This paper presents a nonconforming finite element approximation of the space of symmetric tensors with square integrable divergence, on tetrahedral meshes. Used for stress approximation together with the full space of piecewise linear vector fields for displacement, this gives a stable mixed finite element method which is shown to be linearly convergent for both the stress and displacement, and which is significantly simpler than any stable conforming mixed finite element method. The method may be viewed as the three-dimensional analogue of a previously developed element in two dimensions. As in that case, a variant of the method is proposed as well, in which the displacement approximation is reduced to piecewise rigid motions and the stress space is reduced accordingly, but the linear convergence is retained.
|Original language||English (US)|
|Number of pages||14|
|Journal||Mathematical Models and Methods in Applied Sciences|
|State||Published - Apr 2014|
Bibliographical noteFunding Information:
The work of the first author was supported by NSF Grant DMS-1115291. The work of the second author was supported by NSF Grant DMS-0811052 and the Sloan Foundation. The work of the third author was supported by the Research Council of Norway through a Centre of Excellence Grant to the Centre of Mathematics for Applications.
- Mixed method
- finite element
- linear elasticity