In this study the isogeometric B-Rep mortar-based mapping method for geometry models stemming directly from Computer-Aided Design (CAD) is systematically augmented and applied to partitioned Fluid-Structure Interaction (FSI) simulations. Thus, the newly proposed methodology is applied to geometries described by their Boundary Representation (B-Rep) in terms of trimmed multipatch Non-Uniform Rational B-Spline (NURBS) discretizations as standard in modern CAD. The proposed isogeometric B-Rep mortar-based mapping method is herein extended for the transformation of fields between a B-Rep model and a low order discrete surface representation of the geometry which typically results when the Finite Volume Method (FVM) or the Finite Element Method (FEM) are employed. This enables the transformation of such fields as tractions and displacements along the FSI interface when Isogeometric B-Rep Analysis (IBRA) is used for the structural discretization and the FVM is used for the fluid discretization. The latter allows for diverse discretization schemes between the structural and the fluid Boundary Value Problem (BVP), taking into consideration the special properties of each BVP separately while the constraints along the FSI interface are satisfied in an iterative manner within partitioned FSI. The proposed methodology can be exploited in FSI problems with an IBRA structural discretization or to FSI problems with a standard FEM structural discretization in the frame of the Exact Coupling Layer (ECL) where the interface fields are smoothed using the underlying B-Rep parametrization, thus taking advantage of the smoothness that the NURBS basis functions offer. All new developments are systematically investigated and demonstrated by FSI problems with lightweight structures whereby the underlying geometric parametrizations are directly taken from real-world CAD models, thus extending IBRA into coupled problems of the FSI type.

中文翻译：

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基于等几何b-rep砂浆的非匹配网格流固耦合映射方法

在这项研究中，系统地扩充了直接基于计算机辅助设计（CAD）的几何模型的基于等几何B-Rep砂浆的映射方法，并将其应用于分区的流固耦合（FSI）模拟。因此，根据现代CAD中标准的修剪多面体非均匀有理B样条（NURBS）离散化，新提出的方法应用于其边界表示（B-Rep）描述的几何。本文扩展了提出的基于等几何B-Rep灰浆的映射方法，用于在B-Rep模型与几何的低阶离散表面表示之间进行场转换，这通常是由有限体积法（FVM）或有限元产生的使用方法（FEM）。当将等几何B-Rep分析（IBRA）用于结构离散化并将FVM用于流体离散化时，这可以沿FSI界面转换诸如牵引力和位移之类的场。后者允许在结构和流体边界值问题（BVP）之间采用不同的离散化方案，同时考虑了每个BVP的特殊属性，同时在分区FSI中以迭代方式满足了FSI界面上的约束。可以在具有IBRA结构离散化的FSI问题或具有标准FEM结构离散化的FSI问题中的精确耦合层（ECL）框架中使用基础B-Rep参数化对接口字段进行平滑处理，从而利用所提出的方法。因此，可以利用NURBS基本函数提供的平滑度。FSI问题涉及轻量级结构，系统地研究和证明了所有新进展，从而直接从真实的CAD模型中获取了潜在的几何参数，从而将IBRA扩展到FSI类型的耦合问题中。