## Numerical Analysis Seminar

Date, time & place Tuesday 16:30 - 18:00 Room #056 (Graduate School of Math. Sci. Bldg.)

Next seminar

### 2017/11/28

16:50-18:20   Room #117 (Graduate School of Math. Sci. Bldg.)
Daisuke Koyama (The University of Electro-Communications)
Hybrid discontinuous Galerkin methods for nearly incompressible elasticity problems
(Japanese)
[ Abstract ]
A Hybrid discontinuous Galerkin (HDG) method for linear elasticity problems has been introduced by Kikuchi et al. [Theor. Appl. Mech. Japan, vol.57, 395--404 (2009)], [RIMS Kokyuroku, vol.1971, 28--46 (2015)]. We consider to seek numerical solutions of the plane strain problem by the HDG method, especially in the case when materials are nearly incompressible, that is, when the first Lam\'e parameter $\lambda$ is large. In this talk, we consider two cases when the HDG method uses a lifting term and does not use it. When the lifting term is used, the method can be free of volumetric locking. On the other hand, when the lifting term is not used, we have to take an interior penalty parameter of order $\lambda$ as $\lambda$ tends to infinity, in order to guarantee the coercivity of the bilinear form. Taking such an interior penalty parameter causes volumetric locking phenomena. We thus conclude that the lifting term is essential for avoiding the volumetric locking in the HDG method.