CN102252597A - Method for calibrating strain multiplier - Google Patents
Method for calibrating strain multiplier Download PDFInfo
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- CN102252597A CN102252597A CN 201110093818 CN201110093818A CN102252597A CN 102252597 A CN102252597 A CN 102252597A CN 201110093818 CN201110093818 CN 201110093818 CN 201110093818 A CN201110093818 A CN 201110093818A CN 102252597 A CN102252597 A CN 102252597A
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- 238000000034 method Methods 0.000 title claims abstract description 49
- 238000012360 testing method Methods 0.000 claims abstract description 123
- 238000011068 loading method Methods 0.000 claims abstract description 18
- 239000011888 foil Substances 0.000 claims description 42
- 230000004087 circulation Effects 0.000 claims description 5
- 239000004576 sand Substances 0.000 claims description 4
- 230000003447 ipsilateral effect Effects 0.000 claims description 3
- 230000003321 amplification Effects 0.000 abstract 2
- 238000003199 nucleic acid amplification method Methods 0.000 abstract 2
- 206010016256 fatigue Diseases 0.000 description 15
- 238000009434 installation Methods 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000926 A-3 tool steel Inorganic materials 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a method for calibrating a strain multiplier. The method comprises the following steps of: a, mounting the strain multiplier on a test piece; b, loading force to the test piece, so that the test piece strains; c, acquiring a strain value epsilon b of the strain multiplier and a strain value epsilon s of the test piece; and d, determining an amplification factor of the strain multiplier according to the strain value epsilon b of the strain multiplier and the strain value epsilon s of the test piece; wherein in the step a, a first strain piece is arranged on the test piece; and in the step c, the strain value epsilon s of the test piece is acquired by measuring a strain value of the first strain piece. Due to the technical scheme, because the strain value epsilon s of the test piece is obtained by directly measuring the strain value of the first strain piece which is arranged on the test piece, deviation is hardly present, and the obtained amplification factor of the strain multiplier is accurate; therefore, a using effect of the strain multiplier is improved.
Description
Technical field
The present invention relates to a kind of scaling method, more specifically, relate to a kind of scaling method of strain multiplier.
Background technology
The strain multiplier is under the condition that does not influence the test specimen strain, transmits by distortion to make on the multiplier a part mechanical strain greater than the test specimen strain.The strain multiplier is usually as the kit that is used for the fatigue life gage of fatigue monitoring.Fatigue life gage is a kind of fatigue damage sensing element, and it writes down the alternate strain course of institute location for paste by the automatic accumulation of resistance change, is applicable to structure chronic fatigue damage monitoring.At present, fatigue life gage is mainly used in the monitoring of aerospace structure fatigue damage, as the material 30CrMnSi etc. that navigates.Because the strain threshold value of fatigue life gage is 1000 μ ε, therefore when the strain amplitude is lower than this threshold value, the fatigue life gage cumulative effect that can not have a resistance, this has limited its application in other engineering widely, as steel A3 steel commonly used in the engineering, when its stress amplitude reaches fatigue limit, its strain amplitude still is lower than the fatigue life gage threshold value, therefore must be by means of the strain multiplier, the big ten fatigue life gage threshold values of the strain that fatigue life gage is experienced just can be finished the fatigue monitoring to this structured material.
Arc displacement concentrated strain multiplier is a kind of existing strain multiplier, as shown in Figure 1, this kind strain multiplier generally includes bow-shaped structural 1, elastic body 4, two support arms 2 and two installation feet 3, bow-shaped structural 1 comprises the connecting portion 12 that two sidepieces 11 are connected with a end with these two sidepieces 11, one end of two support arms 2 is separately positioned on two sidepieces 11 of bow-shaped structural 1, two installation feet 3 are separately positioned on the below of the other end of two support arms 2, and elastic body 4 is arranged between two sidepieces 11 so that bow-shaped structural 1 is in the precompression state.During use, the strain multiplier is installed on the position to be measured, on elastic body 4, foil gauge is installed by installation foot 3.Because the rigidity of support arm 2 is bigger, the rigidity of bow-shaped structural 1 is less, bow-shaped structural 1 flexural deformation is more much bigger than the axial deformation of support arm 2, by support arm 2 displacement between the installation foot 3 at two ends is concentrated on bow-shaped structural 1 opening part (being between two sidepieces 11 of bow-shaped structural 1), make that the strain on the rubber elastomer 4 of opening part is amplified.Thereby can measure the strain value of this elastic body 4 (strain value after promptly being amplified) by the strain multiplier by being installed in foil gauge on the elastic body 4.
