Bolt pretightening force monitoring device

Abstract

The invention discloses a bolt pre-tightening force monitoring device, which comprises a base provided with a first bolt hole; the plurality of strain gauges are arranged on the base and are arranged along the circumferential direction of the first bolt hole; the stress attenuation mechanism comprises a connecting part provided with a second bolt hole and a plurality of stress attenuation parts, one end of each stress attenuation part is connected to the connecting part, and the stress attenuation parts are arranged in the circumferential direction of the second bolt hole; the connecting part is arranged on the base, the second bolt holes are opposite to the first bolt holes, and the other ends of the stress attenuation parts are opposite to the strain gauges in a one-to-one correspondence manner; wherein the first bolt hole and the second bolt hole are used for allowing bolts to penetrate through, pre-tightening force applied to the connecting part by the bolts can be transmitted to the stress attenuation parts, and the stress attenuation parts extrude the strain gauges.

Description

Technical Field

[0001] The invention relates to the technical field of bolt preload monitoring, and in particular to a bolt preload monitoring device. Background Art

[0002] Bolt connection has a wide range of important applications in the field of engineering structures. It has the advantages of easy disassembly, high reliability and low cost, and is widely used as an important connection component in aerospace and offshore wind power generation. In order to ensure the quality of bolt connection, it is necessary to apply preload to the bolt. At present, the main methods for monitoring bolt preload are torque tightening method and strain gauge test method.

[0003] The torque tightening method uses a torque wrench to apply torque. However, since the friction between the threaded pairs and the friction between the bolt and the connected parts are affected by factors such as lubrication conditions and their own roughness, they are highly dispersed. Therefore, when a torque wrench is used as a test tool for bolt preload, there will be a large test error.

[0004] Strain gauge testing methods mainly include those based on ultrasound, acoustic emission and vibration transfer analysis.

[0005] The ultrasonic method is a non-destructive measurement method that can determine the change of bolt preload based on the change of ultrasonic signal. The change of ultrasonic wave is caused by reflection, resonance and other phenomena in the bolt connection, which contains the state signal of bolt preload. Although this method has good accuracy in the experimental stage, it is easily disturbed by environmental vibration, noise and other signals, making its practical application challenging.

[0006] Acoustic emission is a non-destructive monitoring method. It uses the phenomenon that when a structure is under stress, it may produce initial cracks or crack expansion, and a certain amount of energy will be released in a short time inside the structure, thereby exciting transient elastic waves in the structure. It completely relies on the structure itself to emit weak signals for detection, so it cannot achieve real-time detection. At the same time, due to the complexity of the engineering structure, its own material vibration and even stress release will affect the generation and characteristics of the signal, so acoustic emission technology cannot be widely used in actual engineering.

[0007] Based on electromechanical impedance technology, a sinusoidal alternating voltage is applied to the piezoelectric element attached to the workpiece to generate forced vibration through the electrostrictive effect, and the vibration is transmitted to the structure through coupling with the structure. At the same time, the structure will deform the piezoelectric element when it vibrates, thereby changing the current in the circuit through the positive piezoelectric effect, and then changing the electrical impedance of the piezoelectric element. It is difficult to accurately quantify the preload of a single bolt by monitoring the bolt preload based on electromechanical impedance technology. In addition, the complexity of the bolt structure and its coupling system with the piezoelectric element are difficult to describe analytically. Finite element software is needed for simulation and the electrical admittance parameters of the piezoelectric element under different preloads are extracted for analysis, which results in certain errors.

[0008] Since the bolts are in a harsh working environment such as high load, high temperature and humidity, vibration and impact, high noise, and strong interference signals for a long time, it is difficult to accurately monitor the bolt preload using the existing testing methods. Studies have shown that the normal stress of the bolt head is linearly related to the bolt preload, so it is effective to use the piezoresistance of the material to achieve long-term monitoring of pressure changes. Under certain external forces, its resistivity will change, which can reliably and effectively monitor the connection status of the engineering structure. However, in the face of the harsh working environment of wind power bolts, ordinary piezoresistive materials are difficult to guarantee their accuracy.

