CN218524103U - Strain gauge pasting quality testing device - Google Patents
Strain gauge pasting quality testing device Download PDFInfo
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- CN218524103U CN218524103U CN202222707217.9U CN202222707217U CN218524103U CN 218524103 U CN218524103 U CN 218524103U CN 202222707217 U CN202222707217 U CN 202222707217U CN 218524103 U CN218524103 U CN 218524103U
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Abstract
A strain gauge pasting quality testing device is composed of a cushion block, a pressing block and a fastening bolt. One side of the cushion block in the thickness direction is an outward convex arc surface with fixed curvature, one side of the pressing block in the thickness direction is an inward concave arc surface with the same curvature as the cushion block arc surface, and the cushion block and the pressing block are connected together through the bolt holes by the fastening bolts. During testing, the cushion block and the pressing block are used for clamping the component to be tested from two sides of the component to be tested respectively, the component to be tested is forced to generate micro deformation along the known cambered surface by tightening the fastening bolt, and the bonding quality of the strain gauge is judged by comparing the error between the actual strain value and the theoretical strain value of the strain gauge. The utility model provides a reference standard for judging the sticking quality of the strain gauge on the premise of no damage to the component, which is helpful for finding the sticking quality problem of the strain gauge in advance and improving the quality of strain detection data; the utility model discloses the principle is simple, and is easy and simple to handle, need not large-scale loading equipment, adapts to different detection ring border such as laboratory, engineering scene, is favorable to using widely.
Description
Technical Field
The utility model relates to a mechanics of materials performance test device field especially relates to a detect testing arrangement of quality is pasted to foil gage.
Background
The strain gauge is an element formed by a sensitive grid and the like and used for measuring the strain magnitude of a component, and has very wide application in the professional production and scientific research of civil engineering, machinery, materials and the like. The strain gauge is deformed after being stressed, so that the resistance of the strain gauge is changed. When the strain gauge is used, the strain gauge is firmly adhered to the surface of a component, and when the component deforms under stress, the strain value of the measuring point of the component can be obtained through conversion by measuring the change of the resistance value of the strain gauge.
The accuracy of the finally acquired strain value is directly influenced by the quality of the pasting quality of the strain gauge. Due to various stress environments, in practical application, the strain gauge is usually adhered manually by an inspector according to experience. However, the sticking of the strain gauge comprises relatively complicated procedures such as interface cleaning, gluing, sticking and the like, and the whole process is greatly influenced by human factors, such as whether the sticking surface is cleaned and polished in place, whether the glue is selected properly, whether the gluing thickness is uniform and reasonable, whether bubbles are cleaned during sticking and the like. In actual engineering and scientific research, the problem of measurement failure caused by low pasting quality of the strain gauge is very common, and currently, no proper method exists for quantitatively testing whether the strain gauge is pasted in place before work. In engineering, the problem of sticking the strain gauge can be found only after the member is actually stressed, the data precision is seriously influenced by replacing and adding the strain gauge at the moment, the working surface is completely lost after the concealment work of some concealed projects, and the data loss is directly caused if the sticking quality problem occurs.
The existing national patents on the strain gauge are all improved aiming at the structure of the strain gauge and the design of a strain adhering device, and the content of detection before working on the adhering quality of the strain gauge is not found. But actually the foil gage pastes the quality and is a very critical ring among the testing process, pastes the back at the foil gage, if can adopt a simple convenient mode test foil gage whether firm, accurate paste on the component, will let the detector discover in advance that the foil gage that has a problem and in time change to reduce detection problem frequency of occurrence, improve the strain detection data quality.
Disclosure of Invention
An object of the utility model is to the needs that prior art is not enough and engineering safety, provide a foil gage pastes quality test device, can be simple, convenient, test the quality of pasting of foil gage fast.
The utility model discloses a following technical scheme realizes.
A quality test device is pasted to foil gage, constitute by cushion, briquetting and fastening bolt triplex.
The width of the cushion block can be manufactured into various sizes in advance, and the cushion block with the width larger than that of the component to be detected is selected according to the actual condition of the component to be detected.
The cushion block should have sufficient thickness to ensure the overall rigidity of the cushion block.
