Fastener anti-slip coefficient test device, system and method

Abstract

The invention belongs to the technical field of bolt detection, and discloses a fastener anti-slip coefficient test device, system and method.The fastener anti-slip coefficient test device comprises an intelligent bolt, ultrasonic detection equipment, a measurement cable and an ultrasonic probe, and the two ends of the measurement cable are connected with the ultrasonic probe and the ultrasonic detection equipment respectively; the ultrasonic probe is electrically connected to the head of the intelligent bolt and attached to the end face of the head of the intelligent bolt. By using the intelligent bolt based on ultrasonic waves, the length of the bolt used for the test can be greatly reduced, and the test cost is saved; the bolts are low in price and can be discarded together with the test plate after the test, so that the disassembly time is shortened, and the test efficiency is improved; and equipment such as a pressure sensor and an intelligent detector is not needed in the test process, so that the purpose of real-time monitoring in the actual working process is conveniently achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bolt detection, and particularly relates to a fastener anti-slippage coefficient testing device, system and method. BACKGROUND

[0002] The anti-slippage coefficient of high-strength bolts is a key indicator for evaluating the reliability of high-strength bolt connections, and directly affects the bearing safety and stability of bolt connection structures in the fields of steel structures and engineering machinery.

[0003] In a high-strength bolt connection system, the anti-slippage coefficient is the ratio of the sum of the external force (shear force) that causes the friction surface of the connecting piece to slide and the vertical pre-tension of the high-strength bolt (axial force) in the high-strength bolt connection. The accurate detection of this coefficient is the core basis for determining whether the bolt connection meets the design bearing requirements and avoiding the failure of the connection structure due to slippage, and therefore has important application value in the fields of engineering construction and equipment manufacturing.

[0004] Currently, when conducting high-strength bolt anti-slippage coefficient tests, the detection equipment system used in the industry has formed a relatively fixed configuration, mainly including a universal testing machine, a torque wrench, and an intelligent detector. When connecting and assembling the test piece for anti-slippage coefficient testing, a specific operation process must be strictly followed: first, punch the bolts into the bolt holes of the test piece to achieve accurate positioning of the connecting pieces of the test piece through the punch, preventing the parts from shifting during assembly; after positioning is completed, the punch is removed one by one and replaced with high-strength bolts equipped with pressure sensors, the pre-tension data of the bolts are collected in real time through the pressure sensors, the shear force is applied by the universal testing machine, and the data is processed by the intelligent detector, finally completing the calculation and detection of the anti-slippage coefficient.

[0005] However, the above existing detection technology has significant limitations in actual application: first, since a pressure sensor needs to be installed on the high-strength bolt to obtain the pre-tension signal, the installation of the pressure sensor requires additional space, which necessitates the use of extended high-strength bolts to meet the assembly requirements, increasing the cost and procurement difficulty of special-purpose test bolts; second, as a high-precision measuring element, the pressure sensor is generally expensive, and it needs to be removed and recovered from the bolt after each test, which is a tedious process that not only prolongs the test period but also may affect the measurement accuracy and service life of the sensor due to repeated disassembly and assembly; third, the entire test process is highly dependent on large or special-purpose equipment such as universal testing machines and intelligent detectors, which are bulky and inconvenient to move, and can only be used in laboratories or fixed detection sites, making it impossible to carry out real-time monitoring of the anti-slippage coefficient of high-strength bolts actually installed on site (such as steel structure installation sites and equipment operation and maintenance sites), which makes it difficult to meet the needs of rapid verification and immediate control of bolt connection quality on site. SUMMARY

[0006] The purpose of the present application is to provide a fastener anti-slip coefficient test device, system and method, by using an intelligent bolt based on ultrasonic waves, the length of the bolt used for testing can be greatly reduced, saving test cost; and because it is inexpensive, it can be discarded together with the test plate after testing, reducing disassembly time and improving test efficiency; and during the test process, no pressure sensor, intelligent detector and other equipment are required, facilitating real-time monitoring during actual work.

[0007] The specific scheme content is as follows:

[0008] A fastener anti-slip coefficient test device, comprising an intelligent bolt, an ultrasonic detection device, a measuring cable and an ultrasonic probe, the two ends of the measuring cable are respectively connected to the ultrasonic probe and the ultrasonic detection device, and the ultrasonic probe is electrically connected to the head of the intelligent bolt and adheres to the end face of the head of the intelligent bolt.

