CN104392057A - Finite element analysis method of roll bending of variable-curvature section - Google Patents
Finite element analysis method of roll bending of variable-curvature section Download PDFInfo
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- CN104392057A CN104392057A CN201410711574.XA CN201410711574A CN104392057A CN 104392057 A CN104392057 A CN 104392057A CN 201410711574 A CN201410711574 A CN 201410711574A CN 104392057 A CN104392057 A CN 104392057A
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Abstract
The invention discloses a finite element analysis method of roll bending of a variable-curvature section and belongs to the technical field of sheet metal forming of aircrafts. The finite element analysis method includes firstly analyzing the geometric structure and the motion relation of a four-roll bending machine tool, constructing a mathematic model of various rolls and the section in large finite element software and assembling the mathematic model according to the geometric structure of the roll bending machine tool, setting the initial left roll displacement and the initial right roll displacement of the section, establishing an equal-curvature roll-bending standard static analysis model and submitting for computing to obtain the curvature radius of the formed section in this condition; changing the left and right roll displacements to repeatedly compute to obtain the one-to-one correspondence between the left and right roll displacements and the curvature radius of the formed roll-bending section; finally subjecting the section to static segment variable-curvature roll-bending finite-element analysis by the correspondence, properly rectifying the left and right roll displacements of various equal-arc-length segment points at the position with large error by comparing the curvature radius of the finite-element analysis result with the digital-analog curvature radius of the section, and repeating computing until the error complies with the requirement.
Description
Technical field
The present invention relates to a kind of novel variable curvature section bar roll bending finite element method, belong to sheet metal forming technique.
Background technology
In recent years, in Aircraft Production, roll forming is complicated for these cross sectional shapes of section and the long purlin of engine nacelle etc. before and after be shaped frame costal margin bar, fuselage, the bool of variable curvature, adopts the analytical approach of FEM (finite element) calculation energy cost-saving, raises the efficiency.Variable curvature section bar roll bending finite element method in the section bar roll bending research Master's thesis of Zhou Yangping adopts variable curvature section bar iso-curvature to approach, first the method is studied the elastic recovery in the basic theories of section bar roll forming and roll bending based on elastic plastic theory, derive the expression formula of section bar roll forming Resilience radius, establish iso-curvature roll bending Resilience radius computation model, utilize springback calculation model inference to go out roll bending technological parameter, then utilize finite element analysis software to carry out the sunykatuib analysis of segmentation iso-curvature roll bending to section bar.It is arc-shaped that the method itself is based upon the flexural deformation part of supposition section bar between bending roller by the springback calculation model that theory deduction draws, and the firm modulus parameter of material strain in Resilience radius formula is difficult to obtain; This kind of method is iso-curvature in each segmentation simultaneously, and in fact section bar is not iso-curvature in each segmentation.The section bar forming accuracy that this kind of finite element method roll bending obtains is not high, simulate the section bar radius-of-curvature that obtains and section bar digital-to-analogue radius-of-curvature error larger.
Summary of the invention
It is comparatively large that the object of the invention is to solve existing variable curvature section bar roll bending Finite element analysis results error, and the problem that precision is not high, provides the variable curvature section bar roll bending finite element method that a kind of error is little, precision is high.
