论文标题
关于压力鲁棒性和独立确定不可压缩线性弹性的位移和压力
On pressure robustness and independent determination of displacement and pressure in incompressible linear elasticity
论文作者
论文摘要
我们研究了从压力反应$ p $ p $ p $中的一类无压线性线性弹性中的边界价值问题中,从压力反应$ p $确定无差位移的可能性。如果不可能,我们是否可以调查是否可以确定\ emph {worgustly},即没有压力反应的污染。 对于凸形域,研究中只有一个变异边界值问题,可以独立确定。它是具有必不可少条件的必需条件的一种,结合了均匀的切向牵引条件。 此外,在大多数但并非全部研究的情况下,只要将总体力量分解为使用Helmholtz分解的无差异和无旋转组件的直接总和。使用这些组件作为单独的右侧解决弹性问题。使用叠加原理获得总溶液。 我们采用$(\ mathbf {u},p)$带有不连续压力元素的高阶有限元公式。它是\ emph {inf-sup}稳定的多项式$ p \ ge 2 $,但本身不是强大的压力。 我们提出了一个三步程序,以解决总体力量的螺旋性问题之前的弹性问题。三步过程的额外成本本质上是组装全身力量的Helmholtz分解的成本,而用一个额外的右侧左侧解决弹性问题的小成本。结果通过理论推导以及数值结果证实了结果。
We investigate the possibility to determine the divergence-free displacement $\mathbf{u}$ \emph{independently} from the pressure reaction $p$ for a class of boundary value problems in incompressible linear elasticity. If not possible, we investigate if it is possible to determine it \emph{pressure robustly}, i.e. pollution free from the pressure reaction. For convex domains there is but one variational boundary value problem among the investigated that allows the independent determination. It is the one with essential no-penetration conditions combined with homogeneous tangential traction conditions. Further, in most but not all investigated cases, the weakly divergence-free displacement can be computed pressure robustly provided the total body force is decomposed into its direct sum of divergence- and rotation-free components using a Helmholtz decomposition. The elasticity problem is solved using these components as separate right-hand sides. The total solution is obtained using the superposition principle. We employ a $(\mathbf{u},p)$ higher-order finite element formulation with discontinuous pressure elements. It is \emph{inf-sup} stable for polynomial degree $p\ge 2$ but not pressure robust by itself. We propose a three step procedure to solve the elasticity problem preceded by the Helmholtz decomposition of the total body force. The extra cost for the three-step procedure is essentially the cost for the Helmholtz decomposition of the assembled total body force, and the small cost of solving the elasticity problem with one extra right-hand side. The results are corroborated by theoretical derivations as well as numerical results.