Strain gauge sticking device for composite material

Abstract

The present application relates to a kind of strain gauge sticking device for composite material, including strain gauge pressing positioning device, negative pressure device and sample positioning device, strain gauge pressing positioning device is installed in the upper end surface of sample positioning device, negative pressure device is used to release strain gauge by negative pressure suction, sample positioning device is used for the fixation of sample and the determination of sticking position;Strain gauge pressing positioning device includes shell, suction head, pressure guide rod, compression spring, side pressure spring and clamping plate, shell is fixed to the upper end surface of sample positioning device, pressure guide rod is worn in shell and its one end is equipped with suction head for suction strain gauge, compression spring is sleeved on pressure guide rod and is in elastic contact with suction head;Two ends of side pressure spring are respectively connected with the inner wall of shell and clamping plate, and clamping plate is used to lock pressure guide rod when pressure guide rod moves down to set position.The purpose of the strain gauge sticking device for composite material is to solve the problems of high cost, complex structure and large size of existing automatic patch device.

Description

Technical Field

[0001] The present invention relates to the technical field of strain measurement, and in particular to a strain gauge pasting device for composite materials. Background Art

[0002] As a traditional strain measurement element, resistance strain gauges have many advantages, including high measurement sensitivity and accuracy, a wide measurement range, good frequency response, and the ability to measure in a variety of complex environments. They are widely used in the field of composite mechanical properties testing, and are an important means of measuring strain with strain gauges. This is especially true for specimens with smaller test areas, such as those specified in ASTM D6641, "Standard Test Method for Compression Properties of Polymer-Based Composite Laminates Using a Combined Loading Compression Test Fixture." Non-contact and contact extensometers are not yet capable of high-precision strain measurement of specimens, so resistance strain gauges still play an important role in composite strain measurement. Currently, strain gauges are often attached by having the operator pre-mark the center of the specimen surface, and then positioning the gauge according to the marked line to measure strain in a specific direction.

[0003] Measuring strain using strain gauges is a highly technical task, involving numerous steps, including strain gauge selection, adhesive selection, specimen surface polishing, surface cleaning, marking and positioning, strain gauge attachment, clamping and curing, patch quality inspection, lead connection, parameter correction and compensation, strain gauge performance testing, and protective treatment. Each of these steps is difficult to perform post-quality inspection using instruments. Currently, strain gauge attachment relies primarily on operator experience. However, due to the light weight and small size of strain gauges, manual positioning and attachment often fall short of ideal results. The quality of attachment varies significantly between operators, and the quality of attachment directly determines the accuracy and reliability of strain measurement. Manual application and fixation are less effective, especially with some specialized adhesives, which cannot be applied for extended periods. Automated attachment devices are also available, but these are costly, complex, and bulky, making them unsuitable for small sample batches.

[0004] Therefore, the inventors provide a strain gauge bonding device for composite materials. Summary of the Invention

[0005] (1) Technical problems to be solved

[0006] The embodiment of the present invention provides a strain gauge pasting device for composite materials, which solves the technical problems of existing automatic patch devices such as high cost, complex structure and large size.

[0007] (2) Technical solution

[0008] The present invention provides a strain gauge pasting device for composite materials, comprising a strain gauge pressing and positioning device, a negative pressure device, and a sample positioning device. The strain gauge pressing and positioning device is installed on the upper end surface of the sample positioning device. The negative pressure device is used to absorb and release the strain gauge through negative pressure. The sample positioning device is used to fix the sample and determine the pasting position.

[0009] The strain gauge pressing and positioning device includes a housing, an adsorption head, a pressure-guiding rod, a compression spring, a side pressure spring, and a clamping plate. The housing is fixed to the upper end surface of the sample positioning device. The pressure-guiding rod is inserted through the housing and has an adsorption head at one end thereof for adsorbing the strain gauge. The compression spring is sleeved on the pressure-guiding rod and is in elastic contact with the adsorption head.

[0010] One end of the side pressure spring is fixed to the inner wall of the shell, and the other end of the side pressure spring is connected to the clamping plate, and the clamping plate is used to lock the pressure guiding rod when the pressure guiding rod moves down to a set position.

[0011] Furthermore, a pressure-guiding rod notch is provided on the pressure-guiding rod and is used to cooperate and lock with the clamping plate when the pressure-guiding rod reaches a set position.

[0012] Furthermore, the strain gauge pressing and positioning device further includes a card plate switch, which is connected to the card plate and is used to release the locked state of the pressure-guiding rod.

[0013] Furthermore, the negative pressure device includes a negative pressure hollow ball and a catheter, one end of the catheter is connected to the negative pressure hollow ball, and the other end of the catheter is connected to the adsorption head.

