CN113642129B - Workpiece correction load rapid application and deformation finite element acquisition method - Google Patents
Workpiece correction load rapid application and deformation finite element acquisition method Download PDFInfo
- Publication number
- CN113642129B CN113642129B CN202110976049.0A CN202110976049A CN113642129B CN 113642129 B CN113642129 B CN 113642129B CN 202110976049 A CN202110976049 A CN 202110976049A CN 113642129 B CN113642129 B CN 113642129B
- Authority
- CN
- China
- Prior art keywords
- workpiece
- deformation
- correction
- load
- machining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/02—Reliability analysis or reliability optimisation; Failure analysis, e.g. worst case scenario performance, failure mode and effects analysis [FMEA]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Evolutionary Computation (AREA)
- General Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Numerical Control (AREA)
Abstract
The invention discloses a method for rapidly applying a workpiece correcting load and acquiring a deformation finite element, which solves the problem of lower correcting load prediction precision in the prior art, has the beneficial effect of ensuring the reliability of data in the correcting load optimization process, and has the following specific scheme: a finite element acquisition method for rapid application and deformation of workpiece correction load comprises the following steps of correcting workpiece model input: acquiring material attributes of a workpiece and an initial residual stress field mathematical model of a workpiece blank, and introducing the mathematical model into a workpiece blank model of the workpiece with an integral structure; residual deformation acquisition pretreatment: obtaining an integral structural workpiece subjected to machining deformation through finite element analysis, selecting a deformation monitoring point for the integral structural workpiece subjected to machining deformation, and providing a reference point for obtaining residual deformation of the workpiece; selecting a correction load application area: dividing a correction area for the whole structural workpiece subjected to machining deformation, and determining a correction load application surface; and acquiring the residual deformation amount.
Description
Technical Field
The invention relates to the field of workpiece deformation control, in particular to a method for quickly applying workpiece correcting load and acquiring a deformation finite element.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
With the rapid development of the domestic traffic industry, the requirements on high speed, high maneuverability, high load capacity and service life of vehicles such as automobiles, airplanes, ships and the like are continuously improved, an integral structure workpiece machining process for reducing the assembly quantity is provided, and the integral structure workpiece is widely applied to modern high-performance vehicles. The integral structure workpiece is manufactured by adopting processing modes such as direct blank milling and the like, and the problem of processing deformation is easily caused due to the fact that the balance of residual stress in the material is broken in the material removing process, the material removing rate is high, the geometric structure is asymmetric, the rigidity of the workpiece is low and the like.
The deformation correction technology is the most effective method for reducing the processing deformation of the workpiece, but due to the complex shape of the workpiece with the integral structure, the non-linearity of materials and the like, an accurate mathematical relationship between the correction load and the correction value is difficult to find, and the residual deformation under different correction loads is required to be used as data before optimization for iterative calculation, so that the optimal correction load is obtained.
In order to obtain the residual deformation under different conditions, the existing method is to manually and sequentially input the correction load to be applied to the correction area in the finite element model, gradually perform finite element simulation analysis, and manually output the residual deformation of the deformation monitoring point. The method is a very time-consuming and labor-consuming process, and after each simulation analysis is completed, deformation monitoring points need to be manually selected, the selection repetition rate of the deformation monitoring points is low, the error is large, and the prediction precision of the workpiece machining deformation correction load is reduced.
In conclusion, in the workpiece machining deformation correcting process, after finite element simulation analysis, the residual deformation of the workpiece is difficult to obtain, the existing method has high limitation, and a large amount of manpower and more time are needed to complete the finite element simulation analysis and the residual deformation obtaining work.
The inventor finds that the whole process is manually operated, the workpiece deformation monitoring points are difficult to reproduce, the repeatability of the acquiring method is low, the residual deformation data acquired by manual operation are difficult to ensure the prediction precision of the correction load, and the correction quality of the final workpiece is difficult to improve.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method for quickly applying a workpiece correction load and acquiring a deformation finite element, which can realize accurate acquisition of residual deformation after workpiece processing deformation correction.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a finite element acquisition method for rapid application and deformation of workpiece correction load comprises the following steps:
correcting workpiece model input: acquiring material attributes of a workpiece and an initial residual stress field mathematical model of a workpiece blank, and introducing the mathematical model into a workpiece blank model of the workpiece with an integral structure;
residual deformation acquisition pretreatment: obtaining an integral structural workpiece subjected to machining deformation through finite element analysis, selecting a deformation monitoring point for the integral structural workpiece subjected to machining deformation, and providing a reference point for obtaining residual deformation of the workpiece;
selecting a correction load application area: dividing a correction area for the whole structural workpiece subjected to machining deformation, and determining a correction load application surface and a correction load application direction;
obtaining residual deformation: and sequentially applying set correction load values to different correction load application surfaces according to the correction load application direction, and acquiring the residual deformation of the deformation monitoring points under the corresponding correction loads.
