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Isogeometric form-finding method for space truss cable-net antenna

A technology of cable-net antenna and space truss, applied in the field of geometric form-finding, can solve the problems of inability to obtain the shape and surface accuracy of the reflective surface that meets the engineering precision, the failure of the form-finding task of the antenna reflective surface, and the poor uniformity of the tension of the cable segment, etc. Surface accuracy, wide application range, and the effect of improving form-finding accuracy

Active Publication Date: 2017-07-07
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

However, this method has great limitations on the grid configuration of the reflective surface, and cannot obtain the surface accuracy of the reflective surface that meets the engineering precision requirements; the third method: the third form-finding method is the minimum norm method, which will The average value of the segment tension is used as the design variable, and the maximum tension ratio of the cable segment is used as the objective function to solve the minimum norm solution of the statically indeterminate equilibrium equation, so as to obtain the pretension distribution of all cable segments
Compared with the first force density method, the tension uniformity of the cable segment obtained by the minimum norm method is much worse, and the solution interval of the minimum norm method is limited, and negative tension will appear for some complex cable network structures, which is out of reality. As a result, the antenna reflector form-finding task fails

Method used

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  • Isogeometric form-finding method for space truss cable-net antenna
  • Isogeometric form-finding method for space truss cable-net antenna
  • Isogeometric form-finding method for space truss cable-net antenna

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specific Embodiment approach

[0049] The following is a description of the geometric form-finding method, taking the hexagonal prism module cable-net antenna as the object. The specific implementation is as follows:

[0050] Step 101: For the hexagonal prism module cable net antenna such as figure 2 As shown, given antenna design parameters, such as antenna focal length f = 13.76m, eccentricity h = 3.44m, cable net is Kevlar rope, Young's modulus is 2e10Pa, Poisson's ratio is 0, and wire diameter is 1mm; The truss is a carbon fiber rod with a Young's modulus of 1.6e11Pa, a Poisson's ratio of 0.3, an outer diameter of 22 mm, and an inner diameter of 20 mm;

[0051] Step 102: According to the antenna design parameters, the least square method is used to perform spherical fitting on the reflective surface of the parabolic antenna. The process is as follows image 3 As shown, the fitted spherical center coordinates (0,-2.787,37.12) are obtained, and the spherical radius r=37.577m. design to obtain support ...

Embodiment approach

[0058] The specific implementation method of step 102 is as follows:

[0059] Step 201: using the least square method to perform arc fitting on the parabolic antenna;

[0060] Step 202: Determine the coordinates P_down of seven nodes on the lower surface of the antenna truss on the fitting spherical surface obtained in step 201 according to the antenna topology relationship;

[0061] Step 203: Design the height H of the truss, H=0.72m, so as to obtain the corresponding seven node coordinates P_up on the upper surface of the truss;

[0062] Step 204: According to the design requirements, the shape and surface accuracy δ rms <0.5mm, it is necessary to divide the cable net into 5 equal parts;

[0063] Step 205: the intersection of the cable net node after solving and the line connecting the fitting sphere center and the parabolic antenna is used as the previous cable net node;

[0064] The specific implementation method of step 104 is as follows:

[0065] Step 401: According ...

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Abstract

The invention discloses an isogeometric form-finding method for a space truss cable-net antenna. The method is capable of performing form finding on the truss cable-net antenna simply and effectively while improving accuracy. The method comprises the steps of obtaining a support truss and current node coordinates of a cable net based on a topological relation of the antenna according to set design parameters of the antenna; according to a set tension value of a cable section and the current node coordinates of the cable net, calculating an initial length of the cable section, obtaining a current force density coefficient of the cable section, and performing form-finding analysis on the cable net by adopting an asymptotic iterative force density method based on the initial force density coefficient of the cable section on the basis of not considering truss deformation; performing static balance iteration on finite element models of the truss and the cable net; and judging whether the antenna satisfies a static balance error or not, thereby finishing form finding of the truss cable net.

Description

technical field [0001] The invention belongs to the technical field of form-finding for space cable-net antennas, in particular to a geometric form-finding method for space truss cable-net antennas and the like. Background technique [0002] In recent years, the development of aerospace science and technology urgently requires large-diameter truss cable-net antennas to meet the needs of mobile communications, radio astronomy, earth observation, and military reconnaissance. The truss cable-net antenna is mainly composed of a supporting truss, a main net, a sub-net, a tension array, and a metal net. In the design and analysis of the antenna structure, the influence of the metal mesh on the reflective surface can be considered equivalent to the main mesh, that is, this type of antenna structure can be regarded as a system composed of only supporting trusses and cable nets. In the design of the reflecting surface of the truss cable-net antenna, many problems and challenges need...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/23
Inventor 田强常汉江李培王碧
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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