CN103822754B - A kind of compressive stress generating means for stress measurement system calibration - Google Patents

Abstract

The present invention designs a kind of compressive stress generating means for stress measurement system calibration, and this device has that structure is simple, good looking appearance, feature easy to use.By tightening the bolt at two ends, coming to flexible member imposed load, making calibration region on elasticity compressive stress generating device produce certain compressive stress.Then by ultrasonic stress mornitoring system, the value of compressive stress in calibration region on elasticity compressive stress generating device is measured, on the force value that value of compressive stress is measured by toroid load cell and the flexible member that dimensional measurement instrument is measured, the cross-section lengths of calibration region and width calculation obtain, and as standard value of compressive stress.Toroid load cell and dimensional measurement instrument are traced to the source through calibration, and the value of compressive stress can demonstrate,proving the generation of compressive stress generating means has trace back originality and high accuracy.Assessed and the accuracy of calibrating ultrasonic stress mornitoring system compressive stress being measured by the deviation between measurement of comparison value and standard value of compressive stress.

Description

A kind of compressive stress generating means for stress measurement system calibration

One, technical field

The present invention relates to a kind of compressive stress generating means for stress measurement system calibration, this device is applicable to assessment and the calibration of ultrasonic stress mornitoring system compressive stress measurement performance.

Two, background technology

Along with the development of the structural stress Dynamic Non-Destruction Measurement of material, ultrasonic method stress measurement technology becomes one of main detection method.Especially ultrasonic critical refraction longitudinal wave method has prospect widely.

Any one pick-up unit has its specific degree of accuracy, all needs corresponding prover carry out assessing to its testing result and calibrate.What describe in Vocal cord injection that supercritical ultrasonics technology measures is corresponding force value, only has to be calibrated it by corresponding prover just to obtain real absolute stress value.Therefore design can produce standard compressive stress generating means and carries out assess for the measurement performance of ultrasonic unstressed detection system and calibrate, and has to the value of compressive stress of the ultrasonic stress mornitoring systematic survey of guarantee trace back originality and accuracy, significant.

Three, summary of the invention

The object of this invention is to provide a kind of compressive stress generating means for stress measurement system calibration, and have that structure is simple, good looking appearance and the little feature of volume.

The object of the present invention is achieved like this, elasticity compressive stress generating device is made with measured material, two bolts are screwed from the two ends of device, calibration region on elasticity compressive stress generating device is made to produce compressive stress, the pressure acting on elasticity compressive stress generating device is measured by toroid load cell, measure the transversal face length of calibration region on elasticity compressive stress generating device again, wide, the value of compressive stress on elasticity compressive stress generating device in calibration region is gone out by formulae discovery, can carry out in advance calibrating and tracing to the source for the annular force snesor of dynamometry and the length measuring instrument of flexible member section gauge, therefore, the value of compressive stress calculated can as compressive stress standard value, then by ultrasonic stress mornitoring system, the value of compressive stress in calibration region on elasticity compressive stress generating device is measured, by with calculate the contrast of acquired results and assess and the accuracy of calibrating ultrasonic stress mornitoring system compressive stress being measured.

Four, accompanying drawing explanation

Fig. 1 compressive stress generating means wiring layout;

The ultrasonic stress mornitoring detection system of Fig. 2 is to the compressive stress instrumentation plan of calibration region on elasticity compressive stress generating device.

Description of reference numerals is as follows:

Fig. 1: bolt 1, packing ring 2, toroid load cell 3, elasticity compressive stress generating device 4, nut 5, bolt 6

Fig. 2: the sensor 7 of ultrasonic stress mornitoring system, elasticity compressive stress generating device 4

Five, embodiment

Below the specific embodiment of the present invention is described in detail:

1. the generation of elasticity compressive stress generating device calibration region compressive stress and calculating

(1) generation of elasticity compressive stress generating device calibration region compressive stress and Computing Principle