In the acquisition method, a finite element simulation model is established through the input of a corrected workpiece model, the finite element analysis is realized through the residual deformation acquisition pretreatment, the whole structure workpiece which generates deformation after processing is obtained, and then the correction area is divided for the whole structure workpiece to realize the segmented application of the correction load; and calculating a correction load application surface and a correction load application direction, applying a correction load to the divided correction area, further acquiring the residual deformation of the workpiece with the integral structure under different correction loads, and providing data support for the optimal calculation of the correction load of the workpiece with the integral structure, thereby ensuring the optimal processing deformation correction load of the workpiece with the integral structure and realizing the accurate acquisition of the residual deformation after the processing deformation correction of the workpiece.
According to the method for acquiring the finite element of the workpiece correcting load rapid application and deformation, the milling process of the workpiece with the integral structure is simulated and processed by using the dead and live unit technology in the finite element, and the workpiece with the integral structure and the deformation is obtained.
According to the finite element acquisition method for rapid application and deformation of the workpiece correcting load, all surfaces of the correcting region are traversed, the normal basis for selecting the correcting load surface is established, the correcting load applying surface is determined, and the normal vector pointing to the outer side of the surface is used as the basis for correcting the load applying direction, so that the correcting load in the corresponding direction is applied to the correcting region.
In order to further automatically generate support data for accurate prediction of the correction load, after the residual deformation is acquired, the data of the residual deformation is stored, and the data of the residual deformation are stored according to a storage criterion that each row represents the residual deformation of different nodes under the same load and each column represents the residual deformation of different correction loads under the same node.
The method for acquiring the finite element of the workpiece calibration load rapid application and deformation specifically comprises the following steps of:
establishing a workpiece blank model of the workpiece with the integral structure;
establishing a constitutive relation between the flow stress and the strain on the surface of the workpiece with the integral structure, and introducing a constitutive relation model into the established workpiece blank model;
and (4) leading the mathematical model of the overall structure workpiece blank thickness and the residual stress in each direction into the established workpiece blank model to obtain the initial processing state of the overall structure workpiece blank, wherein the residual stress in each direction comprises the residual stress in the X direction and the residual stress in the Y direction.
The method for acquiring the finite element of the workpiece correcting load rapid application and deformation comprises the following steps:
dividing machining blocks of a workpiece blank model machining area according to an actual machining process, and establishing a relation between the machining blocks and a milling layered machining area;
based on the established machining area relation, simulating the process of the workpiece blank model in the milling machining process by utilizing a life-dead unit technology to obtain a workpiece with an overall machining deformation structure;
selecting deformation monitoring points of the overall-structure workpiece subjected to machining deformation, and providing reference points for obtaining residual deformation of the overall-structure workpiece;
setting different value sets of the correction load of the workpiece with the integral structure; initial conditions are provided for obtaining the residual deformation amount of the workpiece with the integral structure under different correction loads.
By milling layering and region division, the machining conditions of the workpiece with the integral structure in the actual milling process can be ensured to be consistent, namely the deformation of the workpiece with the integral structure under the finite element analysis and the actual machining conditions is ensured to be consistent.
The method for quickly applying the workpiece correcting load and acquiring the deformation finite element comprises the following steps: and aiming at the workpiece with the integral structure of processing deformation, selecting grid nodes at the bottom of the workpiece with the integral structure to obtain a set of selected residual deformation monitoring points of the workpiece.
According to the method for acquiring the finite element for rapid application and deformation of the workpiece correcting load, the selection of the correcting load application area specifically comprises the following steps:
dividing a correction area of the side wall of the edge strip of the overall-structure workpiece subjected to machining deformation, and traversing all the surfaces of the correction area and storing the surfaces into a set;
establishing a normal basis for selecting a calibration load surface in all the obtained surface sets, and determining a calibration load application surface set;
the surface of the workpiece has the characteristics of a first direction and a second direction, the application direction of the correction load is determined by a normal vector pointing to the outer side of the surface through establishing a criterion of the application direction of the correction load, and the set of correction load values is applied to the correction load application surface set of the workpiece with the whole structure.