Because all multifactor enlargement factors that can influence the strain multiplier such as the dimensioned precision of strain multiplier and the elastomeric stickup of arched opening part, so each strain multiplier all need be demarcated before use.Therefore the scaling method of strain multiplier reasonable in design is extremely important, and it directly has influence on the result of use of strain multiplier.
The scaling method of existing strain multiplier generally includes following steps: step a: the strain multiplier is installed on the test specimen; Step b:, make test specimen produce strain to the test specimen loading force; Step c: the strain value ε that obtains the strain multiplier
bStrain value ε with test specimen
sAnd steps d: according to the strain value ε of strain multiplier
bStrain value ε with test specimen
sDetermine the enlargement factor of strain multiplier.And, in the step c of existing scaling method, the strain value ε of test specimen
sUsually the theoretical value that obtains of the size Theoretical Calculation of size by the power that in step b, loads and test specimen, therefore can there be deviation with the actual strain value that is subjected to of test specimen, thereby make that the enlargement factor of demarcating the strain multiplier that obtains is inaccurate, and then influence the result of use of strain multiplier.
Summary of the invention
The scaling method that the purpose of this invention is to provide a kind of strain multiplier, the enlargement factor of the strain multiplier that this method demarcation obtains is more accurate, thereby has improved the result of use of strain multiplier.
To achieve these goals, the invention provides a kind of scaling method of strain multiplier, this method may further comprise the steps: step a: the strain multiplier is installed on the test specimen; Step b:, make test specimen produce strain to the test specimen loading force; Step c: the strain value ε that obtains the strain multiplier
bStrain value ε with test specimen
sAnd steps d: according to the strain value ε of strain multiplier
bStrain value ε with test specimen
sDetermine the enlargement factor of strain multiplier; Wherein: in described step a, first foil gauge is installed on described test specimen also; And in described step c, obtain the strain value ε of described test specimen by the strain value of measuring described first foil gauge
s
Preferably, in described step a, second foil gauge is installed on described strain multiplier also; And in described step c, obtain the strain value ε of described strain multiplier by the strain value of measuring described second foil gauge
b
Preferably, utilize the strain acquirement instrument to measure the strain value of described first foil gauge and/or described second foil gauge.
Preferably, in described step a, a plurality of strain multipliers and a plurality of first foil gauge are installed on the described test specimen.
Preferably, in described step b, described test specimen is loaded multistage power.
Preferably, in described step b, the process of described test specimen loading force is comprised a plurality of circulations, the multistage power of each CYCLIC LOADING.
Preferably, in described step c, obtain the strain value of each strain multiplier when each loading force
Strain value with each test specimen
, wherein i represents to load progression, and j represents period; And in described steps d, according to the strain value of each strain multiplier
Strain value with each test specimen
Determine the enlargement factor of strain multiplier.
Preferably, in described steps d, with the strain value of test specimen
Be horizontal ordinate, the strain value of strain multiplier
Be ordinate, obtain a plurality of discrete points
, and should a plurality of discrete points
Match obtains an order polynomial φ (ε
b)=a ε
s+ b, wherein φ (ε
b) be strain value ε with test specimen
sFunction for independent variable.
Preferably, match obtains a described order polynomial φ (ε according to principle of least square method
Bk)=a ε
Sk+ b.
Preferably, described test specimen is a rod, and the shape of cross section of described test specimen is a polygon, in described step a, a plurality of strain multipliers and a plurality of first foil gauge is respectively installed on the not ipsilateral of described test specimen.
Preferably, described polygon has four edges at least, in described step a, two strain multipliers is installed in respectively on wherein two sides of described test specimen, and two described first foil gauges are respectively installed on two other side of described test specimen.
Preferably, described polygon is a square, in described step a, two strain multipliers is installed in respectively on two relative sides of described test specimen, and two described first foil gauges are respectively installed on two other relative side of described test specimen.
By technique scheme, because the strain value ε of test specimen
sThe strain value that is installed in first foil gauge on the test specimen by direct measurement obtains, so this strain value ε that records
sThere is deviation hardly in the strain value that is subjected to for test specimen is actual, thus this method to demarcate the enlargement factor of the strain multiplier that obtains more accurate, thereby improved the result of use of strain multiplier.
Other features and advantages of the present invention will partly be described in detail in embodiment subsequently.
