A test structure and method for inherited large deformation resistance strain gauge

Abstract

The present invention proposes a test structure and a test method for a large deformation resistance strain gauge, wherein two consolidation zones are provided at both ends of a test zone L, and a plurality of resistance strain gauges Y are connected to the test zone L. i Both ends are fixed to the test object; within the test area L, each resistance strain gauge Y i The length is L i‑1 <L i ≤L i‑1 (1+δ)(i=2,...,i,...n), δ represents the effective test strain range of the resistance strain gauge. i When failure occurs, the i+1th resistance strain gauge Y 1+1 Enter the test state; deformation test data is strain gauge Y i Data Overlay Y i Y at the same time point as the starting point i‑1 The present invention extends the advantages of small deformation test of resistance strain gauge to the field of large deformation test, can improve the accuracy of large deformation detection, expand the detection range of large deformation, and has a good application market prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of deformation testing, and in particular relates to a test structure and a test method for an inherited large deformation resistance strain gauge. Background Art

[0002] The resistance strain gauge testing technology has a history of several decades and has been widely used in engineering deformation detection. It is one of the most commonly used deformation detection methods.

[0003] The resistance strain gauge is a sheet-shaped deformation sensing element. The main material is very thin constantan wire. The working principle is: after deformation, the constantan wire is stretched, the cross-sectional area is reduced, and the resistance value increases; according to the relationship between the resistance value and the deformation, the deformation data is obtained by detecting the change in the resistance value. The manufacturer bends the constantan wire into a certain shape and then consolidates it into a sheet-shaped sensing element with a polymer material, and performs unified calibration and mass production. The resistance strain gauge has the characteristics of simple and clear working principle, low cost, easy implementation, and high precision, and is widely used. However, the resistance strain gauge is limited by the deformation capacity of the constantan wire. When the deformation is too large, the constantan wire will be broken, and the effective strain range is usually about 1.0%. For large deformation projects such as structural engineering and geotechnical engineering that use plastic deformation, the range of the resistance strain gauge is obviously not enough, so it cannot be used. This is a technical problem that needs to be solved in large deformation detection. Summary of the invention

[0004] In view of the problems existing in the background technology, the present invention aims to provide a test structure and a test method for an inherited large deformation resistance strain gauge.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution.

[0006] A test structure for a large deformation resistance strain gauge, characterized in that: a plurality of resistance strain gauges Y with different lengths are arranged at the test point. i Each resistance strain gauge is connected to the test instrument 3 through the wire 2; two consolidation areas 1 are set at both ends of the test area L, and the resistance strain gauge Y i The two ends are fixed on the test object 4, or the resistance strain gauge Y i The test carrier 5 is fixed to the test object 4. Within the test area L, the length of the first resistance strain gauge Y1 is L1=L, and the length of other resistance strain gauges Y i The length is L i-1 <L i ≤L i-1 (1+δ)(i=2,...,i,...n), i represents the resistance strain gauge number, n≥2 is the number of strain gauges, δ represents the effective test strain of the resistance strain gauge, which is provided by the manufacturer.

[0007] Furthermore, each resistance strain gauge Y i There are common consolidation zones 1, and the initial clear distance between the consolidation zones 1 is L.

[0008] Furthermore, the resistance strain gauge Y is determined according to the maximum value of the test deformation. i The number n.

[0009] Furthermore, the material, shape and size of the test carrier 5 are determined according to the test object and environment.

[0010] The test method based on the aforementioned inherited large deformation resistance strain gauge test structure comprises the following steps:

[0011] The resistance strain gauge Y i The group is fixed to the test object 4, or fixed to the test object 4 through the test carrier 5;

[0012] Resistance strain gauge Y i An external test instrument 3 is connected via a wire 2;

[0013] During the deformation test, the deformation is first tested by the first resistance strain gauge Y1; when the first resistance strain gauge Y1 fails, the second resistance strain gauge Y2 enters the test state; when the second resistance strain gauge Y2 fails, the third resistance strain gauge Y3 enters the test state; ...; and so on, until the large deformation test is completed;

[0014] The deformation test results are: strain gauge Y i Data Overlay Y i Y at the same time point as the starting point i-1 Terminal data.

