CN211740574U - Monitoring system for evaluating bolt looseness and failure - Google Patents
Monitoring system for evaluating bolt looseness and failure Download PDFInfo
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- CN211740574U CN211740574U CN201921989988.3U CN201921989988U CN211740574U CN 211740574 U CN211740574 U CN 211740574U CN 201921989988 U CN201921989988 U CN 201921989988U CN 211740574 U CN211740574 U CN 211740574U
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Abstract
The utility model discloses a monitoring system for evaluating bolt looseness and failure, which comprises a threaded fastener, wherein the bolt is firstly sleeved with an intelligent gasket in a threaded section extending out of an upper workpiece and then is screwed up through a nut; the intelligent gasket is provided with a first electrode layer, a second electrode layer and a flexible piezoelectric material layer arranged between the first electrode layer and the second electrode layer; a first insulating layer and a second insulating layer are respectively arranged on the upper part of the first electrode layer and the lower part of the second electrode layer; the first electrode layer and the second electrode layer are respectively connected with a first connecting terminal and a second connecting terminal; the first wiring terminal and the second wiring terminal are respectively connected with the signal data acquisition processing terminal. The system monitors the whole process of loosening or failure of the threaded connecting piece, provides early warning in time, monitors the loosening or failure condition of the bolt in real time through acquisition and analysis of piezoelectric signals, can give an alarm in time when the bolt is loosened or failed, and avoids safety accidents caused by loosening or failure of the bolt during the operation of mechanical equipment.
Description
Technical Field
The utility model relates to a monitoring system for aassessment bolt is not hard up and became invalid.
Background
The bolt connection is a universal connection mode and widely applied to the fields of rail transit equipment, wind power, buildings, automobiles and other engineering, but the detachability of the bolt connection is easier to lose efficacy compared with a non-detachable part. The failure modes of the bolts are also various, the most common failure mode is bolt loosening, the bolt can be loosened or failed to different degrees under the impact of cyclic load and forced vibration, and the loosening or failure of the bolt can cause destructive consequences and great property loss. In order to avoid safety accidents caused by loosened or failed bolts, monitoring and maintaining the health state of the bolts are very necessary.
The structure health monitoring technology is a field monitoring technology developed based on the idea of an intelligent structure. In the structural health monitoring system, the intelligent material is used as a sensor, so that the health monitoring system has the basis of obtaining more accurate information. The piezoelectric material is the most applied sensing and driving material in the current intelligent structure system research, and has huge application potential in the aspect of engineering structure health monitoring due to the characteristics of fast response, wide frequency response range, easiness in cutting, low price and the like. And traditional piezoelectric element fragility is big, receives the easy fracture that takes place of oppression when the bolt pretension, and this patent adopts flexible piezoelectric element can solve this difficult problem.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a main aim at provides a monitoring system for assessing bolt is not hard up and became invalid aims at not hard up or become invalid to threaded connection spare and carry out the overall process monitoring, and in time propose the early warning, wherein the change of bolt pretightning force leads to flexible piezoelectric element's piezoelectric performance change in the intelligent gasket, through piezoelectric signal's collection and analysis, the not hard up or the inefficacy condition of real-time supervision bolt, and can in time report to the police in becoming flexible or becoming invalid, remind the staff to maintain and change threaded connection spare, avoid mechanical equipment in service because the not hard up or the incident that the inefficacy caused of bolt.
According to the electromechanical coupling characteristic of the piezoelectric material, if the bolt is loosened or fails, the mechanical impedance of the bolt changes, and the change of the mechanical impedance of the structure can be intuitively reflected through the change of the electric admittance of the piezoelectric material adhered to the surface of the structure; meanwhile, whether the bolt is loosened or failed can be analyzed by monitoring vibration signals of the structure under the action of impact and forced vibration of cyclic load. The monitoring can realize the uninterrupted monitoring of the whole process of the threaded connecting piece, so that the faults and the loss caused by mechanical equipment are greatly reduced. This application makes intelligent gasket through flexible piezoelectric material, can real-time incessant monitoring bolt not hard up or lose efficacy. According to the change of the pretightening force of the threaded connecting piece, the piezoelectric admittance data or the acquired vibration signals of the intelligent gasket are transmitted to the signal data acquisition and processing terminal for analysis, and when the piezoelectric admittance data or the acquired vibration signals are not in a normal change range, an alarm can be given out, so that the bolt loosening or failure can be monitored in real time, and the maintenance or the replacement can be carried out in time.
