CN108458940A - The biaxial stretch-formed fatigue test piece and its test method of conic section transition - Google Patents
The biaxial stretch-formed fatigue test piece and its test method of conic section transition Download PDFInfo
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- CN108458940A CN108458940A CN201810035039.5A CN201810035039A CN108458940A CN 108458940 A CN108458940 A CN 108458940A CN 201810035039 A CN201810035039 A CN 201810035039A CN 108458940 A CN108458940 A CN 108458940A
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- conic section
- center
- testpieces
- biaxial stretch
- test piece
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0073—Fatigue
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0272—Cruciform specimens
Abstract
The invention discloses a kind of biaxial stretch-formed fatigue test piece of conic section transition and its test methods, the testpieces is in integrally cross, there are four loading arms for tool, center is converged into one end of four loading arms, the other end is clamp area, the transition region that conic section is formed is equipped between the root of adjacent load arm, the symmetry axis of conic section at least with a symmetrical overlapping of axles of testpieces, thickness thinning area is equipped between transition region and center, thickness thinning area is thinned using bicircular arcs, spline curve or single circular arc wise manner.It is an advantage of the invention that：The conic section interim form taken keeps the ess-strain in center more uniform and reduces the influence between adjacent load arm as far as possible；Design is thinned with center by seamlessly transitting, so that testpieces is destroyed during the test and is first occurred in center with crackle.
Description
Technical field
The present invention relates to a kind of tensile fatigue test parts, and in particular to a kind of biaxial stretch-formed fatigue examination of conic section transition
Test part and its test method.
Background technology
Traditional detection test method that is uniaxially stretched can not reflect stressing conditions of the material in Practical Project strictly according to the facts, together
When, many materials have apparent anisotropy, and material standard can be obtained by carrying out the experiment of the mechanical test under biaxial stress state
True mechanical property, therefore, the design of testpieces are just particularly important.Currently, realizing that Biaxial stress experiment is main to material
There are the convex swollen biaxial tensile test method of film, pressure vessel biaxial tensile test method and curciform specimen biaxial tensile test method.
In the conventional method, the convex swollen method of film is only applicable to film member, and convex swollen vertex is two-way 1：1 stress state；
Pressure vessel method is 2 to the two-dimensional state of stress of barrel shell：1, it is 1 to spherical shell：1；And cross testpieces method it is most intuitive, most can be straight
The two-dimensional state of stress for connecing reaction material coordinates suitable loading equipemtn or testing machine, can obtain arbitrary biaxial stress ratio.
Invention content
Goal of the invention：The first object of the present invention is to provide that a kind of measurement is convenient, stress is uniform, the accurate conic of result
The biaxial stretch-formed fatigue test piece of line transition；The second object of the present invention is to provide the experiment side of the biaxial stretch-formed fatigue test piece
Method.
Technical solution：A kind of biaxial stretch-formed fatigue test piece of conic section transition, the testpieces are in integrally cross, tool
There are four loading arm, center is converged into one end of four loading arms, and the other end is clamp area, the root of the adjacent load arm
Be equipped with the transition region that conic section is formed between portion, the symmetry axis of the conic section at least with a symmetry axis weight of testpieces
It closes, thickness thinning area is equipped between the transition region and the center, the thickness thinning area is using bicircular arcs, spline curve
Or single circular arc wise manner is thinned.
The thickness thinning area is for connecting thicker transition region and relatively thin center, wherein the thickness thinning area
Being thinned using single circular arc wise manner can be such that transition region is seamlessly transitted with center；And bicircular arcs or spline curve mode is used to be thinned
When, meet testpieces on the basis of thickness direction seamlessly transits, for the fatigue test that low Zhou Xunhuan or loaded load are larger,
The influence to fatigue test final result can be reduced as far as possible.
The conic section is oval, hyperbola or parabola.Since each point curvature is different on conic section,
Constantly change as distance is different when conic section transition, this accumulation plasticity to metal material or composite material in deformation
Deformation is influential, and then influences fatigue rupture.Transition between conic section and clamp area is fillet part, works as conic
Line does not intersect with clamp area, then fillet part is used for the straight flange of transition conic section and transition region.