[0009] The piezoresistance effect of materials is used to monitor the bolt preload. Since the working environment of bolts is in harsh working environments such as high load, high temperature, high humidity, vibration and impact, the preload force of some bolts in the preload of large equipment is as high as hundreds of kN. If the piezoresistance of materials is used to monitor the bolt preload, it is a great test for the material to directly bear high load stress and harsh working environment for a long time. Summary of the invention

[0010] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a bolt preload monitoring device, which can reduce the actual pressure on the strain gauge during the monitoring of the bolt preload, so as to achieve the purpose of monitoring the large bolt preload with the help of the existing strain gauge.

[0011] According to some embodiments of the present invention, a bolt preload force monitoring device includes: a base, the base is provided with a first bolt hole; a plurality of strain gauges, the plurality of strain gauges are all arranged on the base and arranged along the circumference of the first bolt hole; a stress attenuation mechanism, the stress attenuation mechanism includes a connecting portion provided with a second bolt hole, and a stress attenuation portion connected to the connecting portion at one end, the number of the stress attenuation portions is multiple, the plurality of stress attenuation portions are arranged along the circumference of the second bolt hole, the connecting portion is provided on the base and the second bolt hole is opposite to the first bolt hole, and the other ends of the plurality of stress attenuation portions are arranged one-to-one with the plurality of strain gauges; wherein the first bolt hole and the second bolt hole are used for bolts to pass through, and the preload force applied by the bolts to the connecting portion can be transmitted to each of the stress attenuation portions, and each of the stress attenuation portions squeezes each of the strain gauges.

[0012] The bolt preload monitoring device according to the embodiment of the present invention has at least the following beneficial effects:

[0013] In the bolt preload monitoring device of the present invention, the bolt passes through the second bolt hole and the first bolt hole in sequence, and the bolt head of the bolt is located on the side of the connection part away from the base. The bolt will generate downward positive pressure (preload) during the tightening process, and the pressure will be transmitted to the connection part, and then transmitted to each strain gauge under the attenuation effect of the stress attenuation part. It can be understood that under the action of the stress attenuation part, the pressure on the connection part can be reduced before being transmitted to the strain gauge, so that the actual pressure on the strain gauge is reduced. In this way, the risk of damage to the strain gauge can be reduced, thereby achieving the purpose of monitoring the large preload of the bolt with the help of the existing strain gauge.

[0014] According to some embodiments of the present invention, the stress attenuation portion includes a flexible hinge having one end connected to the connecting portion, and a pressing block connected to the other end of the flexible hinge, wherein the pressing block is arranged opposite to the stress sheet.

[0015] According to some embodiments of the present invention, the flexible hinge is a straight beam type flexible hinge, a straight circular type flexible hinge, an elliptical type flexible hinge, a shallow cut elliptical type flexible hinge, a bow-shaped flexible hinge, a triangular flexible hinge, a leaf-shaped flexible hinge, a reed type flexible hinge, a parabolic cut type flexible hinge, a hyperbolic cut type flexible hinge, a rounded parabolic cut type flexible hinge, a rounded straight beam type cut flexible hinge, a right rounded parabolic type flexible hinge, a corrugated flexible hinge, an exponential sinusoidal type flexible hinge, a circular curve beam flexible hinge, a uniaxial symmetrical straight beam type flexible hinge, a uniaxial flexible hinge, a rectangular biaxial flexible hinge, a biaxial flexible hinge, a multi-axis flexible hinge, an arc type flexible hinge or a leaf type flexible hinge.

[0016] According to some embodiments of the present invention, a side of the pressing block close to the strain gauge is a planar structure, and a side of the strain gauge close to the pressing block is also a planar structure.