In order to realize the purpose, the utility model discloses a technical scheme is: a monitoring system for evaluating bolt looseness and failure comprises a threaded fastener, wherein the threaded fastener comprises a nut and a bolt, an upper workpiece and a lower workpiece, the upper workpiece and the lower workpiece are fastened through the threaded fastener, and the bolt is firstly sleeved with an intelligent gasket in a threaded section extending out of the upper workpiece and then is screwed through the nut; the intelligent gasket is provided with a first electrode layer, a second electrode layer and a flexible piezoelectric material layer arranged between the first electrode layer and the second electrode layer; a first insulating layer and a second insulating layer are respectively arranged on the upper part of the first electrode layer and the lower part of the second electrode layer; the first electrode layer and the second electrode layer are respectively connected with a first connecting terminal and a second connecting terminal; the first connecting terminal and the second connecting terminal are connected with the signal data acquisition and processing terminal;
furthermore, the first insulating layer, the first electrode layer, the flexible piezoelectric material layer and the second electrode layer are all arranged in an annular sheet structure with the same outer diameter, and the diameters of the middle through holes are the same; the second insulating layer is of an annular structure, and an annular groove coaxial with an inner hole of the annular structure is formed in the annular surface at the upper part of the second insulating layer; the outer wall of the annular groove is provided with a first square through hole and a second square through hole which are arranged in a vertically staggered manner; the second electrode layer is coaxially arranged in the annular groove, a second connecting terminal arranged on the second electrode layer penetrates through the second square through hole, and the flexible piezoelectric material layer is also coaxially arranged in the annular groove and is in contact with the second electrode layer; the first electrode layer is coaxially arranged in the annular groove and is in contact with the flexible piezoelectric material layer, and a first connecting terminal arranged on the first electrode layer penetrates through the first square through hole; the first insulating layer is coaxially arranged on the second insulating layer and is in contact with the first electrode layer, and the diameter of the outer ring of the first insulating layer is equal to that of the outer ring of the second insulating layer.
Furthermore, the top surface of the anti-torsion groove top gasket is wound around a middle through hole to form a first fan-shaped boss structure in an annular array, and the outer circular surface of the fan-shaped boss structure is in clearance fit with the inner through hole of the second insulating layer; the top of the first insulating layer is matched with the anti-torsion groove top gasket, a second fan-shaped boss structure matched with the fan-shaped boss structure gap groove is arranged on the bottom surface of the anti-torsion groove top gasket around the middle through hole of the anti-torsion groove top gasket, and the groove of the first fan-shaped boss structure and the protrusion of the second fan-shaped boss structure are mutually clamped to enable the intelligent gasket to form an integral structure.
Furthermore, the anti-torsion groove top gasket and the anti-torsion boss bottom gasket are made of low-carbon steel; the first insulating layer and the second insulating layer are made of flexible insulating materials with the thickness within the range of 0.1mm-1 cm; the first electrode layer and the second electrode layer are made of red copper sheets; the flexible piezoelectric material layer is a 0-3 type PZT/epoxy resin composite material.
Furthermore, the signal data acquisition and processing terminal comprises a display, a wiring terminal block, a control panel, a reset switch and an alarm; an admittance testing module, a vibration testing module and a result analysis and early warning module based on the piezoelectric impedance technology are arranged in the signal data acquisition and processing terminal; the admittance signal acquisition and processing module is connected with the admittance signal acquisition wiring terminal block, and the vibration signal acquisition and processing module is connected with the vibration piezoelectric signal acquisition wiring terminal block; an admittance testing module and a vibration testing module which are arranged in the signal data acquisition and processing terminal are respectively connected with a result analysis and early warning module, and the result analysis and early warning module takes a display and an alarm as output equipment; and the admittance signal acquisition connecting terminal strip or the vibration piezoelectric signal acquisition connecting terminal strip is connected with the first connecting terminal and the second connecting terminal of the first electrode layer and the second electrode layer through wires.