As shown in Figure 1, packing ring 2, toroid load cell 3, elasticity compressive stress generating device 4 are placed from top to bottom with one heart, it is inner that nut 5 is placed in elasticity compressive stress generating device, two bolts 1 and 6 are screwed into nut 5 from the two ends of device, and calibration region on elasticity compressive stress generating device just can be made to produce compressive stress.The size of value of compressive stress is calculated by measured pressure value and flexible member sectional area, the pressure size acting on flexible member is measured with toroid load cell, measure length and width elasticity compressive stress generating device being calibrated zone cross-sectional with Measuring instrument for geometrical quantity, then the compressive stress that on elasticity compressive stress generating device, calibration region produces can calculate as follows:

${\mathrm{\σ}}_{\mathrm{bc}}=\frac{F}{A}=\frac{F}{\mathrm{bh}}$

Wherein, F is the force value acted on flexible member that toroid load cell is measured

A is the cross-sectional area of calibration region on elasticity compressive stress generating device

B is width elasticity compressive stress generating device being calibrated zone cross-sectional

H is the length of elasticity compressive stress generating device being calibrated zone cross-sectional.

(2) explanation of the accuracy of calibration region compressive stress result of calculation on elasticity compressive stress generating device

Because act on the force value F of calibration region on elasticity compressive stress generating device, elasticity compressive stress generating device are calibrated zone cross-sectional areas wide b and elasticity compressive stress generating device on calibrate the long h of zone cross-sectional areas, three value degree have originality of well tracing back, so just ensure that by the accuracy of formulae discovery acquired results, i.e. the value of compressive stress σ of formulae discovery gained _bcthere is higher precision.

2. the compressive stress calibration steps of ultrasonic stress mornitoring system

As shown in Figure 2, after the force value F recorded when toroid load cell 3 is stable, namely on elasticity compressive stress generating device calibration region pressure stability after, the sensor 7 of the ultrasonic stress mornitoring system needing calibration is placed on elasticity compressive stress generating device in calibration region, the compressive stress of calibration region on elasticity compressive stress generating device is measured.

The compressive stress result survey ultrasonic stress mornitoring system and formulae discovery result compare, and obtain measured value deviation, can evaluating the measurement accuracy of compressive stress or providing foundation to its adjustment and guarantee ultrasonic stress mornitoring system.

Different pressure can be applied to flexible member by the rotation amount controlling bolts at two ends 1 and 6, therefore the standard compressive stress generating means utilizing the present invention to design, can carry out general calibration to the measurement accuracy of ultrasonic stress mornitoring system under multiple value of compressive stress.

3. the processing spec of two bolts 1 and 6

As shown in Figure 1, in the A level of the screw thread specification D >=M48 of upper and lower two bolts 1 and 6, performance class >=10.9 grade, surface oxidation, the reprocessing of hexagonal cylindrical screw is made.The diameter of socket cap is D1 >=72mm, add and according to the prescriptive procedure of GB, the external thread of bolt is processed into screw thread specification D2 >=24mm man-hour, and guaranteed performance grade is constant.

Why two bolts 1 and 6 are in order to attractive in appearance by the reason that interior hexagonal cylindrical screw makes, and select to be because the diameter of its socket cap is large by the bolt of screw thread specification D >=M48, can ensure elasticity compressive stress generating device uniform force.

4. the making explanation of elasticity compressive stress generating device 4

As shown in Figure 2, elasticity compressive stress generating device 4 is made up of upper and lower two annulus and middle four rectangular columns, wherein the main work of annulus is the stability increasing elasticity compressive stress generating device 4, and increase the contact area of elasticity compressive stress generating device 4 and toroid load cell 3 and lower end nut 6, reduce the compressive stress load that toroid load cell 3 under uniform pressure bears with nut 6.

Elasticity compressive stress generating device 4 material therefor when making is consistent with the material of tested component or structure.

The scope of the height H of elasticity compressive stress generating device 4 is 100 ~ 130mm, and the thickness range of upper and lower annulus is 10 ~ 20mm, and occurrence can be determined according to the transducer spacing of ultrasonic stress mornitoring system, ensures not unstability.