[0014] Furthermore, the sample positioning device includes a sample positioning groove, a slide and a pasting hole. The sample positioning groove is used to place the sample. The slide is slidably connected to the sample positioning groove. The slide is provided with the pasting hole that is adapted to the adsorption head and connected to the sample. The outer shell is fixed to the upper end surface of the slide.

[0015] Furthermore, the pasting hole is square.

[0016] Furthermore, the sample positioning groove is a retractable structure.

[0017] Furthermore, the sample positioning groove includes a base and positioning blocks slidably arranged at both ends of the base, and the two positioning blocks are elastically connected by an elastic element, the free length of the elastic element is less than or equal to the length of the sample, and the maximum tensile length of the elastic element is greater than or equal to the length of the sample.

[0018] Furthermore, two ends of the base are provided with limiting protrusions.

[0019] Furthermore, the end surface of the pressure-guiding rod facing the sample positioning device is square.

[0020] (3) Beneficial effects

[0021] In summary, the present invention realizes automatic positioning of strain gauge pasting according to the different shapes of the samples. The pasting process is not limited by the operating space and can automatically maintain pressure until the adhesive is solidified, avoiding the loosening and possible offset of the strain gauge caused by the disassembly process when the adhesive is not firmly adhered. The use process is not limited by the site and supporting facilities. It has a small size, simple structure, and low cost. It can be used for small space operations and realize the positioning and pasting of small working section samples. Depending on the different adhesives, long-term uniform force pressing can be achieved, the pressing effect is uniform, and the pasting quality is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is a schematic structural diagram of a strain gauge bonding device for composite materials provided by an embodiment of the present invention;

[0024] Figure 2 1 is a schematic structural diagram of a strain gauge pressing and positioning device in a strain gauge pasting device for composite materials provided by an embodiment of the present invention;

[0025] Figure 3 1 is a schematic structural diagram of a negative pressure device in a composite material strain gauge bonding device provided by an embodiment of the present invention;

[0026] Figure 4 The present invention is a schematic structural diagram of a sample positioning device in a strain gauge pasting device for composite materials provided by an embodiment of the present invention.

[0027] In the picture:

[0028] 1-strain gauge pressing and positioning device; 101-housing; 102-adsorption head; 103-pressure-guiding rod; 104-anti-compression spring; 105-side pressure spring; 106-cage; 107-cage switch; 108-pressure-guiding rod notch; 2-negative pressure device; 201-negative pressure hollow ball; 202-catheter; 3-sample positioning device; 301-sample positioning groove; 3011-base; 3012-positioning block; 3013-elastic element; 302-slide plate; 303-adhesive hole. DETAILED DESCRIPTION

[0029] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are intended to illustrate the principles of the present invention and are not intended to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments and covers any modifications, replacements, and improvements to the parts, components, and connection methods without departing from the spirit of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] Figure 1 Schematic diagram of a structure of a strain gauge bonding device for composite materials provided by an embodiment of the present invention. Figure 1-2 As shown, the device may include a strain gauge pressing and positioning device 1, a negative pressure device 2, and a sample positioning device 3. The strain gauge pressing and positioning device 1 is installed on the upper end surface of the sample positioning device 3. The negative pressure device 2 is used to absorb and release the strain gauge through negative pressure. The sample positioning device 3 is used to fix the sample and determine the pasting position.

[0032] The strain gauge pressing and positioning device 1 includes a housing 101, an adsorption head 102, a pressure-guiding rod 103, a compression spring 104, a side pressure spring 105, and a clamping plate 106. The housing 101 is fixed to the upper end surface of the sample positioning device 3. The pressure-guiding rod 103 is inserted into the housing 101 and has an adsorption head 102 at one end for adsorbing the strain gauge. The compression spring 104 is sleeved on the pressure-guiding rod 103 and is in elastic contact with the adsorption head 102.

[0033] One end of the side pressure spring 105 is fixed to the inner wall of the housing 101 , and the other end of the side pressure spring 105 is connected to the clamping plate 106 . The clamping plate 106 is used to lock the pressure guiding rod 103 when the pressure guiding rod 103 moves down to a set position.

[0034] In the above-described embodiment, the strain gauge pressing and positioning device 1 can achieve both positioning of the strain gauge during attachment and automatic locking and pressure-maintaining after attachment. This allows the strain gauge to be pressed for any period of time before the adhesive cures, while maintaining a stable pressing force. The entire system should be constructed of materials as lightweight and high-strength as possible, such as aluminum alloy, to reduce the device's weight and facilitate operation.