A monitoring method for a monitoring system for assessing bolt loosening and failure, comprising the steps of:
s1: sequentially placing a second electrode layer, a flexible piezoelectric material layer, a first electrode layer and a first insulating layer in an intelligent gasket into an annular groove of a second insulating layer, and respectively extending a first terminal of the first electrode layer and a second terminal of the second electrode layer from a first square through hole and a second square through hole on the outer wall of the annular groove of the second insulating layer to form an intelligent gasket sensitive component taking the first insulating layer and the second insulating layer as a shell; then coaxially assembling the intelligent gasket sensitive assembly on the anti-torsion boss bottom gasket, coaxially covering the anti-torsion groove top gasket, and keeping the groove structure of the anti-torsion groove top gasket buckled on the boss structure of the anti-torsion boss bottom gasket to form the intelligent gasket;
s2: coaxially aligning holes of a lower workpiece and an upper workpiece, installing a threaded connecting piece and an intelligent gasket according to the assembly sequence of a threaded standard piece and a common gasket, and then slowly screwing the threaded connecting piece to the required torque by using a torque wrench;
s3: the signal data acquisition and processing terminal is started to carry out testing, and the following two conditions exist:
(1) if the first connecting terminal and the second connecting terminal of the first electrode layer and the second electrode layer are connected with the admittance signal acquisition connecting terminal row; under the action of an electric signal, a display in the signal data acquisition and processing terminal displays a piezoelectric admittance data curve of the flexible piezoelectric material layer; if the bolt is loosened or fails, the maximum value of the curve of the piezoelectric admittance is obviously deviated, and when the amplitude value continuously drops to a threshold value, an alarm is given out;
(2) if the first connecting terminal and the second connecting terminal of the first electrode layer and the second electrode layer are connected with the vibration signal acquisition connecting terminal row; a display in the signal data acquisition and processing terminal displays the vibration signal acquired by the flexible piezoelectric material layer; if the bolt is loosened or fails, the displayed vibration signal does not accord with the chaotic signal or signal characteristic in the signal database of the signal data acquisition and processing terminal, and the alarm gives an alarm;
s4: if the alarm gives an alarm, the threaded fastener where the intelligent gasket is located is maintained or replaced in time.
The utility model has the advantages that:
1. the utility model discloses can realize carrying out real-time supervision to the operating condition of fastener, the bolt damages or sends out the police dispatch newspaper when becoming invalid, has saved artifical check-out time, and real-time supervision bolt operating condition has guaranteed staff's safety, has saved the cost that mechanical equipment shut down because of regular timing detection. And manual detection can be influenced by weather factors, and high temperature, rain and the like can influence the monitoring progress, and the monitoring system can solve the problems and can be applied to the industrial field using a large number of bolts.
2. The utility model discloses can differentiate whether the bolt is not hard up or became invalid through the signal of the flexible piezoelectric material layer admittance data of gathering bolt operating condition or vibration, the technique is comparatively ripe, and the discernment rate of accuracy is high, and is fit for different operating mode requirements and selects.
3. Traditional piezoceramics component fragility is big, hardness is high, the utility model discloses a flexible piezoelectric material of flexible piezoelectric sensing element conduct intelligence gasket, like 0-3 type PZT epoxy combined material, with low costs, it has certain elastic modulus, and pretightning force when can avoiding the bolt pretension strikes and makes piezoelectric material break or damage, leads to unable normal test.
4. In the utility model, the piezoelectric constant d33 of the piezoelectric element is the largest compared with d31 and d15, and the characteristic significance of the collected admittance data or the collected signal is in direct proportion to the value of the piezoelectric constant; set up anti unsmooth cooperation groove that twists reverse, make the flexible piezoelectricity sensing element in the intelligent gasket avoid receiving the moment of torsion, produce horizontal stress, its d33 performance of application that can be better, the admittance data that makes the collection or the signal of gathering are better, and it is more accurate to discern not hard up or the inefficacy of bolt.
5. The utility model discloses set up intelligent gasket structure, the part is few, low in production cost, general in the work occasion of ordinary gasket, can with the fine cooperation of threaded connection spare, and be convenient for change, compare with the design of patent in the aspect of most intelligent bolt in the bolt main part, its processing is more simple, operates more aspect, and sensitivity is high moreover.
Drawings
Fig. 1 is a schematic diagram of the system connection structure of the present invention.
Fig. 2 is the utility model discloses an intelligence gasket and threaded connection spare assembly plan view.
Fig. 3 is an explosion view of the intelligent gasket structure of the present invention.
Fig. 4 is the utility model discloses an intelligence gasket structure equipment stereogram.
