have to be differentiated with respect to kinematics, this procedure yields stress distributions, which are generally more roughened compared to the approach of the displacements.