[0017] According to some embodiments of the present invention, the number of the strain gauge and the number of the stress attenuation portion are both four;

[0018] The four strain gauges are evenly arranged along the circumference of the first bolt hole; and the four stress attenuation portions are evenly arranged along the circumference of the second bolt hole.

[0019] According to some embodiments of the present invention, the first bolt hole is a threaded hole.

[0020] According to some embodiments of the present invention, the base is used to be arranged on a support member having a threaded hole, and the threaded hole is arranged opposite to the first bolt hole.

[0021] According to some embodiments of the present invention, the base is provided with a plurality of positioning grooves spaced apart along the circumference of the first bolt hole, and the plurality of strain gauges are arranged in the plurality of positioning grooves in a one-to-one correspondence.

[0022] According to some embodiments of the present invention, wiring grooves are provided on both sides of each positioning groove.

[0023] According to some embodiments of the present invention, an avoidance groove is further provided at each corner of the positioning groove.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 A schematic structural diagram of a bolt preload monitoring device according to an embodiment of the present invention;

[0027] Figure 2 A schematic cross-sectional view of a bolt preload monitoring device according to an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the explosion structure of a bolt preload monitoring device according to an embodiment of the present invention;

[0029] Figure 4 A schematic structural diagram of a stress attenuation mechanism according to an embodiment of the present invention;

[0030] Figure 5 A schematic structural diagram of a stress attenuation mechanism according to another embodiment of the present invention;

[0031] Figure 6 The figure is a schematic structural diagram of a base according to an embodiment of the present invention.

[0032] Figure Number:

[0033] 10. Bolts;

[0034] 100, base; 110, first bolt hole; 120, positioning groove; 130, wiring groove; 140, avoidance groove;

[0035] 200, strain gauge;

[0036] 300, stress attenuation mechanism; 310, connection portion; 311, second bolt hole; 320, stress attenuation portion; 321, flexible hinge; 322, pressing block. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] like Figure 1As shown, a bolt preload monitoring device provided by an embodiment of the present invention includes a base 100 , a strain gauge 200 and a stress attenuation mechanism 300 .

[0041] Combination Figure 2 and Figure 3 The base 100 is provided with a first bolt hole 110 .

[0042] Specifically, the first bolt hole 110 is disposed in the middle of the base 100, and the first bolt hole 110 passes through the upper and lower sides of the base 100. Of course, in other embodiments, the first bolt hole 110 may not be disposed in the center.

[0043] There are multiple strain gauges 200 , all of which are disposed on the base 100 , and the multiple strain gauges 200 are arranged along the circumference of the first bolt hole 110 .

[0044] Specifically in this embodiment, the number of strain gauges 200 is four, and the four strain gauges 200 are evenly arranged along the circumference of the first bolt hole 110. Of course, in other embodiments, the number of strain gauges 200 may also be other numbers, such as two, three or four.

[0045] The stress attenuation mechanism 300 is disposed on the base 100, and includes a connecting portion 310 having a second bolt hole 311, and a stress attenuation portion 320 having one end connected to the connecting portion 310. There are multiple stress attenuation portions 320, and the multiple stress attenuation portions 320 are arranged along the circumference of the second bolt hole 311.

[0046] Specifically, the second bolt hole 311 is opened in the middle of the connecting portion 310, and the second bolt hole 311 passes through the upper and lower sides of the connecting portion 310. Of course, in other embodiments, the second bolt hole 311 may not be arranged in the center. The number of stress attenuation parts 320 is the same as the number of strain gauges 200. Specifically in this embodiment, the number of stress attenuation parts 320 is four, and the four stress attenuation parts 320 are evenly arranged along the circumference of the second bolt hole 311.

[0047] It should be noted that the connection portion 310 is disposed on the base 100 so that the second bolt hole 311 is opposite to the first bolt hole 110 , and the stress attenuation portions 320 are disposed opposite to the strain gauges 200 at one end away from the connection portion 310 in a one-to-one correspondence.