Fig. 5 is the utility model discloses the inside functional principle schematic diagram of signal data acquisition processing terminal.
In the figure: 1. a threaded fastener; 2. a signal data acquisition processing terminal; 3. loading a workpiece; 4. a lower workpiece; 11. a nut; 12. an intelligent gasket; 13. a bolt; 21. a display; 22. a terminal block; 23. a control panel; 24. a reset switch; 25. an alarm; 121. an anti-twist groove top shim; 122. a first insulating layer; 123. a first electrode layer; 124. a layer of flexible piezoelectric material; 125. a second electrode layer; 126. a second insulating layer; 127. an anti-torsion boss base gasket; 221. admittance signal acquisition terminal blocks; 222. a vibration signal acquisition terminal block; 1211. a groove structure; 1231. a first terminal; 1251. a second terminal; 1261. an annular groove; 1262. a first square through hole; 1263. a second square through hole; 1271. and (4) a boss structure.
Detailed Description
In order to make the technical solution of the present invention better understood, the present invention is described in detail below with reference to the accompanying drawings, and the description of the present invention is only exemplary and explanatory, and should not be construed as limiting the scope of the present invention.
As shown in fig. 1-4, a monitoring system for evaluating bolt loosening and failure comprises a threaded fastener 1, a signal data acquisition and processing terminal 2, an intelligent gasket 12, an upper workpiece 3 and a lower workpiece 4, wherein the threaded fastener 1 comprises a nut 11 and a bolt 13; the upper workpiece 3 and the lower workpiece 4 are fastened by a threaded fastener 1; the bolt 13 is firstly sleeved with the intelligent gasket 12 in the thread section extending out of the upper workpiece 3 and then is screwed up through the nut 11; the intelligent gasket 12 is provided with a first electrode layer 123, a second electrode layer 125 and a flexible piezoelectric material layer 124 arranged between the first electrode layer and the second electrode layer; a first insulating layer 122 and a second insulating layer 126 are respectively arranged on the upper portion of the first electrode layer 123 and the lower portion of the second electrode layer 125; a first connection terminal 1231 and a second connection terminal 1251 are connected to the first electrode layer 123 and the second electrode layer 125, respectively; the first connection terminal 1231 and the second connection terminal 1251 are connected to the signal data acquisition and processing terminal 2. The upper part of the first electrode layer 123 and the lower part of the second electrode layer 125 are respectively provided with the first insulating layer 122 and the second insulating layer 126 to form a sensitive component of a piezoelectric film, the change of the mechanical impedance of the structure can be intuitively reflected through the change of the electric admittance of the piezoelectric material, and whether the bolt is loosened or fails is analyzed through monitoring the vibration signal of the structure under the action of the impact of the cyclic load and the forced vibration.
Preferably, the first insulating layer 122, the first electrode layer 123, the flexible piezoelectric material layer 124, and the second electrode layer 125 are all configured as an annular thin sheet structure with the same outer diameter and the same diameter of the middle through hole; the second insulating layer 126 is arranged into an annular structure, and an annular groove 1261 which is coaxial with an inner hole of the annular structure is arranged on the upper annular surface of the second insulating layer 126; the outer wall of the annular groove 1261 is provided with a first square through hole 1262 and a second square through hole 1263 which are arranged in a vertically staggered mode; the second electrode layer 125 is coaxially disposed in the annular groove 1261, and the second connection terminal 1251 disposed thereon is disposed through the second square through hole 1263, and the flexible piezoelectric material layer 124 is also coaxially disposed in the annular groove 1261 and is in contact with the second electrode layer 125; the first electrode layer 123 is coaxially disposed in the annular groove 1261 and is in contact with the flexible piezoelectric material layer 124, and a first connection terminal 1231 disposed thereon is disposed through the first square through hole 1262; the first insulating layer 122 is coaxially arranged on the second insulating layer 126 and is in contact with the first electrode layer 123, and the diameter of the outer circle of the first insulating layer is equal to that of the outer circle of the second insulating layer; the first electrode layer 123, the flexible piezoelectric material layer 124 and the second electrode layer 125 are received in an annular groove 1261 formed in the second insulating layer 126, the top of the second insulating layer 126 is covered by the first insulating layer 122, the first electrode layer 123 and the second electrode layer 125 respectively extend out of the first connection terminal 1231 and the second connection terminal 1251, a simple piezoelectric film sensitive element is formed, and whether the bolt 13 is loosened or not is obtained by measuring admittance or vibration conditions of the first electrode layer 123 and the second electrode layer 125.