[0015] Beneficial effects:

[0016] (1) The test accuracy of small deformation magnitude based on resistance strain gauges can measure the large deformation of the test object, which fundamentally solves the situation that the accuracy of traditional large deformation testing is far lower than that of small deformation testing. This is a breakthrough in traditional large deformation detection technology and has broad prospects.

[0017] (2) It can test large deformation items that cannot be tested by existing resistance strain gauge testing technology. In principle, as long as necessary protective measures are taken, the present invention can test the deformation of almost all materials, providing more possibilities and new directions for the development of deformation technology;

[0018] (3) The inherited large deformation resistance strain gauge test structure and method provided by the present invention have the advantages of simple structure, good stability, high detection accuracy, mass production, low structural cost and implementation cost, and have great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the top view of the inherited large deformation resistance strain gauge test structure in Example 1;

[0020] Figure 2 It is a front view schematic diagram of the inherited large deformation resistance strain gauge test structure in Example 1;

[0021] Figure 3 Schematic diagram of the combined resistance strain gauge of the inherited large deformation resistance strain gauge test structure in Example 2;

[0022] In the figure: 1—strain gauge consolidation area; 2—conductor; 3—test instrument; 4—test object; 5—test carrier; L—test area (length); Y1, Y2, Y3—the first, second, and third strain gauges; L1, L2, L3—the length of the first, second, and third strain gauges in the test area; P—tension at the end of the test structure; i—strain gauge number. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings and embodiments. The described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. In the description of the present invention, it should be noted that the resistance strain gauges in the embodiments only represent three pieces (Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y10, Y11, Y12, Y13, Y14, Y15, Y16, Y17, Y18, Y19, Y20, Y21, Y22, Y33, Y44, Y55, Y6 i , Y n ), is only used to illustrate the order relationship of the test resistance strain gauges and should not be understood as a limitation to the present invention.

[0024] Example 1: The test object 4 is a tensile member, with a tensile force P acting on both ends. It is now required to test the member in a tensile process with a large deformation within the range of 3.0% in the middle strain. Because the maximum strain of the traditional resistance strain gauge test is 1.0%, only the method of the present invention can be used for testing.

[0025] The maximum effective test strain value of the test resistance strain gauge products purchased on the market is δ=1.0%. According to the inheritance principle of the present invention, 3 resistance strain gauges can be arranged, and their effective test strain value is 3x1.0%=3.0%, which can meet the requirements of this test.

[0026] In order to accurately control the length L of the resistance strain gauge i , a test method is adopted in which the resistance strain gauge is first fixed on the test carrier 5 indoors, and then the test carrier 5 is fixed on the test object 4, see Figure 1 and Figure 2 .

[0027] Consolidation of strain gauges on test carrier 5:

[0028] 1. The test carrier 5 is a polymer sheet material that meets the requirements of deformation ductility;

[0029] 2. The length of the test area is L = 20mm, and the effective test strain of the resistance strain gauge is δ = 1.0%. Within the test area length L, L1 = L = 20mm, L2 = L1 (1 + δ) = 20 (1 + 0.01) = 20.2mm, L3 = L2 (1 + δ) = 20.2 (1 + 0.01) = 20.402mm;

[0030] 3. Use adhesive to fix the resistance strain gauges on the test carrier 5, where the resistance strain gauge Y1 is placed flat and the other strain gauges are placed convexly upwards, see Figure 2 (a) Three figures on the right;

[0031] 4. Pay attention to the length L of the resistance strain gauge during production i The variation is controlled within the test area length L.

[0032] The implementation steps are as follows:

[0033] 1. Fix the pre-fixed test carrier 5 containing three resistance strain gauges on the test point of the test object 4 with an adhesive, and connect the resistance strain gauges to the test instrument 3 with a wire 2;

[0034] 2. According to the site conditions, select several fixed points to fix the wire 2, and prevent the tensile member from deforming and breaking the wire. Take protective measures for the resistance strain gauge and the wire to prevent damage;

[0035] 3. Turn on the test instrument, check whether the line is connected, damaged or otherwise abnormal, and read the initial test data;

[0036] 4. Under working test conditions, apply force P to the tension member and record the deformation data of the resistance strain gauge until the deformation reaches the required detection value;

[0037] 5. The data collection method is as follows: the first stage deformation uses the data of Y1 to remove the initial value of the test, the second stage deformation uses the data of Y2 to superimpose the terminal data of Y1 at the same time point as the starting point of Y2, and the third stage deformation uses the data of Y3 to superimpose the terminal data of Y2 at the same time point as the starting point of Y3.

