检索结果-南通市图书馆

维普期刊数据库

Novel surface design of Deployable Reflector Antenna Based on Polar Scissor Structures

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2020年第5期33卷 4-18页

作者： Pengyuan Zhao Jinguo Liu Chenchen Wu Yangmin Li Keli Chen State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of ScienceShenyang 110016China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169China University of Chinese Academy of Sciences Beijing 100049China Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

Space-deployable mechanisms can be used as supporting structures for large-diameter antennas in space engineering.This study proposes a novel method for constructing the surface design of space reflector antennas based on polar scissor units.The concurrency and deployability equations of the space scissor unit with definite surface constraints are derived using the rod and vector methods.Constraint equations of the spatial transformation for space n-edge polar scissor units are summarized.A new closed-loop deployable structure,called the polar scissor deployable antenna(PSDA),is designed by combining planar polar scissor units with spatial polar scissor units.The overconstrained problem is solved by releasing the curve constraint that locates at the end-point of the planar scissor mechanism.Kinematics simulation and error analysis are performed.The results show that the PSDA can effectively fit the paraboloid of revolution.Finally,deployment experiments verify the validity and feasibility of the proposed design method,which provides a new idea for the construction of large space-reflector antennas.

关键词： Deployable structures Polar scissor unit Reflector antenna surface design

维普期刊数据库

Structural design and mechanical performance of composite vascular grafts

在线全文

学校读者我要写书评

暂无评论

Bio-design and Manufacturing 2022年第4期5卷 757-785页

作者： Abdul Wasy Zia Rong Liu Xinbo Wu School of Fashion and Textiles The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina

This study reviews the state of the art in structural design and the corresponding mechanical behaviours of composite vascular grafts. We critically analyse surface and matrix designs composed of layered, embedded, and hybrid structures along the radial and longitudinal directions;materials and manufacturing techniques, such as tissue engineering and the use of textiles or their combinations;and the corresponding mechanical behaviours of composite vascular grafts in terms of their physical–mechanical properties, especially their stress–strain relationships and elastic recovery. The role of computational studies is discussed with respect to optimizing the geometrics designs and the corresponding mechanical behaviours to satisfy specialized applications, such as those for the aorta and its subparts. Natural and synthetic endothelial materials yield improvements in the mechanical and biological compliance of composite graft surfaces with host arteries. Moreover,the diameter, wall thickness, stiffness, compliance, tensile strength, elasticity, and burst strength of the graft matrix are determined depending on the application and the patient. For composite vascular grafts, hybrid architectures are recommended featuring multiple layers, dimensions, and materials to achieve the desired optimal flexibility and function for complying with user-specific requirements. Rapidly emerging artificial intelligence and big data techniques for diagnostics and the threedimensional(3D) manufacturing of vascular grafts will likely yield highly compliant, subject-specific, long-lasting, and economical vascular grafts in the near-future.

关键词： Vascular grafts surface design Structural design Composite materials Mechanical properties

维普期刊数据库

在线全文

学校读者我要写书评

暂无评论

一种关于函数值的二元有理插值方法

高等学校计算数学学报 2005年第4期27卷 363-370页

作者：张焕玲刘爱奎段奇山东大学数学学院山东大学数学学院济南 250100

1 引言曲线曲面的构造和数学描述是计算机辅助几何设计中的核心问题．现在已有很多这种方法,如多项式样条方法、B-样条及非均匀B-样条(NURBS)方法、Bezier方法等等．这些方法已广泛应用于工业产品的形状设计,如飞机、轮船的外形设计．... 详细信息

1 引言曲线曲面的构造和数学描述是计算机辅助几何设计中的核心问题．现在已有很多这种方法,如多项式样条方法、B-样条及非均匀B-样条(NURBS)方法、Bezier方法等等．这些方法已广泛应用于工业产品的形状设计,如飞机、轮船的外形设计．通常说来, 多项式样条方法一般都是插值型方法,插值曲线和插值曲面均通过插值点．构造这些多项式样条,其插值条件除插值点处的函数值外,一般还需要表示方向的导数值．但在很多实际问题中,导数值是很难得到的．同时,多项式样条方法的一个缺点是它的整体性质,在插值条件不变的情况下,在“插值函数关于插值条件的唯一性”的约束下,无法进行所构造的曲线曲面的整体或局部修改．NURBS方法和Bezier方法是所谓非插值型方法,用这些方法所构造出的曲线曲面一般不通过给定的点,给定的点是作为控制点出现的,通过给

关键词： bivariate interpolation rational interpolation surface design

基于Pro/ENGINEER的复杂零件的曲面造型（英文）

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于Pro/ENGINEER的复杂零件的曲面造型（英文）