CN115046494B - Thread structure looseness measuring device based on distributed shape sensing - Google Patents
Thread structure looseness measuring device based on distributed shape sensing Download PDFInfo
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- CN115046494B CN115046494B CN202210623856.9A CN202210623856A CN115046494B CN 115046494 B CN115046494 B CN 115046494B CN 202210623856 A CN202210623856 A CN 202210623856A CN 115046494 B CN115046494 B CN 115046494B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
The invention provides a thread structure looseness measuring device based on distributed shape sensing, which comprises a looseness measuring device corresponding to a thread structure, wherein the looseness measuring device comprises a spring and an optical fiber section, the optical fiber section is arranged on the spring along the trend of the spring, when the thread structure is loosened, the shape of the spring is correspondingly changed, and one end of the optical fiber section is used for receiving a measuring optical signal; and determining the shape change condition of the spring according to a reflected signal returned after the optical fiber section receives the measuring optical signal, thereby determining the loosening condition of the thread structure. The invention has simple structure, low operation and maintenance cost and no influence of electromagnetic interference on the loosening measurement.
Description
Technical Field
The invention belongs to the field of bolt looseness detection, and particularly relates to a thread structure looseness measuring device based on distributed shape sensing.
Background
The threaded connection is widely applied to the mechanical field due to the advantages of reliable connection, convenience in mounting and dismounting and the like. However, in the actual use process, the threaded connection structure may become loose due to factors such as vibration, impact and corrosion, which brings huge potential safety hazards to the mechanical structure, so that the threaded connection structure has very important significance in identifying the loosening damage degree of the threaded structure. In the current bolt looseness measurement, most measurement systems adopt a strain gauge measurement method, one strain gauge corresponds to one measurement point, and a plurality of strain gauges are generally adopted for measuring the bolt looseness. When large-scale and large-scale structures are detected, the method has the problems that a large number of strain gauges and matched electrical equipment are needed, the strain gauges are easily affected by electromagnetic interference, actual installation is inconvenient, the complexity of the system on hardware is increased, and the operation and maintenance cost of the system is increased.
Disclosure of Invention
The invention provides a thread structure looseness measuring device based on distributed shape sensing, and aims to solve the problems that a conventional thread structure looseness measuring system is high in strain gauge number, matched electrical equipment is easily influenced by electromagnetic interference, the structure is complex, and the operation and maintenance cost is high.
According to a first aspect of the embodiment of the invention, a thread structure looseness measuring device based on distributed shape sensing is provided, and comprises a looseness measuring device corresponding to a thread structure, wherein the looseness measuring device comprises a spring and an optical fiber section, the optical fiber section runs along the spring and is wired on the spring, when the thread structure is loosened, the shape of the spring is correspondingly changed, and one end of the optical fiber section is used for receiving a measuring optical signal; and determining the shape change condition of the spring according to a reflected signal returned after the optical fiber section receives the measuring optical signal, thereby determining the loosening condition of the thread structure.
In an alternative implementation, when the thread structure is loosened, the inclination direction of the spring changes synchronously with the change of the inclination direction of the thread structure, and the stretching or compressing degree of the spring is gradually increased as the loosening degree of the thread structure is increased.
In another optional implementation manner, determining a change in shape of the spring according to a reflected signal returned after the optical fiber segment receives the measuring optical signal, so as to determine a loosening condition of the thread structure includes:
measuring the shape of the spring before and after the thread structure is loosened based on a shape measurement principle according to a reflected signal returned after the optical fiber section receives the measuring optical signal;
and comparing the shapes of the spring measured before and after the thread structure is loosened, calculating the shape distortion of the spring, and determining the loosening condition of the thread structure according to the shape distortion of the spring.