Preferably, the top surface of the anti-twist boss base gasket 127 is provided with a first fan-shaped boss structure 1271 in an annular array around the central through hole thereof, the outer circumferential surface of said fan-shaped boss structure 1271 being in clearance fit with the through hole in the second insulating layer 126; the top of the first insulating layer 122 is matched with an anti-torsion groove top gasket 121, a second fan-shaped boss structure 1211 matched with a clearance groove of the fan-shaped boss structure 1271 is arranged on the bottom surface of the anti-torsion groove top gasket 121 around a middle through hole of the anti-torsion groove top gasket, and the groove of the first fan-shaped boss structure 1271 is clamped with the protrusion of the second fan-shaped boss structure 1211 to enable the intelligent gasket 12 to form an integral structure; through the mutual block of antitorque commentaries on classics recess top gasket 121 and antitorque commentaries on classics boss gasket 127 for intelligent gasket 12 constitutes a whole, can prevent simultaneously that each layer between each other in intelligent gasket 12 from taking place to remove the dislocation influence measurement accuracy.
Preferably, the anti-twist groove top shim 121 and the anti-twist boss bottom shim 127 are low carbon steel; the first insulating layer 122 and the second insulating layer 126 are made of flexible insulating materials with the thickness in the range of 0.1mm-1 cm; the first electrode layer 123 and the second electrode layer 125 are made of red copper sheets; the flexible piezoelectric material layer 124 is a type 0-3 PZT/epoxy composite.
Preferably, as shown in fig. 1 and 5, the signal data acquisition and processing terminal 2 includes a display 21, a terminal block 22, a control panel 23, a reset switch 24 and an alarm 25; the signal data acquisition and processing terminal 2 is internally provided with an admittance testing module, a vibration testing module and a result analysis and early warning module based on the piezoelectric impedance technology; the admittance signal acquisition and processing module is connected with the admittance signal acquisition terminal block 221, the vibration signal acquisition and processing module is connected with the vibration piezoelectric signal acquisition terminal block 222, the admittance testing module and the vibration testing module of the signal data acquisition and processing terminal 2 are respectively connected with the result analysis and early warning module, and the result analysis and early warning module takes the display 21 and the alarm 25 as output equipment; the admittance signal acquisition terminal block 221 or the vibration piezoelectric signal acquisition terminal block 222 is connected with the first terminal 1231 and the second terminal 1251 of the first electrode layer and the second electrode layer by wires.
Preferably, as shown in fig. 5, the internal function module of the signal data acquisition and processing terminal 2 includes an admittance testing module, a vibration testing module and a result analysis and early warning module; the admittance testing module comprises an alternating current signal generator, a signal filtering module, a signal power amplifying module, a piezoelectric admittance signal acquisition module, a piezoelectric admittance signal processor, a first arithmetic unit and an admittance signal characteristic quantity database; the vibration testing module comprises a vibration signal acquisition module, a vibration signal processor, a second arithmetic unit and a vibration signal characteristic quantity database; the structural analysis and early warning module comprises a result analysis display module and an alarm module, as shown in fig. 1 and 5, the internal function execution flow and principle of the signal data acquisition and processing terminal are as follows:
(1) the piezoelectric admittance signal test execution flow comprises the following steps: the built-in alternating current signal generator sends a simple harmonic alternating current test signal with required frequency, the test signal passes through the signal filtering module to filter interference signals such as clutter and harmonic waves, and then passes through the signal power amplifying module to amplify amplitude and power, and the amplified signals act on the intelligent gasket 12; the intelligent gasket feeds back a response signal, the piezoelectric admittance signal acquisition module acquires the response signal of the intelligent gasket, and the response signal is calculated and processed by the piezoelectric admittance signal processor to obtain a piezoelectric admittance signal and characteristic quantity; the piezoelectric admittance signal characteristic quantity obtained by calculation is sent to an arithmetic unit I, is compared with a preset threshold value in an admittance signal characteristic quantity database, and a comparison result is transmitted to a result analysis display module to display an output result; and if the calculated piezoelectric admittance signal characteristic quantity is not within the preset threshold range, the alarm module is started to give an alarm prompt.