[0048] The first bolt hole 110 and the second bolt hole 311 are used for the bolt 10 to pass through. The pre-tightening force applied by the bolt 10 to the connecting portion 310 can be transmitted to each stress attenuation portion 320 and make each stress attenuation portion 320 squeeze each strain gauge 200 .

[0049] Specifically, the bolt 10 passes through the second bolt hole 311 and the first bolt hole 110 in sequence, and the bolt head of the bolt 10 is located on the side of the connecting part 310 away from the base 100. The bolt 10 will generate downward positive pressure (pre-tightening force) during the tightening process, and the pressure will be transmitted to the connecting part 310, and then transmitted to each strain gauge 200 under the attenuation effect of the stress attenuation part 320.

[0050] It can be understood that, under the action of the stress attenuation portion 320, the pressure on the connecting portion 310 can be reduced and then transmitted to the strain gauge 200, thereby reducing the actual pressure on the strain gauge 200. In this way, the large preload force of the bolt 10 can be monitored and the risk of damage to the strain gauge 200 can be reduced.

[0051] In some embodiments, the first bolt hole 110 is a threaded hole, the second bolt hole 311 is a common non-threaded through hole, the bolt 10 passes through the second bolt hole 311 and the first bolt hole 110 in sequence, and the bolt 10 can be tightened so that the bolt head squeezes the connecting portion 310.

[0052] In other embodiments, the base 100 is used to be arranged on a support member (not shown) having a threaded hole, and the threaded hole is arranged opposite to the first bolt hole 110, wherein the first bolt hole 110 and the second bolt hole 311 are ordinary non-threaded through holes. The bolt 10 passes through the second bolt hole 311, the first bolt hole 110 and the threaded hole in sequence, and the bolt 10 can be tightened so that the bolt head presses the connecting portion 310.

[0053] Combination Figure 2 and Figure 3 In some embodiments, the stress attenuation portion 320 includes a flexible hinge 321 having one end connected to the connecting portion 310 , and a pressing block 322 connected to the other end of the flexible hinge 321 , and the pressing block 322 is disposed opposite to the strain gauge 200 .

[0054] It is understandable that the bolt 10 passes through the second bolt hole 311 and the first bolt hole 110 in sequence, and the bolt head of the bolt 10 is located on the side of the connection part 310 away from the base 100. The bolt 10 will generate downward positive pressure (preload force) during the tightening process, and the pressure will be transmitted to the connection part 310, and then transmitted to each pressure block 322 under the attenuation effect of the flexible hinge 321, and each pressure block 322 will squeeze each strain gauge 200. In this way, under the action of the flexible hinge 321, the preload force on the connection part 310 can be reduced and then transmitted to the pressure block 322, so that the actual pressure on the strain gauge 200 is reduced.

[0055] Among them, the flexible hinge 321 can be a straight beam type flexible hinge, a straight circular flexible hinge, an elliptical flexible hinge, a shallow cut elliptical flexible hinge, a bow-shaped flexible hinge, a triangular flexible hinge, a leaf-shaped flexible hinge, a reed flexible hinge, a parabolic cut type flexible hinge, a hyperbolic cut type flexible hinge, a rounded parabolic cut type flexible hinge, a chamfered straight beam type cut flexible hinge, a right rounded parabolic flexible hinge, a corrugated flexible hinge, an exponential sinusoidal flexible hinge, a circular curve beam flexible hinge, a uniaxial symmetrical straight beam type flexible hinge, a uniaxial flexible hinge, a rectangular biaxial flexible hinge, a new biaxial flexible hinge, a multi-axis flexible hinge, an arc-shaped flexible hinge or a leaf-shaped flexible hinge.

[0056] in, Figure 4 The flexible hinge 321 shown is a double straight circular flexible hinge. Figure 5 The flexible hinge 321 shown is a single straight circular flexible hinge 3 .