Description of drawings
Accompanying drawing is to be used to provide further understanding of the present invention, and constitutes the part of instructions, is used from explanation the present invention with following embodiment one, but is not construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the structural representation of existing a kind of strain multiplier;
Fig. 2 is the structural representation that is used for according to the test specimen of the scaling method of the strain multiplier of one embodiment of the present invention.
Description of reference numerals
1 bow-shaped structural, 2 support arms
3 installation feet, 4 elastic bodys
11 sidepieces, 12 connecting portions
S test specimen S1 side
The S2 xsect
Embodiment
Below in conjunction with accompanying drawing the specific embodiment of the present invention is elaborated.Should be understood that embodiment described herein only is used for description and interpretation the present invention, is not limited to the present invention.
The invention provides a kind of scaling method of strain multiplier, this method may further comprise the steps: step a: the strain multiplier is installed on the test specimen; Step b:, make test specimen produce strain to the test specimen loading force; Step c: the strain value ε that obtains the strain multiplier
bStrain value ε with test specimen
sAnd steps d: according to the strain value ε of strain multiplier
bStrain value ε with test specimen
sDetermine the enlargement factor of strain multiplier; Wherein: in described step a, first foil gauge is installed on described test specimen also; And in described step c, obtain the strain value ε of described test specimen by the strain value of measuring described first foil gauge
s
By technique scheme, because the strain value ε of test specimen
sThe strain value that is installed in first foil gauge on the test specimen by direct measurement obtains, so this strain value ε that records
sThere is deviation hardly in the strain value that is subjected to for test specimen is actual, thus this method to demarcate the enlargement factor of the strain multiplier that obtains more accurate, thereby improved the result of use of strain multiplier.
The strain value of described strain multiplier can record by various suitable modes, for example can measure by fatigue life gage is installed on the strain multiplier, but the result that this indirect metering system obtains is not accurate enough, thereby make that the enlargement factor of demarcating the strain multiplier that obtains is inaccurate, and then influence the result of use of strain multiplier.Therefore preferably, in described step a, second foil gauge is installed on described strain multiplier also; And in described step c, obtain the strain value ε of described strain multiplier by the strain value of measuring described second foil gauge
bThereby, can access the strain value ε of strain multiplier more accurately
b
The strain value of described first foil gauge and/or described second foil gauge can adopt various suitable modes or device to measure, and more preferably, utilizes the strain acquirement instrument to measure the strain value of described first foil gauge and/or described second foil gauge.Described strain acquirement instrument is a kind of known equipment, the SA-8 type dynamic strain indicator that for example can adopt Beijing Orient vibration and noise technique research institute to produce.
In above-mentioned steps a, the one or more strain multipliers and first foil gauge can be installed as required.In described step b, can load multistage power to test specimen as required, promptly repeatedly test specimen is loaded different power; Perhaps, the process to described test specimen loading force can comprise a plurality of circulations, the multistage power of each CYCLIC LOADING.For example each circulation loads 0kN, 4kN, 8kN, 12kN, 16kN, 12kN, 8kN, 4kN, 0kN successively, and totally nine grades of loadings can comprise three circulations.Can adopt known device to the test specimen loading force, the MTS-810 electro-hydraulic servo universal testing machine that for example can adopt MTS Systm Corp. to produce loads.
In described step c, obtain the strain value of each strain multiplier when each loading force
Strain value with each test specimen
, wherein i represents to load progression, and j represents that period is (for example
The strain value of the strain multiplier when expression loads the 1st round-robin 4kN level power to test specimen,
Be illustrated in the strain value of the test specimen when test specimen loaded the 3rd round-robin 16kN level power); And in described steps d, according to the strain value of each strain multiplier
Strain value with each test specimen
Determine the enlargement factor of strain multiplier.
In described steps d, can adopt the next strain value ε of various suitable modes according to the strain multiplier
bStrain value ε with test specimen
sDetermine the enlargement factor of strain multiplier.For example can obtain by the picture method.That is, with the strain value of test specimen
Be horizontal ordinate, the strain value of strain multiplier
Be ordinate, in coordinate system, draw a plurality of discrete points
, and draw near these discrete points with the method for mapping
Straight line, can obtain the enlargement factor of strain multiplier by the slope of measuring this straight line.But the enlargement factor of the strain multiplier that obtains by this method is not accurate enough, therefore preferably, and should a plurality of discrete points
Match obtains an order polynomial φ (ε
b)=a ε
s+ b, wherein φ (ε
b) be strain value ε with test specimen
sBe the function of independent variable, more preferably, match obtains a described order polynomial φ (ε according to principle of least square method
Bk)=a ε
Sk+ b.The coefficient a that wherein obtains is exactly the enlargement factor of demarcating the strain multiplier that obtains.The enlargement factor of the strain multiplier that this method demarcation obtains is more accurate.Relevant principle of least square method and to come the once polynomial detailed process of match according to principle of least square method be well known in the art does not repeat them here.
