Resistance strain type displacement meter and application

Abstract

The invention relates to the technical field of strain displacement meters, in particular to a resistance-based strain displacement meter and application thereof, and the resistance-based strain displacement meter comprises a protection mechanism, a resistance strain mechanism and a strain displacement mechanism; the protection mechanism is arranged on the outer side of the resistance strain mechanism in a sleeving mode, and the strain displacement mechanism is arranged at the end of the protection mechanism, connected with the resistance strain mechanism and used for transmitting displacement changes to the resistance strain mechanism. The resistance strain mechanism is arranged in the protection mechanism, on one hand, strain and displacement monitoring can be achieved, different use requirements are met, and the monitoring effect is improved; on the other hand, the structure is simple, installation is convenient, the influence of the external environment on the resistance strain mechanism can be avoided, monitoring is stable and reliable, monitoring accuracy is ensured, and the actual use requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of strain gauge displacement meters, and in particular to a resistance strain gauge displacement meter and its application. Background Art

[0002] Buildings, bridges, roads, tunnels, dams, and large steel structures in the civil engineering field can experience deformation, stress, cracks, and fissures when subjected to their own weight, external loads, geological changes, and natural disasters. This can reduce structural strength and even lead to damage and accidents, shortening their service life and causing significant losses. Testing and monitoring changes in deformation, stress, cracks, and fissures has become a crucial component of routine maintenance, monitoring, and accident prevention.

[0003] Typically, resistance strain gauges, strain displacement gauges, and fiber Bragg grating displacement gauges are used to test and monitor deformation, stress, and strain. Resistance strain crack growth gauges, vibrating wire displacement gauges, and pull-rope displacement gauges are used to monitor displacement, cracks, and fractures. These displacement gauges have the following problems during use: 1) Strain and displacement monitoring cannot be taken into account at the same time and the test accuracy is low; 2) The gauge length is long and the measuring range is low; 3) The installation process is complex and easily affected by the environment, such as outdoor temperature and humidity, wind and sand, and concrete or asphalt burial; 4) Measurement stability, test accuracy, and lifespan are easily affected by environmental changes, such as temperature and shock.

[0004] Therefore, it cannot meet the actual usage needs. Summary of the Invention

[0005] The purpose of the present invention is to provide a displacement meter based on resistance strain and its application to solve the technical problem of low monitoring reliability of current displacement meters.

[0006] The present invention solves the above-mentioned technical problems by: A resistance strain type displacement meter, comprising a protection mechanism, a resistance strain mechanism and a strain displacement mechanism; The protection mechanism is sleeved on the outside of the resistance strain mechanism. The strain displacement mechanism is arranged at the end of the protection mechanism and connected to the resistance strain mechanism for transmitting displacement changes to the resistance strain mechanism.

[0007] It is further defined that the strain displacement mechanism includes a thread lock head and a tail stock, the protective mechanism is sleeved between the thread lock head and the tail stock, the thread lock head and the tail stock are both sealed with the protective mechanism, and the resistance strain mechanism is connected between the thread lock head and the tail stock.

[0008] It is further defined that one end of the locking wire head is provided with a first connecting flange, one end of the protective mechanism is sleeved on the outside of the other end of the locking wire head, the locking wire head is sealed and connected to the protective mechanism through a first soldering ring, and the first soldering ring is welded on the outside of the connection position between the locking wire head and the protective mechanism; one end of the tail stock is provided with a second connecting flange, the other end of the protective mechanism is sleeved on the outside of the other end of the tail stock, the tail stock is sealed and connected to the protective mechanism through a second soldering ring, and the second soldering ring is welded on the outside of the connection position between the tail stock and the protective mechanism.

[0009] It is further defined that the tailstock outer shell is provided with a bellows, the bellows is located between the second connecting flange and the protective mechanism, one end of the bellows is sealed and connected to the protective mechanism through a second soldering ring, and the other end of the bellows is ultrasonically welded to the tailstock.

[0010] It is further defined that the resistance strain mechanism includes a strain gauge, an elastic member, a cable and an adapter plate; The strain gauge is pasted on the elastic member, and the elastic member is connected between the locking head and the tailstock. The adapter plate is arranged inside the locking head. One end of the cable is located outside the adapter plate, and the other end of the cable extends to the inside of the locking head and is connected to the output end of the adapter plate. The input end of the adapter plate is connected to the strain gauge.

