CN1529133A - Supersonic deformeter - Google Patents
Supersonic deformeter Download PDFInfo
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- CN1529133A CN1529133A CNA031254594A CN03125459A CN1529133A CN 1529133 A CN1529133 A CN 1529133A CN A031254594 A CNA031254594 A CN A031254594A CN 03125459 A CN03125459 A CN 03125459A CN 1529133 A CN1529133 A CN 1529133A
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- type piezoelectric
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Abstract
The invention is a kind of ultrasonic deformeter, which is mainly made up of emission piezo-electric, sound insulating material, metal shell, transmitting end power outgoing line, receiving end power outgoing line. It has merits of high accuracy, low cost, no electromagnetism interference, no loose, adjustable strain absolute magnitude, small size. It especially is suitable for long time strain measurement and the rheopectic measurement of construction structure safe monitoring, hill arpon.
Description
Technical field
The present invention relates to a kind of stress of material and structure, instrument of strain measurement of being used for.
Background technology
Heavy construction structure and infrastructure, as pipe network systems such as bridge, high-rise building, large span spatial structure, large-scale dam, nuclear power station, offshore oil production platform and oil transportation, water supply, air feed, their operating period all reaches decades, even goes up century-old.In its military service process, because environmental load effect, fatigue effect, corrosion is peeled off and the influence of unfavorable factor such as material aging, structure can produce damage accumulation inevitably, thereby drag is reduced, even causes burst accident.As not making timely, correct evaluation to the damage of structure, just can not the health status of solution structure, make correct resolution; In case accident takes place, and will bring tremendous loss.In recent years, the monitoring for important structure more and more is subject to people's attention.Strain (or stress) is one of the parameter of the particular importance of reflect structure state, and more accurately especially the secular strain state is most important to engineering safety in the measurement structure strain.But traditional sensor performance is difficult to satisfy the requirement of engineering structure safety monitoring.
Strain measurement method commonly used has following several: electrical measuring method, magnetic survey method, piezoelectric method, vibratory string method, flash spotting, sound detection, rays method etc.
Electrical measuring method is most widely used a kind of method, common component has resistance strain gage or strain silk, its principle is the variation that strain causes length, because of linear between length and the resistance, measure resistance variations (in fact often surveying change in voltage) and can calculate strain increment.The weak point of electrical measuring method is: resistance strain gage life-span weak point, poor anti jamming capability, can only to measure relative quantity be strain increment, is unsuitable for doing long term monitoring.
Magnetic survey method has two kinds: a kind of STRESS VARIATION that is based on causes this rule of variation in magnetic field and directly measurement; Another kind is to measure according to the mangneto acoustic emission phenomenon, is mainly used in the survey unrelieved stress.
The piezoelectric effect that piezoelectric method is based on some material proposes.Piezoelectric (as piezoelectric ceramics or crystal) can produce voltage (or electric current) when stressed, measure this voltage and can obtain pressure, stress and strain.Because electric current can not be preserved, thereby can only survey increment, can not be used for long-term static(al) and measure, be applicable to dynamic test.
The foundation of vibratory string method is that the lateral stiffness and the string axis power of string wire has one-to-one relationship, with the horizontal natural frequency of vibration corresponding relation is arranged also simultaneously, therefore, can extrapolate string axis power, stress and strain by measuring the natural frequency of vibration.Vibratory strain ga(u)ge has obtained more application in reinforced concrete structure and steel construction.But the string wire in the vibratory strain ga(u)ge easily produces lax under action of long-term load, be unsuitable for and do long-term the measurement, and size is bigger.
Classical flash spotting comprises photoelastic method and light holography method etc., obtained using more widely, but these methods generally can only be used for especially transparent model test of model, and the internal stress that is difficult to use in actual engineering is measured.
Along with the proposition and the development of structure intelligentization, a kind of novel smart sensor---fiber optic sensor has appearred in recent years, for new vitality has been injected in the development of structure monitoring.
Fibre Optical Sensor in the research mainly contains Bragg grating fibers sensor, Fabry-Perot (F-P) Fibre Optical Sensor, high birefringence optical fiber sensor, distributed fiberoptic sensor etc. at present.Wherein studying maximum is Bragg grating fibers sensor.People such as Prohaska imbedded fiber grating first and measure strain in the xoncrete structure in 1992.
Fibre optic strain sensor is a kind of promising strainometer, but from present case, fibre optic strain sensor is tighter to manufacturing technique requirent, and cost is also higher, and the effect in long-term the measurement is still waiting textual criticism.In addition, it also has certain difficulty aspect embedding.