(2) Vibration signal test execution flow: exciting the threaded fastener by an external vibration signal; the vibration signal acquisition module acquires a response signal of the intelligent gasket 12 in the threaded fastener, performs signal processing on the response signal through the vibration signal processor to obtain a vibration signal characteristic quantity, and displays the response signal and the characteristic quantity on a display; the calculated vibration signal characteristic quantity is sent to a second arithmetic unit, the second arithmetic unit is compared with a preset threshold value in a vibration signal characteristic quantity database, the comparison result is transmitted to a result analysis display module, and an output result is displayed; and if the calculated vibration signal characteristic quantity is not within the preset threshold range, starting an alarm module to give an alarm prompt.
A monitoring method for a monitoring system for assessing bolt loosening and failure, comprising the steps of:
s1: sequentially placing the second electrode layer 125, the flexible piezoelectric material layer 124, the first electrode layer 123 and the first insulating layer 122 in the intelligent gasket 12 into an annular groove of the second insulating layer 126, and respectively extending the first terminal 1231 of the first electrode layer 123 and the second terminal 1251 of the second electrode layer 125 out of the first square through hole 1262 and the second square through hole 1263 on the outer wall of the annular groove of the second insulating layer 126 to form a sensitive component of the intelligent gasket 12 with the insulating layers 122 and 126 as shells; the sensitive components of the intelligent gasket 12 are coaxially assembled on the anti-torsion boss bottom gasket 127, the anti-torsion groove top gasket 121 is coaxially covered, and the groove structure 1211 of the anti-torsion groove top gasket 121 is retained to be buckled into the boss structure 1271 of the anti-torsion boss bottom gasket 127 to form the intelligent gasket 12;
s2: coaxially aligning holes of a lower workpiece 3 and an upper workpiece 4, installing a threaded connecting piece and an intelligent gasket 12 according to the assembly sequence of a threaded standard piece and a common gasket, and then slowly screwing the threaded connecting piece to the required torque by using a torque wrench;
s3: starting a signal data acquisition and processing terminal for testing;
1) if the first electrode layer 123, the first connection terminal 1231 and the second connection terminal 1251 of the second electrode layer 125 are connected to the admittance signal collecting connection terminal block 221; under the action of the electric signal, the display 21 in the signal data acquisition and processing terminal 2 displays the piezoelectric admittance data curve of the flexible piezoelectric material layer 124; if the bolt is loosened or fails, the maximum value of the curve of the piezoelectric admittance is obviously deviated, and when the amplitude value continuously drops to a threshold value, the alarm 25 gives an alarm.
2) If the first connection terminal 1231 and the second connection terminal 1251 of the first electrode layer 123 and the second electrode layer 125 are connected to the vibration signal collecting connection terminal row 222; the display 21 in the signal data acquisition processing terminal 2 displays the vibration signal acquired by the flexible piezoelectric material layer 124; if the bolt is loosened or fails, the displayed vibration signal does not accord with the disordered signal or signal characteristics in the signal database of the signal data acquisition and processing terminal, and the alarm 25 gives an alarm.
S4: if the alarm 25 gives an alarm, the threaded fastener 1 where the intelligent gasket 12 is located is repaired or replaced in time.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The principles and embodiments of the present invention have been explained herein using specific examples, which are presented only to assist in understanding the methods and their core concepts. The foregoing is only a preferred embodiment of the present invention, and it should be noted that there are objectively infinite specific structures due to the limited character expressions, and it will be apparent to those skilled in the art that a plurality of modifications, decorations or changes can be made without departing from the principle of the present invention, and the above technical features can be combined in a proper manner; the application of these modifications, variations or combinations, or the application of the concepts and solutions of the present invention in other contexts without modification, is not intended to be considered as a limitation of the present invention.
Claims (5)
1. A monitoring system for evaluating bolt loosening and failure, comprising a threaded fastener including a nut and a bolt, an upper workpiece and a lower workpiece fastened by the threaded fastener, characterized in that: the bolt is firstly sleeved with the intelligent gasket in the threaded section extending out of the upper workpiece and then is screwed down through the nut; the intelligent gasket is provided with a first electrode layer, a second electrode layer and a flexible piezoelectric material layer arranged between the first electrode layer and the second electrode layer; a first insulating layer and a second insulating layer are respectively arranged on the upper part of the first electrode layer and the lower part of the second electrode layer; the first electrode layer and the second electrode layer are respectively connected with a first connecting terminal and a second connecting terminal; the first wiring terminal and the second wiring terminal are connected with the signal data acquisition processing terminal.