The center is circle, for biaxial stretch-formed fatigue test, as the ratio in both direction is different, center
Stress distribution it is also different, therefore center is preferably the circle of ideal symmetrical.
The clamp area is equipped with tapped through hole and/or pin hole to provide enough intensifying forces.
The test method of the biaxial stretch-formed fatigue test piece of conic section transition, includes the following steps：
(I) is as needed using electromotive strain method or the dependent variable of loading by means of digital image correlation method acquisition center upper and lower surface
According to；
The clamp area is connect and is clamped with experiment loading equipemtn or fixture by (II), it is ensured that in testpieces center and load
Heart concentricity is within the scope of allowable error, and plane and loaded planar angle are within the scope of allowable error where testpieces, testpieces
Straight line where support arm is with the angle of corresponding loading direction within the scope of allowable error；
(III) after the completion of Preparatory work of experiment, using stress or strain controlling mode, setting loading curve waveform is loaded,
And strain data is acquired as needed.
Advantageous effect：Compared with prior art, it is an advantage of the invention that：(1) the conic section interim form taken, in making
Ess-strain in heart district more reduces uniformly and as far as possible the influence between adjacent load arm.(2) by seamlessly transitting in
Design is thinned in heart district, so that testpieces is destroyed during the test and is first occurred in center with crackle.(3) it is processed in clamp area
Go out tapped through hole and pin hole, cooperation suitable fixture can easily be accurately positioned, and realize that original position is biaxial stretch-formed, make experiment data measured
It is more acurrate.
Description of the drawings
Fig. 1 a are the structural schematic diagram of embodiment 1；
Fig. 1 b are sectional view of the embodiment 1 along the directions A-A；
Fig. 1 c are the local I enlarged drawing in embodiment 1；
Fig. 2 is the local I enlarged drawing in embodiment 2；
Fig. 3 is the local I enlarged drawing in embodiment 3；
Fig. 4 a are the structural schematic diagram of embodiment 4；
Fig. 4 b are sectional view of the embodiment 4 along the directions A-A；
Fig. 5 a are the structural schematic diagram of embodiment 5；
Fig. 5 b are sectional view of the embodiment 5 along the directions A-A；
Fig. 6 is the structural schematic diagram of embodiment 6；
Fig. 7 is the structural schematic diagram of embodiment 7；
Fig. 8 is the structural schematic diagram of embodiment 8.
Specific implementation mode
Technical scheme of the present invention is described further below in conjunction with the accompanying drawings.
Embodiment 1
As shown in Figure 1a, a kind of biaxial stretch-formed fatigue test piece of conic section transition, the testpieces integrally be in it is cross,
There are four loading arm, one end of four loading arms to converge into center 4 for tool, and the other end is clamp area 1, will be tried by modes such as clamps
Part clamping is tested, the transition region 2 that conic section 5 is formed is equipped between the root of adjacent load arm, conic section 5 is ellipse, oval
Long axis and testpieces a symmetrical overlapping of axles, the transition of conic section 5 and clamp area 1 is fillet part 6；Clamp area 1 is thick
Degree is thick compared with center 4, and thickness thinning area 3 is equipped between transition region 2 and center 4；Thickness thinning area 3 is thicker for connecting
Transition region 2 and relatively thin center 4, the sectional view along the directions A-A is as shown in Figure 1 b, and thickness direction transient mode is bicircular arcs
7, as illustrated in figure 1 c, parameter meets testpieces when determining and is seamlessly transitted in thickness direction；4 geometry of the center is
Circle, size acquire strain data and generate fatigue crack enough；The testpieces, can be according to material when manufacturing processing
Characteristic direction (such as rolling direction) determine the materials direction of testpieces, to obtain the performance parameter of material on different directions.