The calibration region of elasticity compressive stress generating device 4, on four rectangular columns, adds and will ensure that must not there be the defects such as cut, pit, burr on its surface man-hour.Surface roughness Ra≤1.6 of its calibration region.What the sensor 7 of ultrasonic stress mornitoring system can be made like this to be coupled with calibration region is better, improves calibration accuracy.

The cross-sectional area of four rectangular columns of elasticity compressive stress generating device 4 calibration region will within 400mm2, to guarantee that bolt can bear corresponding compressive stress load, the concrete length and width value of xsect can be determined according to the width of the sensor of ultrasonic stress mornitoring system and actual conditions.

Two annulus of elasticity compressive stress generating device 4 will process corresponding rounding between four rectangular columns, ensure that it seamlessly transits, prevent concentrated stress.

The stress that elasticity compressive stress generating device 4 also needs corresponding thermal treatment to produce to eliminate process after machining.

5. the effect of packing ring 2

As shown in Figure 1, packing ring 2 is mainly used for protecting toroid load cell 3, prevents the relative sliding between ring washer sensor 3 and bolt 1 from damaging toroid load cell 3, so the two sides of packing ring 2 will ensure surface roughness Ra≤3.2.

6., as shown in Figure 2, in order to ensure that load can be fully transmitted to the calibration region of flexible member, concentric alignment wanted by bolt 1, packing ring 2, toroid load cell 3, elasticity compressive stress generating device 4, nut 5 and bolt 6.

Claims (8)

1. the compressive stress generating means for stress measurement system calibration, it is characterized in that: it comprises bolt, nut, toroid load cell, packing ring, elasticity compressive stress generating device, it is inner that nut is put in elasticity compressive stress generating device, two bolts are contained in the two ends of device, rotate the bolt at two ends, make flexible member stressed generation definite value compressive stress, by ultrasonic stress mornitoring system, the value of compressive stress in calibration region on elasticity compressive stress generating device is measured, carry out contrasting the accuracy assessed with calibrating ultrasonic stress mornitoring system and measuring compressive stress by the standard value of compressive stress occurred with device.

2. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its feature of standard value of compressive stress occurred is: the value of compressive stress that device produces is by the flexible member force value measured with toroid load cell and draw with the flexible member Size calculation that geometric measurement instrument is measured, because toroid load cell and geometric measurement instrument are easily calibrated, so the value of compressive stress that this device occurs has trace back originality and higher accuracy, can be used as standard value of compressive stress and use.

3. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its elasticity compressive stress generating device is characterised in that: the material of device Elastic compressive stress generating device is identical with the material of the component that the ultrasonic stress mornitoring system be calibrated will detect or structure, can meet the constraint that in ultrasonic stress mornitoring system, sonic elastic modulus is relevant to material category.

4. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its elasticity compressive stress generating device is characterised in that: two circular ring structures up and down of flexible member and four rectangular columns can increase the stability of elasticity compressive stress generating device.

5. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its elasticity compressive stress generating device is characterised in that: the sensor four rectangular columns of elasticity compressive stress generating device all can being placed ultrasonic stress mornitoring system, to measure the value of compressive stress in calibration region on elasticity compressive stress generating device.

6. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its elasticity compressive stress generating device is characterised in that: adding man-hour, the structure that two annulus of elasticity compressive stress generating device are connected with four rectangular columns has rounding, can prevent stress from concentrating.

7. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, its elasticity compressive stress generating device is characterised in that: it is separated with the bolt of lower end, can make separately.

8. a kind of compressive stress generating means for stress measurement system calibration according to claim 1, it rotates the bolt at two ends, flexible member stressed generation definite value compressive stress is characterised in that: by controlling the rotation amount of bolts at two ends, different pressure can be applied to flexible member, thus in the elastic range of flexible member material, general calibration can be carried out to ultrasonic stress mornitoring systematic survey accuracy under multiple standard value of compressive stress.