Geometric constraint calculation technology suitable for free deformation parameterization

A parametric, geometric technique used in the field of geometric constraint computing technology

Pending Publication Date: 2022-04-15
JIANGSU UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

Considering the difference between the FFD parameterization method and the CAD parameterization method, the traditional geometric constraint calculation method suitable for CAD parameterization is no longer applicable

Method used

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  • Geometric constraint calculation technology suitable for free deformation parameterization
  • Geometric constraint calculation technology suitable for free deformation parameterization
  • Geometric constraint calculation technology suitable for free deformation parameterization

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Embodiment 1

[0088] The invention discloses a space point O p along the set direction The calculation method of the intersection point intersecting with the geometric shape surface, said geometric shape surface is the overall shape surface or partial shape surface of an aerospace vehicle, or a ship, or an automobile. In this embodiment, the method is illustrated by taking the optimal design of the wing of the wing-body fusion underwater glider as an example, and the process is as follows figure 1 shown, including the following steps:

[0089] S11. Carrying out triangular meshing on the surface of the initial geometric shape, and converting it into a discrete surface composed of a plurality of triangular planes;

[0090] Transform the initial geometric shape described by different surface modeling methods into discrete surfaces described by triangular meshes, such as figure 2 Shown is the triangular discrete surface of the initial shape of the wing-body fusion underwater glider. The s...

Embodiment 2

[0143] This embodiment provides a thickness constraint calculation method suitable for free deformation parameterization. The thickness constraint mainly meets the installation size requirements of the equipment mechanism, etc. Taking the wing-body fusion underwater glider as an example, Figure 7 A schematic diagram of the thickness constraint in the FFD control volume is given. In the figure, the dots are the intersection points of the thickness constraint and the upper and lower surfaces, and the length of the line segment between the dots is the size of the thickness constraint. The key to thickness constraint calculation is to calculate accurately after the deformation of FFD control body Figure 7 The location of the dot. Such as Figure 8 As shown, the specific calculation includes the following steps:

[0144] S21. Determine the starting point and direction of the thickness constraint in the geometric shape surface;

[0145] S22. Dividing the geometric shape surface...

Embodiment 3

[0157] This embodiment discloses a volume constraint calculation method suitable for free deformation parameterization. The volume constraint requires that the specified space meet certain volume requirements, such as meeting the space requirements required by battery mechanisms and the like. Taking wing-body fusion underwater glider as an example, Figure 10 is a schematic diagram of the volume constraint in the FFD control volume, Figure 10 The volume of the small and medium grid part needs to meet certain requirements, and the specific mathematical expression can be described as V≥V th , where V is the volume of the small grid part, V th Volume threshold required for volume constraints. The key to the volume constraint calculation is to accurately calculate the volume size of the small mesh part after the deformation of the FFD control volume. Such as Figure 11 shown, including the following steps:

[0158] S31. Determine the boundary curve and direction of the volum...

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Abstract

The invention discloses a geometric constraint calculation technology suitable for free deformation parameterization. The geometric constraint calculation technology comprises an intersection point calculation method for intersection of a space passing point Op and a geometric appearance curved surface in the set direction, a thickness constraint calculation method and system applying the intersection point calculation method, and a volume constraint calculation method and system applying the intersection point calculation method. The intersection point calculation method comprises the following steps of: 1, performing triangular gridding on an initial geometric appearance curved surface, and converting the initial geometric appearance curved surface into a discrete curved surface consisting of a plurality of triangular planes; 2, calculating a coordinate of an intersection point O'p of a space passing point Op and a triangular plane in the discrete curved surface in a Cartesian coordinate system along a set direction; 3, constructing a B-spline-based FFD control body for the geometric shape curved surface, embedding the intersection point O'p into the FFD control body, and performing FFD control on the geometric shape curved surface; and calculating the parameterized local coordinates of the intersection point O'p in the FFD control body. The method can efficiently calculate the local coordinates of the intersection point of the spatial point and the geometric profile curved surface in the FFD control body along the set direction, and realizes the calculation of geometric constraints under free deformation parameterization.

Description

technical field [0001] The invention belongs to the technical field of engineering design and optimization, and in particular relates to a geometric constraint calculation technology applicable to free deformation parameterization. Background technique [0002] High-precision optimization technology is widely used in fluid power, engineering structures and other fields. For the overall or local shape of aerospace vehicles, ships, or automobiles, geometric deformation is an important part of it. The Free Form Deformation (FFD) method is mainly based on the idea of ​​elastic objects being deformed by force. The geometric shape surface to be deformed is embedded in a control body, and the geometric shape of the control body is indirectly changed by changing the shape of the control body during deformation. surface. Compared with the secondary development of conventional computer-aided design (Computer Aided Design, CAD) software, it does not need to generate geometric shapes, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F30/15G06F30/28G06F113/08G06F119/14G06F111/04
Inventor 张代雨曹磊胡俊明李志富朱信尧刘倩
Owner JIANGSU UNIV OF SCI & TECH
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