According to the method for acquiring the finite element for rapid application and deformation of the workpiece calibration load, the establishment of the calibration load surface and the selection of the normal basis comprise the following steps:
selecting a side line in the overall structural workpiece model subjected to machining deformation, and acquiring a unit vector parallel to the side line, wherein the side line is perpendicular to a correction load application surface;
acquiring unit normal vectors of all surfaces in all surface sets, and forming the acquired normal vectors into a surface normal vector set, wherein the unit normal vector direction is as follows: pointing from the surface in an out-of-plane direction;
performing point multiplication on each unit normal vector in the surface normal vector set and the unit vector transposed vector, judging whether the point multiplication result is 1 or not, or outputting the surface normal vector set into a matrix format, and obtaining a column vector by solving the product numerical value of the matrix format and the transposed vector;
and storing the corresponding surface number with the dot product result of 1 into a correction load application surface set, or storing the corresponding surface with the element of 1 in the column vector into the correction load application surface set.
The method for judging the direction of the application of the correcting load comprises the following steps:
automatically drawing a sketch for each surface in the set of the obtained corrected load applying surfaces, obtaining geometric information in the sketch, and obtaining a unit vector of the surface of the sketch;
performing point multiplication on the unit normal vector with the point multiplication result of 1 or the element of 1 in the column vector and the transposed vector of the unit vector on the surface of the sketch to output a result Q;
if the output result Q is larger than 0, the selection direction of the correction load is the first direction, otherwise, the direction of the applied correction load is selected as the second direction, and therefore the surface pressure stress of the correction load is always applied to the correction load applying surface.
The beneficial effects of the invention are as follows:
1) according to the method, the residual deformation under different loads is automatically obtained in the process of optimizing the corrected load according to the machining deformation characteristics of the workpiece with the integral structure, and the problem that the residual deformation after correction is difficult to obtain in the process of finite element simulation of the workpiece with the integral structure is solved; in addition, the whole method reduces the manual participation time, saves the manpower, improves the corrected load obtaining efficiency and has good application value.
2) The method provided by the invention can automatically acquire the residual deformation of the whole-structure workpiece with machining deformation in the process of deformation correction load optimization, meets the requirement of high repeatability of the residual deformation in acquiring the whole-structure workpiece, and ensures the reliability of data in the process of correction load optimization.
3) The calibration load surface provided by the invention selects the normal basis and the criterion of the calibration load application direction, is favorable for accurately selecting the surface for applying the calibration load, and the accuracy of the calibration load direction, is favorable for automatically applying the calibration load, and does not need to spend a large amount of labor and time.
4) According to the method, the problem that deformation amounts of different correction areas are different is considered, the correction areas are divided for the workpiece with the integral processing deformation structure, correction loads are applied to the divided correction areas, segmented application of the correction loads is achieved, and the accuracy of application of a correction load surface and the accuracy of the correction load direction are fully guaranteed in cooperation with selection of the correction load direction.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 is a flow chart of a finite element acquisition method for rapid load application and deformation correction in an embodiment of the present invention.
Fig. 2 is a flowchart illustrating the normal direction of the calibration load surface in step 3.2) according to the embodiment of the present invention.
Fig. 3 is a flowchart of the criterion method for correcting the load applying direction in step 3.3) in the embodiment of the present invention.
Fig. 4 is a schematic diagram illustrating the division of the workpiece blank model machining area in the embodiment of the present invention.
FIG. 5 is a schematic diagram illustrating the division of the workpiece calibration area in the overall processing deformation structure according to an embodiment of the present invention.
Fig. 6 is a partial view of the calibration area 1 of fig. 5 in an embodiment of the present invention.
Fig. 7 is a path diagram of processing deformation monitoring points according to an embodiment of the present invention.
In the figure: 1. a workpiece blank model; 2 a workpiece of unitary construction.
Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the invention expressly state otherwise, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, it indicates the presence of the stated features, steps, operations, devices, components, and/or combinations thereof.
As introduced in the background art, the problem that the residual deformation amount of a workpiece is difficult to obtain in the process of simulating, analyzing and processing deformation correction in a finite element exists in the prior art, and in order to solve the technical problem, the invention provides a method for quickly applying a workpiece correction load and obtaining a deformation finite element.
