CN-116341304-B - Engine rotor blade plane stress unit grid conversion method and system

CN116341304BCN 116341304 BCN116341304 BCN 116341304BCN-116341304-B

Abstract

The invention relates to a method and a system for converting plane stress unit grids of an engine rotor blade, wherein the method comprises the steps of setting a 3D unit array and a 2D unit array; traversing node numbers of all units of all layers in the 3D unit to obtain a 2D total node number, calculating coordinate values of the 2D total node number, calculating unit node numbers of the 2D unit according to the 2D total node number, traversing nodes of all units of all layers in the 3D unit, calculating the volume of the 3D unit, traversing all nodes in the 2D unit, calculating the area of the 2D unit, calculating the thickness of the 2D unit according to the volume of the 3D unit and the area of the 2D unit, and outputting node coordinates and unit information of the 2D unit. The invention can realize the automatic conversion of the aeroengine rotor blade from the 20-node 6-surface solid unit grid to the 8-node 4-edge plane stress unit, thereby saving a great deal of manpower, greatly shortening the calculation period and providing a basis for the high-precision finite element calculation and the optimization design of the subsequent rotor.

Inventors

ZHAO ZHENXING
FU MINGWEI
PAN XINYU
DAI YU
XUE YUANYUAN
ZHAO YUNSHENG
DING JIANGUO
CAI XIANXIN

Assignees

太仓点石航空动力有限公司

Dates

Publication Date: 20260505
Application Date: 20221214

Claims (6)