[0011] It is further defined that the adapter plate includes an insulating plate and four copper columns, the four copper columns are arranged in an array on the insulating plate and connected to the insulating plate, the copper columns are arranged perpendicular to the insulating plate, and the strain gauge is connected to the cable through the copper columns.

[0012] It is further defined that the elastic member includes a strain segment, two connecting segments and two arc segments, the strain gauge is pasted on the strain segment, the strain segment is connected between the two arc segments, and the lock thread head and tailstock are both connected to the corresponding arc segments through the connecting segment.

[0013] It is further defined that the connecting section and the strain section are both arranged horizontally, and the connecting section is located at the center of the upper and lower geometric surfaces of the arc section and the strain section.

[0014] It is further defined that the protective mechanism includes a copper tube, a sealing ring and a locking screw; the copper tube is connected to the locking wire head through a first soldering ring, and the copper tube is connected to the tail stock through a second soldering ring, and the elastic member is arranged in the copper tube; a tightening hole is opened at one end of the locking head, the sealing ring is sleeved on the outside of the cable, the tightening hole is sleeved on the outside of the sealing ring, the locking screw is threadedly connected to the tightening hole, and the locking screw is in contact with the sealing ring.

[0015] An application of the above-mentioned resistance strain type displacement meter in displacement monitoring.

[0016] The beneficial effects of the present invention are: 1. The present invention arranges the resistance strain mechanism inside the protective mechanism, which can realize strain and displacement monitoring, meet different usage requirements, and improve the monitoring effect. On the other hand, the structure is simple and easy to install, and at the same time, it can avoid the influence of the external environment on the resistance strain mechanism, ensuring stable and reliable monitoring while ensuring accurate monitoring to meet actual usage requirements.

[0017] 2. The present invention utilizes the first connecting flange and the second connecting flange for easy installation, and also facilitates the transmission of external displacement changes to the elastic member. The deformation of the elastic member drives the change of the resistance of the strain gauge, thereby realizing displacement monitoring; the elastic member is small in size, avoiding contact with external structures and reducing interference; at the same time, it is waterproof and dustproof through the sealing ring, and can tighten the cable to increase the service life, further ensuring that the monitoring results are accurate and reliable.

[0018] 3. The present invention realizes the sealing of both ends of the copper tube by the first soldering ring and the second soldering ring, and can ensure the displacement transmission of the locking head and the tailstock at the same time, meet the use requirements, and ensure reliable internal sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of a resistance strain type displacement meter based on the present invention; Figure 2 This is a cross-sectional view of the resistance strain gauge of the present invention; Figure 3 This is a schematic diagram of the elastic member structure of the present invention; Figure 4 This is a schematic diagram of the connection state of the elastic member of the present invention; Figure 5 This is a cross-sectional view of the end portion of the thread lock head of the present invention; In the figure, 10-protective mechanism; 11-copper tube; 12-sealing ring; 13-locking screw; 20-resistance strain mechanism; 21-strain gauge; 22-cable; 23-adapter plate; 24-connecting section; 25-arc section; 26-strain section; 27-screw; 30-strain displacement mechanism; 31-locking wire head; 32-tailstock; 33-first soldering ring; 34-second soldering ring; 35-bellows. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Example 1 refer to Figure 1 and Figure 2 The present invention provides a resistance strain type displacement meter, including a protective mechanism 10, a resistance strain mechanism 20 and a strain displacement mechanism 30; the protective mechanism 10 is sleeved on the outside of the resistance strain mechanism 20 to protect the resistance strain mechanism 20, thereby increasing the service life and preventing the external environment from interfering with the monitoring results, thereby ensuring that the monitoring results are accurate and reliable; the strain displacement mechanism 30 is arranged at the end of the protective mechanism 10 and connected to the resistance strain mechanism 20, and is used to transmit displacement changes to the resistance strain mechanism 20 to realize the monitoring of tensile and compressive displacements.