In another optional implementation manner, the measuring the shape of the spring based on the shape measurement principle according to a reflected signal returned after the optical fiber segment receives the measurement optical signal includes: according to the reflected signal, measuring the three-dimensional space coordinate set of each point on the spring before the thread structure loosens based on the shape measurement principle to be (x 1) i ,y1 i ,z1 i ) And the three-dimensional space coordinate set of each point on the spring after the thread structure is loosened is (x 2) i ,y2 i ,z2 i ) N is an integer which is more than 0 and is used for representing the number of each point on the spring, and i is an integer which is less than or equal to N and is more than 0; from points on said springThree-dimensional space coordinate set (x 1) i ,y1 i ,z1 i ) And (x 2) i ,y2 i ,z2 i ) Respectively showing the shapes of the spring before and after the thread structure loosens;
comparing the shapes of the spring measured before and after the thread structure loosens, and calculating the spring shape distortion quantity comprises the following steps: calculating a Euclidean distance d of a three-dimensional space according to the following formula, wherein the Euclidean distance represents the spring shape distortion quantity:
in another optional implementation manner, determining the loosening condition of the thread structure according to the distortion amount of the spring shape includes: and judging whether the spring shape distortion exceeds a corresponding set threshold, and if so, determining the loosening condition of the thread structure according to the set threshold.
In another optional implementation manner, the looseness measuring device further includes a sleeve and a top cover, a spiral groove is provided in the sleeve, the spring is vertically provided in the spiral groove matched with the spring, and the upper end of the spring is fixedly connected with a fastener on the top cover, one end of the optical fiber section penetrates through a through hole of the sleeve to receive a measuring optical signal, the sleeve is supported by a support member, the top cover and the thread structure are located in the sleeve, and the top cover is located on the thread structure; when the threaded structure loosens and rotates spirally, the top cover is driven to move in a first vertical direction relative to the sleeve, and therefore the shape of the spring is changed.
In another optional implementation manner, the looseness measuring device further comprises a bottom plate, the sleeve is fixed on the bottom plate, and the thread structure penetrates through the bottom plate and extends out of the sleeve; the supporting piece is a nut, the nut is positioned below the bottom plate, is in threaded connection with the threaded structure, is fixedly abutted against the bottom plate on the upper surface of the nut, and is used for supporting the sleeve; when the threaded structure is loosened and spirally rotated, the top cover is driven to move in the first vertical direction, the nut moves in the second vertical direction under the action of the gravity of the bottom plate and the sleeve on the bottom plate, so that the bottom plate and the sleeve on the bottom plate are driven to move in the second vertical direction, and the first vertical direction is opposite to the second vertical direction.
In another optional implementation manner, after the other end of the optical fiber segment corresponding to the current thread structure passes through the through hole of the sleeve, the other end of the optical fiber segment is connected with the optical fiber segment corresponding to the next thread structure through the connecting segment in the optical fiber.
In another optional implementation manner, the looseness measuring device further comprises a washer, the washer is located between the threaded structure and the bottom plate, in an initial state, the washer is pressed between the bottom plate and the threaded structure by the support piece, and the washer is used for avoiding radial displacement when the threaded structure is not loosened.
In another optional implementation manner, the looseness measuring device further comprises a base and a sleeve cap, wherein openings are formed in the upper end and the lower end of the sleeve, the lower end of the sleeve is in threaded connection with the base, and the base is fixed on the bottom plate; the upper end of the sleeve is connected with the sleeve cap;
the fasteners are uniformly distributed on the periphery of the top end of the top cover; and the bottom end of the top cover is provided with a containing groove matched with the top end of the threaded structure.