One side of the cushion block in the thickness direction is a plane and is used for installing a bolt; the other side is an outer convex cambered surface with fixed curvature, and the curvature radius R of the outer convex cambered surface ensures that the thickness of the component to be measured H/the curvature radius R of the cushion block is =1 per thousand-1%. Wherein the cambered surface is a surface which is contacted with a component to be measured.
The length direction of the cushion block is consistent with that of the member to be measured. And four corners of the cushion block are respectively provided with bolt holes penetrating through the thickness direction and used for installing fastening bolts to connect the fastening bolts with the pressing block.
The width of the pressing block is consistent with that of the cushion block.
The compact should be of sufficient thickness to ensure the overall rigidity of the compact. One side of the pressing block in the thickness direction is a plane, and the other side of the pressing block is an inwards concave cambered surface with the same curvature as the cambered surface of the cushion block.
The length direction of the pressing block is consistent with that of the cushion block.
The inner concave cambered surface of the pressing block is provided with a hidden groove slightly larger than the size of the strain gauge along the radian direction, and the hidden groove is aligned to the strain gauge on the component to be tested when the testing device is installed, so that the strain gauge can freely deform in the hidden groove.
The inner side of the concave cambered surface of the pressing block is made into different types of section shapes according to different shapes of the components to be detected. Selecting a pressing block with a smooth cross section for the sheet, plate and square rod-shaped components to be detected; the pressing block comprising the triangular inclined plane guide groove is selected for the round bar-shaped member to be tested, so that the member to be tested is prevented from sliding after being stressed.
And four corners of the pressing block are respectively provided with bolt holes which are consistent with the cushion blocks and penetrate through the thickness direction.
The fastening bolt connects the cushion block and the pressing block together through the bolt hole.
The cushion block and the pressing block can be made of solid steel or other materials with high rigidity.
A use method of a strain gauge pasting quality testing device, go on according to following step:
(1) Connecting a strain gauge on a component to be measured with the strain gauge in a natural state, measuring and reading strain data, and measuring the thickness value H of the component to be measured;
(2) Coating a small amount of vaseline on the surface of a component to be detected, clamping the component to be detected from two sides of the component to be detected by using a cushion block and a pressing block respectively, and enabling the strain gauge to fall into a blind groove, wherein the length directions of the cushion block and the pressing block are consistent with that of the component to be detected;
(3) The fastening bolt penetrates through bolt holes at four corners of the cushion block and the pressing block, the bolt and the nut are fastened through a wrench, the component to be tested is bent along with the cambered surface of the pressing block until the component to be tested is completely attached to the cushion block, strain data are measured and read, and an actual strain value epsilon generated by the strain gauge after bending is calculated r If the data is obviously unstable at this time, the strain gauge is considered to be adheredThe adhesive needs to be pasted again when the quantity is poor;
(4) In the direction along the length of the member to be measured, the theoretical strain value of the member to be measured should be:
h is the thickness of the component to be measured, and R is the curvature radius of the cushion block. For the condition that the pasting direction of the strain gauge is completely consistent with the length direction of the component to be measured, the epsilon can be directly compared r And
if the deviation between the values is large, the bonding quality of the strain gauge is considered to be poor, and the strain gauge needs to be bonded again. For the condition that the pasting direction of the strain gauge requires an included angle alpha with the length direction of the component to be measured, epsilon needs to be adjusted r Converted into strain value in the member length direction:
then comparing ε' r And with
If the deviation between the values is large, the bonding quality of the strain gauge is considered to be poor, and the strain gauge needs to be bonded again.
The beneficial effects of the utility model reside in that:
(1) The utility model discloses under the prerequisite that does not damage the component, provide a reference standard who judges foil gage and paste the quality for the inspector, help very much the inspector to discover the foil gage problem in advance and in time make the adjustment, reduce the detection problem frequency of occurrence, improve the detection data quality that meets an emergency.
(2) The device provided by the utility model does not need to adopt large-scale loading equipment, and can be well adapted to different detection environments such as laboratories, engineering sites and the like;
(3) The utility model discloses the realization principle is simple, and is easy and simple to handle, and supporting instrument is traditional detection equipment that meets an emergency, need not add other detection equipment and calculation software, is favorable to social popularization.
The utility model discloses the device is mainly not big for rigidity to the component that awaits measuring, can produce certain elastic deformation's the condition and test.
Drawings
Fig. 1 is an assembly view (overlooking) of the device for testing the pasting quality of the strain gauge of the utility model.