[0022] Specifically, the protection mechanism 10 includes a copper tube 11 , a sealing ring 12 and a locking screw 13 ; the resistance strain mechanism 20 includes a strain gauge 21 , an elastic member, a cable 22 and an adapter plate 23 ; and the strain displacement mechanism 30 includes a locking wire head 31 and a tailstock 32 .

[0023] The strain gauge 21 is pasted on the elastic part, and the strain gauge 21 is connected to the cable 22 through the adapter plate 23. The copper tube 11 is sleeved between the locking head 31 and the tail seat 32. The locking head 31 and the tail seat 32 are both sealed with the copper tube 11. The elastic part is connected between the locking head 31 and the tail seat 32, which can cause the locking head 31 and the tail seat 32 to produce relative displacement, which can realize the transmission of displacement to the elastic part. At the same time, the sealed connection can avoid the interference of the external environment on the elastic part and the strain gauge 21, thereby improving their service life and applicable environment.

[0024] When in use, the thread lock head 31 and the tailstock 32 are respectively connected to the external environment to sense the displacement changes of the external environment and transmit the displacement changes of the external environment to the elastic member. When the elastic member is deformed, the strain gauge 21 is driven to deform. The electrical signal generated by the deformation of the strain gauge 21 is transmitted through the cable, thereby realizing the monitoring of the displacement.

[0025] Among them, a first connecting flange is provided at one end of the locking wire head 31, and one end of the protective mechanism 10 is sleeved on the outside of the other end of the locking wire head 31. The locking wire head 31 is sealed and connected to the copper tube 11 through a first soldering ring 33, and the first soldering ring 33 is welded on the outside of the connection position between the locking wire head 31 and the copper tube 11; a second connecting flange is provided at one end of the tail stock 32, and the other end of the protective mechanism 10 is sleeved on the outside of the other end of the tail stock 32, and the tail stock 32 is sealed and connected to the copper tube 11 through a second soldering ring 34, and the second soldering ring 34 is welded on the outside of the connection position between the tail stock 32 and the copper tube 11.

[0026] The first soldering ring 33 and the second soldering ring 34 are both obtained by soldering. The solder contains metallic bismuth, has a relatively low melting point, and has high ductility. After welding and sealing, it can form a full metal seal to protect the elastomer and the strain gauge 21 from the influence of the external environment, and can also be ductile and deformed to withstand impact, vibration, and avoid damage to the displacement gauge by particulate matter and concrete; the solder has strong welding ability and can be tightly welded with the copper tube 11 to form a sealed welded metal body. When the strain gauge 21 is subjected to large deformation displacement, the soldering area is reliably connected, plays a buffering role, and will not produce cracks, and can stably seal and protect the internal displacement transmission unit.

[0027] Further explanation: a bellows 35 is provided on the tailstock 32, and the bellows 35 is located between the second connecting flange and the copper tube 11. One end of the bellows 35 is connected to the end of the copper tube 11 through a second soldering ring 34. After the other end of the bellows 35 is ultrasonically welded to the tailstock 32, a third soldering ring is provided at the welding position for sealing, thereby further improving the service life and sealing performance; at this time, the end of the tailstock 32 extends to the interior of the copper tube 11 and is connected to the elastic member.

[0028] The copper tube 11 has a stable structure and can resist a certain degree of corrosion. The bellows 35 has a flexible property. When stretched or compressed, the bellows 35 is also stretched or compressed. While ensuring that it does not affect the use, the bellows 35 will not be damaged and at the same time plays a role in shock absorption and buffering.

[0029] Further explanation, the adapter board 23 includes an insulating board and four copper columns. The four copper columns are arranged in an array on the insulating board. The insulating board can be an acrylic board. The acrylic board has four through holes that match the copper columns. The copper columns are inserted into the through holes of the acrylic board and then bonded. The copper columns are arranged vertically to the insulating board. The strain gauge 21 and the cable 22 are connected to the corresponding ends of the copper columns by soldering.

[0030] Acrylic sheet has excellent insulation properties, which can prevent the copper column from contacting and conducting with other metal parts. Copper has excellent welding performance, which improves the operability during welding.