The invention has the beneficial effects that:
1. according to the invention, the optical fiber is arranged on the spring along the spring direction, so that the shape of the spring is changed in the process that the thread structure is spirally rotated due to looseness, and the shape of the spring is determined based on a reflected signal returned after the optical fiber section receives a measurement signal, thereby determining the looseness condition of the thread structure;
2. according to the invention, based on the three-dimensional space coordinate set of each point on the spring before and after the thread structure loosens, the Euclidean distance of the three-dimensional space of the spring and the spring is calculated, the loosening condition of the thread structure is determined according to the Euclidean distance, and the loosening condition determining method is simple;
3. the optical fiber is arranged on the spring along the direction of the spring, the upper end of the spring is fixedly connected with the fastener of the top cover, the threaded structure positioned below the top cover can drive the top cover to move in a first vertical direction relative to the sleeve in the process of spiral rotation due to looseness, and the top cover is fixedly connected with the upper end of the spring, so that the top cover can drive the spring to deform and correspondingly change the shape of an optical fiber section on the spring; secondly, when the loosening condition of the thread structure is determined, the rotation angle of the thread structure is not measured, but the thread structure drives the top cover to move relative to the sleeve, so that the spring is stretched and deformed, namely, the angle measurement is converted into linear measurement, and the rotation angle can be detected even if the rotation angle is small, so that the method has higher resolution and sensitivity; moreover, compared with the strain gauge limited by the fatigue life, the strain gauge adopts the deformation of the spring to reflect the loosening condition of the thread structure, so that the service life of the strain gauge is longer;
4. according to the invention, the sleeve is fixed on the bottom plate, the bottom plate is abutted and fixed with the upper surface of the nut, and then the nut is in threaded connection with the threaded structure, because the bottom plate and the sleeve have certain weight, the threaded structure loosens, when the nut rotates spirally, the threaded structure cannot drive the bottom plate and the sleeve to rotate synchronously, the bottom plate and the sleeve apply a force to the nut to fix the nut, so that the nut and the threaded structure generate relative displacement in the spiral rotation process of the threaded structure, namely, the bottom plate and the sleeve supported by the nut can both generate second vertical movement; because the top cover can move in the first vertical direction and the sleeve can move in the second vertical direction when the thread structure loosens and rotates in a spiral manner, and the first vertical direction is opposite to the second vertical direction, the nut in threaded connection with the thread structure not only plays a role in supporting the bottom plate and the sleeve, but also can increase the relative displacement between the top cover and the sleeve caused by the spiral rotation process of the thread structure, thereby increasing the spring deformation quantity caused by the rotation of the thread structure in a unit angle, and further improving the measurement sensitivity of loosening; in addition, the nut is used as a support frame for supporting the sleeve, and is in threaded connection with the threaded structure, so that the sleeve can be prevented from being fixed additionally, the threaded structure is assembled with a device related to the loosening measurement before leaving a factory, and the device related to the loosening measurement does not need to be installed on site, so that the installation efficiency of the invention is greatly improved; according to the invention, devices related to the looseness measurement are all assembled on the thread structure, certain pressure can be applied to the thread structure, and the thread structure is prevented from loosening to a certain extent;
5. the invention can measure the loosening condition of a plurality of thread structures by using one optical fiber;
6. according to the invention, the sleeve is set to be of a structure with the upper end and the lower end being open, the upper end of the sleeve is in threaded connection with the sleeve cap, the lower end of the sleeve is in threaded connection with the base, the sleeve cap can prevent dust, rainwater and the like from falling into the sleeve, and the sleeve is detachably designed, so that the assembly in the sleeve is convenient to install and the subsequent assembly maintenance is convenient;
7. the top end of the top cover is provided with the plurality of fasteners which are uniformly distributed on the periphery of the top end of the top cover, and the upper end of the spring connected with the fasteners can sequentially penetrate through the fasteners for fixing so as to ensure that the spring deforms along with the rotation of the top cover.
Drawings
FIG. 1 is a side view of the overall structure of one embodiment of a thread structure looseness measuring device based on distributed shape sensing of the invention;
FIG. 2 isbase:Sub>A view A-A of FIG. 1;
FIG. 3 is a schematic view of the relationship of the spring and the optical fiber of the present invention;
FIG. 4 is a perspective view of one embodiment of the sleeve of the present invention;
FIGS. 5 (a) and (b) are side and top views, respectively, of one embodiment of a sleeve of the present invention;
FIG. 6 is a perspective view of one embodiment of the sleeve cap of the present invention;
FIGS. 7 (a) and (b) are side and top views, respectively, of one embodiment of a sleeve cap of the present invention;
FIG. 8 is a perspective view of one embodiment of a base of the present invention;
FIGS. 9 (a) and (b) are side and top views, respectively, of one embodiment of a base of the present invention;
FIG. 10 is a perspective view of one embodiment of the base plate of the present invention;
FIGS. 11 (a) and (b) are side and top views, respectively, of one embodiment of a base plate of the present invention;
FIG. 12 is a perspective view of one embodiment of a top cover of the present invention;
FIGS. 13 (a) and (b) are side and top views, respectively, of an embodiment of a top lid of the present invention;
FIG. 14 is a perspective view of one embodiment of the nut of the present invention;
FIGS. 15 (a) and (b) are side and top views, respectively, of one embodiment of a nut of the present invention;
FIG. 16 is a perspective view of one embodiment of a gasket of the present invention;
fig. 17 is a perspective view of one embodiment of a fastener on the cap.