[0035] The negative pressure device 2 can generate negative pressure by adsorbing the strain gauge through the adsorption head; and can eliminate the negative pressure after the adhesive is pasted and cured.

[0036] As a preferred embodiment, Figure 2 As shown, a pressure-guiding rod notch 107 is provided on the pressure-guiding rod 103 and is used to lock with the clamping plate 106 when the pressure-guiding rod 103 reaches a set position.

[0037] Specifically, if Figure 1 As shown, the clamping plate 106 is sleeved on the pressure-guiding rod 103 . When the pressure-guiding rod 103 moves down to the set position, the clamping plate 106 abuts against the pressure-guiding rod notch 107 under the pressure of the side pressure spring 105 , thereby locking the pressure-guiding rod 103 .

[0038] As a preferred embodiment, Figure 2 As shown, the strain gauge pressing and positioning device 1 further includes a card switch 108, which is connected to the card 106 and is used to release the locked state of the pressure-guiding rod 103. The provision of the card switch 108 can facilitate the rapid release of the locked state of the card 106 with respect to the pressure-guiding rod 103.

[0039] As a preferred embodiment, Figure 3 As shown, the negative pressure device 2 includes a negative pressure hollow ball 201 and a conduit 202 , one end of the conduit 202 is connected to the negative pressure hollow ball 201 , and the other end of the conduit 202 is connected to the adsorption head 102 .

[0040] Specifically, the negative pressure hollow ball 201 is pressed to adsorb the strain gauge onto the adsorption head 102 at the front end of the strain gauge pressing and positioning device 1 through the catheter 202, and the front end of the pressure-guiding rod 103 is pressed to bring the strain gauge close to the adhesive until it fits the sample.

[0041] As a preferred embodiment, Figure 4 As shown, the sample positioning device 3 includes a sample positioning groove 301, a slide 302 and an adhesive hole 303. The sample positioning groove 301 is used to place the sample. The slide 302 is slidably connected to the sample positioning groove 301. The slide 302 is provided with an adhesive hole 303 that is compatible with the adsorption head 102 and connected to the sample. The shell 101 is fixed to the upper end surface of the slide 302.

[0042] Specifically, the housing 101 is fixed to the slide 302 using a tightening nut to reduce the position deviation caused by the shaking of the device during the pasting process. The slide 302 can adjust its position, and the strain gauge pressing and positioning device 1 and the slide 302 can move freely and synchronously, which can meet the needs of strain gauge pasting at any position as needed.

[0043] As a preferred embodiment, Figure 4 As shown, the pasting hole 303 is square. The square structure can realize the positioning of the strain gauge during the movement process and prevent angular deviation.

[0044] As a preferred embodiment, Figure 4 As shown, the sample positioning groove 301 is a retractable structure, wherein the retractable structure can be suitable for fixing samples of various sizes.

[0045] As a preferred embodiment, the sample positioning groove 301 includes a base 3011 and positioning blocks 3012 slidably arranged at both ends of the base. The two positioning blocks 3011 are elastically connected by an elastic element 3013. The free length of the elastic element 3013 is less than or equal to the length of the sample, and the maximum tensile length of the elastic element 3013 is greater than or equal to the length of the sample.

[0046] Specifically, the elastic element 3013 is a spring, which elastically connects the two positioning blocks. When the sample is placed between the two positioning blocks, the spring will cause elastic deformation. Since the free length of the spring is smaller than the length of the sample, the spring is always in a stretched state after the sample is placed, thereby ensuring that the two positioning blocks always press the sample to achieve positioning of the sample.

[0047] As a preferred embodiment, limiting protrusions are provided at both ends of the base 3011. The limiting protrusions are provided at both ends of the base 3011 to prevent the positioning block 3012 from detaching from the base 3011 when sliding to the edge, resulting in failure of the clamping effect on the sample.

[0048] As a preferred embodiment, the end surface of the pressure-guiding rod 103 facing the sample positioning device 3 is square. The square structure can realize the positioning of the strain gauge during the movement process and prevent angular deviation.