[0009] Further, the intelligent bolt comprises an axial force ultrasonic sensor and a shear force ultrasonic sensor, the axial force ultrasonic sensor is arranged in the head of the intelligent bolt, the shear force ultrasonic sensor is arranged in the tail of the intelligent bolt, the ultrasonic probe is connected to the axial sensor and adheres to the end face of the head of the intelligent bolt, for forming a coupling effect and generating an ultrasonic signal in the bolt.

[0010] The conventional fastener anti-slip coefficient test usually uses high-strength bolts for testing, the present application uses an intelligent bolt, the head and tail of the intelligent bolt are each provided with an independent ultrasonic sensor, the head of the intelligent bolt of the present application is provided with an axial force ultrasonic sensor, the tail is provided with a shear force ultrasonic sensor, one end of the measuring cable is connected to the ultrasonic probe, and the other end is connected to the ultrasonic detection device. The ultrasonic probe is electrically connected to the axial force ultrasonic sensor, and the ultrasonic probe adheres to the end face of the head of the intelligent bolt, forming a coupling effect and generating an ultrasonic signal in the bolt. The fastener anti-slip coefficient test device of the present application is tested in combination with the test method of the present application, the ultrasonic detection device returns data information through the ultrasonic probe, automatically calculates the axial force borne by the intelligent bolt according to a preset calculation formula, and the test personnel obtain the shear force borne by the intelligent bolt according to the data information obtained by the ultrasonic detection device , and the anti-slip coefficient can be obtained by using the calculated axial force and shear force according to the formula of the anti-slip coefficient, and the test is completed. The axial force borne by the intelligent bolt formula includes two, the first formula: , and the result calculated by the first formula usually has sufficient accuracy. If a more accurate result is required, the second formula: , .

[0011] The fastener anti-slippage coefficient test system comprises the fastener anti-slippage coefficient test device, a test piece, test nuts and a universal testing machine, the test nuts are matched with intelligent bolts, the intelligent bolts are arranged in vertical through threaded holes of the test piece and are fixed to the test piece by the test nuts according to a preset fastening force, and the universal testing machine comprises hydraulic jaws, the test piece comprises two test pull plates, the hydraulic jaws clamp the pull plates at left and right ends of the test piece respectively, and the hydraulic jaws are used to apply external force to make the intelligent bolt friction surface slide.

[0012] Further, the test piece further comprises two test cover plates, the two test cover plates are horizontally and vertically spaced, the two test pull plates are horizontally clamped between the two test cover plates, distal ends of the two test pull plates are symmetrically exposed outside left and right ends of the test cover plates, four vertical through threaded holes are arranged on left and right sides of the test piece, the four intelligent bolts are arranged in the corresponding threaded holes and are threadedly fixed to the two test cover plates and the two test pull plates by the matched test nuts, and a bolt connection pair is formed.

[0013] The test piece is formed by clamping the two test pull plates between the two test cover plates, the whole test piece has a symmetrical structure, four vertical through threaded holes are arranged on end faces of left and right sides of the test piece, namely two on the left and two on the right, the four intelligent bolts are arranged in the corresponding threaded holes and are threadedly fixed by the corresponding test nuts, the two test cover plates and the two test pull plates are fixed, and a bolt connection pair is formed. The test piece is made according to the requirements of the national fastener anti-slippage coefficient test. The present application uses four intelligent bolts for testing, and the traditional method usually uses high-strength bolts for testing.

[0014] A fastener anti-slippage coefficient test method is applied to the fastener anti-slippage coefficient test system, and the steps comprise:

[0015] S1, the intelligent bolt is connected to an ultrasonic detection device through a measuring cable and an ultrasonic probe;

[0016] S2, the test piece is threadedly fixed by the four intelligent bolts and the matched test nuts, and a bolt connection pair is formed;

[0017] S3, the test starts, the universal testing machine applies pulling force to the two test pull plates through the hydraulic jaws, the intelligent bolt friction surface slides, the ultrasonic probe detects echo signals and transmits the echo signals to the ultrasonic detection device, the ultrasonic detection device analyzes signals, automatically calculates the axial force applied to the intelligent bolt according to obtained data information according to a preset program, and outputs the result;

[0018] S4, the shear force borne by the intelligent bolt is calculated according to a preset shear force formula according to the data information obtained by the ultrasonic detection device, and the anti-slippage coefficient is obtained according to the axial force and the shear force of the intelligent bolt and an anti-slippage coefficient formula;

[0019] S5, remove the ultrasonic probe connected to the intelligent bolt, and the test is completed.