Ultrasonic method is used for stress measurement and also is concerned by people already, especially aspect residual stress measurement.Existing ultrasonic ratio juris is as follows: the variation of stress can cause the variation of the velocity of sound in structure or the material, and the change of measuring the velocity of sound gets final product the variation of inverse stress.Theoretically, this method is feasible, and very high value is also arranged, and does not let alone what sensing element because it does not need to bury in advance, can record the absolute magnitude of strain at any time.But it is very difficult that it has a fatal weakness to demarcate exactly, because stress is responsive like that not as defective to sonic velocity change.For actual engineering, be difficult to judge that the variation of the velocity of sound is caused or caused by defective by stress.
All kinds of rays methods generally only are used for skin stress to be measured, because the penetration depth of ray is limited.
Summary of the invention
Technical matters to be solved by this invention is: provide a kind of and have precision height, low, the no electromagnetic interference (EMI) of cost, do not have lax, can measure strain absolute magnitude, size little, easily advantage such as lay, at the ultrasonic strainometer that has good result aspect the long-term measurement.
The present invention solves the problems of the technologies described above the technical scheme that is adopted:
Principle of the present invention is as follows: by piezoelectric or giant magnetostrictive material excitation ultrasound ripple, can measure the size of medium by the travel-time of ultrasound wave in medium (as air), as the length in space, air place.If be embedded in medium among the member or invest component surface, member can be come out by the ultrasonic propagation time inverse because of load action is out of shape the variation of caused media size, can try to achieve strain and strain increment thus.The defective of it and member is irrelevant.
The present invention mainly by emission type piezoelectric patches (piezoelectric crystal or piezoelectric ceramics), sound bearing medium (tinsel or air grille), reception type piezoelectric patches (piezoelectric crystal or piezoelectric ceramics), sound insulating material (as polyfoam etc., when sound bearing medium was used tinsel, also vacuum available insulated against sound), composition such as metal shell (available stainless steel or other alloy steels are made), transmitting terminal power outlet, receiving end power outlet.
The plating of the two sides of emission type piezoelectric patches, reception type piezoelectric patches is made electrode with silverskin, and connects a lead-in wire respectively link with external heart yearn on electrode surface, as power circuit.Emission type piezoelectric patches, reception type piezoelectric patches and metal shell are fixed by sound insulating material such as foam.Sound bearing medium respectively with emission type piezoelectric patches, reception type piezoelectric patches adhering with epoxy resin.Its complementary space in the metal shell is vacuum or fills sound insulating material.Seal with epoxy resin at the metal shell two ends, and pull out transmitting terminal power outlet, receiving end power outlet.
When the present invention works, the energising of transmitting terminal power outlet, the emission type piezoelectric patches is because inverse piezoelectric effect produces ultrasound wave, ultrasound wave passes to receiving end by the sound bearing medium in the sound insulating material, reception type piezoelectric patches is because piezoelectric effect produces electric current, and electric current is delivered to supporting Ultrasound Instrument from the receiving end power outlet.
By the passing time of ultrasound wave in air grille (or metal wire grid) and the velocity of sound of demarcating in advance, can be regarded as out the length of air grille (or metal wire grid).When ultrasonic strainometer during with isostructure generation modification, the length of the air grille in the strainometer (or metal wire grid) also will change, thereby the passing time of ultrasound wave in air grille (or metal wire grid) changed.But the variation inverse of Measuring Time goes out the length change amount of air grille (or metal wire grid), can obtain strain value and strain increment.
The present invention is different with piezoelectric sensor, and the latter is to serve as according to developing with the electric current (voltage) that piezoelectric is produced under pressure.And ultrasonic strainometer is to be foundation with the ultrasonic propagation time, is similar to radar for backing car, but precision is much higher.With existing a kind of residual stress measuring method---ultrasonic method has the difference of essence, the latter directly measures the travel-time of ultrasound wave in member to obtain strain value, because the influence during to sound such as the defective of material is much larger than the influence of stress during to sound, and the defective in the member is difficult to quantitative description, make demarcation and measurement very difficult, particularly to anisotropic compound substance.And the sound wave of ultrasonic strainometer be with the irrelevant particular medium of member in propagate, isotropic particular medium of selected standard has not had great difficulty, thereby demarcates and measure than being easier to yet.
Advantages such as the present invention has precision height, low, the no electromagnetic interference (EMI) of cost, it is lax not have, can measure the strain absolute magnitude, size is little, easily lay are specially adapted to online secular strain and measure and flow measurement.Having good result aspect the long-term measurement, in engineering structure safety monitoring, landslide and other flow measurements, have been widely used.