In a typical embodiment of the present invention, referring to fig. 1, a method for acquiring a finite element for rapid application and deformation of a workpiece calibration load is provided, wherein a CAD (Computer Aided Design) modeling technique, a pre-processing simulation of a workpiece model, a calibration load surface, a calibration load application direction criterion, and a storage criterion of a residual deformation amount are combined in a process of acquiring a residual deformation finite element after workpiece calibration, so that a large amount of accurate residual deformation amount data can be provided in an optimized calculation process of a workpiece machining deformation calibration load, thereby achieving rapid and accurate acquisition of a residual deformation amount after workpiece calibration, and the method includes the following steps:
step 1) correcting workpiece model input: introducing a workpiece blank model 1 shown in the attached figure 4, acquiring and introducing material attributes by inquiring the material mechanical properties of a workpiece, acquiring an initial residual stress field mathematical model of the workpiece blank by a residual stress measurement technology, and introducing the initial residual stress field mathematical model into the workpiece blank model 1 to provide a model basis for acquiring the machining deformation condition of the workpiece;
step 2) residual deformation acquisition pretreatment: according to the actual processing process situation, dividing blocks of a processing area of a workpiece blank model 1, establishing a relation between the blocks and a milling layered processing area, applying boundary conditions to an overall structure workpiece 2 shown in fig. 5, simulating the milling process of the overall structure workpiece by using a living and dead unit technology in a finite element to obtain the overall structure workpiece 2 with processing deformation, selecting deformation monitoring points for the overall structure workpiece 2 with processing deformation, and providing reference points for obtaining residual deformation of the workpiece;
step 3), selecting a correction load application area: dividing a correction area on the edge strip side wall of the overall-structure workpiece 2 subjected to machining deformation, traversing all surfaces of the correction area, establishing a normal basis for selecting a correction load surface, determining a correction load application surface, and taking a normal vector pointing to the outer side of the surface as a basis for correcting the load application direction, so as to apply a correction load in a corresponding direction to the correction area;
step 4), obtaining residual deformation: and according to the selected correction load application direction, sequentially applying set correction load values to different correction load application surfaces, acquiring residual deformation of deformation monitoring points under the corresponding correction loads, and storing the acquired residual deformation values in the data set DS.
Step 5), a post-processing output module: and storing the residual deformation data stored in the data set DS in the row in the step 4) into a DAT file according to the storage criterion that each row represents the residual deformation of different nodes under the same load and each column represents the residual deformation of different correction loads under the same node.
The specific steps for correcting the workpiece model input in the step 1) are as follows:
step 1.1) establishing a workpiece blank model 1 of a workpiece 2 with an integral structure by a CAD (computer aided design) modeling technology;
step 1.2) establishing a constitutive relation between the flow stress and the strain of the surface of the workpiece with the integral structure by utilizing an automatic ball indentation principle, and introducing a constitutive relation model into an established workpiece blank model 1;
and step 1.3) introducing the mathematical model of the blank thickness and the residual stress in each direction of the overall-structure workpiece 2 into the established workpiece blank model 1 to obtain the initial processing state of the blank of the overall-structure workpiece 2.
It is understood that the directional residual stress includes residual stresses in the X direction and the Y direction.
Further, the step 2) of preprocessing the residual deformation acquisition comprises the following specific steps:
step 2.1) realizing the full-freedom constraint of the overall-structure workpiece 2 according to the overall-structure workpiece constraint state in the actual machining process;
step 2.2) dividing the processing area of the workpiece blank model 1 into processing blocks, and establishing the relation between the processing blocks and the milling layered processing area;
step 2.3) simulating the milling process of the workpiece blank model 1 by utilizing a life-dead unit technology based on the machining area relation established in the step 2.2) to obtain a machined and deformed workpiece 2 with an integral structure;
step 2.4) selecting deformation monitoring points of the overall-structure workpiece 2 subjected to machining deformation, and providing reference points for obtaining residual deformation of the overall-structure workpiece;
step 2.5) setting different value sets Load _ all of the correction Load of the overall structure workpiece 2; initial conditions are provided for obtaining residual deformation of the overall structural workpiece 2 under different corrective loads.
Referring to fig. 7, step 2.4) in step 2) is a method for selecting deformation monitoring points of the workpiece 2 with the deformed integral structure: and selecting grid nodes at the bottom of the overall-structure workpiece 2 by simulating the overall-structure workpiece 2 with machining deformation obtained in the milling process, wherein the selected path is three characteristic lines at the bottom, and the selected deformation monitoring points fully reflect the workpiece machining deformation condition to obtain a selected workpiece residual deformation monitoring point set Nodel _ List.