The test method of the biaxial stretch-formed fatigue test piece of conic section transition of the present invention, includes the following steps：
(I) is as needed using electromotive strain method or the dependent variable of loading by means of digital image correlation method acquisition 4 upper and lower surface of center
According to；
Clamp area 1 is connect and is clamped with experiment loading equipemtn or fixture by (II), it is ensured that testpieces center and load center
Concentricity is within the scope of allowable error, and plane and loaded planar angle are within the scope of allowable error where testpieces, testpieces branch
Straight line where arm is with the angle of corresponding loading direction within the scope of allowable error；
(III) after the completion of Preparatory work of experiment, using stress or strain controlling mode, setting loading curve waveform is loaded,
And strain data is acquired as needed.
Fatigue test of the biaxial stretch-formed fatigue test piece of conic section transition of the present invention in metal material or composite material
Aspect is widely used, and can be realized that original position is biaxial stretch-formed, be kept experiment data measured more acurrate.
Embodiment 2
Testpieces basic structure is same as Example 1, institute the difference is that：Mistake of the thickness thinning area 3 in thickness direction
The mode of crossing is changed to spline curve 8, as shown in Figure 2, wherein spline curve 8 meets 2 junction of heart district 4 and transition region in this connection
It seamlessly transits.
Embodiment 3
Testpieces basic structure is same as Example 1, institute the difference is that：Mistake of the thickness thinning area 3 in thickness direction
The mode of crossing is changed to single circular arc 9, as shown in Figure 3, wherein single circular arc 9 meets to be seamlessly transitted at heart district 4 in this connection.
Embodiment 4
Testpieces basic structure is same as Example 1, institute the difference is that：Tapped through hole 11 is processed on clamp area 1,
Coordinate suitable fixture to provide positioning action and clamping force, as shown in Fig. 4 a, 4b.
Embodiment 5
Testpieces basic structure is same as Example 1, institute the difference is that：Tapped through hole 11 is processed on clamp area 1
It is combined with pin hole 12, cooperation suitable fixture is to provide positioning action and clamping force, as shown in Fig. 5 a, 5b.
Embodiment 6
Testpieces basic structure is same as Example 1, institute the difference is that：Fillet 6 is for transition conic section 5 and folder
Area 1 is held, because conic section 5 does not intersect with clamp area 1, therefore fillet 6 is used for the straight flange 10 of transition conic section 5 and transition region 2, such as
Shown in Fig. 6.
Embodiment 7
Testpieces basic structure is same as Example 1, institute the difference is that：Conic section 5 is parabola, parabola 5
Symmetry axis and testpieces a symmetrical overlapping of axles, as shown in Figure 7.
Embodiment 8
Testpieces basic structure is same as Example 1, institute the difference is that：Conic section 5 is hyperbola, hyperbola 5
A symmetry axis and testpieces a symmetrical overlapping of axles, as shown in Figure 8.
Claims (5)
1. a kind of biaxial stretch-formed fatigue test piece of conic section transition, which is in integrally cross, and there are four loads for tool
Center (4) is converged into one end of arm, four loading arms, and the other end is clamp area (1), it is characterised in that：It is described it is adjacent plus
Be equipped with the transition region (2) that conic section is formed between the root of load arm, the symmetry axis of the conic section at least with testpieces
One symmetrical overlapping of axles is equipped with thickness thinning area (3) between the transition region (2) and the center (4), and the thickness is thinned
Area (3) is thinned using bicircular arcs, spline curve or single circular arc wise manner.
2. the biaxial stretch-formed fatigue test piece of conic section transition according to claim 1, it is characterised in that：The circular cone
Curve is oval, hyperbola or parabola.
3. the biaxial stretch-formed fatigue test piece of conic section transition according to claim 1, it is characterised in that：The center
Area (4) is circle.
4. the biaxial stretch-formed fatigue test piece of conic section transition according to claim 1, it is characterised in that：The clamping
Area (1) is equipped with tapped through hole (11) or pin hole (12).