1. A method for converting plane stress unit grids of an engine rotor blade is characterized by comprising the following steps: S1, setting a 3D unit array and a 2D unit array, inputting the node number of each 3D unit and storing the node number in the 3D unit array; s2, traversing node numbers of all units of all layers in the 3D unit to obtain node numbers of the 2D unit, and calculating coordinate values of the node numbers of the 2D unit; The method for calculating the coordinate value of the 2D unit node number comprises the following steps: And traversing node numbers of all units of all layers in the 3D unit to obtain node coordinates of the 2D unit which are still rectangular coordinates of a space, and converting the node rectangular coordinates into cylindrical coordinates by the following formula: , , wherein, the method comprises the following steps of , ) The cylindrical coordinates of the nodes are represented, Expressing rectangular coordinates of the nodes; S3, calculating the unit node number of the 2D unit according to the 2D total node number and storing the unit node number into a 2D unit array; S4, traversing nodes of all units of all layers in the 3D unit, calculating the volume of the 3D unit, traversing all nodes in the 2D unit, and calculating the area of the 2D unit; a method of computing a volume of the 3D cell by traversing nodes of all cells of all layers in the 3D cell, comprising: transforming the node of the 3D unit from a local coordinate to an integral rectangular coordinate through isoparameter, wherein the local coordinate is positioned at the center of the cube, and the coordinate transformation formula is as follows: , , ; Wherein, the Representing rectangular coordinates of nodes, (ζ, η, ζ) representing local coordinates, and N i representing a shape function; Calculating the volume of the 3D unit according to the local coordinates (ζ, eta, ζ) of the nodes, wherein the calculation formula is as follows: , Wherein: ; Traversing all nodes in the 2D unit, and calculating the area of the 2D unit, wherein the method comprises the following steps: Transforming the node of the 2D unit from a local coordinate to an integral rectangular coordinate through isoparameter, wherein the local coordinate is positioned at the center of a square, and the coordinate transformation formula is as follows: , ; wherein, the method comprises the following steps of , ) Representing the cylindrical coordinates of the nodes, (ζ, η) representing the local coordinates and N i representing the shape function; calculating the area of the 2D unit according to the local coordinates (ζ, η) of the nodes, wherein a calculation formula is as follows: , Wherein: , , , , ; S5, calculating the thickness of the 2D unit according to the volume of the 3D unit and the area of the 2D unit; the calculation formula of the thickness of the 2D unit is as follows: , Wherein, the For the volume of the 3D-cell, The area of the corresponding 2D unit is the number of blades; And S6, outputting the node coordinates and the unit information of the 2D unit.
2. The method for converting plane stress unit grids of engine rotor blades according to claim 1, wherein in step S2, the method for traversing node numbers of all units of all layers in the 3D unit to obtain node numbers of 2D units comprises the following steps: providing that the ordering mode of the 3D units is the same as the ordering mode of the 2D units, wherein the ordering mode is firstly from left to right and then from bottom to top; Let the number of units per layer be NC, and the number of units per layer be NL, i=1, 2,..nl is the layer number from bottom to top, j=1, 2,..nc is the row number from left to right of the units per layer, and L is the 2D unit node number, then there is: for the 3D cell local node number 12 there is: L=(i-1)(3NC+2)+2(j-1)+1; for 3D cell local node numbers 9, 11, there are: L=(i-1)(3NC+2)+2(j-1)+2; For the 3D cell local node numbers 17, 20, there are: L=(i-1)(3NC+2)+2NC+j+1; When i=1 and j increases from 1 to j=nc, 1-12 nodes and 14-19 nodes are obtained, j=nc+1 is set again at this time, 13-20 nodes are obtained, 1-20 nodes of the first layer are all obtained, and then all node numbers of the remaining layers are obtained.
3. The method for converting plane stress cell grids of engine rotor blades according to claim 2, wherein in step S3, the method for calculating cell node numbers of 2D cells according to 2D total node numbers and storing the cell node numbers into a 2D cell array comprises the following steps: Let the 2D cell array be E2D [ ], then there are: Ie=i×NC+j, E2d[Ie][1]=(i-1)(3NC+2)+2(j-1)+1, E2d[Ie][2]=E2d[Ie][1]+2, E2d[Ie][5]=E2d[Ie][1]+1, E2d[Ie][8]=(i-1)(3NC+2)+2NC+j+1, E2d[Ie][6]=E2d[Ie][8]+1, E2d[Ie][4]=E2d[Ie][1]+3NC+2, E2d[Ie][3]=E2d[Ie][4]-2, E2d[Ie][7]=E2d[Ie][4]-1; where i=1, 2..nl, j=1, 2..nc, ie is the unit number.
4. An engine rotor blade planar stress cell grid conversion system, comprising: The array setting module is used for setting a 3D unit array and a 2D unit array, inputting the node number of each 3D unit and storing the node number in the 3D unit array; the 2D unit coordinate calculation module is used for traversing the node numbers of all units of all layers in the 3D unit to obtain the node numbers of the 2D unit, and calculating the coordinate values of the node numbers of the 2D unit; The method for calculating the coordinate value of the 2D unit node number comprises the following steps: And traversing node numbers of all units of all layers in the 3D unit to obtain node coordinates of the 2D unit which are still rectangular coordinates of a space, and converting the node rectangular coordinates into cylindrical coordinates by the following formula: , , wherein, the method comprises the following steps of , ) The cylindrical coordinates of the nodes are represented, Expressing rectangular coordinates of the nodes; The 2D unit node numbering module is used for calculating the 2D unit node number according to the coordinate value of the 2D total node number and storing the 2D unit node number into a 2D unit array; The computing module is used for traversing nodes of all units of all layers in the 3D unit, computing the volume of the 3D unit, traversing all nodes in the 2D unit and computing the area of the 2D unit; a method of computing a volume of the 3D cell by traversing nodes of all cells of all layers in the 3D cell, comprising: transforming the node of the 3D unit from a local coordinate to an integral rectangular coordinate through isoparameter, wherein the local coordinate is positioned at the center of the cube, and the coordinate transformation formula is as follows: , , ; Wherein, the Representing rectangular coordinates of nodes, (ζ, η, ζ) representing local coordinates, and N i representing a shape function; Calculating the volume of the 3D unit according to the local coordinates (ζ, eta, ζ) of the nodes, wherein the calculation formula is as follows: , Wherein: ; Traversing all nodes in the 2D unit, and calculating the area of the 2D unit, wherein the method comprises the following steps: Transforming the node of the 2D unit from a local coordinate to an integral rectangular coordinate through isoparameter, wherein the local coordinate is positioned at the center of a square, and the coordinate transformation formula is as follows: , ; wherein, the method comprises the following steps of , ) Representing the cylindrical coordinates of the nodes, (ζ, η) representing the local coordinates and N i representing the shape function; calculating the area of the 2D unit according to the local coordinates (ζ, η) of the nodes, wherein a calculation formula is as follows: , Wherein: , , , , ; the calculation formula of the thickness of the 2D unit is as follows: , Wherein, the For the volume of the 3D-cell, The area of the corresponding 2D unit is the number of blades; and the 2D unit information output module is used for outputting the node coordinates and the unit information of the 2D unit.
5. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of a method for converting an engine rotor blade plane stress cell grid according to any one of claims 1 to 3 when the computer program is executed by the processor.
6. A computer readable storage medium having stored thereon a computer program, characterized in that the program when executed by a processor implements the steps of a method of converting an engine rotor blade planar stress cell grid according to any of claims 1 to 3.