The specific steps for selecting the correction load application area in the step 3) are as follows:
step 3.1) dividing the correction area of the side wall of the edge strip of the workpiece 2 with the integral structure deformed by machining, traversing all the surfaces of the correction area and storing the surfaces into a set Faceall；
Step 3.2) will obtain all surface set FaceallIn the method, a normal basis for selecting a calibration load surface is established, and a calibration load application surface set Face is determinedcorr；
Step 3.3) the surface of the workpiece has the characteristics of SIDE1 and SIDE2, the application direction of the correcting load is determined by establishing a criterion of the application direction of the correcting load and using a normal vector pointing to the outer SIDE of the surface, and the correcting load is applied to the workpiece with the whole structureFace set FacecorrThe set corrective Load value is applied in conjunction with Load _ all.
The step of establishing a normal basis for selecting a calibration load surface in step 3) of step 3.2) is shown with reference to fig. 2 and 6:
step 3.2.1) selecting one side Edge in the overall structure workpiece 2 subjected to machining deformation, and obtaining a unit vector e parallel to the side EdgeEdge＝[xe,ye,ze]The Edge line Edge is perpendicular to the correction load application surfaces Face1 and Face 2;
step 3.2.2) obtaining all surface sets FaceallUnit normal vector e of each surface ii＝[xi,yi,zi]All the obtained normal vectors form a surface normal vector set Facevector；
Step 3.2.3) set Face of surface normal vectorvectorEach unit normal vector e iniAnd a unit vector eEdgeTransposed vector
Performing dot multiplication and judgment
Whether it is 1, or surface normal quantities are aggregated into FacevectorOutput as matrix form Facen×3(n denotes the collective Face of all surfacesallBy solving for
Numerically obtaining a column vector Rn×1；
Step 3.2.4) will
Corresponding surface numbers of (A) are stored in a corrected load application surface set FacecorrOr a column vector Rn×1Middle elementThe corresponding surface with element 1 is stored into a correction load application surface set Facecorr；
Step 3.2.5) since each of the correction regions divided in step 3.1) contains 8 surfaces, the set Face of the load application surfaces is correctedcorrNumber of elements of
The criterion method for establishing the direction of application of the corrective load of step 3) is illustrated with reference to fig. 3 and 6:
step 3.3.1) to obtain the corrected load applying surface set FacecorrEach surface in the sketch map is automatically drawn, geometric information in the sketch is obtained, and a unit vector t of the surface of the sketch map is obtained as [ x [t,yt,zt]；
Step 3.3.2) will
Or column vector Rn×1Unit normal vector e with middle element as 1iTransposed vector t to unit vector t on the surface of sketchTPerforming dot product to output a result Q;
step 3.3.3) if the output result Q > 0, it means that the calibration load is selected in the first direction SIDE1, otherwise, the direction of the applied calibration load is selected in the second direction SIDE2, thereby ensuring that the calibration load application surface is always subjected to the surface compressive stress of the calibration load, where SIDE1 denotes the direction perpendicular to the surface and directed towards the interior of the calibration area body and SIDE2 denotes the direction perpendicular to the surface and directed towards the exterior of the calibration area body.
And 3.3.4) deleting the automatic draft drawing setting, so that the storage space of the model and the simulation time are reduced.
The specific steps for obtaining the residual deformation in the step 4) are as follows:
step 4.1) obtaining a correction Load application direction based on the step 3.3.3), and sequentially applying correction Load sets Load _ all to different correction Load application surfaces;
step 4.2) calculating the residual deformation condition of the workpiece with the integral structure, which is processed and deformed under different correction loads, after correction in finite element software;
and 4.3) acquiring residual deformation of the corresponding deformation monitoring points in the overall-structure workpiece after correction in the simulation result by using the selected overall-structure workpiece deformation monitoring point set Nobel _ List, and storing the residual deformation in a data set DS shown in the table 1.
The post-processing output module in the step 5) comprises the following specific steps: because the obtained residual deformation of the workpiece with the integral structure after correction is stored in the data set DS in a single-row format, the storage criterion of the residual deformation is required to be satisfied: each row represents the residual deformation of different nodes under the same load, each column represents the residual deformation of different correction loads under the same node, and the acquired data is stored in a DAT file (a computer data file storage format, which stores data by using a DAT extension) in table 2 in a matrix form.
The method for correcting the load comprises the following steps that in the selection of a correction load surface, because a correction area is provided with a plurality of surfaces, each surface only needs to apply a correction load on the ground in a specific direction, the specific direction refers to the selection of a 'side Edge', only the surface perpendicular to the 'side Edge' is the surface to be applied with the correction load, and other surfaces are not the surfaces to be applied with the correction load, so that the correction load can be accurately applied by selecting the application direction of the correction load, and the intellectualization of the application process of the correction load is ensured.