Fig. 2 is an assembly drawing (front view) of the device for testing the pasting quality of the strain gauge of the present invention.
Fig. 3 is a block structure diagram (front view) of the present invention.
Fig. 4 is a block diagram (side view) of the present invention.
Fig. 5 is a structural view (front view) of the pressing block 1 of the present invention for the sheet-like, plate-like, or square-rod-like member to be measured.
Fig. 6 is a structural view (side view) of the press block 1 of the present invention for the sheet-like, plate-like, or square-bar-like member to be measured.
Fig. 7 is a structural view (viewed from the bottom) of the pressing block of the present invention for the sheet-like, plate-like, or square-bar-like measurement target member.
Fig. 8 is a structural diagram (front view) of the pressing block of the circular rod-shaped member to be measured according to the present invention.
Fig. 9 is a block diagram (side view) of the circular rod-shaped member to be measured according to the present invention.
Fig. 10 is a structural view (viewed from below) of the pressing block of the round bar-shaped member to be measured according to the present invention.
Fig. 11 is a schematic view showing the connection between the member to be measured and the strain gauge of the present invention (the direction of the strain gauge is the same as that of the member).
Fig. 12 is a schematic view of the connection between the component to be tested and the strain gauge of the present invention (the strain gauge is at a certain angle with respect to the component).
Fig. 13 is a theoretical strain value calculation schematic diagram of the test of the utility model.
Wherein, 1 is the briquetting, 2 is the cushion, 3 is fastening bolt, 4 is the bolt hole, 5 is the camera obscura, 6 is the component that awaits measuring, 7 is the guide slot, 8 is the foil gage, 9 is the strain gauge.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples, it being understood that the examples are illustrative and explanatory only and are not restrictive of the invention as claimed.
Fig. 1 and 2 show the device in operation after the entire assembly is completed, from two angles, top and front, respectively. Fig. 3 and 4 show the configuration of the spacer block device from two angles, front and side, respectively. Fig. 5 to 10 show the structure of the pressure block device from front, side and bottom views. The utility model discloses a briquetting of two kinds for adapt to the test component of different grade type, wherein the briquetting pressurized surface that figure 5 ~ figure 7 show is smooth, is applicable to slice, platelike, square rod shape component, and the briquetting that figure 8 ~ figure 10 show has added guiding groove 7 on the pressurized surface for prevent to slide after the component atress, be applicable to round bar shape component. Fig. 11 and 12 show connection conditions when a strain test is performed after a strain gauge is adhered to a member to be tested, wherein the length directions of the strain gauge and the member in fig. 11 are the same, and an included angle α is formed between the strain gauge and the member in fig. 12. FIG. 13 is a schematic diagram of strain value calculation to understand the derivation of theoretical strain value calculation formula during testing of a component.
Example 1.
As shown in fig. 1, fig. 2, and fig. 5 to fig. 7, the device for testing the bonding quality of a strain gage of the present invention comprises a spacer 2, a pressing block 1, and a fastening bolt 3.
The width of the cushion block 2 is larger than that of the member to be measured 6.
The spacer 2 should have a sufficient thickness to ensure the overall stiffness of the spacer 2.
One side of the cushion block 2 in the thickness direction is a plane and is used for installing a bolt 3; the other side is an outer convex cambered surface with fixed curvature, and the curvature radius R of the outer convex cambered surface enables the thickness H of the component 6 to be measured/the curvature radius R of the cushion block to be =1 per thousand-1%. Wherein the arc surface is a surface in contact with the member to be measured 6.
The length direction of the cushion block 2 is consistent with the length direction of the member to be measured 6. Four corners of the cushion block 2 are respectively provided with bolt holes 4 penetrating through the thickness direction and used for installing fastening bolts 3 to connect the pressing block 1.
The width of the pressing block 1 is consistent with that of the cushion block 2.
The compact 1 should have a sufficient thickness to ensure the overall rigidity of the compact 1. One side of the pressing block 1 in the thickness direction is a plane, and the other side of the pressing block is an inwards concave cambered surface with the same curvature as the cambered surface of the cushion block 2.
The length direction of the pressing block 1 is consistent with that of the cushion block 2.