[0031] refer to Figure 2 and Figure 3 The elastic member includes a strain segment 26, two connecting segments 24 and two arc segments 25. The strain gauge 21 is pasted on the strain segment 26. The strain segment 26 is connected between the two arc segments 25. The lock thread head 31 and the tailstock 32 are both connected to the corresponding arc segments 25 through the connecting segment 24.

[0032] In order to unify the definition standard of the displacement of the structure under tension or compression, that is, the output must be symmetrical when the same displacement is stretched or compressed, the elastic body structure must be symmetrical on the left and right. The strain gauge 21 is pasted at the symmetrical center position of the elastic body. To facilitate the pasting of the strain gauge 21, the strain segment 26 is designed to be a plane. The strain segment 26 is connected between the two arc segments 25. When the elastic body is deformed, the strain is concentrated on the strain segment 26, so that the strain can be fully utilized. The size of the elastic body can be adjusted according to the range and the volume of the copper tube 11 to meet the displacement monitoring requirements while avoiding interference with the internal structure of the copper tube 11.

[0033] The connecting section 24 is arranged horizontally and is connected to the thread lock head 31 and the tailstock 32 respectively. The connecting section 24 is located at the center of the upper and lower geometric surfaces of the arc section 25 and the strain section 26. The size of the arc section 25 and the distribution position on the elastic body can be adjusted according to the range of the displacement meter to make the strain within a reasonable required range.

[0034] refer to Figure 4 Connecting blocks are provided on both the thread lock head 31 and the tailstock 32, and the connecting section 24 is provided on the upper end surface of the connecting block. The connecting section 24 is connected to the corresponding connecting block by a screw 27, which facilitates disassembly and assembly while ensuring stable and reliable displacement transmission.

[0035] When the elastomer is deformed, the strain gauges 21 are combined to form a Wheatstone bridge to convert the deformation into a differential electrical signal. In order to improve the corrosion resistance and environmental adaptability of the elastomer, stainless steel is selected as the material, which can quickly respond to large deformations and recover quickly.

[0036] refer to Figure 5 A tightening hole is provided at one end of the locking head 31, and the tightening hole includes a cylindrical section and a conical section. The conical section is close to the copper tube 11, and a thread is provided on the inner wall of the cylindrical section. The sealing ring 12 is sleeved on the outside of the cable 22, and the tightening hole is sleeved on the outside of the sealing ring 12. The locking screw 13 is threadedly connected to the cylindrical section. The locking screw 13 contacts the sealing ring 12. By rotating the locking screw 13, the sealing ring 12 can be pushed to move to the conical section. Under the extrusion of the locking screw 13 and the limit of the conical section, the sealing ring 12 is tightly attached to the cable 22, thereby achieving sealing while improving the structural stability of the cable 22.

[0037] In one embodiment, in order to achieve a large strain range of ±5000μm / m and for the convenience of installation, the outer diameters of the copper tube 11, the locking wire head 31 and the bellows 35 can be set to 15mm, and the outer diameters of the first connecting flange and the second connecting flange can be set to 20mm. Based on the length of the resistance strain gauge, the gauge length is 104mm, the gauge length is 100mm, and the thickness of the first connecting flange and the second connecting flange are both 2mm.

[0038] The resistance strain gauge provided in this embodiment has an accuracy of up to 5‰ and can be used in an environment of -20°C to 80°C, with a wide range of use. Specific test results are shown in Table 1.

[0039] Table 1 Test data based on resistance strain gauge

[0040] It can be equipped with mounting accessories to achieve flexible installation. It can solve and realize the monitoring of subtle and large-span deformation inside buildings, such as concrete, soil, etc., or on the surface of buildings, such as roads and steel structures. It has a high fatigue life, which can reach 1,000,000 times as verified by fatigue testing machines.

[0041] Effects achieved by the present invention: The resistance strain type displacement meter based on the present invention described in Example 1 has the advantages of high measurement accuracy, impact resistance and high reliability, and can be used in monitoring fine and large-span deformation displacements of concrete, soil, or building surfaces such as roads and steel structures.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the present invention.