The test specimen that is used for the scaling method of described strain multiplier can adopt various suitable test specimens, preferably, as shown in Figure 2, described test specimen S is a rod, the shape of cross section of described test specimen S is a polygon, in described step a, a plurality of strain multipliers and a plurality of first foil gauge are respectively installed on the not ipsilateral S1 of described test specimen S.Thereby, utilize a plurality of side S1 of described test specimen S that a plurality of strain multipliers and a plurality of first foil gauge can be installed easily.In the test specimen S of above-mentioned rod, test specimen S extends along the axis direction of bar, described xsect S2 is meant and the vertical substantially plane of described axis direction, the side S1 of described test specimen is meant the test specimen surface substantially parallel with described axis direction, and can be called the end face of test specimen S usually with the vertical substantially test specimen surface of axis direction, for example in test specimen S as shown in Figure 2, have four side S1 and two end faces.
Described polygon can be various polygons, for example more specifically, described polygon has four edges at least, in described step a, two strain multipliers are installed in respectively on wherein two sides of described test specimen, two described first foil gauges are respectively installed on two other side of described test specimen.
Preferably, as shown in Figure 2, described polygon is a square, in described step a, two strain multipliers are installed in respectively on two relative sides of described test specimen S, two described first foil gauges are respectively installed on two other relative side of described test specimen S.Thereby relatively the measured value of both sides can be eliminated the error that the off-centre of loading force is brought, thereby further improves the accuracy of the enlargement factor of demarcating the strain multiplier that obtains.
According to a further aspect in the invention, also provide a kind of test specimen that is used for the scaling method of strain multiplier, wherein, as shown in Figure 2, this test specimen S is a rod, and the shape of cross section of described test specimen S is a polygon, and each side of described test specimen S is used to install strain multiplier and foil gauge.Thereby, utilize a plurality of side S1 of described test specimen S that a plurality of strain multipliers and a plurality of foil gauge (being first foil gauge as indicated above) can be installed easily.。In the test specimen S of above-mentioned rod, test specimen S extends along the axis direction of bar, described xsect S2 is meant and the vertical substantially plane of described axis direction, the side S1 of described test specimen is meant the test specimen surface substantially parallel with described axis direction, and can be called the end face of test specimen S usually with the vertical substantially test specimen surface of axis direction, for example in test specimen S as shown in Figure 2, have four side S1 and two end faces.
Described polygon can be various polygons, and for example more specifically, described polygon has four edges at least, and at least two side S1 of described test specimen S are used to install the strain multiplier, and the S1 of two other side at least of described test specimen S is used to install foil gauge.
Preferably, described polygon is a square, and wherein two relative side S1 of described test specimen S are used to install the strain multiplier, and the side S1 that two other of described test specimen S is relative is used to install foil gauge.Thereby relatively the measured value of both sides can be eliminated the error that the off-centre of loading force is brought, thereby further improves the accuracy of the enlargement factor of demarcating the strain multiplier that obtains.
Described test specimen can be made by various suitable materials as required, for example can be made by the Q235 steel.
Below describe preferred implementation of the present invention in conjunction with the accompanying drawings in detail; but; the present invention is not limited to the detail in the above-mentioned embodiment; in technical conceive scope of the present invention; can carry out multiple simple variant to technical scheme of the present invention, these simple variant all belong to protection scope of the present invention.
Need to prove that in addition each the concrete technical characterictic described in above-mentioned embodiment under reconcilable situation, can make up by any suitable manner.For fear of unnecessary repetition, the present invention is to the explanation no longer separately of various possible array modes.
In addition, also can carry out combination in any between the various embodiment of the present invention, as long as it is without prejudice to thought of the present invention, it should be considered as content disclosed in this invention equally.