The inner concave cambered surface of the pressing block 1 is provided with a blind groove 5 slightly larger than the size of the strain gauge 8 along the radian direction, and the blind groove 5 is aligned to the strain gauge 8 on the component 6 to be tested when the testing device is installed, so that the strain gauge 8 can be freely deformed in the blind groove 5.
For the sheet, plate, and square rod-shaped member to be measured 6, the pressing block 1 in this embodiment is a pressing block 1 with a smooth cross section on the inner side of the concave arc surface.
Four corners of the pressing block 1 are respectively provided with bolt holes 4 which are consistent with the cushion blocks 2 and penetrate through the thickness direction.
The cushion block 2 and the pressing block 1 are connected together through the bolt holes 4 by the fastening bolts 3.
The cushion block 2 and the pressing block 1 can be made of solid steel or other materials with high rigidity.
In this embodiment, the pressing block 1 and the cushion block 2 both have arc surfaces that match each other. And clamping the component 6 to be tested between the cushion block 1 and the pressing block 2, wherein the arc surface is a contact surface with the component 6. Four fastening bolts 3 pass through the bolt holes 4 to integrally connect the whole device.
Example 2.
As shown in fig. 8 to 10, for the round bar-shaped member to be measured 6, the press block 1 of the embodiment is a press block 1 having an inner concave cambered surface and a triangular inclined plane guide groove 7, so as to prevent the member to be measured 6 from slipping after being stressed. The other parts and structures are the same as those of embodiment 1.
Example 3.
In this embodiment, it is considered that the member to be measured 6 is sheet-shaped, and the strain gauge 8 is attached to the member to be measured 6, and the longitudinal directions of both are the same. The pressing block is selected to be a smooth cambered surface as shown in figures 5-7, meanwhile, the wiring mode of the strain gauge is as shown in figure 11, and the main steps of the test of the sticking quality of the strain gauge comprise:
(1) Measuring the thickness H of the component 6 to be measured by using a vernier caliper, connecting the strain gauge 8 with the strain gauge 9 through a lead, and measuring and reading strain data without external force as initial data;
(2) And smearing a small amount of vaseline on the surface of the component 6 to be detected. The cambered surfaces of the cushion block 2 and the pressing block 1 are opposite and clamped at two sides of a component 6 to be tested, the length directions of the cushion block 2 and the pressing block 1 are required to be consistent with the component 6 to be tested during installation, and the position of the adhered strain gauge 8 can fall into the blind groove 5, so that the pressing block 1 is ensured not to be directly contacted with the strain gauge 8 during compression;
(3) The fastening bolt 3 passes through the bolt hole 4, connects the cushion block 2 and the pressing block 1 together, and the bolt and the nut are fastened through a wrench, so that the fastening bolt 3 in the diagonal direction is sequentially pulled in the fastening process. And the member 6 to be tested is bent along with the cambered surface of the pressing block 1 until the member is completely attached to the cushion block 2, the strain data at the moment is tested and read, and whether the strain gauge is firmly attached is judged according to the stability of the data. If the data has no obvious drift phenomenon, calculating an actual strain value epsilon generated in the bending process of the component to be measured r ；
(4) Using the formula
Calculating the theoretical strain value of the component 6 to be measured
Comparing epsilon r And with
And judging whether the bonding quality of the strain gauge is good or bad through errors.
Example 4.
In this embodiment, a case where the member to be measured 6 is a round bar and the bonding direction of the strain gauge 8 and the longitudinal direction of the member to be measured 6 form an angle α is considered. The cambered surface of the selected pressing block is provided with a guide groove 7 as shown in figures 8-10, and meanwhile, the wiring mode of the strain gauge is as shown in figure 12, and the main steps of the test of the sticking quality of the strain gauge comprise:
(1) Measuring the thickness H of the component 6 to be measured by using a vernier caliper, connecting the strain gauge 8 with the strain gauge 9 through a lead, and measuring and reading strain data under the condition of no external force as initial data;
(2) And smearing a small amount of vaseline on the surface of the component 6 to be detected. The cambered surfaces of the cushion block 2 and the pressing block 1 are opposite and clamped at two sides of the component 6 to be tested, the component 6 to be tested is aligned to the guide groove 7 during installation, the component 6 to be tested is ensured not to slide out of the guide groove 7 when being pressed, the position of the adhered strain gauge 8 can fall into the blind groove 5, and the pressing block 1 is ensured not to be directly contacted with the strain gauge 8 when being pressed;
(3) And the fastening bolt 3 passes through the bolt hole 4 to connect the cushion block 2 and the pressing block 1 together, and the bolt nut is fastened through a wrench. And the member 6 to be tested is bent along with the cambered surface of the pressing block 1 until the member is completely attached to the cushion block 2, the strain data at the moment is measured and read, and whether the strain gauge is firmly adhered or not is judged according to the stability of the data. If the data has no obvious drift phenomenon, calculating the actual strain value epsilon generated in the bending process of the strain gauge 8 r ；
(4) Using a formula
Converting actual strain value epsilon 'of member to be measured 6 in bending direction' r By using
Calculating the theoretical strain value of the component 6 to be measured
Comparison of ε' r And with
And judging the bonding quality of the strain gauge through the error.