[0020] Further, in step S1, two test cover plates and two test pull plates are prepared, the two test pull plates are symmetrically clamped in the middle of the two test cover plates, four symmetric vertical through threaded holes are first punched on the end faces of the test pieces on the left and right sides, the test pieces are positioned, and then the four intelligent bolts are threaded through the corresponding threaded holes and are fixed on the end faces of the test pieces through test nuts, to form a bolt connection pair.

[0021] Further, in step S3, the axial force borne by the intelligent bolt is calculated according to the formula:

[0022]

[0023] In the formula, F is the axial force borne by the bolt;

[0024] is the measured value of the acoustic time difference before and after the bolt is loaded;

[0025] is the acoustic time measurement value of the bolt under the condition of no load;

[0026] is the acoustic time measurement value of the bolt under the condition of load;

[0027] is a proportional factor related to the material and shape of the bolt and the installation parameters.

[0028] Further, in step S3, the axial force borne by the intelligent bolt is calculated according to the formula:

[0029] ;

[0030] ;

[0031] In the formula, F is the axial force borne by the bolt;

[0032] is the measured value of the acoustic time difference before and after the bolt is loaded;

[0033] is the measured value of the length difference before and after the bolt is loaded;

[0034] is the length measurement value of the bolt under the condition of no load;

[0035] is the length measurement value of the bolt under the condition of load;

[0036] 、 a proportional factor related to bolt material and shape and installation parameters;

[0037] a proportional factor according to the relationship between bolt length change and ultrasonic sound time difference.

[0038] Further, in step S4, the calculation formula of the shear force borne by the intelligent bolt is:

[0039]

[0040] In the formula, is the shear force borne by the bolt;

[0041] K is a shear load calibration coefficient.

[0042] The axial force and the shear force borne by the intelligent bolt calculated by the fastener slip resistance coefficient test method of the application are used to calculate the slip resistance coefficient through the calculation formula of the slip resistance coefficient. In the formula, is the slip resistance coefficient; is the shear force borne by the intelligent bolt; is the number of friction surfaces, and =2; is the sum of the axial forces of the intelligent bolts on one side of the test piece; is the number of intelligent bolts on one side of the test piece, and =2.

[0043] Further, the pulling force applied by the universal testing machine can be replaced by the shear force borne by the test piece.

[0044] In actual work, the pulling force applied by the universal testing machine can be replaced by the shear force borne by the test piece to achieve the purpose of real-time monitoring.

[0045] Compared with the prior art, the application has the following beneficial effects:

[0046] The application uses intelligent bolts based on ultrasonic waves, which can greatly reduce the length of the bolts used in the test and save test costs. The intelligent bolts are inexpensive and can be discarded together with the test plate after the test, reducing disassembly time and improving test efficiency. In the test process, no pressure sensor, intelligent detector or other equipment is needed, which is convenient for achieving the purpose of real-time monitoring in actual work. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 Fig. 2 is a schematic diagram of the installation position of the intelligent bolt in the slip resistance coefficient test of the application.

[0048] Figure 2 Fig. 3 is a schematic diagram of the installation position of the high-strength bolt in the original slip resistance coefficient test.​

[0049] In the drawings:

[0050] 1. Intelligent bolt; 2. Axial force ultrasonic sensor; 3. Shear force ultrasonic sensor; 4. Test nut; 5. Test pull plate; 6. Test cover plate; 7. High-strength bolt; 8. Pressure sensor. DETAILED DESCRIPTION

[0051] In order to make the objects, technical solutions and advantages of the present application clearer, the following will further describe the present application in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Any other embodiments obtained by a person of ordinary skill in the art without creative work on the basis of the embodiments of the present application belong to the scope of protection of the present application.

[0052] The terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0053] It should be noted that the terms "front", "back", "inner", "outer", "left", "right" and the like in the present application indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0054] The following will be described by embodiments Figure 1 And Figure 2 The present application will be described in detail.

[0055] Embodiment 1:

[0056] A fastener anti-slip coefficient test device, comprising an intelligent bolt 1, an ultrasonic detection device, a measuring cable and an ultrasonic probe, the two ends of the measuring cable are respectively connected to the ultrasonic probe and the ultrasonic detection device, and the ultrasonic probe is electrically connected to the head of the intelligent bolt 1 and adheres to the end face of the head of the intelligent bolt 1.

