CN-121980848-A - Hexahedral mesh division precise quartz table finite element modeling method

CN121980848ACN 121980848 ACN121980848 ACN 121980848ACN-121980848-A

Abstract

The invention relates to a hexahedral mesh division precise quartz table finite element modeling method, which is suitable for the field of precise instrument finite element simulation, and is characterized in that firstly, a precise quartz table geometric model is simplified, and geometric characteristics which are unfavorable in geometry and do not influence mesh division are deleted; and then respectively carrying out geometric cutting on the swinging sheet assembly and the torquer, dividing the overall complex geometric structure into a plurality of geometric parts conforming to the topological mapping relation, generating characteristic lines on the surface of the model and the geometric contact surface as grid dividing boundaries, dividing two-dimensional plane grids according to the characteristic lines, and taking the two-dimensional grids as mapping matching references of hexahedral grids so as to ensure the grid quality and node connection. The invention can effectively develop the geometric division of the precise quartz watch with complex structure and difficult grid mapping, improve the grid quality of the finite element simulation of the precise quartz watch, give consideration to the simulation precision and efficiency, and can be popularized and applied to hexahedral grid division of precise instruments like the quartz watch.

Inventors

ZHANG XIAONA
YAN WENMIN
SI GAOLU
WANG ERWEI
MU YANG
ZHAO YOU

Assignees

北京航天控制仪器研究所

Dates

Publication Date: 20260505
Application Date: 20251224

Claims (10)

