Method for verifying measurement accuracy of strain measurement system

Abstract

The invention belongs to the technical field of strain measurement, and relates to a method for verifying the measurement accuracy of a strain measurement system, which comprises the following steps of: 1, locally depainting and polishing the periphery of a pasting area of a strain sensor; 2, symmetrically pasting an extensometer clamping tool I and an extensometer clamping tool II on two sides of the strain sensor; 3, measuring the center distance L between the supporting beam of the first extensometer clamping tool and the supporting beam of the second extensometer clamping tool; 4, a digital display extensometer is installed on a cross beam of the first extensometer clamping tool and a cross beam of the second extensometer clamping tool in parallel, whether the distance between an installation point e on the cross beam and an installation point f on the cross beam meets the requirement or not is judged, and then indication values of the digital display extensometer and the strain tester are reset; 5, under the condition that the surface of the component is greatly deformed, reading the indicating values epsilon 1 and epsilon 2 of the digital display extensometer and the strain tester at the same time; and step 6, calculating a measurement deviation delta between the digital display extensometer and the strain tester, thereby completing verification.

Description

Technical Field

[0001] The invention belongs to the technical field of strain measurement and relates to a method for verifying the measurement accuracy of a strain measurement system. Background Art

[0002] The strain measurement system is generally composed of strain sensors and strain testers, and is mainly used for small deformation measurement of load-bearing components and structural strength analysis. The accuracy of its measurement is related to equipment and personal safety, and it is a very common strength monitoring device in engineering applications. At present, the accuracy of the strain measurement system is mainly guaranteed by pasting the strain sensor on the standard strain beam in the laboratory and comparing its strain measurement value with the standard strain data. However, in actual use, the strain sensor needs to be re-pasted, and the difference in the shape, roughness and quality of the pasting surface each time will have a great impact on the measurement results. Therefore, the accuracy verification method in the laboratory is difficult to guarantee the accuracy in actual use. Summary of the invention

[0003] The purpose of the present invention is to provide a simple, efficient and easy-to-implement online verification method for the measurement accuracy of a strain measurement system, so as to solve the problems existing in the prior art.

[0004] Technical solution:

[0005] A method for verifying the measurement accuracy of a strain measurement system comprises the following steps:

[0006] Step 1: On the surface of the component, locally remove the paint and polish around the area where the strain sensor is to be pasted;

[0007] Step 2: The horizontal center line of the strain sensor is parallel to the strain measurement direction of the strain sensor, and its vertical center line is perpendicular to the strain measurement direction of the strain sensor; symmetrically stick the extensometer clamping fixture 1 and the extensometer clamping fixture 2 on both sides of the strain sensor, and the bottom center lines of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 coincide with the horizontal center line of the strain sensor;

[0008] Step 3: Measure the center distance L between the support beam of the extensometer clamping fixture 1 and the support beam of the extensometer clamping fixture 2;

[0009] Step 4: Install the digital extensometer in parallel on the crossbeam of the extensometer clamping fixture 1 and the crossbeam of the extensometer clamping fixture 2, and measure whether the distance between the installation point e on the crossbeam of the extensometer clamping fixture 1 and the installation point f on the crossbeam of the extensometer clamping fixture 2 meets the requirements, and then clear the indications of the digital extensometer and the strain tester;

[0010] Step 5: When a large deformation occurs on the component surface, read the indications ε1 and ε2 of the digital extensometer and strain tester at the same time;

[0011] Step 6: Calculate the measurement deviation δ between the digital extensometer and the strain tester to complete the verification.

[0012] Furthermore, the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are symmetrically adhered to the two sides of the strain sensor using metal quick bonding adhesive.

[0013] Furthermore, the structural dimensions of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are exactly the same, and the bonding bottom surfaces of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 both adopt an I-shaped cross-section design, and each side thereof is 3 mm wide.

[0014] Furthermore, the distance between the edge of the strain sensor and the first extensometer clamping fixture and the second extensometer clamping fixture along the horizontal center line of the strain sensor is no more than 1 mm.

[0015] Furthermore, a caliper is used to measure the center distance L between the support beam of the extensometer clamping fixture 1 and the support beam of the extensometer clamping fixture 2.

[0016] Further, measure whether the distance between the mounting point e on the crossbeam of the extensometer clamping fixture 1 and the mounting point f on the crossbeam of the extensometer clamping fixture 2 is 10 mm.

[0017] Furthermore, the measurement deviation δ between the digital extensometer and the strain tester is calculated by the following formula:

[0018]

[0019] Furthermore, the digital extensometer has a gauge length of 10 mm, a deformation range of 0-1 mm, and an accuracy level of 0.5.