[0038] The test inheritance principle of the present invention is as follows:

[0039] 1. When the component is subjected to stress in the first stage, the first resistance strain gauge Y1 is arranged in a straight line, which can detect the deformation of the component. Figure 2 (a) Three figures on the right;

[0040] 2. At the end of the first stage of stress on the component, the deformation of the first resistance strain gauge Y1 gradually enters the edge of the detection range. At this time, the second resistance strain gauge Y2 is gradually straightened and enters the deformation detection preparation stage;

[0041] 3. When the component is subjected to stress in the second stage, the first resistance strain gauge Y1 deforms and enters the failure stage, which is manifested as irregular deformation or being broken. At this time, the second resistance strain gauge Y2 enters the deformation detection working state and completes the first inheritance. Figure 2 (b) Three figures on the right;

[0042] 4. According to the principles of 1, 2, and 3, when the component is subjected to the third stage of stress, the third resistance strain gauge Y3 enters the deformation detection working state and completes the second inheritance, see Figure 2 (c) Three figures on the right;

[0043] 5. According to the above principle, this method can be inherited n-1 times to meet various large deformation detection.

[0044] In addition, according to the detection accuracy requirements, each succession can be partially overlapped. That is: in the previous level of resistance strain gauge Y i Before quitting work, the next level of inspection fiber Y i+1 Enter the working state in advance, and then according to the test time nodes, adopt the stable and reasonable values ​​of the two-level test data, and then superimpose them.

[0045] Embodiment 2: The detection content of embodiment 1 is completed by using the finished product of combined inherited large deformation resistance strain gauge.

[0046] The resistance strain gauge manufacturer mass produces various combined inherited large deformation resistance strain gauges, please refer to Figure 3 .

[0047] During the test, directly purchase the finished product of the combined inherited large deformation resistance strain gauge that meets the specific requirements, fix it on the test point, and then perform the test according to the steps of Example 1.

Claims

1. A test structure of an inherited large deformation resistance strain gauge, characterized in that: Arrange multiple resistance strain gauges Y of different lengths at the test point i Each resistance strain gauge is connected to an external test instrument (3) through a wire (2); two consolidation areas (1) are set at both ends of the test area L, and the resistance strain gauge Y i The two ends are fixed to the test object (4), or the resistance strain gauge Y i The test carrier (5) is fixed to the test object (4); within the test area L, the length of the first resistance strain gauge Y1 is L1=L, and the length of the other resistance strain gauges Y i The length is L i-1 <L i ≤L i-1 (1+δ)(i=2,...,i,...n), i represents the resistance strain gauge number, n≥2 is the number of strain gauges, δ represents the effective test strain of the resistance strain gauge; the resistance strain gauge Y is determined according to the maximum test deformation. i The number n.

2. The inherited large deformation resistance strain gauge test structure according to claim 1, characterized in that: Each resistance strain gauge Y i There are common consolidation zones (1), and the initial clear spacing between the consolidation zones (1) is L.

3. The inherited large deformation resistance strain gauge test structure according to claim 1, characterized in that: The material, shape and size of the test carrier (5) are determined according to the test object and environment.

4. The test method of the inherited large deformation resistance strain gauge test structure according to any one of claims 1 to 3, comprising the steps of: The resistance strain gauge Y i The group is fixed to the test object (4), or fixed to the test object (4) through a test carrier (5); Resistance strain gauge Y i An external test instrument (3) is connected via a wire (2); During the deformation test, the deformation is first tested by the first resistance strain gauge Y1; when the first resistance strain gauge Y1 fails, the second resistance strain gauge Y2 enters the test state; when the second resistance strain gauge Y2 fails, the third resistance strain gauge Y3 enters the test state; ...; and so on, until the large deformation test is completed; The deformation test results are: strain gauge Y i Data Overlay Y i Y at the same time point as the starting point i-1 Terminal data.

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