5. the test method of the biaxial stretch-formed fatigue test piece of any conic section transition of Claims 1 to 4, feature
It is to include the following steps：
(I) is as needed using electromotive strain method or the strain data of loading by means of digital image correlation method acquisition center (4) upper and lower surface；
Clamp area (1) is connect and is clamped with experiment loading equipemtn or fixture by (II), it is ensured that testpieces center and load center are same
Axis degree is within the scope of allowable error, and plane and loaded planar angle are within the scope of allowable error where testpieces, testpieces support arm
Place straight line is with the angle of corresponding loading direction within the scope of allowable error；
(III) after the completion of Preparatory work of experiment, using stress or strain controlling mode, setting loading curve waveform is loaded, and root
According to need acquire strain data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810035039.5A CN108458940A (en) | 2018-01-15 | 2018-01-15 | The biaxial stretch-formed fatigue test piece and its test method of conic section transition |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810035039.5A CN108458940A (en) | 2018-01-15 | 2018-01-15 | The biaxial stretch-formed fatigue test piece and its test method of conic section transition |
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| CN108458940A true CN108458940A (en) | 2018-08-28 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109724879A (en) * | 2019-01-07 | 2019-05-07 | 中国人民解放军国防科技大学 | Flexible fiber reinforced film biaxial stress fatigue loading test device |
| CN109765019A (en) * | 2019-03-12 | 2019-05-17 | 四川大学 | A kind of ultrasonic resonance multiaxis bending fatigue experimental device |
| CN110296882A (en) * | 2019-04-22 | 2019-10-01 | 上海大学 | A kind of biaxial stretch-formed test specimen of cross silica gel and its preparation and stretching test method |
| CN110618023A (en) * | 2019-09-20 | 2019-12-27 | 大连理工大学 | Test method for obtaining large bidirectional strain by utilizing male die bulging based on thinned test piece |
| CN111220464A (en) * | 2020-01-22 | 2020-06-02 | 南京航空航天大学 | Biaxial tensile fatigue test piece with annular welding seam |
| CN111855399A (en) * | 2020-06-09 | 2020-10-30 | 北京航空航天大学 | Uniaxial loading of spherical working section realizes biax stress state test piece |
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| CN106198219A (en) * | 2016-07-06 | 2016-12-07 | 北京航空航天大学 | A kind of method of testing of composite laminated plate biaxial stretching performance |
| CN107271287A (en) * | 2017-07-06 | 2017-10-20 | 东南大学 | A kind of horizontal-type biaxial extension test testing machine and tensile test method |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109724879A (en) * | 2019-01-07 | 2019-05-07 | 中国人民解放军国防科技大学 | Flexible fiber reinforced film biaxial stress fatigue loading test device |
| CN109724879B (en) * | 2019-01-07 | 2021-08-10 | 中国人民解放军国防科技大学 | Flexible fiber reinforced film biaxial stress fatigue loading test device |
| CN109765019A (en) * | 2019-03-12 | 2019-05-17 | 四川大学 | A kind of ultrasonic resonance multiaxis bending fatigue experimental device |
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| CN110296882A (en) * | 2019-04-22 | 2019-10-01 | 上海大学 | A kind of biaxial stretch-formed test specimen of cross silica gel and its preparation and stretching test method |
| CN110296882B (en) * | 2019-04-22 | 2022-01-07 | 上海大学 | Cross-shaped silica gel biaxial tensile test piece and preparation and tensile test method thereof |
| CN110618023A (en) * | 2019-09-20 | 2019-12-27 | 大连理工大学 | Test method for obtaining large bidirectional strain by utilizing male die bulging based on thinned test piece |
| CN110618023B (en) * | 2019-09-20 | 2021-10-26 | 大连理工大学 | Test method for obtaining large bidirectional strain by utilizing male die bulging based on thinned test piece |
| CN111220464A (en) * | 2020-01-22 | 2020-06-02 | 南京航空航天大学 | Biaxial tensile fatigue test piece with annular welding seam |
| CN111220464B (en) * | 2020-01-22 | 2021-10-26 | 南京航空航天大学 | Biaxial tensile fatigue test piece with annular welding seam |
| CN111855399A (en) * | 2020-06-09 | 2020-10-30 | 北京航空航天大学 | Uniaxial loading of spherical working section realizes biax stress state test piece |
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Application publication date: 20180828 |