Claims

1. A displacement meter based on resistance strain gauge, characterized in that: It includes a protection mechanism (10), a resistance strain mechanism (20) and a strain displacement mechanism (30); The protection mechanism (10) is sleeved on the outside of the resistance strain mechanism (20), and the strain displacement mechanism (30) is arranged at the end of the protection mechanism (10) and connected to the resistance strain mechanism (20) for transmitting displacement changes to the resistance strain mechanism (20).

2. The resistance strain type displacement meter according to claim 1, characterized in that: The strain displacement mechanism (30) comprises a thread lock head (31) and a tailstock (32); the protective mechanism (10) is sleeved between the thread lock head (31) and the tailstock (32); the thread lock head (31) and the tailstock (32) are both sealedly connected to the protective mechanism (10); and the resistance strain mechanism (20) is connected between the thread lock head (31) and the tailstock (32).

3. The resistance strain type displacement meter according to claim 2, characterized in that: One end of the locking wire head (31) is provided with a first connecting flange, one end of the protective mechanism (10) is sleeved on the outside of the other end of the locking wire head (31), and the locking wire head (31) is sealed and connected to the protective mechanism (10) through a first soldering ring (33), and the first soldering ring (33) is welded on the outside of the position where the locking wire head (31) and the protective mechanism (10) are connected; one end of the tailstock (32) is provided with a second connecting flange, and the other end of the protective mechanism (10) is sleeved on the outside of the other end of the tailstock (32), and the tailstock (32) is sealed and connected to the protective mechanism (10) through a second soldering ring (34), and the second soldering ring (34) is welded on the outside of the position where the tailstock (32) and the protective mechanism (10) are connected.

4. The resistance strain type displacement meter according to claim 3, characterized in that: The tailstock (32) is provided with a bellows (35) on its outer sleeve. The bellows (35) is located between the second connecting flange and the protective mechanism (10). One end of the bellows (35) is sealedly connected to the protective mechanism (10) via a second soldering ring (34), and the other end of the bellows (35) is ultrasonically welded to the tailstock (32).

5. The resistance strain type displacement meter according to claim 4, characterized in that: The resistance strain mechanism (20) includes a strain gauge (21), an elastic member, a cable (22), and an adapter plate (23); The strain gauge (21) is adhered to an elastic member, and the elastic member is connected between the locking head (31) and the tailstock (32). The adapter plate (23) is arranged inside the locking head (31). One end of the cable (22) is located outside the adapter plate (23). The other end of the cable (22) extends to the inside of the locking head (31) and is connected to the output end of the adapter plate (23). The input end of the adapter plate (23) is connected to the strain gauge (21).

6. The resistance strain type displacement meter according to claim 5, characterized in that: The adapter plate (23) comprises an insulating plate and four copper columns. The four copper columns are arranged in an array on the insulating plate and connected to the insulating plate. The copper columns are arranged perpendicular to the insulating plate. The strain gauge (21) is connected to the cable (22) via the copper columns.

7. The resistance strain type displacement meter according to claim 5, characterized in that: The elastic member comprises a strain section (26), two connecting sections (24) and two arc sections (25); the strain gauge (21) is adhered to the strain section (26); the strain section (26) is connected between the two arc sections (25); and the thread lock head (31) and the tailstock (32) are both connected to the corresponding arc sections (25) via the connecting section (24).

8. The resistance strain type displacement meter according to claim 7, characterized in that: The connecting section (24) and the strain section (26) are both arranged horizontally, and the connecting section (24) is located at the center of the upper and lower geometric surfaces of the arc section (25) and the strain section (26).

9. The resistance strain type displacement meter according to claim 7, characterized in that: The protective mechanism (10) includes a copper tube (11), a sealing ring (12) and a locking screw (13); the copper tube (11) is connected to the locking wire head (31) through a first soldering ring (33), and the copper tube (11) is connected to the tailstock (32) through a second soldering ring (34), and the elastic member is arranged in the copper tube (11); a pressing hole is opened at one end of the locking head (31), the sealing ring (12) is sleeved on the outside of the cable (22), the pressing hole is sleeved on the outside of the sealing ring (12), the locking screw (13) is threadedly connected to the pressing hole, and the locking screw (13) is in contact with the sealing ring (12).

10. Application of the resistance strain gauge according to any one of claims 1 to 9 in displacement monitoring.

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