Detailed Description
In order to make the technical solutions in the embodiments of the present invention better understood and make the above objects, features and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.
In the description of the present invention, unless otherwise specified and limited, it should be noted that the term "connected" should be interpreted broadly, for example, as being mechanically or electrically connected, or as being interconnected between two elements, directly or indirectly through an intermediate medium, and the specific meaning of the term is understood by those skilled in the art according to the specific situation.
The thread structure looseness measuring device based on the distributed shape sensing can comprise a looseness measuring device corresponding to a thread structure, wherein the looseness measuring device comprises a spring and an optical fiber section, the optical fiber section is arranged on the spring along the trend of the spring, when the thread structure is loosened, the shape of the spring is correspondingly changed, and one end of the optical fiber section is used for receiving a measuring optical signal; and determining the shape change condition of the spring according to a reflected signal returned after the optical fiber section receives the measuring optical signal, thereby determining the loosening condition of the thread structure.
In this embodiment, when the thread structure becomes loose, the inclination direction of the spring changes synchronously with the change of the inclination direction of the thread structure, and as the loosening degree of the thread structure increases, the stretching or compressing degree of the spring also increases gradually. The determining the shape of the spring according to the reflected signal returned by the optical fiber segment after receiving the measuring optical signal, so as to determine the loosening condition of the thread structure, may include: measuring the shape of the spring based on a shape measurement principle according to a reflected signal returned after the optical fiber section receives the measuring optical signal; and comparing the shapes of the spring measured before and after the thread structure is loosened, calculating the shape distortion of the spring, and determining the loosening condition of the thread structure according to the shape distortion of the spring. Wherein, according to a reflected signal returned after the optical fiber section receives the measuring optical signal, measuring the shape of the spring based on a shape measurement principle comprises: according to the reflection signal, measuring the three-dimensional space coordinate set (x 1) of each point on the spring before the loosening of the thread structure based on the shape measurement principle i ,y1 i ,z1 i ) And the three-dimensional space coordinate set of each point on the spring after the thread structure is loosened is (x 2) i ,y2 i ,z2 i ) Which isWherein N is an integer greater than 0 and is used to represent the number of (measurable) points on the spring, and i is an integer less than or equal to N and greater than 0; from a set of three-dimensional spatial coordinates (x 1) of points on said spring i ,y1 i ,z1 i ) And (x 2) i ,y2 i ,z2 i ) Respectively showing the shapes of the spring before and after the screw structure loosens. Since the measurement of the three-dimensional space coordinates of each point on the spring can be realized by adopting the prior art (for example, the optical frequency domain reflectometer-based optical fiber distributed three-dimensional shape sensing technology mentioned in volume 42 of No. 1 of 2022), the measurement principle of the three-dimensional space coordinates is not described in detail in the present invention. In addition, comparing the shapes of the spring measured before and after the thread structure is loosened, and calculating the spring shape distortion amount may include: calculating a Euclidean distance d of a three-dimensional space according to the following formula, wherein the Euclidean distance represents the spring shape distortion quantity:
in this embodiment, when the screw structure is loosened, if only the inclination direction of the spring is changed synchronously with the change of the inclination direction of the screw structure, the euclidean distance indicates the change amount of the overall shape of the spring, and therefore, when the screw structure is rotated by different turns, but inclined in the same direction, the calculated euclidean distances are equal, and therefore, if only the inclination direction of the spring is changed synchronously with the rotation of the screw structure, the loosening of the screw structure cannot be accurately identified. Therefore, the inclination direction of the spring is synchronously changed along with the change of the inclination direction of the thread structure, and the stretching or compressing degree of the spring is gradually increased along with the increasing of the loosening degree of the thread structure. In addition, when the shape of the spring is changed only by the spiral rotation of the thread structure, the maximum value of the shape change (namely the Euclidean distance) exists, and the shape change is further increased due to the gradual increase of the stretching or compressing degree of the spring in the invention, so that when the shape change is larger than the maximum value, the thread structure can be determined to be loosened, and the loosening degree of the thread structure can be determined according to the size of the shape change. Therefore, in this embodiment, determining the loosening condition of the thread structure according to the amount of the spring shape distortion may include: and judging whether the spring shape distortion exceeds a corresponding set threshold value, and if so, determining the loosening condition of the thread structure according to the set threshold value. Wherein the corresponding set threshold may be a maximum euclidean distance that the spring may reach when only the inclination direction of the spring is changed synchronously with the change of the inclination direction of the thread structure; or euclidean distance values for indicating different degrees of loosening of the thread structure, the euclidean distance values being greater than the maximum euclidean distance value.
