论文标题
浸入线性椭圆问题的浸入边界符号几何方法
Immersed Boundary-Conformal Isogeometric Method for Linear Elliptic Problems
论文作者
论文摘要
我们提出了一种新颖的等几何方法,即浸入边界符号法(IBCM),该方法具有与边界的离散化层,同时使用简单的背景网格为其余域。以这种方式,我们利用了浸没边界方法的几何柔韧性,具有保形离散化的优点,例如直观地控制边界周围的网格分辨率,每个自由度的较高精度,对界面运动条件的自动满意度以及强烈强烈的Dirichlet边界条件的能力。在提出的方法中,从几何模型的边界表示开始,我们将其挤出以获得相应的保形层。接下来,给定的背景b-spline网格与保形层切割,导致两个断开的区域:外部区域和一个内部区域。根据感兴趣的问题,选择了两个区域之一,通过Nitsche的方法将其与共形层结合。这种结构涉及诸如差异和工会之类的布尔操作,因此需要适当的稳定才能处理任意削减要素。在这方面,我们遵循称为最小稳定方法的先例工作[1]。最后,我们解决了几个2D基准问题,以证明与IBCM的准确性和预期收敛的提高。还研究了涉及复杂几何形状的两种应用,以显示IBCM的潜力,包括扳手模型和纤维增强的复合模型。此外,我们证明了IBCM在表现出边界现象的应用中的有效性。
We present a novel isogeometric method, namely the Immersed Boundary-Conformal Method (IBCM), that features a layer of discretization conformal to the boundary while employing a simple background mesh for the remaining domain. In this manner, we leverage the geometric flexibility of the immersed boundary method with the advantages of a conformal discretization, such as intuitive control of mesh resolution around the boundary, higher accuracy per degree of freedom, automatic satisfaction of interface kinematic conditions, and the ability to strongly impose Dirichlet boundary conditions. In the proposed method, starting with a boundary representation of a geometric model, we extrude it to obtain a corresponding conformal layer. Next, a given background B-spline mesh is cut with the conformal layer, leading to two disconnected regions: an exterior region and an interior region. Depending on the problem of interest, one of the two regions is selected to be coupled with the conformal layer through Nitsche's method. Such a construction involves Boolean operations such as difference and union, which therefore require proper stabilization to deal with arbitrarily cut elements. In this regard, we follow our precedent work called the minimal stabilization method [1]. In the end, we solve several 2D benchmark problems to demonstrate improved accuracy and expected convergence with IBCM. Two applications that involve complex geometries are also studied to show the potential of IBCM, including a spanner model and a fiber-reinforced composite model. Moreover, we demonstrate the effectiveness of IBCM in an application that exhibits boundary-layer phenomena.