CN112014021B - Cable safety state monitoring and evaluating method - Google Patents
Cable safety state monitoring and evaluating method Download PDFInfo
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- CN112014021B CN112014021B CN202010875749.6A CN202010875749A CN112014021B CN 112014021 B CN112014021 B CN 112014021B CN 202010875749 A CN202010875749 A CN 202010875749A CN 112014021 B CN112014021 B CN 112014021B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
Abstract
The application belongs to the technical field of cables, and particularly relates to a cable safety state monitoring and evaluating method. The existing various methods calculate the stress and the tensile force of the cable by different principles, but the working stress of the effective section of the cable cannot be accurately calculated if the effective section of the cable is reduced due to environmental corrosion and fatigue corrosion. The application provides a cable safety state monitoring method, which comprises the following steps: carrying out factory parameter calibration on the cable; obtaining a cable extension value; calculating the working stress of the effective section of the cable by adopting the factory parameters and the extension value; and judging the safety state of the cable through the working stress of the effective section. The working stress of the effective section of the cable can be directly calculated without knowing the effective section area of the cable.
Description
Technical Field
The application belongs to the technical field of cables, and particularly relates to a cable safety state monitoring and evaluating method.
Background
The main categories of cable structures are classified by the action of the cables, such as single independent members, a surface layer structure made up of cables, or a three-dimensional net structure. Cable constructions using a single tensile member as the primary support, known as linear support systems or cable support constructions; the cable system may form a surface by directly supporting the roof deck, which is typical of catenary roof structures. The main reasons for the breakage of the cable are that the section of the cable part is out of operation due to environmental corrosion and fatigue corrosion, the effective section area of the cable is reduced, and the whole allowable tension of the cable is reduced to be smaller than that of the cable which bears the tension load, so the main reasons are that the effective section area of the cable is reduced due to the environmental corrosion and the fatigue corrosion.
The resistance sheet method in the cable safety state detection, monitoring and evaluation method is a fiber bragg grating method, wherein strain gauges or fiber bragg gratings are stuck at local positions of the cable, the local strain of the cable is directly measured, and the stress and the cable tension of the whole cable are calculated by locally replacing the whole cable. The stress calculation formula is: stress = strain x elastic modulus. The method can only measure the cable strain at the position where the strain gauge is stuck, so as to calculate the stress of the steel wire where the strain gauge is stuck, and the strain at other positions where the strain gauge is not stuck cannot be measured or calculated. The calculation formula of the cable tension is as follows: tension = strain × elastic modulus × cross-sectional area, the effective cross-sectional area of the test cable must be known to calculate the cable tension, and if there is a partial cross-section exit working condition during use of the cable, the cable tension cannot be accurately calculated. The hydraulic jack measuring method is similar to the pressure sensor method, and although the hydraulic jack measuring method can directly measure the tensile force of the cable, the working stress of the effective section of the cable cannot be calculated because the effective section area of the cable is unknown. Both the frequency method and the magnetic flux method require a given cable cross-sectional area to calculate the cable stress and tension.
The existing various methods calculate the stress and the tensile force of the cable by different principles, but the working stress of the effective section of the cable cannot be accurately calculated if the effective section of the cable is reduced due to environmental corrosion and fatigue corrosion.
Disclosure of Invention
1. Technical problem to be solved
The detection, monitoring and safety state evaluation methods based on the current cable are more, and mainly comprise a resistance card measurement method, a hydraulic jack force measurement method, a pressure sensor method, a frequency method, a magnetic flux method, a fiber bragg grating method and the like. The purpose of detection, monitoring and safe state evaluation of cable is in order to avoid the cable burst to break, ensure cable safety in utilization. The main cause of cable breakage is the reduction in allowable tension of the cable due to environmental corrosion and fatigue corrosion. The existing method for detecting, monitoring and evaluating the safety state of the cable can not accurately calculate the working stress of the effective section of the cable when the effective section of the cable is reduced due to environmental corrosion and fatigue corrosion, and is insensitive to the reduction of the effective section. The application provides a cable safety state monitoring and evaluating method for cable safety state detection and automatic monitoring.
2. Technical proposal
In order to achieve the above object, the present application provides a cable safety state monitoring method, which includes the following steps:
1) Carrying out factory parameter calibration on the cable;
2) Obtaining a cable extension value;
3) Calculating the working stress of the effective section of the cable by adopting the factory parameters and the extension value;
4) And judging the safety state of the cable through the working stress of the effective section.