It can be seen from the above embodiments that the optical fiber is routed on the spring along the direction of the spring, so that the shape of the spring changes in the process of the screw thread structure spirally rotating due to loosening, and the shape of the spring is determined based on the reflected signal returned after the optical fiber section receives the measurement signal, thereby determining the loosening condition of the screw thread structure. In addition, the invention calculates the Euclidean distance of the three-dimensional space of the thread structure and the spring based on the three-dimensional space coordinate set of each point on the spring before and after the thread structure loosens, and determines the loosening condition of the thread structure according to the Euclidean distance, and the method for determining the loosening condition is simple.
Referring to fig. 1, there is shown a side view of the overall structure of an embodiment of the thread loosening measuring device based on distributed shape sensing according to the present invention. As shown in fig. 2 to 16, the looseness measuring device may further include a sleeve 1 and a top cover 4, where a corresponding optical fiber section of the optical fiber 3 runs along the spring 2 and is routed on the spring 2, as shown in fig. 4 and 5, a spiral groove 11 is provided in the sleeve 1, the spring 2 is vertically provided in the spiral groove 11 matching therewith, and an upper end of the spring is fixedly connected with a fastener 41 on the top cover 4 (the top cover structure is shown in fig. 6 and 7), one end of the optical fiber section passes through a through hole of the sleeve 1 for receiving a measuring light signal, the sleeve 1 is supported by a support member, as shown in fig. 2, the top cover 4 and the thread structure 5 are located in the sleeve 1, and the top cover 4 is located on the thread structure 5; when the screw thread structure 5 loosens and rotates spirally, the top cap 4 is driven to move in a first vertical direction (for example, move upwards vertically) relative to the sleeve 1, so as to drive the spring 2 to deform.
The optical fiber is arranged on the spring along the spring direction, the upper end of the spring (namely the upper free end when the spring is axially and vertically arranged) is fixedly connected with the fastening piece of the top cover, the threaded structure positioned below the top cover can drive the top cover to move in a first vertical direction relative to the sleeve in the process of spiral rotation caused by looseness, and the top cover is fixedly connected with the upper end of the spring, so that the top cover can drive the spring to deform (wherein, when the top cover moves upwards relative to the sleeve, the spring can stretch and deform), and correspondingly, the shape of the optical fiber section on the spring can also change; secondly, when the loosening condition of the thread structure is determined, the rotation angle of the thread structure is not measured, but the thread structure drives the top cover to move relative to the sleeve, so that the spring is stretched and deformed, namely, the angle measurement is converted into linear measurement, and the rotation angle can be detected even if the rotation angle is small, so that the thread structure has higher resolution and sensitivity; moreover, compared with the strain gauge limited by the fatigue life, the strain gauge provided by the invention adopts the deformation of the spring to reflect the loosening condition of the thread structure, so that the service life of the strain gauge is longer.
In addition, as shown in fig. 1 and fig. 2, the thread structure looseness measuring device based on distributed shape sensing of the present invention may further include a bottom plate 6, the sleeve 1 is fixed on the bottom plate 6, and the thread structure 5 penetrates through the bottom plate 6 and protrudes from the sleeve 1; the supporting piece can be a nut 7, the nut 7 is positioned below the bottom plate, is in threaded connection with the threaded structure 5, and is fixedly abutted against the bottom plate 6 on the upper surface, and the nut 7 is used for supporting the sleeve 1; when the screw structure 5 is loosened and screwed, the top cover 4 is driven to move in the first vertical direction (for example, vertically move upwards), and the nut 7 moves in the second vertical direction (for example, vertically move downwards) under the action of the gravity of the bottom plate 6 and the sleeve 1 thereon, so as to drive the bottom plate 6 and the sleeve 1 thereon to move in the second vertical direction, wherein the first vertical direction is opposite to the second vertical direction.