[0057] It should be noted that the relationship between the actual pressure on the connection part 310 and the actual pressure on the strain gauge 200 under the stress reduction effect of the flexible hinge 321 can be simulated in advance by finite element software. For example, by continuously applying a positive pressure in the range of 0-500kN to the connection part 310, the pressure curve of the pressure block 322 when the connection part 310 is subjected to a positive pressure in the range of 0-500kN can be obtained, thereby obtaining the pressure curve of the strain gauge 200 when the connection part 310 is subjected to a positive pressure of 0-500kN. Therefore, when the above device is used to actually test the preload force of the bolt 10, when the pressure of the strain gauge 200 is known, the actual preload force of the bolt 10 on the connection part 310 can be obtained through the above pressure curve.

[0058] Of course, the attenuation effect of the flexible hinge 321 can also be calculated based on its own type and parameters, that is, when the connecting portion 310 is subjected to a certain positive pressure, the actual pressure received by the pressing block 322 can be calculated.

[0059] It should be noted that the pressure value exerted on the strain gauge 200 can be obtained according to existing methods, which will not be described in detail here.

[0060] In addition, the resistance of the strain gauge 200 changes with the pressure it is subjected to. The minimum value of the bolt preload can be set in the host computer connected to the strain gauge 200, and the resistance of the strain gauge 200 corresponding to the minimum value of the preload can be marked; when the bolt 10 becomes loose, the resistance of the strain gauge 200 will change. When the preload of the bolt 10 is lower than the minimum value and the resistance of the strain gauge 200 reaches the corresponding marked value, the host computer will issue an alarm message to prompt the staff to tighten the bolt 10.

[0061] like Figure 2As shown, it can be understood that the side of the pressing block 322 close to the strain gauge 200 is a planar structure, and the side of the strain gauge 200 close to the pressing block 322 is also a planar structure.

[0062] Specifically, for each set of the pressure block 322 and the strain gauge 200, that is, the pressure block 322 and the strain gauge 200 that are arranged relatively, the side of the pressure block 322 close to the strain gauge 200 is a planar structure, and the side of the strain gauge 200 close to the pressure block 322 is also a planar structure. In this way, the contact range between the strain gauge 200 and the pressure block 322 is larger, which can make the measurement result more accurate.

[0063] Combination Figure 2 and Figure 6 Furthermore, the base 100 is provided with a plurality of positioning grooves 120 spaced apart along the circumference of the first bolt hole 110 , and the plurality of strain gauges 200 are arranged in the plurality of positioning grooves 120 in a one-to-one correspondence.

[0064] Specifically, the positioning grooves 120 are opened on the upper surface of the base 100, and the plurality of positioning grooves 120 are evenly and spaced apart along the circumference of the first bolt hole 110. The number of the positioning grooves 120 is the same as the number of the strain gauges 200. The plurality of strain gauges 200 are arranged in the plurality of positioning grooves 120 in a one-to-one correspondence. The positioning grooves 120 are used to position the strain gauges 200 to improve the installation accuracy of the strain gauges 200.

[0065] Specifically in this embodiment, the number of the positioning grooves 120 , the number of the strain gauges 200 , and the number of the stress attenuation portions 320 are all four.

[0066] In some embodiments, wiring grooves 130 are further disposed on both sides of each positioning groove 120 .

[0067] It is understandable that the positive and negative electrodes of the strain gauge 200 need to be connected to positive and negative wires respectively, and the positive and negative wires can pass through the wiring grooves 130 on both sides of the positioning groove 120 respectively.

[0068] Furthermore, an avoidance groove 140 is provided at each corner of the positioning groove 120 .

[0069] It is understandable that burrs may exist on the edges of the pressing block 322 . By providing avoidance grooves 140 at the corners of the positioning groove 120 , it is possible to avoid a sense of frustration of the pressing block 322 during the lifting process.