2. The monitoring system for evaluating bolt loosening and failure according to claim 1, wherein the first insulating layer, the first electrode layer, the flexible piezoelectric material layer and the second electrode layer are all provided in an annular thin-plate structure with the same outer diameter and the same diameter of the middle through hole; the second insulating layer is of an annular structure, and an annular groove coaxial with an inner hole of the annular structure is formed in the annular surface at the upper part of the second insulating layer; the outer wall of the annular groove is provided with a first square through hole and a second square through hole which are arranged in a vertically staggered manner; the second electrode layer is coaxially arranged in the annular groove, a second connecting terminal arranged on the second electrode layer penetrates through the second square through hole, and the flexible piezoelectric material layer is also coaxially arranged in the annular groove and is in contact with the second electrode layer; the first electrode layer is coaxially arranged in the annular groove and is in contact with the flexible piezoelectric material layer, and a first connecting terminal arranged on the first electrode layer penetrates through the first square through hole; the first insulating layer is coaxially arranged on the second insulating layer and is in contact with the first electrode layer, and the diameter of the outer ring of the first insulating layer is equal to that of the outer ring of the second insulating layer.
3. The monitoring system for evaluating bolt loosening and failure of claim 2 wherein the top surface of the anti-twist boss base gasket is in an annular array of a first scalloped boss structure around its central through hole, the outer circumferential surface of said scalloped boss structure being in clearance fit with the inner through hole of the second insulator layer; the top of the first insulating layer is matched with the anti-torsion groove top gasket, a second fan-shaped boss structure matched with the fan-shaped boss structure gap groove is arranged on the bottom surface of the anti-torsion groove top gasket around the middle through hole of the anti-torsion groove top gasket, and the groove of the first fan-shaped boss structure and the protrusion of the second fan-shaped boss structure are mutually clamped to enable the intelligent gasket to form an integral structure.
4. A monitoring system for assessing bolt loosening and failure as claimed in claim 3, wherein the anti-twist groove top washer and anti-twist boss bottom washer are low carbon steel; the first insulating layer and the second insulating layer are made of flexible insulating materials with the thickness within the range of 0.1mm-1 cm; the first electrode layer and the second electrode layer are made of red copper sheets; the flexible piezoelectric material layer (124) is a 0-3 type PZT/epoxy resin composite material.
5. The monitoring system for evaluating the loosening and failure of the bolt according to claim 1, wherein the signal data acquisition and processing terminal comprises a display, a wiring terminal block, a control panel, a reset switch and an alarm; an admittance testing module, a vibration testing module and a result analysis and early warning module based on the piezoelectric impedance technology are arranged in the signal data acquisition and processing terminal; the admittance signal acquisition and processing module is connected with the admittance signal acquisition wiring terminal block, and the vibration signal acquisition and processing module is connected with the vibration piezoelectric signal acquisition wiring terminal block; an admittance testing module and a vibration testing module which are arranged in the signal data acquisition and processing terminal are respectively connected with a result analysis and early warning module, and the result analysis and early warning module takes a display and an alarm as output equipment; and the admittance signal acquisition connecting terminal strip or the vibration piezoelectric signal acquisition connecting terminal strip is connected with the first connecting terminal and the second connecting terminal of the first electrode layer and the second electrode layer through wires.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921989988.3U CN211740574U (en) | 2019-11-18 | 2019-11-18 | Monitoring system for evaluating bolt looseness and failure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921989988.3U CN211740574U (en) | 2019-11-18 | 2019-11-18 | Monitoring system for evaluating bolt looseness and failure |
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| CN211740574U true CN211740574U (en) | 2020-10-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114748781A (en) * | 2021-06-02 | 2022-07-15 | 张彧 | Needle head assembly and microneedle drum-type skin physiotherapy instrument |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114748781A (en) * | 2021-06-02 | 2022-07-15 | 张彧 | Needle head assembly and microneedle drum-type skin physiotherapy instrument |
| CN114748781B (en) * | 2021-06-02 | 2023-10-20 | 张彧 | Needle head assembly and microneedle roller type skin physiotherapy instrument |
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