According to the invention, the sleeve is fixed on the bottom plate, the bottom plate is abutted and fixed with the upper surface of the nut, and then the nut is in threaded connection with the threaded structure, as the bottom plate and the sleeve have certain weight, the threaded structure loosens, when the nut rotates spirally, the threaded structure cannot drive the bottom plate and the sleeve to rotate synchronously, the bottom plate and the sleeve apply a force to the nut to fix the nut, so that the nut and the threaded structure generate relative displacement in the spiral rotation process of the threaded structure, namely, the bottom plate and the sleeve supported by the nut can move in a second vertical direction (such as vertical downward movement). Because the top cover can move in the first vertical direction and the sleeve can move in the second vertical direction when the thread structure loosens and rotates in a spiral manner, and the first vertical direction is opposite to the second vertical direction, the nut in threaded connection with the thread structure not only plays a role in supporting the bottom plate and the sleeve, but also can increase the relative displacement between the top cover and the sleeve caused by the spiral rotation process of the thread structure, thereby increasing the spring deformation quantity caused by the rotation of the thread structure in a unit angle, and further improving the measurement sensitivity of loosening; in addition, the nut is used as a support frame for supporting the sleeve, and is in threaded connection with the threaded structure, so that the sleeve can be prevented from being fixed additionally, the threaded structure is assembled with a device related to the loosening measurement before leaving a factory, and the device related to the loosening measurement does not need to be installed on site, so that the installation efficiency of the invention is greatly improved; the invention assembles the devices related to the looseness measurement on the thread structure, can apply certain pressure to the thread structure, and avoids the looseness of the thread structure to a certain extent. The radial dimension of the cap 4 in the present invention may be greater than the radial dimension of the thread structure 5, the radial direction being in the horizontal direction. It should be noted that: after the other end of the optical fiber section corresponding to the current thread structure penetrates out of the through hole of the sleeve, the other end of the optical fiber section corresponding to the current thread structure can be connected with the optical fiber section corresponding to the next thread structure through the connecting section in the optical fiber, and therefore the looseness of a plurality of thread structures can be measured by using one optical fiber.
In addition, as shown in fig. 2, the device for measuring the loosening of the threaded structure according to the present invention may further include a washer 8, the washer 8 is located between the threaded structure 5 and the bottom plate 6, the washer 8 is initially compressed between the bottom plate 6 and the threaded structure 5 by the support member 7 (i.e., the nut), and the washer 8 is used for preventing the threaded structure 5 from being radially displaced when the threaded structure 5 is not loosened. The thread structure looseness measuring device can further comprise a base 9 and a sleeve cap 10, the upper end and the lower end of the sleeve 1 are provided with openings, the lower end of the sleeve 1 is in threaded connection with the base 9, and the base 9 is fixed on the bottom plate 6; the upper end of the sleeve 1 is in threaded connection with a sleeve cap 10. According to the invention, the sleeve is arranged to be of a structure with the upper end and the lower end being open, the upper end of the sleeve is in threaded connection with the sleeve cap, the lower end of the sleeve is in threaded connection with the base, the sleeve cap can prevent dust, rainwater and the like from falling into the sleeve, and the sleeve is detachably designed, so that the assembly in the sleeve is convenient to install and the subsequent assembly maintenance is convenient. In addition, the fastening pieces 41 are uniformly distributed on the top end periphery of the top cover 4; the bottom end of the top cover 4 is provided with a containing groove 42 matched with the top end of the thread structure 5. The top end of the top cover is provided with a plurality of fasteners which are uniformly distributed on the periphery of the top end of the top cover, and the upper end of the spring 2 connected with the fasteners can sequentially penetrate through the fasteners for fixing so as to ensure that the spring deforms along with the rotation of the top cover.