Description of drawings
Fig. 1 is a structural representation of the present invention.
1-emission type piezoelectric patches wherein; The 2-sound bearing medium; 3-reception type piezoelectric patches; The 4-sound insulating material; The 5-metal shell; 6-transmitting terminal power outlet; 7-receiving end power outlet.
Embodiment
The present invention mainly by emission type piezoelectric patches (piezoelectric crystal or piezoelectric ceramics), sound bearing medium (tinsel or air grille), reception type piezoelectric patches (piezoelectric crystal or piezoelectric ceramics), sound insulating material (as foam etc., when sound bearing medium was used tinsel, also vacuum available insulated against sound), composition such as metal shell (available stainless steel or other alloy steels are made), transmitting terminal power outlet, receiving end power outlet.
The plating of the two sides of emission type piezoelectric patches, reception type piezoelectric patches is made electrode with silverskin, and connects a lead-in wire respectively link with external heart yearn on electrode surface, as power circuit.Emission type piezoelectric patches, reception type piezoelectric patches and metal shell are fixed by sound insulating material such as foam.Sound bearing medium respectively with emission type piezoelectric patches, reception type piezoelectric patches adhering with epoxy resin.Its complementary space in the metal shell is vacuum or fills sound insulating material.Seal with epoxy resin at the metal shell two ends, and pull out transmitting terminal power outlet, receiving end power outlet.
Claims (3)
1. a ultrasonic strainometer mainly is made up of emission type piezoelectric patches (1), sound bearing medium (2), reception type piezoelectric patches (3), sound insulating material (4), metal shell (5), transmitting terminal power outlet (6), receiving end power outlet (7); It is characterized in that: the two sides plating of emission type piezoelectric patches (1), reception type piezoelectric patches (3) is made electrode with silverskin, and on electrode surface, connect transmitting terminal power outlet (6) respectively, receiving end power outlet (7) links with external heart yearn respectively, as power circuit; Emission type piezoelectric patches (1), reception type piezoelectric patches (3) are fixed by sound insulating material (4) with metal shell; Sound bearing medium (2) is used adhering with epoxy resin with emission type piezoelectric patches (1), reception type piezoelectric patches (3) respectively; Its complementary space in the metal shell is sound insulating material (4); Seal with epoxy resin at metal shell (5) two ends, and pull out transmitting terminal power outlet (6), receiving end power outlet (7).
2. ultrasonic strainometer according to claim 1 is characterized in that: described emission type piezoelectric patches (1), reception type piezoelectric patches (3) can be piezoelectric crystal or piezoelectric ceramics.
3. ultrasonic strainometer according to claim 1 and 2 is characterized in that: described sound insulating material (4) can be polyfoam etc., and when sound bearing medium was used tinsel, also vacuum available insulated against sound.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031254594A CN1529133A (en) | 2003-09-28 | 2003-09-28 | Supersonic deformeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031254594A CN1529133A (en) | 2003-09-28 | 2003-09-28 | Supersonic deformeter |
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| Publication Number | Publication Date |
|---|---|
| CN1529133A true CN1529133A (en) | 2004-09-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA031254594A Pending CN1529133A (en) | 2003-09-28 | 2003-09-28 | Supersonic deformeter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104034252A (en) * | 2014-07-01 | 2014-09-10 | 重庆材料研究院有限公司 | Strain gauge based on magnetorheological elastomer |
| CN104484962A (en) * | 2014-10-30 | 2015-04-01 | 深圳市易联技术有限公司 | Safety detection method and device for POS machine |
| CN107976485A (en) * | 2016-10-25 | 2018-05-01 | 费希尔控制产品国际有限公司 | acoustic emission sensor with integrated acoustic generator |
| CN110608691A (en) * | 2019-09-05 | 2019-12-24 | 三峡大学 | Landslide deep displacement real-time monitoring system and method based on sound source positioning |
-
2003
- 2003-09-28 CN CNA031254594A patent/CN1529133A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104034252A (en) * | 2014-07-01 | 2014-09-10 | 重庆材料研究院有限公司 | Strain gauge based on magnetorheological elastomer |
| CN104484962A (en) * | 2014-10-30 | 2015-04-01 | 深圳市易联技术有限公司 | Safety detection method and device for POS machine |
| CN107976485A (en) * | 2016-10-25 | 2018-05-01 | 费希尔控制产品国际有限公司 | acoustic emission sensor with integrated acoustic generator |
| CN110608691A (en) * | 2019-09-05 | 2019-12-24 | 三峡大学 | Landslide deep displacement real-time monitoring system and method based on sound source positioning |
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