E of obtaining cable after factory parameter calibration of cable p For the measured modulus of elasticity of the cable, L is the length of the cable, sigma 1 Is the initial stress of the cable.
The cable extension value is obtained by manual measurement or displacement sensing device in the use process of the cable.
Another embodiment provided by the application is: the factory parameters in the step 1) comprise a cable initial stress corresponding to a reference displacement value, a cable actual measurement elastic modulus and a cable initial stress.
Another embodiment provided by the application is: the extension value in the step 2) is obtained through manual measurement or a cable built-in extension displacement sensing device; the extension value is continuously obtained over time.
Another embodiment provided by the application is: the effective section working stress in the step 3) is represented by the formula sigma e ＝△L*Ep/L+σ 1 Calculating to obtain;
wherein sigma e Is the working stress of the effective section of the cable, delta L is the extension of the cable, E p For the measured modulus of elasticity of the cable, L is the length of the cable, sigma 1 Is the initial stress of the cable.
Another embodiment provided by the application is: the Δl=l n -L 1 Wherein L is n For measuring the value of the displacement sensor, L 1 The initial stress of the cable corresponds to a reference displacement value.
Another embodiment provided by the application is: step 4) further comprises alerting of the abnormal condition.
Another embodiment provided by the application is: the method also comprises pushing and displaying the cable safety state.
The application also provides a cable safety state evaluation method, which comprises the steps of calculating the ratio of the standard strength of the cable to the safety coefficient of the cable, and evaluating the safety state of the cable by comparing the working stress of the effective section with the ratio.
Another embodiment provided by the application is: the method comprises the step that when the working stress of the effective section is smaller than or equal to the ratio, the cable is in a safe state, and when the working stress of the effective section is larger than the ratio, the cable is in a dangerous state.
Another embodiment provided by the application is: the cable safety coefficient can be set to be a plurality of, and multi-state evaluation is carried out on the cable safety states of different levels.
3. Advantageous effects
Compared with the prior art, the cable safety state monitoring and evaluating method provided by the application has the beneficial effects that:
the cable safety state monitoring method provided by the application can directly calculate the working stress of the effective section of the cable without knowing the effective section area of the cable.
According to the cable safety state monitoring method provided by the application, the cable extension amount is used for detecting, monitoring and evaluating the cable safety state.
The cable safety state monitoring method provided by the application calculates the cable stress by adopting the formula sigma e ＝(L n -L 1 )*E p /L+σ 1 Ln is the direct measurement value of the built-in displacement sensor of the cable, the remaining parameters L 1 ，E p ，L，σ 1 All are obtained by testing before the cable leaves the factory.
The cable safety state monitoring and evaluating method provided by the application has the advantages that the environment corrosion and fatigue corrosion appear in the cable in the use process, the section of the broken part of the steel wire is withdrawn from operation, and the effective section area is reduced, and no section area factor of the cable exists, so that the sigma of the cable can be accurately calculated no matter whether the section area is changed or not e Effective cross-section working stress (MPa) of the cable.
Drawings
FIG. 1 is a schematic diagram of a parameter calibration calculation curve of the present application;
fig. 2 is an operational phase calculation curve of the present application.
Detailed Description
Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings, and according to these detailed descriptions, those skilled in the art can clearly understand the present application and can practice the present application. Features from various embodiments may be combined to obtain new implementations, or substituted for certain features from certain embodiments to obtain further preferred implementations, without departing from the principles of the application.
Referring to fig. 1-2, the present application provides a cable safety condition monitoring method, comprising the steps of:
1) Carrying out factory parameter calibration on the cable;
2) Obtaining a cable extension value;
3) Calculating the working stress of the effective section of the cable by adopting the factory parameters and the extension value;
4) And judging the safety state of the cable through the working stress of the effective section.
Carrying out factory parameter calibration on the cable, and calibrating the following three main technical parameters of the cable, L 1 For the initial stress of the cable to correspond to the reference displacement value E p For the cable to measure modulus of elasticity, sigma 1 Is the initial stress of the cable. L is the length value of the cable and is an inherent characteristic parameter of the cable.
The cable safety state monitoring method can realize online real-time monitoring.
The working stress in the working stress of the effective section is the stress of the stressed steel wire in the cable, and the effective section is the cross section of the stressed steel wire.
Further, the factory parameters in the step 1) include a cable initial stress corresponding to a reference displacement value, a cable measured elastic modulus and a cable initial stress.
Further, the extension value in the step 2) is obtained through manual measurement or a cable built-in extension displacement sensing device; the extension value is continuously obtained over time.