In one example, the screw structure may be a bolt 5, and as shown in fig. 4, 5 (a) and (b), the sleeve 1 may be a cylinder with an open upper end and an open lower end, the inner side of the cylinder is provided with an upper screw 12, a spiral groove 11 in the middle, and a lower screw 13, and the side wall of the cylinder is provided with a first through hole 14 and a second through hole 15, wherein the sleeve 1 is in threaded connection with a sleeve cap 10 through the upper screw 12, the sleeve cap 10 is in a structure as shown in fig. 6, 7 (a) and (b), the upper end of the sleeve cap 10 is closed, and the lower end of the sleeve cap is provided with an external screw 101 for being in threaded connection with the upper screw 12 of the sleeve 1. The lower thread 13 of the sleeve 1 is in threaded connection with the base 9, the base 9 is structured as shown in fig. 8, fig. 9 (a) and fig. 9 (b), the base 9 can be a cylinder, the upper end and the lower end of the base are openings, the sidewall of the base is provided with an external thread 91 for being in threaded connection with the lower thread 13 of the sleeve 1, two opposite sides of the base 9 respectively extend to form a fixing block 92, the fixing block 92 is provided with a through hole, and correspondingly, the bottom plate 6 is also provided with a through hole. The bottom plate 6 is configured as shown in fig. 10, 11 (a) and (b), the bottom plate 6 is provided with a middle through hole 61 and side through holes 62 located at two sides of the middle through hole 61 and opposite to each other, the through holes on the fixing blocks 92 in the base 9 are aligned with the corresponding side through holes 62, the base 9 can be fixed on the bottom plate 6 by using fixing members, and the middle through hole 61 on the bottom plate 6 is used for enabling the screw structure to pass through the sleeve 1. In addition, the structure of the top cover 4 is as shown in fig. 12, fig. 13 (a) and fig. 13 (b), the top cover 4 is a cylinder, 6 fasteners 41 are uniformly distributed on the periphery of the upper end of the top cover 4, a hexagonal accommodating groove 42 is formed in the lower end of the top cover to match the nut shape of the bolt 5, the spring 2 provided with the optical fiber section is placed in the spiral groove 11 of the sleeve 1, then the washer 8 is placed on the upper surface of the bottom plate 6, the bolt 5 passes through the washer 8 and the middle through hole 61 on the bottom plate 6 in sequence, the bolt 5 penetrates into the nut 7, and the bolt 5 or the nut 7 is rotated to enable the bolt 5 to press the washer 8 between the bolt 5 and the bottom plate 6. Thereafter, the cap of the bolt 5 is placed in the receiving groove 42 of the top cover 4. The washer 8 may have a circular ring shape as shown in fig. 16, and the nut may have an M48 nut as shown in fig. 14, 15 (a) and (b).
In addition, the fastening elements 41 on the top cover 4 may be configured as shown in fig. 17, each fastening element is composed of two opposite sheet-like structures 411, at least one pair of grooves 412 is disposed on opposite sides of the two sheet-like structures 411 for holding one end of the spring 2, fixing through holes 413 are further disposed on the two sheet-like structures 411, and after the spring 2 passes through one of the pair of grooves 412 between the two sheet-like structures, the fixing element sequentially passes through the fixing through holes 413 on the two sheet-like structures 411 to fix the two sheet-like structures 411, thereby fixing the spring 2 between the two sheet-like structures 411. When the optical fiber section is arranged on the spring, the spring steel wire and the optical fiber section are arranged in the heat shrinkage pipe in a heat shrinkage mode, and the spring steel wire and the optical fiber section can be tightly attached together after the heat shrinkage of the heat shrinkage pipe.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is to be controlled solely by the appended claims.
