Static condensation of the Three-Field-Formulation (u,p,J)

[adtzlr]

A very well-structured paper was recently published on how to perform the static condensation of the Three-Field-Formulation u,p,J [1]. This approach is frequently used and discussed in FElupe, however, no static condensation is performed. In FElupe, we just hand-over all of the DOF (even the non-global ones) to the solver. This could be enhanced by static condensation.

[1] J. A. Schönherr, P. Schneider, and C. Mittelstedt, “Robust hybrid/mixed finite elements for rubber-like materials under severe compression,” Computational Mechanics, vol. 70, no. 1. Springer Science and Business Media LLC, pp. 101–122, Mar. 31, 2022. doi: ↓10.1007/s00466-022-02157-y.

[adtzlr]

In the meanwhile, this has been implemented as felupe.SolidBodyNearlyIncompressible.