Claims (12)
1. the scaling method of strain multiplier, this method may further comprise the steps:
Step a: the strain multiplier is installed on the test specimen;
Step b:, make test specimen produce strain to the test specimen loading force;
Step c: the strain value ε that obtains the strain multiplier
bStrain value ε with test specimen
sAnd
Steps d: according to the strain value ε of strain multiplier
bStrain value ε with test specimen
sDetermine the enlargement factor of strain multiplier; It is characterized in that:
In described step a, first foil gauge is installed on described test specimen also; And
In described step c, obtain the strain value ε of described test specimen by the strain value of measuring described first foil gauge
s
2. the scaling method of strain multiplier according to claim 1 is characterized in that:
In described step a, second foil gauge is installed on described strain multiplier also; And
In described step c, obtain the strain value ε of described strain multiplier by the strain value of measuring described second foil gauge
b
3. the scaling method of strain multiplier according to claim 1 and 2 is characterized in that: utilize the strain acquirement instrument to measure the strain value of described first foil gauge and/or described second foil gauge.
4. the scaling method of strain multiplier according to claim 2 is characterized in that:
In described step a, a plurality of strain multipliers and a plurality of first foil gauge are installed on the described test specimen.
5. according to the scaling method of claim 1 or 4 described strain multipliers, it is characterized in that: in described step b, described test specimen is loaded multistage power.
6. according to the scaling method of claim 1 or 4 described strain multipliers, it is characterized in that: in described step b, the process of described test specimen loading force is comprised a plurality of circulations, the multistage power of each CYCLIC LOADING.
7. according to the scaling method of claim 1,4,5 or 6 described strain multipliers, it is characterized in that: in described step c, obtain the strain value of each strain multiplier when each loading force
Strain value with each test specimen
, wherein i represents to load progression, and j represents period; And in described steps d, according to the strain value of each strain multiplier
Strain value with each test specimen
Determine the enlargement factor of strain multiplier.
8. the scaling method of strain multiplier according to claim 7 is characterized in that, in described steps d, with the strain value of test specimen
Be horizontal ordinate, the strain value of strain multiplier
Be ordinate, obtain a plurality of discrete points
, and should a plurality of discrete points
Match obtains an order polynomial φ (ε
b)=a ε
s+ b, wherein φ (ε
b) be strain value ε with test specimen
sFunction for independent variable.
9. the scaling method of strain multiplier according to claim 8 is characterized in that, match obtains a described order polynomial φ (ε according to principle of least square method
Bk)=a ε
Sk+ b.
10. the scaling method of strain multiplier according to claim 4 is characterized in that,
Described test specimen is a rod, and the shape of cross section of described test specimen is a polygon, in described step a, a plurality of strain multipliers and a plurality of first foil gauge is respectively installed on the not ipsilateral of described test specimen.
11. the scaling method of strain multiplier according to claim 10 is characterized in that,
Described polygon has four edges at least, in described step a, two strain multipliers is installed in respectively on wherein two sides of described test specimen, and two described first foil gauges are respectively installed on two other side of described test specimen.
12. the scaling method of strain multiplier according to claim 11, it is characterized in that, described polygon is a square, in described step a, two strain multipliers are installed in respectively on two relative sides of described test specimen, two described first foil gauges are respectively installed on two other relative side of described test specimen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110093818 CN102252597A (en) | 2011-04-14 | 2011-04-14 | Method for calibrating strain multiplier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110093818 CN102252597A (en) | 2011-04-14 | 2011-04-14 | Method for calibrating strain multiplier |
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| Publication Number | Publication Date |
|---|---|
| CN102252597A true CN102252597A (en) | 2011-11-23 |
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ID=44980025
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201110093818 Pending CN102252597A (en) | 2011-04-14 | 2011-04-14 | Method for calibrating strain multiplier |
Country Status (1)
| Country | Link |
|---|---|
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3899922A (en) * | 1973-12-05 | 1975-08-19 | Ford Motor Co | Double lever strain multiplier apparatus and method |
-
2011
- 2011-04-14 CN CN 201110093818 patent/CN102252597A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3899922A (en) * | 1973-12-05 | 1975-08-19 | Ford Motor Co | Double lever strain multiplier apparatus and method |
Non-Patent Citations (2)
| Title |
|---|
| 《中国优秀硕士学位论文全文数据库》 20101231 戴恩彬 应变模态分析及参数识别 17-27 1-12 , * |
| 《实验力学》 20070228 胡明敏 等 应变倍增器研制及应用 57-62 1-12 第22卷, 第1期 * |
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Application publication date: 20111123 |