Taking the aviation overall structure workpiece 2 as an example, the structure is simulated by four separation frames, and the corrected residual deformation under different correction loads is obtained.
For the workpiece blank model 1 of the built aviation integral structure workpiece 2, an aluminum alloy 7050-T7451 pre-stretched plate is taken as an example.
According to the method in the step 1), a workpiece blank model 1 is established, and the constitutive relation between the flow stress and the strain of the surface of the workpiece with the integral structure is obtained by adopting the automatic ball indentation principle: true stress sigmatWith true plastic strain epsilonpCan be expressed as a classical metal plasticity model: sigmat＝332(1+222εp)0.153And introduced into the workpiece blank mold 1.
By utilizing a residual stress measurement technology, a mathematical model for obtaining the thickness of the workpiece blank model 1 and the residual stress in each direction is imported into the established workpiece blank model 1, and the mathematical model of the residual stress is expressed as follows:
wherein σxExpressed as the relation of the residual stress in the X direction to the thickness of the blank, σyExpressed as residual stress in the Y direction versus the thickness of the blank.
According to the method in the step 2), determining the milling thickness of the workpiece according to the actual milling process, carrying out layered processing on the processing area of the workpiece blank model 1, applying boundary conditions to the workpiece 2 with the overall structure shown in figure 5, and respectively carrying out (U) processing on three end points of the bottom of the workpiece, which are not on the same straight lineXUYUZ、UYUZ、UZ) The three-point constraint realizes the constraint of six degrees of freedom of the workpiece. And selecting nodes according to the deformation monitoring point selection path shown in fig. 7, and storing the nodes in a set node _ List, where the node _ List is represented as: node _ List ═ 88,678,683,691,766,771,773,776,787,790,1560,1579,1589,1593,1612,1615,1617,1621,1635,1655,1660,1667,1671,1691,1699,13873]The set correction Load value Load _ all is set to [0,100,200,300,400,450,500 ]]。
According to the method in the step 3), the correction area division is carried out on the side wall of the edge strip of the workpiece 2 with the integral structure deformed by machining, all the surfaces of the traversal correction area are stored in a set Faceall，
Normal basis for selecting correction load surface and correction loadObtaining a set Face of a corrected load applying surface according to the criterion of applying directioncorr＝[(349.75,149.0,21.0),(349.75,150.0,21.0),(349.75,100.5,21.0),(349.75,99.5,21.0),(349.75,50.0,21.0),(349.75,51.0,21.0),(150.25,50.0,21.0),(150.25,51.0,21.0),(150.25,99.5,21.0),(150.25,100.5,21.0),(150.25,149.0,21.0),(150.25,150.0,21.0)]。
Applying a surface set Face to the correction load in sequence according to the method in the step 4)corrApplying each numerical value in the correction Load _ all to each group of surfaces, and calculating the residual deformation condition of the whole structural workpiece subjected to machining deformation under different correction loads after correction in finite element software; and acquiring residual deformation of the deformation monitoring points in the overall structure workpiece after correction in the simulation result by using the selected overall structure workpiece deformation monitoring points Nobel _ List, and storing the residual deformation in the data set DS shown in the table 1.
TABLE 1 data set DS
According to the method in step 5), the residual deformation data stored in the data set DS in the form of a single column is stored in the DAT file in table 2 in the form of a matrix according to the residual deformation storage criterion, and the frame lines in table 1 and table 2 are hidden.