[0057] The intelligent bolt 1 comprises an axial force ultrasonic sensor 2 and a shear force ultrasonic sensor 3, the axial force ultrasonic sensor 2 is arranged in the head of the intelligent bolt 1, the shear force ultrasonic sensor 3 is arranged in the tail of the intelligent bolt 1, the ultrasonic probe is connected to the axial sensor and adheres to the end face of the head of the intelligent bolt 1, for forming coupling effect and generating ultrasonic signal in the bolt.

[0058] Embodiment 2:

[0059] The application also provides a fastener anti-slippage coefficient test system, as shown in Figure 1 The fastener anti-slippage coefficient test system comprises the fastener anti-slippage coefficient test device, a test piece, test nuts 4 and a universal testing machine. The test nuts 4 are matched with the intelligent bolts 1. The intelligent bolts 1 are arranged in vertical through threaded holes in the test piece and are fixed to the test piece by the test nuts 4 according to a preset fastening force. The universal testing machine comprises hydraulic jaws. The test piece comprises two test pull plates 5. The hydraulic jaws clamp the test pull plates 5 respectively at left and right ends of the test piece, and are used to apply an external force to make the intelligent bolt friction surface slide.

[0060] The test piece further comprises two test cover plates 6. The two test covers 6 are horizontally and vertically spaced. The two test pull plates 5 are horizontally clamped between the two test cover plates 6. The distal ends of the two test pull plates 5 are symmetrically exposed outside the left and right ends of the test cover plates 6. Four vertical through threaded holes are arranged symmetrically on the left and right sides of the test piece. The four intelligent bolts 1 are arranged in the corresponding threaded holes and threadedly fix the two test cover plates 6 and the two test pull plates 5 through the matched test nuts 4, thereby forming a bolt connection pair.

[0061] In the embodiment, the fastener anti-slippage coefficient test system adopts the intelligent bolts 1. The length of the bolts is greatly reduced. Since the bolts are low in price, they can be discarded together with the test piece after the test, thereby reducing the disassembly time. In the test process, no pressure sensor, intelligent detector and other devices are needed. In the working process, the purpose of real-time monitoring can also be achieved. Compared with the original fastener anti-slippage coefficient test, as shown in Figure 2 The test cost is saved, the test efficiency is greatly improved, and the test result is high in precision.

[0062] Embodiment 3

[0063] The application also provides a fastener anti-slippage coefficient test method, which is applied to the fastener anti-slippage coefficient test system. The steps comprise:

[0064] S1, the intelligent bolt 1 is connected to an ultrasonic detection device through a measuring cable and an ultrasonic probe;

[0065] S2, the test piece is threadedly fixed by the four intelligent bolts 1 and the matched test nuts, thereby forming a bolt connection pair;

[0066] S3, the test starts. The universal testing machine applies a pulling force to the two test pull plates 5 through the hydraulic jaws, so that the intelligent bolt friction surface slides. The ultrasonic probe detects a return signal and transmits it to the ultrasonic detection device. The ultrasonic detection device analyzes the signal and automatically calculates the axial force applied to the intelligent bolt according to the obtained data information according to a preset program, and outputs the result.

[0067] S4, according to the data information obtained by the ultrasonic detection device, the shear force suffered by the intelligent bolt 1 is artificially calculated according to a preset shear force formula, and the anti-slip coefficient is obtained according to the axial force and the shear force of the intelligent bolt 1 and an anti-slip coefficient formula;

[0068] S5, the ultrasonic probe connected to the intelligent bolt 1 is removed, and the test is ended.

[0069] In this embodiment, two test cover plates 6 and two test pull plates 5 are prepared, the two test cover plates 6 are symmetrically clamped in the middle of the two test pull plates, four symmetric vertical through threaded holes are opened on the end faces of the test pieces by punching, the test pieces are positioned, and then four intelligent bolts 1 are threaded through the corresponding threaded holes and are screwed on the end faces of the test pieces through test nuts 4, to form a bolt connection pair.

[0070] The axial force calculation formula of the intelligent bolt 1 is as follows:

[0071]

[0072] In the formula, F is the axial force suffered by the bolt;

[0073] is the measured value of the time difference before and after the load of the bolt;

[0074] is the time difference measurement value of the bolt under the no-load condition;

[0075] is the time difference measurement value of the bolt under the load condition;

[0076] is a proportional factor related to the material and shape of the bolt and the installation parameters.