[0070] In the bolt preload monitoring device of the present invention, the bolt 10 passes through the second bolt hole 311 and the first bolt hole 110 in sequence, and the bolt head of the bolt 10 is located on the side of the connection part 310 away from the base 100. The bolt 10 will generate a downward positive pressure (preload) during the tightening process, and the pressure will be transmitted to the connection part 310, and then transmitted to each strain gauge 200 under the attenuation effect of the stress attenuation part 320. It can be understood that under the action of the stress attenuation part 320, the pressure on the connection part 310 can be reduced and then transmitted to the strain gauge 200, so that the actual pressure on the strain gauge 200 is reduced. In this way, the risk of damage to the strain gauge 200 can be reduced, thereby achieving the purpose of monitoring the maximum preload of the bolt 10 with the help of the existing strain gauge 200.

[0071] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0072] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A bolt preload monitoring device, characterized in that: include: A base, wherein the base is provided with a first bolt hole; A plurality of strain gauges, wherein the plurality of strain gauges are disposed on the base and arranged along the circumference of the first bolt hole; A stress attenuation mechanism, wherein the stress attenuation mechanism comprises a connecting portion provided with a second bolt hole, and a stress attenuation portion connected to the connecting portion at one end, wherein the number of the stress attenuation portions is plural, and the plurality of stress attenuation portions are arranged along the circumference of the second bolt hole, the connecting portion is arranged on the base so that the second bolt hole is opposite to the first bolt hole, and the other ends of the plurality of stress attenuation portions are arranged opposite to the plurality of strain gauges in a one-to-one correspondence; The first bolt hole and the second bolt hole are used for bolts to pass through, and the pre-tightening force applied by the bolts to the connecting portion can be transmitted to each of the stress attenuation portions, so that each of the stress attenuation portions squeezes each of the strain gauges.

2. The bolt preload monitoring device according to claim 1, characterized in that: The stress attenuation portion includes a flexible hinge having one end connected to the connecting portion, and a pressing block connected to the other end of the flexible hinge, wherein the pressing block is arranged opposite to the stress sheet.

3. The bolt preload monitoring device according to claim 2, characterized in that: The flexible hinge is a straight beam type flexible hinge, a straight circular type flexible hinge, an elliptical flexible hinge, a shallow cut elliptical type flexible hinge, a bow-shaped flexible hinge, a triangular flexible hinge, a leaf-shaped flexible hinge, a reed type flexible hinge, a parabolic cut type flexible hinge, a hyperbolic cut type flexible hinge, a rounded parabolic cut type flexible hinge, a rounded straight beam type cut flexible hinge, a right rounded parabolic type flexible hinge, a corrugated flexible hinge, an exponential sine type flexible hinge, a circular curve beam flexible hinge, a uniaxially symmetrical straight beam type flexible hinge, a uniaxial flexible hinge, a rectangular biaxial flexible hinge, a biaxial flexible hinge, a multi-axis flexible hinge, an arc type flexible hinge or a leaf type flexible hinge.

4. The bolt preload monitoring device according to claim 2, characterized in that: The side of the pressing block close to the strain gauge is a planar structure, and the side of the strain gauge close to the pressing block is also a planar structure.

5. The bolt preload monitoring device according to claim 1, characterized in that: The number of the strain gauges and the number of the stress attenuation parts are both four; The four strain gauges are evenly arranged along the circumference of the first bolt hole; and the four stress attenuation portions are evenly arranged along the circumference of the second bolt hole.

6. The bolt preload monitoring device according to claim 1, characterized in that: The first bolt hole is a threaded hole.

7. The bolt preload monitoring device according to claim 1, characterized in that: The base is used to be arranged on a support member having a threaded hole, and the threaded hole is arranged opposite to the first bolt hole.

8. The bolt preload monitoring device according to claim 1, characterized in that: The base is provided with a plurality of positioning grooves spaced apart along the circumference of the first bolt hole, and the plurality of strain gauges are arranged in the plurality of positioning grooves in a one-to-one correspondence.

9. The bolt preload monitoring device according to claim 8, characterized in that: Both sides of each positioning groove are also provided with wiring grooves.

10. The bolt preload monitoring device according to claim 8, characterized in that: Each corner of the positioning groove is also provided with an avoidance groove.

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