1. The method for modeling the finite element of the hexahedral mesh divided precise quartz watch comprises a pendulum piece assembly and a torquer, wherein the pendulum piece assembly comprises a quartz coated pendulum piece and a framework, and the torquer comprises magnetic steel, magnetic pole pieces, a compensation ring and a yoke, and is characterized by comprising the following steps: Step 1, dividing a pendulum piece into grids, namely defining a pendulum piece space coordinate system, wherein a quartz meter axis is taken as a Z axis, a pendulum piece surface is taken as an XY plane, a Y axis is taken as a pendulum piece symmetry axis, and an X axis is determined by a right hand rule; step 2, cutting the swing piece along a Z axis by using a framework circular contour to obtain an approximate semicircular flat plate, wherein two bulges are arranged on the edge of the swing piece, and cutting the swing piece by using a bulge contour line, wherein the cutting direction is the Z axis and the XY plane; the upper part of the swinging piece is provided with an extremely thin rectangular part, the contour line at the chamfer is used for cutting, the cutting direction is an X axis, the cutting direction is a Z axis, the lower half part of the swinging piece is provided with an extremely thin arc part, the arc contour extends outwards, the extended arc contour is used for cutting, the cutting direction is a Z axis, the cutting is performed at the thickness transition, and the cutting direction is a Z axis; Step3, taking the approximately semicircular flat plate as a starting point, carrying out hexahedral mesh mapping, namely dividing a two-dimensional quadrilateral mesh on the surface of the flat plate, and dividing the hexahedral mesh through integrated entity mapping; Step 4, respectively cutting the two raised positions into an upper part, a middle part and a lower part along the Z direction, dividing the XY surface of the middle part into two-dimensional quadrilateral grids, dividing the hexahedral grids through integrated entity mapping, projecting the divided two-dimensional quadrilateral grid nodes onto the upper part of the sheet surface along the Z axis, dividing the two-dimensional quadrilateral grids according to the grid nodes, dividing the hexahedral grids through integrated entity mapping; Step 5, cutting the extremely thin rectangular part into an upper part, a middle part and a lower part along the Y direction, dividing a two-dimensional quadrilateral mesh on YZ cutting surfaces of the three parts respectively, and dividing a hexahedral mesh through integral entity mapping; cutting the extremely thin arc-shaped part into an inner part and an outer part, dividing the outer part into two-dimensional quadrilateral meshes on the YZ cutting surface, mapping and dividing the hexahedral meshes along an arc-shaped path, dividing the inner part into two-dimensional quadrilateral meshes on the XY surface, and dividing the hexahedral meshes through integral entity mapping; Step 6, generating mirror image grids along the YZ plane through mirror image commands after choosing the copying options, and deleting all the two-dimensional grids; Step 7, carrying out hexahedral mesh division on the framework, wherein a framework space coordinate system is obtained by projection of a swing piece space coordinate system, the framework is cut by using the contour of the contact surface of the swing piece and the framework, and the cutting direction is a Z axis; Step 8, carrying out grid division on the torquer, wherein a specified torquer space coordinate system is obtained by projection of a swinging piece space coordinate system, cutting magnetic steel, a magnetic pole piece, a compensation ring and a yoke iron along a symmetrical plane XZ surface, and carrying out grid division on 1/2 geometric parts, namely cutting the magnetic steel along a circular contour line of the compensation ring in the thickness direction to obtain a first magnetic steel section and a second magnetic steel section, cutting the yoke iron along the circular contour line of the compensation ring and the magnetic steel in the thickness direction to obtain a first yoke iron section and a second yoke iron section, and cutting the yoke iron along a yoke iron XY surface in the thickness direction to obtain a third yoke iron section, a fourth yoke iron section and a fifth yoke iron section; Step 9, dividing a two-dimensional quadrilateral mesh on the XY surface of the magnetic pole piece, dividing a hexahedral mesh on the magnetic pole piece, the first magnetic steel section, the second magnetic steel section and the first yoke section through integrated mapping, dividing a two-dimensional quadrilateral mesh on the XY surface of the compensation ring, dividing a hexahedral mesh on the compensation ring and the second yoke section through integrated mapping, dividing a two-dimensional quadrilateral mesh on the XY surface of the third yoke section, dividing a hexahedral mesh on the third yoke section through integrated mapping, projecting the geometric contour line of the third yoke section to the XY surface of the fourth yoke section along the Z axis direction, dividing a two-dimensional quadrilateral mesh on the XY surface of the fourth yoke section, dividing a hexahedral mesh on the fourth yoke section through integrated mapping, dividing a two-dimensional quadrilateral mesh on the upper half of the YZ section of the fifth yoke section, and dividing a hexahedral mesh on the fifth yoke section through integrated mapping; And 10, after the hexahedral mesh divided in the step 9 is checked for the copy option, generating mirror image meshes along the XZ plane through mirror image commands, deleting all two-dimensional meshes, and completing quartz table finite element modeling.
2. The hexahedral mesh partitioned precision quartz table finite element modeling method according to claim 1, wherein the quartz table finite element model is subjected to simplified processing, and redundant structural lines of inner holes, chamfers and other joints in the quartz table finite element model are deleted.
3. The method for modeling a finite element of a hexahedral mesh according to claim 1, wherein the approximately semicircular flat plate map partitions the hexahedral mesh into six layers of mesh in a thickness direction.
4. The method for modeling a finite element of a hexahedral mesh according to claim 1, wherein the intermediate portion of the two protrusions is a six-layer mesh in the thickness direction when the hexahedral mesh is mapped and divided.
5. The method for modeling the finite element of the precise quartz watch divided by the hexahedral mesh according to claim 1, wherein the number of nodes of the quadrilateral mesh at the connecting transition of the three parts in the Z direction is 4, and the number of nodes of the quadrilateral mesh at the connecting transition of the upper part and the lower part with the rest part of the swinging piece in the X direction is 7.
6. The method for modeling the finite element of the precise quartz watch divided by the hexahedral mesh according to claim 1, wherein the number of nodes of the quadrilateral mesh at the connecting transition of the outer part and the inner part in the thickness direction of the extremely thin arc-shaped part is 4, the number of nodes of the quadrilateral mesh at the connecting transition of the outer part and the rest part of the swinging piece is 8, and the number of nodes of the quadrilateral mesh at the connecting transition of the inner part and the outer part in the thickness direction of the extremely thin arc-shaped part is three layers of meshes.
7. The method for modeling a finite element of a hexahedral mesh according to claim 1, wherein the balance of the wobble plate is six layers of mesh in the thickness direction when the hexahedral mesh is mapped and divided.
8. The method for modeling the finite element of the hexahedral mesh partitioned precise quartz watch according to claim 1, wherein the five parts obtained by cutting the skeleton are the same in node units at contact transition positions between any two parts.
9. The hexahedral mesh division precision quartz watch finite element modeling method according to claim 1, wherein the magnetic steel two-section thickness is the same as the compensation ring thickness.
10. The method for modeling the finite element of the hexahedral mesh partitioned precise quartz watch according to claim 1, wherein the number of node units at the transition positions of the compensation ring and the magnetic steel two sections is kept the same, and the number of node units at the transition positions of the yoke two sections and the yoke one section is kept the same.