[0049] The specific method of using the strain gauge bonding device for composite materials is as follows:

[0050] Place the ASTM D6641 standard specimen in the specimen positioning device 3; adjust the position of the slide 302 according to the strain gauge pasting position, and fix the housing 101 of the strain gauge pressing and positioning device 1 and the slide 302 with screws; drip the required volume of adhesive into the pasting hole 303; press the negative pressure hollow ball 201, and adsorb the strain gauge on the adsorption head 102 at the front end of the strain gauge pressing and positioning device 1 through the catheter 202; press the front end of the pressure-guiding rod 103 to bring the strain gauge close to the adhesive until it fits with the specimen, because the pressure-guiding rod 103 fits tightly with the pasting hole 303; at the same time, as the pressure-guiding rod 103 moves downward, the pressure-resistant spring 104 will gradually compress and transmit force to the strain gauge. When it reaches a certain position, the notch 107 of the pressure-guiding rod will coincide with the position of the clamping plate 106 connected to the side pressure spring 105. At this time, the clamping plate 106 locks the pressure-guiding rod 103 to achieve the pressure-maintaining effect. At the same time, it is not limited by time and can maintain a stable pressing force for a long time. If the device needs to release pressure after the adhesive is cured, just press the negative pressure hollow ball 201 in the negative pressure device 2 to eliminate the negative pressure of the adsorbed strain gauge, press the card switch 108, and the pressure guide rod 103 will automatically rebound, completing the strain gauge pasting operation.

[0051] It should be noted that the various embodiments in this specification are described in a progressive manner. References to the same or similar parts between the various embodiments are sufficient. Each embodiment focuses on the differences from the other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and technologies are omitted here.

[0052] The above are merely embodiments of the present application and are not intended to limit the present application. Various modifications and variations are possible for those skilled in the art without departing from the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included within the scope of the claims of the present application.

Claims

1. A strain gauge bonding device for composite materials, characterized in that: The invention comprises a strain gauge pressing and positioning device (1), a negative pressure device (2) and a sample positioning device (3), wherein the strain gauge pressing and positioning device (1) is installed on the upper end surface of the sample positioning device (3), the negative pressure device (2) is used to absorb and release the strain gauge through negative pressure, and the sample positioning device (3) is used to fix the sample and determine the pasting position; wherein, The strain gauge pressing and positioning device (1) comprises a housing (101), an adsorption head (102), a pressure-guiding rod (103), a pressure-resistant spring (104), a side pressure spring (105) and a clamping plate (106); the housing (101) is fixed to the upper end surface of the sample positioning device (3); the pressure-guiding rod (103) is passed through the housing (101) and one end of the pressure-guiding rod is provided with an adsorption head (102) for adsorbing the strain gauge; the pressure-resistant spring (104) is sleeved on the pressure-guiding rod (103) and is in elastic contact with the adsorption head (102); One end of the side pressure spring (105) is fixed to the inner wall of the housing (101), and the other end of the side pressure spring (105) is connected to the clamping plate (106), and the clamping plate (106) is used to lock the pressure guide rod (103) when the pressure guide rod (103) moves down to a set position; The sample positioning device (3) comprises a sample positioning groove (301), a slide (302) and a pasting hole (303); the sample positioning groove (301) is used to place the sample; the slide (302) is slidably connected to the sample positioning groove (301); the slide (302) is provided with the pasting hole (303) adapted to the adsorption head (102) and connected to the sample; the housing (101) is fixed to the upper end surface of the slide (302); the sample positioning groove (301) comprises a base (3011) and positioning blocks (3012) slidably arranged at both ends of the base (3011); the two positioning blocks (3012) are elastically connected via an elastic element (3013).

2. The strain gauge bonding device for composite materials according to claim 1, characterized in that: A pressure-guiding rod notch (107) is provided on the pressure-guiding rod (103) and is used to cooperate and lock with the clamping plate (106) when the pressure-guiding rod (103) reaches a set position.

3. The strain gauge bonding device for composite materials according to claim 1, characterized in that: The strain gauge pressing and positioning device (1) further comprises a card plate switch (108), wherein the card plate switch (108) is connected to the card plate (106) and is used to release the locked state of the pressure guide rod (103).

4. The strain gauge bonding device for composite materials according to claim 1, characterized in that: The negative pressure device (2) comprises a negative pressure hollow ball (201) and a conduit (202), one end of the conduit (202) is connected to the negative pressure hollow ball (201), and the other end of the conduit (202) is connected to the adsorption head (102).

5. The strain gauge bonding device for composite materials according to claim 1, characterized in that: The pasting hole (303) is square.

6. The strain gauge bonding device for composite materials according to claim 1, characterized in that: The sample positioning groove (301) is a retractable structure.

7. The strain gauge bonding device for composite materials according to claim 6, characterized in that: The free length of the elastic element (3013) is less than or equal to the length of the sample, and the maximum tensile length of the elastic element (3013) is greater than or equal to the length of the sample.

8. The strain gauge bonding device for composite materials according to claim 7, characterized in that: The two ends of the base (3011) are provided with limiting protrusions.

9. The strain gauge bonding device for composite materials according to claim 1, characterized in that: The end surface of the pressure-guiding rod (103) facing the sample positioning device (3) is square.

Images