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NURBS流曲线造型新方法及其在船舶设计中的应用 |
A New NURBS Stream Curve Modeling Method and Its Application to Ship Design |
投稿时间:2017-04-07 修订日期:2017-04-27 |
DOI: |
中文关键词: 船体曲面 流曲线 NURBS 功能曲线 几何约束 |
英文关键词: hull surface stream curve NURBS functional curve geometric constraint |
基金项目:国家自然科学基金资助项目“NURBS流曲线曲面研究及其在船体曲面参数化设计中的应用”(E091002-51109033). |
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中文摘要: |
运动物体外形曲面是和流体相互作用的功能曲面,NURBS是当前工业产品几何形状设计的主流表示方法。但是常规的NURBS设计方法不考虑流场信息,而流曲线是能够携带流场信息的功能曲线,两者还未能很好结合。目前,流曲线造型方法仅被应用于已知型值点及其切矢的问题,对于在其他约束(面积、面积心、流场特征值)问题中的应用仍有待发展研究。本文将NURBS与流曲线造型技术相结合,提出了NURBS流曲线单元的概念以及在其他几何约束下,应用NURBS流曲线造型的新方法。该方法将待设计流曲线在已知切矢的型值点处分段以确定NURBS流曲线单元的个数,将NURBS流曲线单元的控制参数的并集作为设计变量,将几何约束处理为曲线设计的目标函数,建立普适性的NURBS流曲线造型框架。该框架模型可用进化算法进行求解。通过设计实例,验证了该方法在相关曲线设计方面的可行性和有效性。 |
英文摘要: |
A moving body surface is a functional surface acting with fluid each other. Presently, NURBS is the main description method of industrial product geometric design. But the flow field information isn't taken into account in the conventional NURBS design method. Stream curve is a functional curve carrying the flow field information. But they have not been integrated well. And the stream curve modeling method has only been applied to the problems with data points and their tangent vectors being given. The application to the problems with other constraints such as area, centroid of area, the eigenvalue of the flow filed, etc. need more research and development. In this paper, NURBS and stream curve modeling method are integrated and the concept of NURBS stream curve unit is proposed. Furthermore, a new NURBS stream curve modeling method base on other geometric constraints is proposed. In this method, the stream curve is segmented at the data points with the given tangent vectors, and the number of the NURBS stream curve cell is determined. The union set of the controls parameter of the NURBS stream curve cell are designated as the design variables. The geometric constraints are regarded as the design objective function. The universal framework of NURBS stream curve modeling is built. This framework model can be solved by an evolutionary algorithm. The design instances indicate that this method is effective and feasible in the related curve design. |
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