TY - JOUR T1 - Two Families of $n$-Rectangle Nonconforming Finite Elements for Sixth-Order Elliptic Equations AU - Jin , Xianlin AU - Wu , Shuonan JO - Journal of Computational Mathematics VL - 1 SP - 121 EP - 142 PY - 2024 DA - 2024/11 SN - 43 DO - http://doi.org/10.4208/jcm.2309-m2023-0052 UR - https://global-sci.org/intro/article_detail/jcm/23532.html KW - Nonconforming finite element method, $n$-Rectangle element, Sixth-order elliptic equation, Exchange of sub-rectangles. AB -

In this paper, we propose two families of nonconforming finite elements on $n$-rectangle meshes of any dimension to solve the sixth-order elliptic equations. The unisolvent property and the approximation ability of the new finite element spaces are established. A new mechanism, called the exchange of sub-rectangles, for investigating the weak continuities of the proposed elements is discovered. With the help of some conforming relatives for the $H^3$ problems, we establish the quasi-optimal error estimate for the triharmonic equation in the broken $H^3$ norm of any dimension. The theoretical results are validated further by the numerical tests in both 2D and 3D situations.