[0020] Beneficial effects:

[0021] The strain measurement system measurement accuracy verification method of the present invention adopts the principle of online strain measurement comparison, takes advantage of the convenience and high accuracy of extensometer measurement, solves the installation universality problem of extensometers on components of different structural sizes, and realizes the accuracy verification of the strain measurement system under working conditions. It solves the problem that the traditional laboratory accuracy verification method does not consider the influence of the bonding quality, bonding surface shape and roughness of the strain sensor on the measurement accuracy during actual use, and the verification result is unreliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the installation diagram of the digital extensometer 3;

[0023] Figure 2 It is a schematic diagram of the bonding surface structure and position of the extensometer clamping fixture 1 and the extensometer clamping fixture 2;

[0024] Figure 3 It is the front view of the extensometer clamping fixture;

[0025] Figure 4 It is the side view of the extensometer clamping fixture;

[0026] Figure 5 It is a top view of the extensometer clamping fixture;

[0027] Among them, 1. Extensometer clamping fixture 1, 2. Extensometer clamping fixture 2, 3. Digital extensometer, 4. Strain sensor, 5. Strain tester, 6. Component surface, 1-1. Bottom surface of extensometer clamping fixture 1, 2-1. Bottom surface of extensometer clamping fixture 2, 1-2. Crossbeam of extensometer clamping fixture 1, 2-2. Crossbeam of extensometer clamping fixture 2, 1-3. Support beam of extensometer clamping fixture 1, 2-3. Support beam of extensometer clamping fixture 2, center line I is the horizontal center line of the strain sensor, center line II is the vertical center line of the strain sensor, and center line III is the bottom center line of extensometer clamping fixture 1 and extensometer clamping fixture 2. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] One embodiment of the present invention provides a method for verifying the measurement accuracy of a strain measurement system, comprising the following steps:

[0030] Step 1: On the component surface 6, partially remove the paint and polish the area around the sticking area of ​​the strain sensor 4 to facilitate the subsequent installation of the extensometer clamping fixture 1 and the extensometer clamping fixture 2;

[0031] Step 2: The horizontal center line of the strain sensor 4 is parallel to the strain measurement direction of the strain sensor 4, and its vertical center line is perpendicular to the strain measurement direction of the strain sensor 4; use metal quick adhesive to symmetrically adhere the extensometer clamping fixture 1 and the extensometer clamping fixture 2 to the two sides of the strain sensor 4, and the bottom center line of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 coincides with the horizontal center line of the strain sensor 4;

[0032] Step 3: Use a caliper to measure the center distance L between the extensometer clamping fixture 1 support beam 1-3 and the extensometer clamping fixture 2 support beam 2-3;

[0033] Step 4: Install the digital extensometer 3 in parallel on the beam 1-2 of the extensometer clamping fixture 1 and the beam 2-2 of the extensometer clamping fixture 2, and measure whether the distance between the installation point e on the beam 1-2 of the extensometer clamping fixture 1 and the installation point f on the beam 2-2 of the extensometer clamping fixture 2 meets the requirements, and then clear the indications of the digital extensometer 3 and the strain tester 5;

[0034] Step 5: When the component surface 6 is greatly deformed, the indications ε1 and ε2 of the digital extensometer 3 and the strain tester 5 are read simultaneously;

[0035] Step 6: Calculate the measurement deviation δ between the digital extensometer 3 and the strain tester 5 by the following formula:

[0036] This completes the verification.

[0037] In this embodiment, the structural dimensions of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are exactly the same, and the bonding bottom surfaces of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are both designed with an I-shaped cross-section, and each side thereof is 3 mm wide.

[0038] In this embodiment, the distance between the edge of the strain sensor 4 and the extensometer clamping fixture 1 and the extensometer clamping fixture 2 along the horizontal center line of the strain sensor 4 is no more than 1 mm.

[0039] In this embodiment, the distance between the mounting point e on the beam 1-2 of the extensometer clamping fixture 1 and the mounting point f on the beam 2-2 of the extensometer clamping fixture 2 is measured to be 10 mm. The mounting point e is the mounting position of the left mounting column of the digital extensometer 3 on the beam 1-2 of the extensometer clamping fixture 1, and the mounting point f is the mounting position of the right mounting column of the digital extensometer 3 on the beam 2-2 of the extensometer clamping fixture 2.

[0040] In this embodiment, the digital extensometer 3 has a gauge length of 10 mm, a deformation range of 0-1 mm, and an accuracy level of 0.5, which ensures the accuracy of the measurement.

[0041] A second embodiment of the present invention is:

[0042] Provided is a method for verifying the measurement accuracy of a strain measurement system. The method of the present invention involves devices and components including: an extensometer clamping fixture 1 and an extensometer clamping fixture 2, a digital extensometer 3, a strain measurement system (including a strain sensor 4 and a strain tester 5), and a component surface 6.

[0043] In this embodiment, on the component surface 6, along the center line I and the center line II of the strain sensor, the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are symmetrically installed, and then the digital extensometer 3 is installed in parallel on the cross beams 1-2 and 2-2 of the extensometer clamping fixture to ensure that the area and direction of the digital extensometer to measure the deformation are consistent with the measurement area and direction of the strain sensor. The strain value of the area is calculated using the measurement results of the digital extensometer and compared with the strain value measured by the strain measurement system, thereby completing the strain measurement accuracy verification of the fixed direction of the area.