For the problems referred to above, novel variable curvature section bar roll bending finite element method of the present invention, comprises the following steps:
1) edge line extracting section bar digital-to-analogue to be processed, as characteristic curve, carries out radius-of-curvature analysis, after wherein considering curvature and length, section bar digital-to-analogue characteristic curve is divided into n section, and obtains the radius-of-curvature of n+1 equal arc length section point;
2) analyze four axle bending roll machine geometry and kinematic relations, this four axles bending roll machine comprises upper roller, bottom roller, left wheel, right roller; The mathematical model setting up roller and profile workblank in finite element analysis software luggage of going forward side by side is joined, and arranges left and right roller initial displacement amount;
3) carry out stress and strain model, contact definition, sets up section bar iso-curvature roll bending standard static analytical model, calculates section bar iso-curvature roll bending analytical model.The section bar iso-curvature grid model calculated is carried out grid model reconstruct, obtains the section bar digital-to-analogue after reconstructing, then the analysis of characteristic curve radius-of-curvature is carried out to this reconstruct section bar digital-to-analogue, radius-of-curvature value corresponding under obtaining this left and right roller displacement;
4) constantly change left and right roller displacement, repeat step 3), thus radius-of-curvature value corresponding under obtaining different left and right roller displacement, i.e. iso-curvature roll bending rule;
5) according to 4) in result derive left and right roller displacement corresponding to each equal segments point place radius-of-curvature of section bar digital-to-analogue characteristic curve to be processed; Left and right roller displacement corresponding for each equal segments point is designated as h1, h2 ... h (n+1);
6) by 4) in the iso-curvature roll bending rule that obtains be applied to the finite element analysis of variable curvature section bar roll bending, process is divided into n+2 standard static analysis step:
Arrange first analysis step, to move to displacement be h1 to left and right roller, upper bottom roller is temporarily motionless;
Second analysis step, corresponding left and right roller displacement at the uniform velocity change to h2 from h1, and upper bottom roller is at the uniform velocity around central rotation s rad;
3rd analysis step, left and right roller displacement at the uniform velocity change to h3 from h2, and upper bottom roller at the uniform velocity rotates s rad;
Set gradually the roller motion state that each analysis step is below corresponding;
The n-th+2 analysis step, upper bottom rollers at the uniform velocity rotate m rad, and section bar is rolled out completely from upper lower whorl;
Above-mentioned s equals section bar digital-to-analogue characteristic curve equal segments length and removes in upper roller maximum radius; M is the upper bottom roller corner guaranteeing that section bar rolls out completely from upper lower whorl;
Carry out stress and strain model, contact definition, sets up variable curvature section bar roll bending analytical model and submits calculating to, the section bar variable curvature grid model calculated is carried out grid model reconstruct, obtains the variable curvature section bar digital-to-analogue after reconstructing;
7) the characteristic curve equal segments point radius-of-curvature that the variable curvature section bar digital-to-analogue after reconstruct is levied in line each equal segments point radius-of-curvature and section bar digital-to-analogue to be processed is contrasted, the waypoint place that error overruns regulates the left and right roller displacement of correspondence analysis step, again analog computation, until section bar characteristic curve radius-of-curvature corresponding to analog result and section bar digital-to-analogue characteristic curve radius-of-curvature to be processed meet error requirements.
Adopt this kind of variable curvature section bar roll bending finite element method, use finite element analysis iso-curvature roll bending process and obtain roll bending rule, this than theoretical formula more directly accurately; And adopt the finite element analysis of segmentation variable curvature roll bending to make each segmentation in roll bending analytic process be also variable curvature, thus make analysis result more accurate, error is less, and precision is higher.
Accompanying drawing explanation
Fig. 1 is variable curvature 2 font section bar digital-to-analogue schematic diagram, and wherein 1 is section bar characteristic curve;
Fig. 2 is the analysis of section bar digital-to-analogue characteristic curve radius-of-curvature, wherein 2,3 ... 12 is characteristic curve equal arc length section point;
Fig. 3 is the radius-of-curvature value at each equal segments point place;
Fig. 4 is the planimetric map of numerical control bending roll machine.Wherein 13 is left wheel central rotating shaft, and 14 is left wheel; 15 is bottom roller gathering sill; 16 is upper roller; 17 is right roller; 18 is bottom roller;
Fig. 5 is section bar sectional dimension figure;
Fig. 6 is finite element analysis assembling model.Wherein 19 is left wheel reference point RP4; 20 is left wheel analytical model; 21 section bar models; 22 is upper roller analytical model; 23 is upper roller reference point RP1; 24 is bottom roller reference point RP2; 25 is right roller analytical model; 26 is right roller reference point RP3; 27 is bottom roller analytical model;
Fig. 7 is the mechanical property parameters of 2099-T83 aluminium lithium alloy;
Fig. 8 is that the finite element analysis of variable curvature roll bending completes result figure;
Fig. 9 is radius-of-curvature distribution after section bar left and right roller ascending amount and roll bending.
Embodiment
Now with the variable curvature roll bending of typical aluminium lithium alloy 2 font section bar for embodiment, by reference to the accompanying drawings, introduce the novel variable curvature section bar roll bending finite element method of 2 fonts based on the three-dimensional four roller numerical control bending roll machines of MC4P type, comprise the following steps:
1, according to 2 section bars (Fig. 1) that will be shaped, profile length to be processed is 1440mm, extracts characteristic curve 1(Fig. 1) carry out radius-of-curvature analysis (Fig. 2).Obtain the radius-of-curvature (Fig. 3) of the arc length branches such as 11.
2, analyze the three-dimensional four roller numerical control bending roll machines (Fig. 4) of MC4P type, upper roller center is fixed, and bottom roller center can move up and down along gathering sill.Left wheel, right roller center are rotated around stationary shaft.
3, according to section bar cross-sectional shape (Fig. 5), determine the geometric configuration of all rollers, in finite element analysis software, set up thickness is 2mm, length is the section bar of 1800mm hull shape formula, roller adopts shell of revolution, according to the geometry of numerical control bending roll machine, sets up the assembling model (Fig. 6) in finite element analysis.Upper roller rotates around RP-1, and bottom roller rotates around RP-2, and left wheel center is rotated around RP-4, and right roller center is rotated around RP-3.
4, the material model (Fig. 7) of input section bar, carry out stress and strain model, the reference point arranging upper roller is RP1, and bottom roller reference point is RP2, and left wheel reference point is RP4, right roller reference point is RP3, the coefficient of contact friction arranging lower whorl and section bar is 0.02, and the friction of left and right roller and section bar is ignored, and carries out stress and strain model and contacts definition.
5, be simulation iso-curvature roll bending, Criterion static analysis walks, and it is 34mm that first analysis step arranges left and right roller Uplifting amount.
In 6, second analysis step, bottom roller at the uniform velocity rotates 10rad around its reference point, and section bar is moved to the left and finally completely rolls out from upper bottom roller, establishes finite element analysis model.
7, analytical model is submitted to and calculates, calculated and be reconstructed section bar digital-to-analogue to the latticed section bar that roll bending has been simulated afterwards, and carried out curvature analysis to the section bar digital-to-analogue characteristic curve after reconstruct, obtaining at left and right roller Uplifting amount is the section bar characteristic curve radius-of-curvature value that 34mm is corresponding.
8, change left and right roller Uplifting amount, repeat step 6,7 thus the one-to-one relationship obtained between left and right roller Uplifting amount and section bar characteristic curve radius-of-curvature.
9, the roll forming rule obtained is applied to the variable curvature roll bending finite element analysis of section bar, in finite element analysis, uses the section bar that length is 2800mm instead, 36.2mm is respectively, 36.4 mm, 37.7 mm according to deriving left and right roller Uplifting amount in roll bending corresponding to Fig. 2 medium waypoint 2 to 12 radius-of-curvature value in step 7,38.3 mm, 39.1 mm, 39.7 mm, 40.6 mm, 39.1 mm, 39.3 mm, 39.2 mm, 38.9 mm.
10, the 1st analysis step is set, left and right roller Uplifting amount is 36.2 mm;
2nd analysis step, left and right roller Uplifting amount at the uniform velocity change to 36.4mm from 36.2mm, and upper bottom roller at the uniform velocity rotates 0.8rad, and section bar is rolled left 144mm, thus the 1st section of variable curvature section bar that be shaped;
3rd analysis step, left and right roller Uplifting amount at the uniform velocity change to 37.7mm from 36.4mm, and upper bottom roller at the uniform velocity rotates 0.8rad, and be shaped the 2nd section of variable curvature section bar;
The like the 11st analysis step, left and right roller Uplifting amount at the uniform velocity change to 38.9mm from 39.2mm, upper bottom roller at the uniform velocity rotates 0.8rad, be shaped the 10th section of variable curvature section bar, finally increases an analysis step, makes bottom roller rotate 5rad and section bar is rolled out completely from upper lower whorl.Carry out stress and strain model, contact definition, establish variable curvature section bar analytical model and submit calculating to.
11, after calculating completes, the latticed section bar complete to variable curvature roll bending finite element analysis computation is reconstructed section bar digital-to-analogue, and curvature analysis is carried out to the section bar digital-to-analogue characteristic curve after reconstruct, the each corresponding equal segments point radius-of-curvature of variable curvature section bar digital-to-analogue characteristic curve after reconstruct and the characteristic curve equal segments point radius-of-curvature in section bar digital-to-analogue to be processed are contrasted, the waypoint place that error overruns regulates the left and right roller displacement of correspondence analysis step, again sunykatuib analysis, until section bar characteristic curve radius-of-curvature corresponding to sunykatuib analysis result and section bar digital-to-analogue characteristic curve radius-of-curvature to be processed meet error requirements,
12, left and right roller Uplifting amount corresponding to each equal segments point place finally determined is 36.2mm, 36.5mm, 37.8mm, 38.3mm, 39.1mm, 39.7mm, 40.6mm, 39.3mm, 39.5mm, 39.4mm, 38.8mm.Obtain Calculation results (Fig. 8), the latticed section bar complete to analytical calculation is reconstructed section bar digital-to-analogue, carries out curvature analysis, obtain each corresponding equal segments radius-of-curvature analysis result (Fig. 9) to the section bar digital-to-analogue after reconstruct.
Claims (1)
1. a variable curvature section bar roll bending finite element method, is characterized in that comprising the following steps:
The edge line extracting section bar digital-to-analogue to be processed, as characteristic curve, carries out radius-of-curvature analysis, after wherein considering curvature and length, section bar digital-to-analogue characteristic curve is divided into n section, and obtains the radius-of-curvature of n+1 equal arc length section point;
Analyze four axle bending roll machine geometry and kinematic relations, this four axles bending roll machine comprises upper roller, bottom roller, left wheel, right roller; The mathematical model setting up roller and profile workblank in finite element analysis software luggage of going forward side by side is joined, and arranges left and right roller initial displacement amount;
Carry out stress and strain model, contact definition, sets up section bar iso-curvature roll bending standard static analytical model, calculates section bar iso-curvature roll bending analytical model; The section bar iso-curvature grid model calculated is carried out grid model reconstruct, obtains the section bar digital-to-analogue after reconstructing, then the analysis of characteristic curve radius-of-curvature is carried out to this reconstruct section bar digital-to-analogue, radius-of-curvature value corresponding under obtaining this left and right roller displacement;
Continuous change left and right roller displacement, repeats step 3), thus radius-of-curvature value corresponding under obtaining different left and right roller displacement, i.e. iso-curvature roll bending rule;
According to 4) in result derive left and right roller displacement corresponding to each equal segments point place radius-of-curvature of section bar digital-to-analogue characteristic curve to be processed; Left and right roller displacement corresponding for each equal segments point is designated as h1, h2 ... h (n+1);
By 4) in the iso-curvature roll bending rule that obtains be applied to the finite element analysis of variable curvature section bar roll bending, process is divided into n+2 standard static analysis step:
Arrange first analysis step, to move to displacement be h1 to left and right roller, upper bottom roller is temporarily motionless;
Second analysis step, corresponding left and right roller displacement at the uniform velocity change to h2 from h1, and upper bottom roller is at the uniform velocity around central rotation s rad;
3rd analysis step, left and right roller displacement at the uniform velocity change to h3 from h2, and upper bottom roller at the uniform velocity rotates s rad;
Set gradually the roller motion state that each analysis step is below corresponding;
The n-th+2 analysis step, upper bottom rollers at the uniform velocity rotate m rad, and section bar is rolled out completely from upper lower whorl;
Above-mentioned s equals section bar digital-to-analogue characteristic curve equal segments length and removes in upper roller maximum radius; M is the upper bottom roller corner guaranteeing that section bar rolls out completely from upper lower whorl;
Carry out stress and strain model, contact definition, sets up variable curvature section bar roll bending analytical model and submits calculating to, the section bar variable curvature grid model calculated is carried out grid model reconstruct, obtains the variable curvature section bar digital-to-analogue after reconstructing;
7) the characteristic curve equal segments point radius-of-curvature that the variable curvature section bar digital-to-analogue after reconstruct is levied in line each equal segments point radius-of-curvature and section bar digital-to-analogue to be processed is contrasted, the waypoint place that error overruns regulates the left and right roller displacement of correspondence analysis step, again analog computation, until section bar characteristic curve radius-of-curvature corresponding to analog result and section bar digital-to-analogue characteristic curve radius-of-curvature to be processed meet error requirements.
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| CN110405020A (en) * | 2019-08-08 | 2019-11-05 | 江阴市宏业机械制造有限公司 | A kind of multifunctional rolling bender and roll bending method |
| CN110457851A (en) * | 2019-08-20 | 2019-11-15 | 吉林大学 | Profile roll bending dynamic resilience finite element method |
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| US20110094278A1 (en) * | 2008-02-12 | 2011-04-28 | Cml International S.P.A. | Method to check and control a roller bending machine for continuously bending an elongated workpiece at variable curvature radii, and machine so controlled |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110405020A (en) * | 2019-08-08 | 2019-11-05 | 江阴市宏业机械制造有限公司 | A kind of multifunctional rolling bender and roll bending method |
| CN110405020B (en) * | 2019-08-08 | 2024-01-05 | 江阴市宏业机械制造有限公司 | Multifunctional rolling machine and rolling method |
| CN110457851A (en) * | 2019-08-20 | 2019-11-15 | 吉林大学 | Profile roll bending dynamic resilience finite element method |
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