Fully discrete DPG methods for the Kirchhoff–Love plate bending model

Thomas Führer and Norbert Heuer
Comput. Methods Appl. Mech. Engrg. 343, 550–571, 2019.

We extend the analysis and discretization of the Kirchhoff–Love plate bending problem from [T. Führer, N. Heuer, A.H. Niemi, An ultraweak formulation of the Kirchhoff–Love plate bending model and DPG approximation, arXiv:1805.07835, DOI:10.1090/mcom/3381] in two aspects. First, we present a well-posed formulation and quasi-optimal DPG discretization that includes the gradient of the deflection. Second, we construct Fortin operators that prove the well-posedness and quasi-optimal convergence of lowest-order discrete schemes with approximated test functions for both formulations. Our results apply to the case of non-convex polygonal plates where shear forces can be less than -regular. Numerical results illustrate expected convergence orders.