The displacement sensing device comprises a displacement sensing assembly and a power supply acquisition assembly which are connected with each other, wherein the displacement sensing assembly comprises a displacement sensor, a sensing steel wire and a measuring steel wire, the displacement sensor is connected with one end of the sensing steel wire, and the other end of the sensing steel wire is connected with one end of the measuring steel wire. One end of the sensing steel wire extends into the displacement sensor.
Of course, the displacement sensor is not limited to the above examples. Meanwhile, the displacement sensing device can also measure by adopting other materials, such as iron wires, copper wires and other metal or nonmetal wires, and the sensing steel wires and the measuring steel wires can be combined into one steel wire.
The sleeve is arranged outside the measuring steel wire, the sleeve with different types and diameters is selected according to the types of different cables, the friction coefficient between the sleeve and the measuring steel wire is different, and the sleeve with the minimum friction coefficient is adopted in the production process of the cables.
The displacement sensor may be a pull-wire type displacement sensor, an acoustic wave type displacement sensor, a resistive type displacement sensor, a voltage type displacement sensor, a current type displacement sensor, an electromagnetic type displacement sensor, or a capacitive type displacement sensor, but is not limited to the examples, and may be any component capable of realizing displacement measurement.
When the cable does not bear any load, the reading of the scale of the sensor wire scale at the position of the orifice of the measuring wire hole is 0, and the length of the sensor wire drawn out of the displacement sensor increases along with the increase of the tensile load borne by the cable, the sensor wire enters the measuring wire hole, and the length value of the sensor wire entering the measuring wire hole is the extension value of the cable.
The range of the displacement sensor adopted by the application can be determined according to the extension change range in the use process of the cable, the displacement sensor can convert the linear mechanical displacement into an electric signal with a specific relation, and the electric signal can be perceived by the power supply acquisition assembly.
Further, the effective section working stress in the step 3) is represented by the formula sigma e ＝△L*E p /L+σ 1 Calculating to obtain;
wherein sigma e Is the working stress of the effective section of the cable, delta L is the extension of the cable, E p For the measured modulus of elasticity of the cable, L is the length of the cable, sigma 1 Is the initial stress of the cable.
Delta L is the extension of the cable, and is characterized in that a length deformation difference value caused by stress difference between a reference steel wire which does not participate in the stress of the cable and a common stress steel wire which bears the tension load of the cable is arranged in parallel in the cable. The delta L displacement difference value has a certain correlation with the technical state of the cable. The application relates to a method for judging that a cable is in different technical states according to the delta L by arranging a datum steel wire which does not participate in the stress of the cable in parallel, detecting the length deformation difference value between the datum steel wire and a common stress steel wire of the cable bearing a tension load in working engineering. The smaller the delta L value, the smaller the cable stress, the effective section working stress of the cable is gradually increased along with the increase of the delta L value, and the cable is in different technical states along with the increase of the delta L value until the cable exceeds the allowable tension stress to break.
The length of the cable is a product parameter given when the cable leaves the factory, and is usually the length of the cable after the anchor anchorage influence factor correction is carried out on the distance between the anchor backing plates at the two ends of the cable or the distance between the anchor backing plates at the two ends of the cable.
Initial stress sigma of cable 1 The method is obtained through a cable calibration test, and comprises the following steps: carrying out a tensioning test on the cable before leaving the factory, and measuring and recording the cable tensioning force F in the tensioning test process n And the measurement value L of the displacement sensor n Fitting and drawing a cable tension and displacement sensor measured value change curve to find F 1 Value of sigma 1 ＝F 1 Sigma is calculated by the formula/S 1 Where S is the designed cross-sectional area for the cable production as shown in fig. 1.
The actual measurement elastic modulus of the cable is a given product parameter when the cable leaves a factory, and the obtaining method comprises the following steps: carrying out a tensioning test on the cable before leaving the factory, and measuring and recording the cable tensioning force F in the tensioning test process n And the measurement value L of the displacement sensor n Fitting and drawing a cable tension and displacement sensor measured value change curve to find F 1 Values, then through the linear fitting curve parameters of the values of the linear change region, through E p ＝(F n -F 1 )*L/S/(L n -L 1 ) The formula is calculated where S is the designed cross-sectional area at the time of cable production, as shown in fig. 1.
Further, the Δl=l n -L 1 Wherein L is n Is a displacement sensorMeasured value, L 1 The initial stress of the cable corresponds to a reference displacement value.
