A hemispherical boundary structure design method for 3D printing design

Abstract

A hemispherical boundary structure design method for 3D printing design belongs to the technical field of digital manufacturing. The specific implementation steps are: 1) grid subdivision of hemispherical projection; 2) conversion of plane coordinate points into hemispherical coordinate points; 3) formation of lattice structure. Step 1), select two mutually perpendicular directions in the plane M, and form grid lines on the plane M according to the set side length L, and the grid lines contained in it can completely cover the projected circular plane S; Step 2), set The hemisphere is properly extended so that all vertices of the entire mesh are mapped to it. Step 3), separate a small curved surface on the spherical surface for each obtained grid, which is the bottom surface of the hexahedral lattice, and offset the curved surface according to the height of the lattice to obtain its top surface, so as to obtain the self-adapted crystal grid area. This method has an important reference value for the surface subdivision of the semi-ellipsoid surface with a single deformation extremum relative to a single projection surface, and is of great significance for structural design.

Description

technical field [0001] The invention relates to a structural design method based on hemispherical quadrilateral subdivision and a hexahedral lattice as a basic unit. It is a structural design oriented to 3D printing technology and belongs to the technical field of digital manufacturing. Background technique [0002] With the maturity of 3D printing technology, it has been able to directly manufacture fine and complex structures. This kind of new lattice-like structure that changes adaptively with a given boundary, compared with traditional materials such as metal foam, is easy to calculate the mechanical properties, and will be widely used in composite materials, optimization of weight reduction, etc., in aviation, aerospace, automotive areas have received widespread attention. [0003] The hexahedral lattice structure design of the hemispherical boundary, the most critical part is the quadrilateral grid division of the (hemispherical) surface. At present, there are mainly...

AI Technical Summary

Problems solved by technology

At present, there are mainly the following types of methods: (1) Longitude and latitude grid division, its disadvantage is that the grid deformation is large, and the shape of the grid at the poles and the equator is very different, especially at the north and south poles, the grid degenerates from a quadrilateral to a triangle ; (2) Regular polyhedron grid subdivision, most of the current research is based on spherical triangular grid, and there are few studies on other grids such as rhombus and hexagon, and the calculation is heavy due to the complex coordinate conversion; (3 ) The traditional adaptive spherical grid subdivision provides a supplement to the regular grid subdivision. Its disadvantage is that it is only suitable for a local small-scale spherical surface

Specific quadrilateral subdivision methods include "ETP projection method", "ZOT projection method", "column approximation method", "three-way interchange algorithm", etc. These grid subdivision methods come from technical fields such as geography, meteorology, and communication , the method of hierarchical subdivision is adopted, that is, the current subdivision result is the basis of the next level subdivision, and the discretization of the grid side length is very serious, which cannot meet the structural design requirements

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