TABLE 2 DAT File
In the embodiment, aiming at the problem that the residual deformation is difficult to obtain in the process of simulation analysis of machining deformation correction of a workpiece in a finite element, a method for quickly applying a workpiece correction load and obtaining a deformation finite element is provided, so that the automatic acquisition of residual deformation data in the process of optimizing the machining deformation correction load of an integral structural member can be realized, the requirement of high repeatability of the residual deformation for obtaining the workpiece of the integral structure is met, and the reliability of the data in the process of optimizing the correction load is ensured; according to the embodiment, aiming at the problem that the deformation amounts of different correction areas are different, the application of the segmented correction load and the automatic selection of the direction of the correction load are realized, and the application accuracy of the correction load surface and the accuracy of the direction of the correction load are ensured.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A finite element acquisition method for rapid application and deformation of workpiece correcting load is characterized by comprising the following steps:
correcting workpiece model input: acquiring material attributes of a workpiece and an initial residual stress field mathematical model of a workpiece blank, and introducing the mathematical model into a workpiece blank model of the workpiece with an integral structure;
residual deformation acquisition pretreatment: obtaining an integral structural workpiece subjected to machining deformation through finite element analysis, selecting a deformation monitoring point for the integral structural workpiece subjected to machining deformation, and providing a reference point for obtaining residual deformation of the workpiece;
selecting a correction load application area: dividing a correction area for the whole structural workpiece subjected to machining deformation, and determining a correction load application surface and a correction load application direction;
obtaining residual deformation: sequentially applying set correction load values to different correction load application surfaces according to the correction load application direction, and acquiring the residual deformation of deformation monitoring points under the corresponding correction loads;
obtaining a mathematical model of an initial residual stress field of a workpiece blank by a residual stress measurement technology;
the correction load application area selection specifically comprises the following contents:
dividing a correction area of the side wall of the edge strip of the overall-structure workpiece subjected to machining deformation, and traversing all the surfaces of the correction area and storing the surfaces into a set;
establishing a normal basis for selecting a calibration load surface in all the obtained surface sets, and determining a calibration load application surface set;
the surface of the workpiece has the characteristics of a first direction and a second direction, the application direction of the correction load is determined by a normal vector pointing to the outer side of the surface through establishing a criterion of the application direction of the correction load, and a set of correction load values is applied to the correction load application surface set of the workpiece with the integral structure;
the first direction represents a direction pointing to the inside of the correction region entity perpendicular to the surface, and the second direction represents a direction pointing to the outside of the correction region entity perpendicular to the surface;
the establishment of the normal basis for selecting the correction load surface comprises the following steps:
selecting a side line in the overall structural workpiece model subjected to machining deformation, and acquiring a unit vector parallel to the side line, wherein the side line is perpendicular to a correction load application surface;
acquiring unit normal vectors of all surfaces in all surface sets, and forming the acquired normal vectors into a surface normal vector set;
performing point multiplication on each unit normal vector in the surface normal vector set and the unit vector transposed vector, judging whether the point multiplication result is 1 or not, or outputting the surface normal vector set into a matrix format, and obtaining a column vector by solving the product numerical value of the matrix format and the transposed vector;
and storing the corresponding surface number with the dot product result of 1 into a correction load application surface set, or storing the corresponding surface with the element of 1 in the column vector into the correction load application surface set.
2. A finite element method for rapid application and deformation of a workpiece calibration load as claimed in claim 1, wherein after the residual deformation is obtained, the data of the residual deformation is stored, and the data of the residual deformation is stored according to a storage criterion that each row represents the residual deformation of different monitoring points under the same load and each column represents the residual deformation of different calibration loads under the same monitoring point.
3. The finite element method for rapidly applying a workpiece correcting load and deforming according to claim 1, wherein the correcting workpiece model input specifically comprises the following contents:
establishing a workpiece blank model of the workpiece with the integral structure;
establishing a constitutive relation model of the flow stress and the strain on the surface of the workpiece with the integral structure, and introducing the constitutive relation model into the established workpiece blank model;
and (4) leading the mathematical model of the thickness and the residual stress in each direction of the workpiece blank with the integral structure into the established workpiece blank model to obtain the initial processing state of the workpiece blank with the integral structure.
4. A finite element method for rapid application and deformation of a workpiece calibration load as claimed in claim 1, wherein the residual deformation acquisition pre-processing comprises the following steps:
dividing machining blocks of a workpiece blank model machining area according to an actual machining process, and establishing a relation between the machining blocks and a milling layered machining area;
based on the established machining area relation, simulating the process of the workpiece blank model in the milling machining process by utilizing a life-dead unit technology to obtain a workpiece with an overall machining deformation structure;
selecting deformation monitoring points of the overall-structure workpiece subjected to machining deformation, and providing reference points for obtaining residual deformation of the overall-structure workpiece;
setting different value sets of the correction load of the workpiece with the integral structure; initial conditions are provided for obtaining the residual deformation amount of the workpiece with the integral structure under different correction loads.
5. The finite element acquisition method for rapid application and deformation of workpiece calibration load according to claim 1, wherein the method for selecting the deformation monitoring points comprises the following steps: and aiming at the workpiece with the integral structure of processing deformation, selecting grid nodes at the bottom of the workpiece with the integral structure to obtain a set of selected residual deformation monitoring points of the workpiece.
