Using membrane elements to better capture surface strains

There has always been some concern with finite element analyses using solid elements that the most exact characterization of field quantities occurs at the integration points, which are located in the interior of the part being modeled, whereas often (particularly where significant bending or torsion is involved) the largest strains occur at the surface, which are traditionally available only by extrapolation from the integration points to the nodal points using the element’s shape functions. The M3D4R membrane elements in this study is to “trick” the solver into providing surface values that are more exact and are not interpolated. (DeHerrera 2009)