When the cable leaves the factory and marks the test, fix the cable on the stretching bench, load and unload according to the specific difference in the stretching loading and unloading process, record the multi-group cable stretching force F n And direct measurement data of the displacement sensor built in the cable. The recorded values were curve fitted to a curve as shown in fig. 1. And simultaneously, the data at different temperatures are recorded in the repeated loading and unloading processes at different temperatures. Through a data fitting algorithm, a reasonable F is found 1 Value of F n Less than F 1 At the time of cable tension F n Direct measurement value data L of displacement sensor built in cable n Nonlinear correlation; when F n Greater than F 1 At the time of cable tension F n Direct measurement value data L of displacement sensor built in cable n A linear correlation is constructed.
Because the cable is usually formed by winding, the cable steel wires are elastically deformed by winding bending in the cable, and the cable has larger deformable gaps between the cable steel wires when the cable bears smaller tension load under the influence of the dead weight of the cable. The deformable gaps among the cable wires can influence the length of the cable, the cable wires are wound more tightly along with the increase of the cable stress, the deformable gaps among the cable wires disappear, and when the cable stress is smaller than sigma 1 The stress of the cable is non-linearly related to the sensor measurement when the cable stress is greater than sigma 1 The cable stress is linearly related to the sensor measurement, where the cable stress is the initial cable stress sigma 1 The corresponding displacement sensor value is the corresponding reference value L of the initial stress of the cable 1 。
L n The direct measurement value of the built-in displacement sensor is used for the cable calibration test and the cable use stage, and is the main measurement parameter of the sensor measurement in the working process of the cable. In the calibration test process before the cable leaves the factory or in the use stage of the cable, the cable is directly obtained through manual measurement and reading communication of the sensor.
Further, the step 4) further includes alerting of the abnormal condition. The alarm mode comprises sound and images.
The sound is buzzing, other music or dangerous sounding, and the image can be a flashing red alarm image or a warning character.
By monitoring and calculating sigma e The effective section working stress of the cable is as follows e ≥(σ s K), the same cable or item can be set with different K values, and the different K values correspond to different safety early warning states. Cable built-in data processing chip pair sigma e And judging if the safety precaution is triggered. The cable built-in data processing chip sends the early warning information to a remote data server through a wireless network signal, and the remote server receives the early warning information of the cable and then transmits the early warning information to a management unit of the cable or a related software system or a related manager mobile phone through modes of WeChat pushing, short message, voice prompt, software information pushing and the like.
The cable built-in data processing chip can also control early warning information through a cable connected to the sensor, and a display screen or an indicator light controller on the connecting cable works, so that the display screen or the indicator light displays different numerical values, different colors, a flashing mode and other modes for early warning prompt.
Further, pushing and displaying the cable safety state are further included.
And transmitting the early warning information to a management unit of the cable or a related software system or a related manager mobile phone through the modes of WeChat pushing, short message, voice prompt, software information pushing and the like.
The cable built-in data processing chip can also control early warning information through a cable connected to the sensor, and a display screen or an indicator light controller on the connecting cable works, so that the display screen or the indicator light displays different numerical values, different colors, a flashing mode and other modes for early warning prompt.
The application also provides a cable safety state evaluation method, which comprises the steps of calculating the ratio of the standard strength of the cable to the safety coefficient of the cable, and evaluating the safety state of the cable by comparing the working stress of the effective section with the ratio.
Further, the method includes the step of placing the cable in a safe state when the effective section working stress is less than or equal to the ratio, and placing the cable in a dangerous state when the effective section working stress is greater than the ratio.
Sigma obtained by the above calculation e The effective section working stress of the cable, generally in MPa, is measured as follows for example σ e ≤(σ s K) the cable is in a safe state; e.g. sigma e ＞(σ s /K) the cable is in a dangerous state.
Further, the cable safety coefficient can be set to be multiple, and multi-state evaluation is carried out on the cable safety states of different levels.
Cable standard strength. Typically in MPa, sigma s The product parameters are given when the cable leaves the factory, are the standard strength parameters of the materials of the steel wire selected by the cable, and are obtained through the standard strength tension test of the steel wire selected by the cable.
The cable safety coefficient K is a cable safety coefficient comprehensively set by the cable according to different use environments and application project requirements and various factors such as relevant standards, specifications, regulations, design habits and the like, is a unitless constant parameter with a numerical value greater than 1, and can be set into a plurality of K values according to different environments or use requirements by the same cable or the same engineering project, wherein the different K values correspond to different safety early warning states, and multi-level and multi-type safety early warning prompt is carried out.