Claims (8)
1. A thread structure looseness measuring device based on distributed shape sensing is characterized by comprising a looseness measuring device corresponding to a thread structure, wherein the looseness measuring device comprises a spring and an optical fiber section, the optical fiber section runs along the spring and is wired on the spring, when the thread structure is loosened, the shape of the spring is correspondingly changed, and one end of the optical fiber section is used for receiving a measuring optical signal; determining the shape change condition of the spring according to a reflected signal returned after the optical fiber section receives the measuring optical signal, so as to determine the loosening condition of the thread structure;
determining the shape change condition of the spring according to a reflected signal returned after the optical fiber segment receives the measuring optical signal, so as to determine the loosening condition of the thread structure, wherein the step of determining the loosening condition of the thread structure comprises the following steps:
measuring the shape of the spring before and after the thread structure is loosened based on a shape measurement principle according to a reflected signal returned after the optical fiber section receives the measuring optical signal;
comparing the shapes of the spring measured before and after the thread structure is loosened, calculating the shape distortion of the spring, and determining the loosening condition of the thread structure according to the shape distortion of the spring;
according to the reflected signal returned after the optical fiber section receives the measuring optical signal, the measuring the shape of the spring based on the shape measuring principle comprises the following steps: according to the reflected signal, measuring the three-dimensional space coordinate set of each point on the spring before the thread structure loosens based on the shape measurement principle to be (x 1) i ,y1 i ,z1 i ) And the three-dimensional space coordinate set of each point on the spring after the thread structure is loosened is (x 2) i ,y2 i ,z2 i ) N is an integer which is more than 0 and is used for representing the number of each point on the spring, and i is an integer which is less than or equal to N and is more than 0; from a set of three-dimensional spatial coordinates (x 1) of points on said spring i ,y1 i ,z1 i ) And (x 2) i ,y2 i ,z2 i ) Respectively showing the shapes of the spring before and after the thread structure loosens;
comparing the shapes of the spring measured before and after the thread structure is loosened, and calculating the distortion quantity of the spring shape comprises the following steps: calculating the Euclidean distance d of a three-dimensional space according to the following formula, wherein the spring shape distortion quantity is represented by the Euclidean distance:
2. the distributed shape sensing-based thread structure loosening measuring device according to claim 1, wherein when the thread structure is loosened, the inclination direction of the spring is changed synchronously with the inclination direction of the thread structure, and the degree of tension or compression of the spring is gradually increased as the loosening degree of the thread structure is increased.
3. The distributed shape sensing-based thread structure loosening measurement device of claim 1, wherein determining the loosening of the thread structure from the amount of spring shape distortion comprises: and judging whether the spring shape distortion exceeds a corresponding set threshold, and if so, determining the loosening condition of the thread structure according to the set threshold.
4. The device for measuring the loosening of the threaded structure based on the distributed shape sensing is characterized by further comprising a sleeve and a top cover, wherein a spiral groove is formed in the sleeve, the spring is vertically arranged in the spiral groove matched with the spring, the upper end of the spring is fixedly connected with a fastener on the top cover, one end of the optical fiber section penetrates out of a through hole of the sleeve and is used for receiving a measuring optical signal, the sleeve is supported by a supporting piece, the top cover and the threaded structure are located in the sleeve, and the top cover is located above the threaded structure; when the threaded structure loosens and rotates spirally, the top cover is driven to move in a first vertical direction relative to the sleeve, and therefore the shape of the spring is changed.
5. The distributed shape sensing based thread form looseness measuring device according to claim 4, further comprising a bottom plate, wherein the sleeve is fixed to the bottom plate, and wherein the thread form penetrates through the bottom plate and protrudes out of the sleeve; the supporting piece is a nut, the nut is positioned below the bottom plate, is in threaded connection with the threaded structure, is fixedly abutted against the bottom plate on the upper surface of the nut, and is used for supporting the sleeve; when the threaded structure is loosened and spirally rotated, the top cover is driven to move in the first vertical direction, the nut moves in the second vertical direction under the action of the gravity of the bottom plate and the sleeve on the bottom plate, so that the bottom plate and the sleeve on the bottom plate are driven to move in the second vertical direction, and the first vertical direction is opposite to the second vertical direction.
6. The device for measuring the loosening of the thread structure based on the distributed shape sensing according to claim 4 or 5, wherein the other end of the optical fiber section corresponding to the current thread structure is connected with the optical fiber section corresponding to the next thread structure through a connecting section in the optical fiber after passing through the through hole of the sleeve.
7. The distributed shape sensing based thread structure loosening measurement device of claim 6 further comprising a washer positioned between the thread structure and the base plate, the washer being initially compressed between the base plate and the thread structure by the support member, the washer being configured to prevent radial displacement of the thread structure when not loosened.
8. The threaded structure looseness measuring device based on distributed shape sensing of claim 5, further comprising a base and a sleeve cap, wherein the upper end and the lower end of the sleeve are open, the lower end of the sleeve is in threaded connection with the base, and the base is fixed on the bottom plate; the upper end of the sleeve is connected with the sleeve cap;
the fasteners are uniformly distributed on the periphery of the top end of the top cover; and the bottom end of the top cover is provided with a containing groove matched with the top end of the threaded structure.
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