Description

Engine rotor blade plane stress unit grid conversion method and system Technical Field The invention relates to the field of engine dynamics design, in particular to a method and a system for converting a plane stress unit grid of an engine rotor blade. Background The aeroengine wheel disc works at high rotation speed, the strength of the aeroengine wheel disc is directly related to the safety of the engine, and the aeroengine wheel disc is a first key part of the aeroengine. As shown in fig. 1, 2D ring elements, such as 8-node 4-sided ring elements, are often used in making the engine disc strength calculations. Such a cell is the most accurate of the finite element common 2D cells. The same order 2D cells (e.g., 2D 8-node 4-sided 2-order cells) are more accurate than the 3D cells (20-node 6-sided 2-order cells). Since the 2D unit has a much smaller computational scale than the 3D unit, the grid can be divided very small (see fig. 2), and thus the computational accuracy can be further improved than with the 3D unit, especially at small rounds with large shape variations, as shown in fig. 2. To account for interactions between the disks, the rotor assembly of multiple disks or, as shown in FIG. 1, the entire engine rotor disk is often calculated together, where using a 2D unit provides a significant advantage over using a 3D unit. When the structural optimization design of the wheel disc is carried out or the elastoplastic analysis is carried out, a large amount of time can be saved by adopting the 2D unit compared with the 3D unit, so that the 2D unit has obvious advantages compared with the 3D unit. Accordingly, there is a strong need to provide an engine rotor blade planar stress cell grid conversion method that overcomes the problems of the prior art. Disclosure of Invention Therefore, the technical problem to be solved by the invention is to overcome the technical defects in the prior art, and provide the method and the system for converting the plane stress unit grid of the rotor blade of the engine, which can realize the automatic conversion of the plane stress unit of the plane of the rotor blade of the aeroengine from the solid unit grid of the body of the 20 nodes 6 to the plane stress unit of the body of the 8 nodes 4, thereby saving a great deal of manpower, greatly shortening the calculation period and providing a basis for the high-precision finite element calculation and the optimization design of the follow-up rotor. In order to solve the technical problems, the invention provides a method for converting a plane stress unit grid of an engine rotor blade, which comprises the following steps: S1, setting a 3D unit array and a 2D unit array, inputting the node number of each 3D unit and storing the node number in the 3D unit array; s2, traversing node numbers of all units of all layers in the 3D unit to obtain node numbers of the 2D unit, and calculating coordinate values of the node numbers of the 2D unit; s3, calculating the unit node number of the 2D unit according to the 2D total node number and storing the unit node number into a 2D unit array; S4, traversing nodes of all units of all layers in the 3D unit, calculating the volume of the 3D unit, traversing all nodes in the 2D unit, and calculating the area of the 2D unit; S5, calculating the thickness of the 2D unit according to the volume of the 3D unit and the area of the 2D unit; And S6, outputting the node coordinates and the unit information of the 2D unit. In one embodiment of the present invention, in step S2, a method for traversing node numbers of all units of all layers in the 3D unit to obtain node numbers of 2D units includes: providing that the ordering mode of the 3D units is the same as the ordering mode of the 2D units, wherein the ordering mode is firstly from left to right and then from bottom to top; Let the number of units per layer be NC, and the number of units per layer be NL, i=1, 2,..nl is the layer number from bottom to top, j=1, 2,..nc is the row number from left to right of the units per layer, and L is the 2D unit node number, then there is: for the 3D cell local node number 12 there is: L=(i-1)(3NC+2)+2(j-1)+1 for 3D cell local node numbers 9, 11, there are: L=(i-1)(3NC+2)+2(j-1)+2 For the 3D cell local node numbers 17, 20, there are: L=(i-1)(3NC+2)+2NC+j+1 When i=1 and j increases from 1 to j=nc, 1-12 nodes and 14-19 nodes are obtained, j=nc+1 is set again at this time, 13-20 nodes are obtained, 1-20 nodes of the first layer are all obtained, and then all node numbers of the remaining layers are obtained. In one embodiment of the present invention, in step S2, the method for calculating the coordinate value of the node number of the 2D unit includes: And traversing node numbers of all units of all layers in the 3D unit to obtain node coordinates of the 2D unit which are still rectangular coordinates of a space, and converting the node rectangular coordinates into cylindrical coordinates by the following formu