L in FIG. 1 1 ，L，E p ，σ 1 Parameters are set for the factory of the cable. L obtained through displacement sensor in use process of cable n Sigma can be calculated according to a formula e -cable effective cross-section working stress.
The external communication module or the sensor data acquisition equipment can acquire L sensed by the sensor n And sigma obtained by conversion e The monitoring and the detection of the working stress of the effective section of the cable are realized.
Sensor pair sigma e -calculation of the working stress of the effective section of the cable, if σ e ≥σ s and/K, evaluating that the cable does not meet the safety use requirement.
And (3) laying a reference steel wire which does not participate in the stress of the cable in parallel with the cable, measuring the variation difference of the length of the reference steel wire and the length of the cable steel wire, detecting, monitoring and evaluating the safety state of the cable, setting various early warning intervals for the variation value of the length of the cable, and changing the length from small to large, thereby safely shifting the dangerous state.
The difference between the measuring reference steel wire and the cable steel wire mainly appears in that the measuring reference steel wire does not participate in stress when the cable is in use, the cable steel wire bears the action of tension load, the measuring reference steel wire and the cable steel wire are in different stress states due to the fact that the measuring reference steel wire and the cable steel wire bear the difference of the tension load, different strains can be generated between the measuring reference steel wire and the cable steel wire, and the length difference of the measuring reference steel wire and the cable steel wire can be increased along with the increase of the tension load borne by the cable steel wire. The length difference is related to the tensile load (and the tensile load conversion cable stress) born by the cable, and in a certain tensile load interval range, the length difference is related to the tensile load (and the tensile load conversion cable stress) born by the cable linearly. And (3) measuring the length difference and the tension data through a tension calibration test when the production of the cable is completed, fitting a data curve of the length difference and the tension load born by the cable, and finding out the linear correlation interval range and the correlation index parameters of the length difference and the tension load born by the cable. In the operation stage, the cable is detected, the cable safety state is monitored and evaluated by converting the detected length difference into the cable stress through the correlation between the length difference and the cable stress.
The greater the difference in length between the measured reference wire and the cable wire, the greater the stress experienced by the cable wire. The cable wire is in safety to danger along with the increase of the length difference, and finally the cable wire breaks, so that the cable wire can be set into various early warning intervals along with the increase of the length difference of the cable wire and the cable wire. When the length difference between the two is passed, the formula sigma is adopted e ＝△L*E p /L+σ 1 And calculating the working stress of the effective section of the cable, wherein the working stress is smaller than the stress generated by the working condition of the cable with the least adverse load design, and the cable is in a normal working state. When the length difference between the two is passed, the formula sigma is adopted e ＝△L*E p /L+σ 1 Calculated cableEffective cross-section working stress, sigma e ≤(σ s K) the cable is in a safe state; e.g. sigma e ＞(σ s /K) the cable is in a dangerous state.
The measuring reference steel wire and the measuring steel wire are different calls of the same component, and the measuring reference steel wire can be provided with scales, and the use is not affected by the fact that the scales are not provided.
The cable safety coefficient K is a cable safety coefficient comprehensively set by the cable according to different use environments and application project requirements and various factors such as relevant standards, specifications, regulations, design habits and the like, is a unitless constant parameter with a numerical value greater than 1, and can be set into a plurality of K values according to different environments or use requirements by the same cable or the same engineering project, wherein the different K values correspond to different safety early warning states, and multi-level and multi-type safety early warning prompt is carried out. If the cable is used for a cable-stayed bridge, the cable is in a construction stage K=2.0, and in an operation stage K=2.5; the cable adopts galvanized high-strength steel wire to take 1.85 when used for the main cable of the suspension bridge and takes 2.2 when used for the pin-joint sling of the suspension bridge; the cable is 2.95 when being used for a straddle type sling of a suspension bridge and 2.2 when being used for a pin joint type sling of the suspension bridge. The cable adopts steel wires and steel strands for the arch bridge sling, for example, 2.5 is taken when a durable load is applied, 2.0 is taken when a short load is applied, and 1.5 is taken when an accidental load or an earthquake load is applied; the cable adopts a steel wire rope for the arch bridge sling, for example, 3.0 is taken when a durable load is applied, 2.4 is taken when a short load is applied, and 1.8 is taken when an accidental load or an earthquake load is applied; when the cable adopts steel wires and steel strands for arch bridge tie bars, if the cable takes 2.0 under the action of a durable load, the cable takes 1.8 under the action of a short load, and the cable takes 1.5 under the action of an accidental load or an earthquake load.