Description

Hexahedral mesh division precise quartz table finite element modeling method Technical Field The invention belongs to the technical field of finite element simulation of precise instruments, and relates to a hexahedral mesh division precise quartz table finite element modeling method. Background In the use process of the quartz watch, noise and errors are generated due to the influence of environmental factors, so that the navigation accuracy of an inertial system is affected. The finite element simulation analysis of the quartz watch is significant for improving the accuracy of an inertial system. In finite element modeling, grid division plays an important role in a simulation flow, and grid quality and quantity influence the accuracy and efficiency of simulation calculation. For the quartz watch, if tetrahedral unit division is selected, the advantage is that the division process is simple, and software can automatically complete the division of parts according to a geometric model. However, under the same unit size, the number of tetrahedral units and nodes is far more than hexahedron, and meanwhile, the calculation result precision and the convergence speed effect of the tetrahedron are poor. The hexahedral mesh unit has obvious advantages in terms of calculation accuracy, mesh number, and degree of distortion resistance. However, the difficulty is that the geometric cutting of the complex parts in the quartz watch is complex, and the grid division difficulty is high. Meanwhile, the quartz watch has precise structure, the internal parts of the quartz watch have multi-scale characteristics, the size difference is large, and the problems that grids cannot be divided or the grids are distorted are easy to generate. The quartz watch mainly comprises a shell, a torquer, an abdominal belt, a swinging piece assembly, an isolating ring and a mixed integrated servo circuit, wherein the torquer and the swinging piece assembly are important assemblies for realizing the acceleration measurement function. How to perform entity topology cutting and planning mapping thought on torquer and swinging sheet components and achieve connection of grid nodes of contact surfaces of different parts is a problem to be solved. Disclosure of Invention The invention solves the technical problems of overcoming the defects of the prior art, providing a hexahedral mesh division precise quartz table finite element modeling method, solving the problems of complex and precise structure of the precise quartz table, difficult mesh mapping and the like, improving the mesh quality of the quartz table finite element modeling, and considering the simulation precision and efficiency. The invention solves the technical problem by adopting a scheme that the method for modeling the finite element of the precise quartz watch divided by hexahedral grids comprises a pendulum piece assembly and a torquer, wherein the pendulum piece assembly comprises a quartz coated pendulum piece and a framework, the torquer comprises magnetic steel, magnetic pole pieces, a compensation ring and a yoke, and the method comprises the following steps of: Step 1, dividing a pendulum piece into grids, namely defining a pendulum piece space coordinate system, wherein a quartz meter axis is taken as a Z axis, a pendulum piece surface is taken as an XY plane, a Y axis is taken as a pendulum piece symmetry axis, and an X axis is determined by a right hand rule; step 2, cutting the swing piece along a Z axis by using a framework circular contour to obtain an approximate semicircular flat plate, wherein two bulges are arranged on the edge of the swing piece, and cutting the swing piece by using a bulge contour line, wherein the cutting direction is the Z axis and the XY plane; the upper part of the swinging piece is provided with an extremely thin rectangular part, the contour line at the chamfer is used for cutting, the cutting direction is an X axis, the cutting direction is a Z axis, the lower half part of the swinging piece is provided with an extremely thin arc part, the arc contour extends outwards, the extended arc contour is used for cutting, the cutting direction is a Z axis, the cutting is performed at the thickness transition, and the cutting direction is a Z axis; Step3, taking the approximately semicircular flat plate as a starting point, carrying out hexahedral mesh mapping, namely dividing a two-dimensional quadrilateral mesh on the surface of the flat plate, and dividing the hexahedral mesh through integrated entity mapping; Step 4, respectively cutting the two raised positions into an upper part, a middle part and a lower part along the Z direction, dividing the XY surface of the middle part into two-dimensional quadrilateral grids, dividing the hexahedral grids through integrated entity mapping, projecting the divided two-dimensional quadrilateral grid nodes onto the upper part of the sheet surface along the Z axis, dividing the two-dimensional quadrilateral