Geometric continuity constraints of automatically derived parametrisations in CAD-based shape optimisation
Geometric continuity constraints of automatically derived parametrisations in CAD-based shape optimisation
复制标题
基于 CAD 的形状优化中自动导出参数化的几何连续性约束
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Yang Wang
中科院分区：
文献类型：
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作者：
Jens;Xingchen Zhang;S. Akbarzadeh;Yang Wang
摘要CAD几何图形最常在分析工具之间交换，使用NURBS曲面片来表示边界（BRep）。我们提出了一种方法，其中的BRep的控制点被用来自动获得参数化适合于形状优化与基于梯度的方法。特别关注的是通过制定离散约束来确保NURBS曲面片之间的几何连续性。然后，设计变量产生从一个正交基的其余设计空间使用奇异值分解（SVD）。该手稿提出了B样条曲面的早期工作的扩展，以充分的NURBS曲面和调查的SVD截止优化结果的影响。提出了一种估计的有效秩，它允许自动确定一个合适的截止值。该算法的有效性被证明为最小化的总压力损失的一部分的汽车气候管道，和U形弯曲冷却通道。
ABSTRACT CAD geometries are most often exchanged between analysis tools using NURBS patches to represent the boundary (BRep). We present a method where the control points of the BRep are used to automatically derive parametrisations suitable for shape optimisation with gradient-based methods. Particular focus is on ensuring geometric continuity between the NURBS patches through formulation of discrete constraints. Design variables then arise from an orthogonal basis to the remaining design space using a singular value decomposition (SVD). The manuscript presents the extension of earlier work on B-spline surfaces to full NURBS surfaces and investigates the effect of the SVD cut-off on the optimisation results. An estimation of the effective rank is proposed which allows to automatically determine a suitable cut-off value. The effectiveness of the algorithm is demonstrated for the minimisation of total pressure loss over a section of an automotive climate duct, and a U-bend cooling channel.