[0077] In step S4, the calculation formula of the shear force suffered by the intelligent bolt 1 is as follows:

[0078]

[0079] In the formula, is the shear force suffered by the bolt;

[0080] K is the shear load calibration coefficient.

[0081] The axial force and the shear force suffered by the intelligent bolt calculated by the fastener anti-slip coefficient test method of the application are calculated by the anti-slip coefficient calculation formula to obtain the anti-slip coefficient. The anti-slip coefficient formula is , in which, is the anti-slip coefficient; is the shear force suffered by the intelligent bolt; ​For the number of friction surfaces, take =2; For the sum of the axial forces of the intelligent bolts on one side of the specimen slip; For the number of intelligent bolts on one side of the specimen, take =2.

[0082] Example 4:

[0083] The application also provides a fastener anti-slippage coefficient test method applied to the fastener anti-slippage coefficient test system, and the steps include:

[0084] S1, the intelligent bolt 1 is connected to the ultrasonic detection device through the measuring cable and the ultrasonic probe;

[0085] S2, the specimen is threadedly fixed through the four intelligent bolts 1 and the matching test nuts 4 to form a bolt connection pair;

[0086] S3, the test starts, the universal testing machine applies pulling force to the two test pull plates 5 through the hydraulic jaws respectively, so that the intelligent bolt friction surface produces sliding, the ultrasonic probe detects the echo signal and transmits it to the ultrasonic detection device, the ultrasonic detection device analyzes the signal and automatically calculates the axial force applied to the intelligent bolt 1 according to the obtained data information according to the preset program, and outputs the result;

[0087] S4, according to the data information obtained by the ultrasonic detection device, the shear force of the intelligent bolt 1 is manually calculated according to the preset shear force formula, and the anti-slippage coefficient is obtained according to the axial force and shear force of the intelligent bolt 1 and the anti-slippage coefficient formula;

[0088] S5, the ultrasonic probe connected to the intelligent bolt is removed, and the test is completed.

[0089] In this embodiment, two test cover plates 6 and two test pull plates 5 are prepared, the two test cover plates 6 are symmetrically clamped in the middle of the two test pull plates 5, four symmetric vertical through-threaded holes are first opened on the end faces of the left and right sides of the specimen by punching, the specimen is positioned, then the four intelligent bolts 1 are threaded through the corresponding threaded holes and are threadedly fixed on the end face of the specimen through the test nuts 4 to form a bolt connection pair.

[0090] The axial force calculation formula of the intelligent bolt 1 in step S3 is as follows:

[0091] ;

[0092] ;

[0093] In the formula, F is the axial force of the bolt;

[0094] is the measured value of the time difference of sound before and after the load of the bolt;

[0095] is the measured value of the length of the bolt under no load condition;

[0096] is the measured value of the length of the bolt under no load condition;

[0097] is the measured value of the length of the bolt under load condition;

[0098] , is the proportional factor related to the material and shape of the bolt and the installation parameters;

[0099] is the proportional factor according to the relationship between the length change of the bolt and the acoustic time difference of the ultrasonic wave.

[0100] In step S4, the calculation formula of the shear force borne by the intelligent bolt 1 is:

[0101] ;

[0102] In the formula, is the shear force borne by the bolt;

[0103] K is the calibration coefficient of the shear load.

[0104] The axial force and the shear force borne by the intelligent bolt calculated by the fastener anti-slip coefficient test method of the present application are used to calculate the anti-slip coefficient by the calculation formula of the anti-slip coefficient. The anti-slip coefficient formula is In the formula, is the anti-slip coefficient; is the shear force borne by the intelligent bolt; is the number of friction surfaces, and = 2; is the sum of the axial forces of the intelligent bolts on the slip side of the test piece; is the number of intelligent bolts on one side of the test piece, and = 2.

[0105] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fastener slip resistance coefficient test apparatus characterized by, The device comprises a smart bolt (1), an ultrasonic detection device, a measuring cable and an ultrasonic probe, the two ends of the measuring cable are connected with the ultrasonic probe and the ultrasonic detection device respectively, and the ultrasonic probe is electrically connected to the head of the smart bolt (1) and adheres to the end face of the head of the smart bolt (1).

2. The fastener slip resistance test apparatus of claim 1, wherein, The smart bolt (1) comprises an axial force ultrasonic sensor (2) and a shear force ultrasonic sensor (3), the axial force ultrasonic sensor (2) is arranged in the head of the smart bolt (1), the shear force ultrasonic sensor (3) is arranged in the tail of the smart bolt (1), the ultrasonic probe is connected to the axial sensor and adheres to the end face of the head of the smart bolt (1), so as to form a coupling effect and generate an ultrasonic signal in the bolt.

