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论文类型：期刊论文

发表时间：2016-11-01

发表刊物：COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

收录刊物：SCIE、EI、Scopus

卷号：311

页面范围：503-536

ISSN号：0045-7825

关键字：B plus plus splines; Isogeometric analysis; Trimmed CAD geometries; NURBS finite element method; Immersed boundary methods

摘要：A novel spline, named B++ Splines (Boundary Plus Plus Splines), is developed to address the expression of a trimmed NURBS patch in an analytic form, which is a central idea of surface representation. The presented method converts each trimmed NURBS patch into a B++ spline patch that incorporates of specific boundary points as the boundary presentation. Emphasis is placed on the construction of a new analytic formula of a trimmed NURBS patch defined by the boundary points at the trimming curves and a group of enriched control points. B++ spline basis functions are linearly independent, build a partition of unity and satisfy the Kronecker delta property. Each B++ spline basis function is a linear combination of the basis functions of the trimmed NURBS patch. These properties allow imposing the Dirichlet boundary conditions strongly at the boundary of the trimmed patch without the necessity of modifying the basis functions of the trimmed patch. Isogeometric analysis using B++ splines for two-dimensional elastic solids is also proposed. Several numerical examples are used to demonstrate the reliability of the presented method. The numerical example for the patch test illustrates that the B++ spline patch passes the standard patch test. (C) 2016 Elsevier B.V. All rights reserved.