Although the application has been described with reference to specific embodiments, those skilled in the art will appreciate that many modifications are possible in the construction and detail of the application disclosed within the spirit and scope thereof. The scope of the application is to be determined by the appended claims, and it is intended that the claims cover all modifications that are within the literal meaning or range of equivalents of the technical features of the claims.
Claims (7)
1. A cable safety state monitoring method is characterized in that: the method comprises the following steps:
1) Carrying out factory parameter calibration on the cable;
2) Obtaining a cable extension value;
3) Calculating the working stress of the effective section of the cable by adopting the factory parameters and the extension value;
4) Judging the safety state of the cable through the working stress of the effective section; the working stress in the working stress of the effective section is the stress of the stressed steel wire in the cable, and the effective section is the cross section of the stressed steel wire; the effective section working stress in the step 3) is represented by the formula sigma e ＝△L*E p /L+σ 1 Calculating to obtain;
wherein sigma e Is the working stress of the effective section of the cable, delta L is the extension of the cable, E p For the measured modulus of elasticity of the cable, L is the length of the cable, sigma 1 Initial stress for the cable;
initial stress sigma of cable 1 The method is obtained through a cable calibration test, and comprises the following steps: carrying out a tensioning test on the cable before leaving the factory, and measuring and recording the cable tensioning force F in the tensioning test process n And the measurement value L of the displacement sensor n Fitting and drawing a cable tension and displacement sensor measured value change curve to find F 1 Value of sigma 1 ＝F 1 Sigma is calculated by the formula/S 1 Wherein S is the designed cross-sectional area at the time of cable production;
measured elastic modulus E of cable p The obtaining method comprises the following steps: carrying out a tensioning test on the cable before leaving the factory, and measuring and recording the cable tensioning force F in the tensioning test process n And the measurement value L of the displacement sensor n Fitting and drawing a cable tension and displacement sensor measured value change curve to find F 1 Values, then through the linear fitting curve parameters of the values of the linear change region, through E p ＝(F n -F 1 )*L/S/(L n -L 1 ) Calculated by a formula, wherein S is the time of cable productionIs a design cross-sectional area of (2);
when the cable leaves the factory and marks the test, fix the cable on the stretching bench, load and unload according to the specific difference in the stretching loading and unloading process, record the multi-group cable stretching force F n And direct measurement data of a displacement sensor arranged in the cable; performing curve fitting on the recorded values; simultaneously, repeatedly loading and unloading the data at different temperatures in the process of recording the data at different temperatures; through a data fitting algorithm, a reasonable F is found 1 Value of F n Less than F 1 At the time of cable tension F n Direct measurement value data L of displacement sensor built in cable n Nonlinear correlation; when F n Greater than F 1 At the time of cable tension F n Direct measurement value data L of displacement sensor built in cable n Forming a linear correlation;
when the cable stress is less than sigma 1 The stress of the cable is non-linearly related to the sensor measurement when the cable stress is greater than sigma 1 When the stress of the cable is linearly related to the measured value of the sensor, the cable stress is the initial stress sigma of the cable 1 The corresponding displacement sensor value is the corresponding reference value L of the initial stress of the cable 1 。
2. The cable safety condition monitoring method of claim 1, wherein: the extension value in the step 2) is obtained through manual measurement or a cable built-in extension displacement sensing device; the extension value is continuously obtained over time.
3. The cable safety condition monitoring method of claim 1, wherein: step 4) further comprises alerting of the abnormal condition.
4. A cable safety condition monitoring method according to any one of claims 1 to 3, wherein: the method also comprises pushing and displaying the cable safety state.
5. A cable safety state evaluation method is characterized in that: the method comprises calculating the ratio of the standard strength of the cable to the safety factor of the cable, and evaluating the safety condition of the cable by comparing the effective section operating stress of claim 1 with the ratio.
6. The cable safety state evaluation method according to claim 5, wherein: the method comprises the step that when the working stress of the effective section is smaller than or equal to the ratio, the cable is in a safe state, and when the working stress of the effective section is larger than the ratio, the cable is in a dangerous state.
7. The cable safety state evaluation method according to claim 5 or 6, wherein: the cable safety coefficient can be set to be a plurality of, and multi-state evaluation is carried out on the cable safety states of different levels.
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| CN111174662A (en) * | 2020-03-13 | 2020-05-19 | 尹恒 | Displacement sensing device and application thereof |
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