[0044] In this embodiment, the extensometer clamping fixture 1 and the extensometer clamping fixture 2 have the same structural dimensions and are symmetrically installed on both sides of the strain sensor, with their center lines III coinciding with the center line I of the strain sensor; the shortest distance from the strain sensor along the center line I direction does not exceed 1 mm. This is used to ensure that the strain measurement area and direction of the digital extensometer are consistent with the measurement area and direction of the strain sensor.

[0045] In this embodiment, the bottom surface 1-1 of the extensometer clamping fixture 1 and the bottom surface 2-1 of the extensometer clamping fixture 2 adopt an I-shaped cross-section design with each side width of 3 mm, which ensures stable installation while minimizing the contact area between the fixture and the component surface and improving the accuracy of the measuring point.

[0046] In this embodiment, the extensometer clamping fixture beam 1-2 and the extensometer clamping fixture beam 2-2 adopt a cylindrical structure design to ensure reliable installation of the digital extensometer and flexibly adjust the initial zero position of the extensometer.

[0047] In this embodiment, the connection between the extensometer clamping fixture and the component surface is bonded by metal quick bonding glue, ensuring that the moving distance can reliably reflect the deformation of the component surface without damaging the component surface.

[0048] In this embodiment, the center line I of the strain sensor is parallel to the strain measurement direction of the strain sensor, and the center line II thereof is perpendicular to the center line I.

[0049] In this embodiment, the digital extensometer has a gauge length of 10 mm, a deformation range of 0-1 mm, and an accuracy level of not less than 0.5.

[0050] The strain measurement system measurement accuracy verification method of the present invention adopts the principle of online strain measurement comparison, takes advantage of the convenience and high accuracy of extensometer measurement, solves the installation universality problem of extensometers on components of different structural sizes, and realizes the accuracy verification of the strain measurement system under working conditions. It solves the problem that the traditional laboratory accuracy verification method does not consider the influence of the bonding quality, bonding surface shape and roughness of the strain sensor on the measurement accuracy during actual use, and the verification result is unreliable.

Claims

1. A method for verifying the measurement accuracy of a strain measurement system, characterized in that: The following steps are involved: Step 1: On the surface of the component, locally remove the paint and polish around the area where the strain sensor is to be pasted; Step 2: The horizontal center line of the strain sensor is parallel to the strain measurement direction of the strain sensor, and its vertical center line is perpendicular to the strain measurement direction of the strain sensor; symmetrically stick the extensometer clamping fixture 1 and the extensometer clamping fixture 2 on both sides of the strain sensor, and the bottom center lines of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 coincide with the horizontal center line of the strain sensor; Step 3: Measure the center distance L between the support beam of the extensometer clamping fixture 1 and the support beam of the extensometer clamping fixture 2; Step 4: Install the digital extensometer in parallel on the crossbeam of the extensometer clamping fixture 1 and the crossbeam of the extensometer clamping fixture 2, and measure whether the distance between the installation point e on the crossbeam of the extensometer clamping fixture 1 and the installation point f on the crossbeam of the extensometer clamping fixture 2 meets the requirements, and then clear the indications of the digital extensometer and the strain tester; Step 5: When a large deformation occurs on the component surface, read the indications s1 and s2 of the digital extensometer and strain tester at the same time; Step 6: Calculate the measurement deviation δ between the digital extensometer and the strain tester to complete the verification.

2. The method for verifying the measurement accuracy of a strain measurement system according to claim 1, characterized in that: Use metal quick adhesive to symmetrically stick the extensometer clamping fixture 1 and the extensometer clamping fixture 2 on both sides of the strain sensor.

3. The method for verifying the measurement accuracy of a strain measurement system according to claim 2, characterized in that: The structural dimensions of the extensometer clamping fixture 1 and the extensometer clamping fixture 2 are completely the same. The bonding bottom surface of the extensometer clamping fixture 1 and the bonding bottom surface of the extensometer clamping fixture 2 both adopt an I-shaped cross-section design, and each side width is 3mm.

4. The method for verifying the measurement accuracy of a strain measurement system according to claim 3, characterized in that: The distance between the edge of the strain sensor and the extensometer clamping fixture 1 and the extensometer clamping fixture 2 along the horizontal center line of the strain sensor is not greater than 1 mm.

5. The method for verifying the measurement accuracy of a strain measurement system according to claim 4, characterized in that: Use a caliper to measure the center distance L between the support beam of the extensometer clamp fixture one and the support beam of the extensometer clamp fixture two.

6. The method for verifying the measurement accuracy of a strain measurement system according to claim 5, characterized in that: Measure whether the distance between the mounting point e on the crossbeam of the extensometer clamping fixture 1 and the mounting point f on the crossbeam of the extensometer clamping fixture 2 is 10 mm.

7. The method for verifying the measurement accuracy of a strain measurement system according to claim 6, characterized in that: The measurement deviation δ between the digital extensometer and the strain tester is calculated by the following formula:

8. The method for verifying the measurement accuracy of a strain measurement system according to claim 7, characterized in that: The digital extensometer has a gauge length of 10 mm, a deformation range of 0-1 mm, and an accuracy level of 0.5.

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