scholarly journals Novel Surface Design of Deployable Reflector Antenna Based on Polar Scissor Structures

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Pengyuan Zhao ◽  
Jinguo Liu ◽  
Chenchen Wu ◽  
Yangmin Li ◽  
Keli Chen
Keyword(s):  
Design Method ◽  
Large Diameter ◽  
Spatial Transformation ◽  
Reflector Antennas ◽  
Large Space ◽  
Surface Design ◽  
Kinematics Simulation ◽  
Paraboloid Of Revolution ◽  
Novel Method ◽  
Surface Constraints

Abstract 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 over-constrained 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.

SIMULTANEOUS MULTIPLE SURFACE DESIGN METHOD

2005 ◽  
pp. 181-218 ◽  
Author(s):  
Roland Winston ◽  
Juan C. Miñano ◽  
Pablo Benítez
Keyword(s):  
Design Method ◽  
Surface Design

scholarly journals A Preliminary Study on the Design Method for Large-Diameter Deep-Hole Presplit Blasting and Its Vibration-Isolation Effect

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shuangshuang Xiao ◽  
Hongsheng Wang ◽  
Guowei Dong
Keyword(s):  
Vibration Isolation ◽  
Design Method ◽  
Blast Hole ◽  
Large Diameter ◽  
Field Testing ◽  
Open Pit ◽  
Vibration Velocity ◽  
Deep Hole ◽  
Charge Mass ◽  
Presplit Blasting

Presplit blasting can reduce vibration and back impact induced by cast blasting, thus resulting in a smooth bench slope. To design reasonable presplit blasting parameters, this research investigated the formation of presplit faces based on the explosion mechanics and revealed the cracking mechanism of presplit blasting. According to the stress distribution in the vicinity of the blast holes under the action of explosive stress waves and blasting gas, we deduced theoretical formulae for parameters including charge mass in blast holes, hole spacing, and distance from presplit blast holes to cushion holes. On this basis, a method was proposed for the design of large-diameter deep-hole presplit blasting. Field testing was conducted by setting different spacing for presplit blast holes, to monitor the blasting-induced vibration. The results showed that appropriate hole spacing can reduce the particle vibration velocity and the attenuation index of blasting-induced vibration changed slightly while the attenuation coefficient decreased significantly; the formed presplit faces were smooth and had a high half-cast factor. Finally, the reasonable hole spacing for presplit blasting, distance from presplit blast hole to the cushion hole, and the charge mass in blast holes in the Heidaigou open-pit coal mine were determined, respectively.

Design of layered structure for thermal cloak with complex shape

2016 ◽  
Vol 30 (20) ◽  
pp. 1650256 ◽  
Author(s):  
Xuebo Yuan ◽  
Guochang Lin ◽  
Youshan Wang
Keyword(s):  
Numerical Simulations ◽  
Layered Structure ◽  
Complex Shape ◽  
Thermal Protection ◽  
Design Method ◽  
Two Dimensional ◽  
Spatial Transformation ◽  
Complex Shapes ◽  
Potential Applications ◽  
Thermal Cloaking

Thermal cloaks have potential applications in thermal protection and sensing, and those cloaks with complex shapes are much more efficient in application. Layered discretization is a valid way to realize thermal cloaks designed through spatial transformation which are usually nonhomogeneous and anisotropic. However, previous studies are limited to two-dimensional cylindrical ones. Based on the theories of spatial transformation and effective medium, a four-step design method for layered structure of thermal cloak with complex shape is proposed. It is expected to realize the designed layered structure by utilizing the existing regular materials. According to the numerical simulations, the thermal cloaking performances of layered structures are good and close to that of the perfect thermal cloaks. This study has provided an effective way for realizing thermal cloak with complex shape.

Design of Pattern Preparation System of Computerized Flat Knitting Machine Based on Delphi

2011 ◽  
Vol 332-334 ◽  
pp. 1395-1399
Author(s):  
Guo Fang Shi ◽  
Sen Lin Zhang
Keyword(s):  
Design Method ◽  
Object Oriented ◽  
Pattern Design ◽  
Control Information ◽  
Mapping System ◽  
Pattern Description ◽  
Novel Method ◽  
Pattern Preparation System

A design method and primary functions of pattern preparation system of computerized flat knitting machine are introduced. The system provides a formidable mapping system based on object-oriented and multi-document, so pattern becomes simple and flexible to be edited and displayed. In addition, the compiler has a novel method of compiling pattern data. Two pattern description files (PAT and CNT) are generated after compiled, which include all control information that computerized flat knitting machine needs. The system also provides a direct and friendly interface, through which user can accomplish pattern design quickly and conveniently.

A Reinforcement Design Method Based on Analysis of Large Openings in Cylindrical Pressure Vessels

1996 ◽  
Vol 118 (4) ◽  
pp. 502-506 ◽  
Author(s):  
M. D. Xue ◽  
K. C. Hwang ◽  
W. Lu¨ ◽  
W. Chen
Keyword(s):  
Fourier Series ◽  
Present Method ◽  
Fourier Coefficients ◽  
Design Method ◽  
Large Diameter ◽  
Pressure Vessels ◽  
Diameter Ratio ◽  
Cylindrical Coordinates ◽  
Reinforcement Design ◽  
Good Agreement

The analytical solution is given for two orthogonally intersecting cylindrical shells with large diameter ratio d/D subjected to internal pressure. The modified Morley equation is used for the shell with cutout and the Love equation for the tube with nonplanar end. The continuity conditions of forces and displacements at the intersection are expressed in 3-D cylindrical coordinates (ρ, θ, z), and are expanded in Fourier series of θ. The Fourier coefficients are obtained by numerical quadrature. The present results are in good agreement with those obtained by tests and by FEM for ρ0 = d/D ≤ 0.8. The typical curves of SCF versus t/T and d/DT and reinforcement coefficients g, h versus D/T0 for each ρ0 are given on the present method.

Application of High-Grade Steels to Onshore Natural Gas Pipelines Using Reliability-Based Design Method

2006 ◽  
Author(s):  
Joe Zhou ◽  
Brian Rothwell ◽  
Wenxing Zhou ◽  
Maher Nessim
Keyword(s):  
High Pressure ◽  
Wall Thickness ◽  
Design Method ◽  
Large Diameter ◽  
Economic Assessment ◽  
High Grade ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Reliability Based Design ◽  
Design Factors

Two example onshore gas pipelines were designed using a reliability-based approach. The first example (1219 mm, 17.2 MPa) represents a high-pressure large-diameter pipeline; the second example has a smaller diameter (762 mm) and lower pressure (9.9 MPa). Three steel grades (X70, X80 and X100) were used to develop three design solutions for each example. The wall thickness-related life cycle costs of the designs were evaluated. The design outcomes show that the reliability targets for both examples can be met using X100 steels and high equivalent design factors (0.93 for the first example and 0.9 for the second example). Moreover, ruptures and excessive plastic deformation of a defect free pipe were found to be insignificant integrity threats even when the design uses X100 and relatively high equivalent design factors such as 0.85 and 0.9. The economic assessment results show that the X100 design is the most economical option for the high-pressure large-diameter example. However, using X100 does not show a clear economic advantage over using X80 for the second example mainly because the wall thickness for the design using X100 is governed by the maximum D/t ratio constraint. The study also demonstrates the advantages of the reliability-based approach as a valuable tool in assessing the feasibility and potential benefits of using high-grade steels on a pipeline project.

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