3. A fastener slip resistance coefficient test system characterized by, The device comprises a fastener anti-slip coefficient test device as claimed in claim 1 or 2, further comprising a test piece, a test nut and a universal testing machine, the test nut (4) is matched with the smart bolt (1), the smart bolt (1) is arranged in a vertical through threaded hole on the test piece and is fixed to the test piece by the test nut (4) according to a preset fastening force, and the universal testing machine comprises a hydraulic jaw, the test piece comprises two test pull plates (5), the hydraulic jaw clamps the test pull plates (5) extending out of the left and right ends of the test piece respectively, and is used to apply an external force to make the smart bolt friction surface slide.

4. The fastener slip resistance test system of claim 3, wherein, The test piece further comprises two test cover plates (6), the two test cover plates are horizontally arranged in an upper and lower spaced manner, the two test pull plates (5) are horizontally clamped between the two test cover plates (6), the distal ends of the two test pull plates (5) are symmetrically exposed outside the left and right ends of the test cover plates (6), four vertical through threaded holes are arranged on the left and right sides of the test piece, and four smart bolts (1) are arranged in the corresponding threaded holes and threadedly fix the two test cover plates (6) and the two test pull plates (5) through the matched test nuts (4) to form a bolt connection pair.

5. A fastener slip resistance coefficient test method characterized by, The device is applied to a fastener anti-slip coefficient test system as claimed in claim 3 or 4, and the steps comprise: S1, the smart bolt (1) is connected with the ultrasonic detection device through the measuring cable and the ultrasonic probe; S2, the test piece is threadedly fixed to form a bolt connection pair through the four smart bolts (1) and the matched test nuts (4); S3, the test starts, the universal testing machine applies a pulling force to the two test pull plates (5) through the hydraulic jaw to make the smart bolt friction surface slide, the ultrasonic probe detects the echo signal and transmits it to the ultrasonic detection device, the ultrasonic detection device analyzes the signal and automatically calculates the axial force applied to the smart bolt (1) according to a preset axial force calculation formula of the smart bolt (1) and outputs the result; S4, the shear force of the smart bolt (1) is calculated according to a preset shear force formula based on the data information obtained by the ultrasonic detection device, and the anti-slip coefficient is obtained according to the axial force and the shear force of the smart bolt (1) and an anti-slip coefficient formula; S5, the ultrasonic probe connected to the smart bolt (1) is removed, and the test is completed.

6. The fastener slip resistance test method according to claim 5, wherein In step S1, two test cover plates (6) and two test pull plates (5) are prepared, the two test cover plates (6) are horizontally and symmetrically clamped in the middle of the two test pull plates (5), four symmetric vertical through threaded holes are first punched on the left and right side end faces of the test piece for positioning, then the four intelligent bolts (1) are passed through the corresponding threaded holes and are threadedly fixed to the end faces of the test piece through the test nuts (4) to form a bolt connection pair.

7. The fastener slip resistance test method according to claim 5, wherein In step S3, the axial force borne by the intelligent bolt (1) is calculated by the formula: In the formula, F is the axial force borne by the bolt; is the measured acoustic time difference before and after the load on the bolt; is the acoustic time measurement value for the unloaded condition of the screw; the acoustic time measurement of the bolt under load conditions; A proportional factor related to the bolt material and shape as well as the installation parameters.

8. The fastener slip resistance test method according to claim 5, wherein In step S3, the axial force borne by the intelligent bolt (1) is calculated by the formula: ； ； In the formula, F is the axial force borne by the bolt; is the measured acoustic time difference before and after the load on the bolt; L is the measured difference in length of the bolt before and after loading; L is the length of the bolt under load-free conditions; L is the length of the bolt measured under load conditions; , a proportionality factor related to the bolt material and shape as well as the installation parameters; is a proportionality factor according to the relationship between the bolt length variation and the ultrasonic time difference.

9. The fastener slip resistance test method according to claim 5, wherein In step S4, the shear force borne by the intelligent bolt (1) is calculated by the formula: ； In the formula, is the shear force experienced by the bolt; K is a shear load calibration coefficient.

10. The fastener slip resistance test method according to claim 5, wherein The pulling force applied by the universal testing machine can be replaced by the shear force borne by the test piece.

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