A locking-free nonconforming finite element method for planar linear elasticity (Q1872005)

The authors are interested in the numerical approximation of displacement fields in planar linear elastic materials by using the finite element method. They modify the discrete weak formulation by using an \(L^2\)-orthogonal projection in the discrete weak formulation, that is, they use the so-called method of reduced integration. The authors present an error estimate in energy norm, and then, by employing duality argument, they obtain an error estimate in \(L^2\)-norm.