6. The finite element acquisition method for workpiece calibration load quick application and deformation according to claim 1, wherein the method for judging the calibration load application direction comprises the following steps:
automatically drawing a sketch for each surface in the set of the obtained corrected load applying surfaces, obtaining geometric information in the sketch, and obtaining a unit vector of the surface of the sketch;
performing point multiplication on the unit normal vector with the point multiplication result of 1 or the element of 1 in the column vector and the transposed vector of the unit vector on the surface of the sketch to output the resultQ；
If the output result Q is larger than 0, the selection direction of the correction load is the first direction, otherwise, the direction of the applied correction load is selected as the second direction, and therefore the surface pressure stress of the correction load is always applied to the correction load applying surface.
7. The method as claimed in claim 1, wherein the finite element method comprises simulating a milling process for machining the workpiece with the integral structure by using a dead-live element technique in the finite element, thereby obtaining the workpiece with the machined and deformed integral structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110976049.0A CN113642129B (en) | 2021-08-24 | 2021-08-24 | Workpiece correction load rapid application and deformation finite element acquisition method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110976049.0A CN113642129B (en) | 2021-08-24 | 2021-08-24 | Workpiece correction load rapid application and deformation finite element acquisition method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113642129A CN113642129A (en) | 2021-11-12 |
| CN113642129B true CN113642129B (en) | 2022-04-05 |
Family
ID=78423730
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110976049.0A Active CN113642129B (en) | 2021-08-24 | 2021-08-24 | Workpiece correction load rapid application and deformation finite element acquisition method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113642129B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115309310B (en) * | 2022-08-31 | 2024-02-02 | 安世亚太科技股份有限公司 | Simulation graphic display method and device and electronic equipment |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111546017B (en) * | 2020-05-28 | 2022-02-08 | 上海工程技术大学 | Method for correcting and strengthening prestress of welded light alloy medium and heavy plates |
| CN112338003B (en) * | 2020-09-29 | 2023-06-20 | 哈尔滨工业大学 | Shape correction method for manufacturing deformation of aluminum-magnesium alloy thin-wall cabin section |
| CN112570491A (en) * | 2020-11-25 | 2021-03-30 | 浙江思印科技有限公司 | Method for correcting and strengthening prestress of welded light alloy medium and heavy plates |
-
2021
- 2021-08-24 CN CN202110976049.0A patent/CN113642129B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113642129A (en) | 2021-11-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108182325B (en) | Prediction analysis method for machining deformation of thin-wall structural part | |
| CN111723440B (en) | Thin-wall part machining precision prediction hybrid modeling method | |
| CN113642129B (en) | Workpiece correction load rapid application and deformation finite element acquisition method | |
| CN109726437B (en) | Cabin door pneumatic load equivalent node force processing method | |
| CN111967172B (en) | Internal high-pressure forming process optimization design method based on kriging model | |
| CN112414668B (en) | Wind tunnel test data static bomb correction method, device, equipment and medium | |
| CN114722686B (en) | Method for designing and optimizing lifting lug of large equipment based on finite element analysis | |
| CN112329140A (en) | Method for optimizing aerodynamics of variant aircraft based on improved position vector expectation improvement degree | |
| CN114444347A (en) | Mirror image milling deformation prediction method for large curved surface thin-wall part based on finite element analysis | |
| CN114662410A (en) | Method and device for determining polishing process parameter combination, electronic equipment and medium | |
| CN115705443A (en) | Method for manufacturing steel pipe cold-drawing die | |
| CN112380650A (en) | Method for designing structural member of working device | |
| CN113496064B (en) | Compensation adjustment method for straightness of numerical control machine tool | |
| CN116595758A (en) | Parameterized design system and parameterized design method for robot research and development application | |
| CN111444619B (en) | Online analysis method and equipment for injection mold cooling system | |
| CN107844646B (en) | Distributed load equivalent reduction method for slender body | |
| CN114347029A (en) | Model order reduction method for rapid simulation of pneumatic soft robot | |
| CN115795770A (en) | Method and system for estimating welding deformation of vehicle body | |
| CN113505435A (en) | Carbon fiber shell analysis method based on response surface model | |
| CN112131665B (en) | Grid classification-based rocket fluid fixed load hybrid conversion method | |
| CN103745038A (en) | Modeling method of ferris wheel structure finite element model | |
| CN115408960A (en) | Method for parametrically processing five-hole probe data | |
| CN112560311A (en) | Method for quickly and automatically extracting structure information and analyzing and optimizing structure | |
| CN111460696B (en) | Method and system for predicting deformation caused by cutting force based on overall stiffness matrix | |
| CN110781615A (en) | CAE simulation accuracy evaluation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |