CN101507996A - Quick determination method of load path of fittings hydraulic formation - Google Patents
Quick determination method of load path of fittings hydraulic formation Download PDFInfo
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- CN101507996A CN101507996A CNA2009100716129A CN200910071612A CN101507996A CN 101507996 A CN101507996 A CN 101507996A CN A2009100716129 A CNA2009100716129 A CN A2009100716129A CN 200910071612 A CN200910071612 A CN 200910071612A CN 101507996 A CN101507996 A CN 101507996A
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- load path
- feed supplement
- supplement amount
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Abstract
The invention provides a method for quickly determining a loading path of hydraulic forming of pipe fittings, relates to the field of pipe fitting hydraulic forming, and solves the problems that the determination of the reasonable loading path of the pipe fitting hydraulic forming depends on the experience and test exploration so as to not only increase the test cost, but also waste a large amount of time. The method comprises the following steps: firstly, calculating out the initial internal pressure by the theory and determining the forming interval; secondly, adjusting axial feed supplementary amount to carry out numerical simulation, and determining reasonable feed supplementary amount according to the calculating result; and finally, adjusting the slope factor of the loading path to obtain the reasonable loading path. The method can accurately and quickly determine the reasonable loading path of the hydraulic forming of the pipe fittings, thereby saving the time and the test cost; and the optimized reasonable loading path is adopted to effectively realize the feed supplement of the forming interval, thereby obtaining smaller wall thickness reduction rate and oppositely-even wall thickness distribution, and improving the forming limit of the pipe fittings. The loading path determined by the invention is applied to pipe fitting hydraulic forming technology.
Description
Technical field
The present invention relates to the fittings hydraulic formation field.
Background technology
The fittings hydraulic formation technology developed rapidly in recent years, advantages such as more and more in the application in fields such as Aero-Space, automobile, weapons, the part that the fittings hydraulic formation technology is produced has the quality of alleviating, economical with materials, raising intensity and rigidity, minimizing part and number of molds, reduce production costs.Can be used for making circle, square-section or the profiled-cross-section member that changes along axis of workpiece.
The advanced manufacturing technology of current optimization member and alleviate architecture quality and become the focus that each side pays close attention to, particularly in recent years owing to the strictness restriction of fuel and cost of raw material reason and environmental regulation to automobile emission, the lightweight of vehicle structure is seemed to become more and more important, for car, every weight reduction 10%, oil consumption can reduce 8%-10%.Light in structure quantizes except adopting light material (magnesium alloy, titanium alloy and composite etc.), the main approach of another of loss of weight is exactly structurally to adopt " real with empty generation ", promptly for the member that bears based on bending or torsional load, adopt hollow-core construction to replace solid construction, so not only can the weight reduction economical with materials but also can make full use of the strength and stiffness of material.For example adopt the hollowness ratio of external diameter (internal diameter with) 0.85 hollow shaft to replace solid shafting, under same anti-twisting property, quality alleviates nearly 50%.Under such background, a kind of loss of weight that develops, material-saving, energy-conservation have the very advanced manufacturing technology of the light body member of wide application prospect to the fittings hydraulic formation technology just.
The shaping principle of fittings hydraulic formation technology is to be former material with pipe, applies fluid pressure and axial afterburning feed supplement by inside and pipe is pressed into mold cavity makes its shaping.Fig. 1 to Fig. 4 is a fittings hydraulic formation processing step schematic diagram.For axis is the member of curve, need be pre-bent to pipe near part shape, then press molding.
Fittings hydraulic formation is the complicated forming process under interior pressure and axial feed supplement synergy, and axially the relation of feed supplement and interior pressure is called load path, only provides rational load path, could obtain qualified final part.In actual forming process, if the load path design is unreasonable, slower when rate of pressure rise, axial feed velocity is very fast, and axial deformation has little time to be converted into circumferential distortion, and material will make pipe produce flexing or wrinkling in that axially gathering formation is folding; Very fast when rate of pressure rise, and axial feed velocity is slower, and promptly axial feeding is not enough to compensate circumferential deflection, attenuate occurs excessively so that break.Load path influences the shape of part section, thickness distribution and final forming dimension.Different load paths are also different to the influence of drip molding Thickness Distribution.So load path is the key parameter in the fittings hydraulic formation, it determine to be subjected to part geometry shape, the influence of many-sided factors such as material property, wall thickness, caliber and formative radius.How optimizing and adjusting load path is technological core in the fittings hydraulic formation, adopt and optimize reasonably load path of back, can realize the feed supplement in district that is shaped effectively, thereby obtain littler wall thickness reduction and relative Thickness Distribution uniformly, improve the forming limit of pipe fitting.
Summary of the invention
The present invention gropes for the definite dependence experience and the test that solve the existing reasonable load path of fittings hydraulic formation, has both increased experimentation cost, wastes the problem of plenty of time again, and a kind of load path fast determination method of fittings hydraulic formation is provided.
Technical scheme of the present invention realizes according to the following steps:
Step 1: determine final initial internal pressure p
h: according to the wall thickness of shaping pipe, the pipe diameter, the yield stress of blank tube material calculates initial bulging pressure p
0, computing formula is:
T is the pipe wall thickness in the formula, and d is the pipe diameter, σ
sBe the yield stress of material, β is axial stress σ
zWith circumference stress σ
θRatio, the axial force that applies during hydroforming is a pressure, the span of β is-1≤β≤0;
By p
0± 0.3 obtains p
1And p
2Calculate theoretical feed supplement amount S according to volume principle of invariance before and after the forming tubular product
0, theoretical feed supplement amount S
0Respectively with p
0, p
1, p
2Cooperate, obtain three load paths, adjust, determine the upper limit p of the bulbs of pressure that shaping is interval according to the analog result of described three load paths
MaxWith lower limit p
Min, and obtain a final initial internal pressure p with described interval
h
Step 2: determine final axial feed supplement amount S
h: S
1Be theoretical feed supplement amount S
090%, S
2Be theoretical feed supplement amount S
080%, the final initial internal pressure p that calculates according to step 1
hRespectively with feed supplement amount S
0, S
1, S
2Cooperate, obtain three load paths, adjust, draw final axial feed supplement amount S according to the analog result of three load paths
h
Step 3: the slope of determining load path: the slope of load path is promptly determined the angle of cut α of load path and axis of abscissas; The load path of choosing different α angle carries out numerical simulation, is optimized according to analog result, draws the α angle, has promptly obtained the best load path of fittings hydraulic formation spare.
The invention has the beneficial effects as follows: determine the rational load path of fittings hydraulic formation at first exactly fast, thereby save time and experimentation cost; Secondly adopt and optimize reasonably load path of back, can realize the feed supplement in district that is shaped effectively, thereby obtain littler wall thickness reduction and relative Thickness Distribution uniformly, improve the forming limit of pipe fitting.
Description of drawings
Fig. 1 to Fig. 4 is a fittings hydraulic formation technical process schematic diagram; Fig. 5 is a schematic diagram of determining initial internal pressure in the specific embodiment two; Fig. 6 is a schematic diagram of determining the feed supplement amount in the specific embodiment four; Fig. 7 is a schematic diagram of determining the slope of load path in the specific embodiment six.
The specific embodiment
The specific embodiment one: the step of present embodiment is as follows:
Step 1: determine final initial internal pressure p
h: initial internal pressure is the important parameter in the fittings hydraulic formation technology, the directly interval division of influence shaping, and according to the wall thickness of shaping pipe, pipe diameter, the σ of blank tube material
sValue calculates initial bulging pressure p
0(MPa), computing formula is:
T is pipe wall thickness (mm) in the formula, and d is pipe diameter (mm), σ
sBe the yield stress (MPa) of material, β is axial stress σ
zWith circumference stress σ
θRatio, the axial force that applies during hydroforming is a pressure, the span of β is-1≤β≤0;
Obtain initial bulging pressure p by formula 1
0Size and the wall thickness t and the yield stress σ of pipe
sBe directly proportional, be inversely proportional to the diameter d of pipe.
By p
0± 0.3 obtains p
1And p
2Calculate theoretical feed supplement amount S according to volume principle of invariance before and after the forming tubular product
0, theoretical feed supplement amount S
0Respectively with p
0, p
1, p
2Cooperate, obtain three load paths, adjust, determine the upper limit p of the bulbs of pressure that shaping is interval according to the analog result of described three load paths
MaxWith lower limit p
Min, and obtain a final initial internal pressure p with described interval
h
Step 2: determine final axial feed supplement amount S
h: axially the feed supplement amount is another important parameter of fittings hydraulic formation technology, directly influences the Thickness Distribution of forming process and formation of parts; S
1Be theoretical feed supplement amount S
090%, S
2Be theoretical feed supplement amount S
080%, the final initial internal pressure p that calculates according to step 1
hRespectively with feed supplement amount S
0, S
1, S
2Cooperate, obtain three load paths, adjust, draw final axial feed supplement amount S according to the analog result of three load paths
h
Step 3: the slope α that determines load path: determined final initial internal pressure p
hWith axial feed supplement amount S
hAfter, the qualified part that can be shaped basically, but, also need determine the slope of load path in order to find out best load path, the slope of load path is promptly determined the angle of cut α of load path and axis of abscissas; 90 °〉α〉0 °; The physical significance of load path slope is meant in same to be depressed, axial advancing the speed of feed supplement amount, and the load path result calculated at different α angle is differentiated; The load path of choosing different α angle carries out numerical simulation, is optimized according to analog result, draws the α angle, has promptly obtained the best load path of fittings hydraulic formation spare.The α angle is good more near 90 ° more in the ordinary course of things, that is to say before extensive feed supplement, earlier pipe is applied certain interior pressure, makes blank tube material produce preliminary bulging, forms slight plasticity and flows, flowing of metal and carrying out smoothly of feed supplement after helping.
The specific embodiment two: in conjunction with Fig. 5 present embodiment is described, present embodiment and the specific embodiment one difference are final initial internal pressure p
hScope be 0.7p
0～1.3p
0MPa.Other step is identical with the specific embodiment one.With this understanding, can be shaped that surperficial flawless, inside and outside wall are smooth, smooth, wall thickness evenly, N/D and do not have the pipe fitting of distortion; The wall thickness deviation of pipe fitting must not surpass 10%～14%; The tube wall minimum of finishing reaches 0.5mm～4mm; Yield rate arrives 99%.
The specific embodiment three: present embodiment and the specific embodiment one difference are final initial internal pressure p
hBe 1.1p
0MPa.Other step is identical with the specific embodiment one.With this understanding, can be shaped that surperficial flawless, inside and outside wall are smooth, smooth, wall thickness evenly, N/D and do not have the pipe fitting of distortion; The wall thickness deviation of pipe fitting must not surpass 12%; The tube wall minimum of finishing reaches 0.5mm; Yield rate arrives 99.95%.
The specific embodiment four: in conjunction with Fig. 6 present embodiment is described, the present embodiment and the specific embodiment one, two or three differences are final axial feed supplement amount S
hScope be 0.8S
0～1.0S
0Other step is identical with the specific embodiment one, two or three.With this understanding, can be shaped that surperficial flawless, inside and outside wall are smooth, smooth, wall thickness evenly, N/D and do not have the pipe fitting of distortion; The wall thickness deviation of pipe fitting must not surpass 10%～14%; The tube wall minimum of finishing reaches 0.5mm～4mm; Yield rate arrives 99%.
The specific embodiment five: in conjunction with Fig. 6 present embodiment is described, present embodiment and the specific embodiment four differences are final axial feed supplement amount S
hBe 0.9S
0Other step is identical with the specific embodiment four.With this understanding, can be shaped that surperficial flawless, inside and outside wall are smooth, smooth, wall thickness evenly, N/D and do not have the pipe fitting of distortion; The wall thickness deviation of pipe fitting must not surpass 12%; The tube wall minimum of finishing reaches 0.5mm; Yield rate arrives 99.95%.
The specific embodiment six: in conjunction with Fig. 7 present embodiment is described, the present embodiment and the specific embodiment one, two, three or five differences are that the angle of cut α of load path and axis of abscissas is 0 °～90 °.Other step is identical with the specific embodiment one, two, three or five.With this understanding, can be shaped that surperficial flawless, inside and outside wall are smooth, smooth, wall thickness evenly, N/D and do not have the pipe fitting of distortion; The wall thickness deviation of pipe fitting must not surpass 12%; The tube wall minimum of finishing reaches 0.5mm; Yield rate arrives 99.95%; The pipe fitting that is shaped can obtain 2% wall thickness reduction.
Content of the present invention is not limited only to the content of the respective embodiments described above, and the combination of one of them or several specific embodiment equally also can realize the purpose of inventing.
The pipe wall thickness t that the present invention is suitable for is the pipe fitting of 1～10mm, the initial bulging pressure p when expanding under the scope of this pipe wall thickness
0Be 20～300Mpa, adopt the final initial internal pressure p that obtains that method of the present invention can be very fast again
h, final axial feed supplement amount S
hWith the slope of load path, determine to obtain a best load path.
Claims (6)
1, the load path fast determination method of fittings hydraulic formation is characterized in that its step is as follows:
Step 1: determine final initial internal pressure p
h: according to the wall thickness of shaping pipe, the pipe diameter, the yield stress of blank tube material calculates initial bulging pressure p
0, computing formula is:
T is the pipe wall thickness in the formula, and d is the pipe diameter, σ
sBe the yield stress of material, β is axial stress σ
zWith circumference stress σ
θRatio, the axial force that applies during hydroforming is a pressure, the span of β is-1≤β≤0;
By p
0± 0.3 obtains p
1And p
2Calculate theoretical feed supplement amount S according to volume principle of invariance before and after the forming tubular product
0, theoretical feed supplement amount S
0Respectively with p
0, p
1, p
2Cooperate, obtain three load paths, adjust, determine the upper limit p of the bulbs of pressure that shaping is interval according to the analog result of described three load paths
MaxWith lower limit p
Min, and obtain a final initial internal pressure ph with described interval;
Step 2: determine final axial feed supplement amount S
h: S
1Be theoretical feed supplement amount S
090%, S
2Be theoretical feed supplement amount S
080%, the final initial internal pressure p that calculates according to step 1
hRespectively with feed supplement amount S
0, S
1, S
2Cooperate, obtain three load paths, adjust, draw final axial feed supplement amount S according to the analog result of described three load paths
h
Step 3: the slope of determining load path: the slope of load path is promptly determined the angle of cut α of load path and axis of abscissas; The load path of choosing different α angle carries out numerical simulation, is optimized according to analog result, draws the α angle, has promptly obtained the best load path of fittings hydraulic formation spare.
2, the load path fast determination method of fittings hydraulic formation according to claim 1 is characterized in that final initial internal pressure p
hScope be 0.7p
0～1.3p
0MPa.
3, the load path fast determination method of fittings hydraulic formation according to claim 1 is characterized in that final initial internal pressure p
hBe 1.1p
0MPa.
4,, it is characterized in that final axial feed supplement amount S according to the load path fast determination method of claim 1,2 or 3 described fittings hydraulic formations
hScope be 0.8S
0～1.0S
0
5, the load path fast determination method of fittings hydraulic formation according to claim 4 is characterized in that final axial feed supplement amount S
hBe 0.9S
0
6, according to the load path fast determination method of claim 1,2,3 or 5 described fittings hydraulic formations, the angle of cut α that it is characterized in that load path and axis of abscissas is 0 °～90 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100716129A CN101507996B (en) | 2009-03-23 | 2009-03-23 | Quick determination method of load path of fittings hydraulic formation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100716129A CN101507996B (en) | 2009-03-23 | 2009-03-23 | Quick determination method of load path of fittings hydraulic formation |
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| Publication Number | Publication Date |
|---|---|
| CN101507996A true CN101507996A (en) | 2009-08-19 |
| CN101507996B CN101507996B (en) | 2011-04-20 |
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ID=41000619
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009100716129A Expired - Fee Related CN101507996B (en) | 2009-03-23 | 2009-03-23 | Quick determination method of load path of fittings hydraulic formation |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102225441A (en) * | 2011-03-22 | 2011-10-26 | 初冠南 | Process method for axial supplement |
| CN103658294A (en) * | 2013-12-31 | 2014-03-26 | 一重集团大连设计研究院有限公司 | High-pressure forming method in pipe |
| CN106311856A (en) * | 2016-10-10 | 2017-01-11 | 广西科技大学 | Hydraulic forming die and method for manufacturing complex panel component through hydraulic forming die |
| CN109158458A (en) * | 2018-09-29 | 2019-01-08 | 天津市天锻压力机有限公司 | A method of pipe liquid filled press-bending is carried out using composite filled medium |
| CN109433864A (en) * | 2018-11-14 | 2019-03-08 | 航天特种材料及工艺技术研究所 | Big L/D ratio ultra-thin-wall stainless steel cylindrical member straightening method and tooling |
| CN112528424A (en) * | 2020-11-03 | 2021-03-19 | 南京工程学院 | Method for improving incremental forming performance of plate |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201201008Y (en) * | 2008-06-07 | 2009-03-04 | 桂林电子科技大学 | Internal fluid infusion pressure boost type hydraulic expanding device for pipe material |
-
2009
- 2009-03-23 CN CN2009100716129A patent/CN101507996B/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102225441A (en) * | 2011-03-22 | 2011-10-26 | 初冠南 | Process method for axial supplement |
| CN103658294A (en) * | 2013-12-31 | 2014-03-26 | 一重集团大连设计研究院有限公司 | High-pressure forming method in pipe |
| CN103658294B (en) * | 2013-12-31 | 2015-10-28 | 一重集团大连设计研究院有限公司 | A kind of forming high pressure in pipe method |
| CN106311856A (en) * | 2016-10-10 | 2017-01-11 | 广西科技大学 | Hydraulic forming die and method for manufacturing complex panel component through hydraulic forming die |
| CN106311856B (en) * | 2016-10-10 | 2019-01-22 | 广西科技大学 | A kind of hydraulic forming mold and the method for manufacturing complicated plate material parts with it |
| CN109158458A (en) * | 2018-09-29 | 2019-01-08 | 天津市天锻压力机有限公司 | A method of pipe liquid filled press-bending is carried out using composite filled medium |
| CN109158458B (en) * | 2018-09-29 | 2020-08-25 | 天津市天锻压力机有限公司 | Method for performing liquid-filled bending on pipe by using composite filling medium |
| CN109433864A (en) * | 2018-11-14 | 2019-03-08 | 航天特种材料及工艺技术研究所 | Big L/D ratio ultra-thin-wall stainless steel cylindrical member straightening method and tooling |
| CN112528424A (en) * | 2020-11-03 | 2021-03-19 | 南京工程学院 | Method for improving incremental forming performance of plate |
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| Publication number | Publication date |
|---|---|
| CN101507996B (en) | 2011-04-20 |
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Granted publication date: 20110420 Termination date: 20120323 |