And (4) analyzing results: by using the device for testing the pasting quality of the strain gauge, whether the pasting of the strain gauge is qualified or not can be quickly tested before a component bears large external force and strain detection. The device principle is simple, easily operates, and efficiency of software testing is high, does not influence original strain detection progress. The testing device can be suitable for various different component shapes and different strain gauge pasting modes, and can be used for various occasions such as laboratory test piece detection, engineering site structure detection and the like. Through a large amount of contrast test discoveries, adopt the utility model discloses a behind the foil gage pasting quality testing arrangement, greatly reduced foil gage probability of failure, the data integrality of strain test has had obvious improvement.
The above-mentioned only be the embodiment of the utility model discloses it is not right the utility model discloses do the restriction in any form, so do not break away from the utility model discloses the scheme content, the foundation the utility model discloses any simple modification, equal transform or decoration that the technical essence was done all still belong to the utility model discloses in the patent protection range.
Claims (2)
1. A strain gauge pasting quality testing device is characterized by comprising a cushion block, a pressing block and a fastening bolt, wherein the cushion block and the pressing block are fixed by the fastening bolt;
the width of the cushion block is larger than that of the component to be detected;
the thickness of the cushion block is required to ensure that the cushion block has enough integral rigidity;
one side of the cushion block in the thickness direction is a plane and is used for mounting a bolt; the other side is an outward convex cambered surface with fixed curvature, the curvature radius R of the outward convex cambered surface is such that the thickness H of the component to be tested/the curvature radius R of the cushion block is =1 per thousand-1%, wherein the cambered surface is a surface which is contacted with the component to be tested;
the length direction of the cushion block is consistent with that of the component to be measured; four corners of the cushion block are respectively provided with bolt holes penetrating through the thickness direction and used for installing fastening bolts to enable the fastening bolts to be connected with the pressing block;
the width of the pressing block is consistent with that of the cushion block;
the thickness of the pressing block is required to ensure that the pressing block has enough integral rigidity; one side of the pressing block in the thickness direction is a plane, and the other side of the pressing block is an inwards concave cambered surface with the curvature consistent with that of the cushion block cambered surface;
the length direction of the pressing block is consistent with that of the cushion block;
the inner concave cambered surface of the pressing block is provided with a hidden groove which is slightly larger than the size of the strain gauge along the radian direction, and the hidden groove is aligned with the strain gauge on the component to be tested when the testing device is installed, so that the strain gauge is arranged in the hidden groove and can be freely deformed;
four corners of the pressing block are respectively provided with bolt holes which are consistent with the cushion blocks and penetrate through the thickness direction;
the fastening bolt connects the cushion block and the pressing block together through the bolt hole.
2. The device for testing the pasting quality of the strain gage as claimed in claim 1, wherein the inner side of the concave cambered surface of the pressing block is a smooth section for a sheet-shaped, plate-shaped or square rod-shaped member to be tested or a section containing a triangular bevel guide groove for a round rod-shaped member to be tested.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222707217.9U CN218524103U (en) | 2022-10-14 | 2022-10-14 | Strain gauge pasting quality testing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222707217.9U CN218524103U (en) | 2022-10-14 | 2022-10-14 | Strain gauge pasting quality testing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218524103U true CN218524103U (en) | 2023-02-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222707217.9U Active CN218524103U (en) | 2022-10-14 | 2022-10-14 | Strain gauge pasting quality testing device |
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| CN (1) | CN218524103U (en) |
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2022
- 2022-10-14 CN CN202222707217.9U patent/CN218524103U/en active Active
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