Cable damage identification method, device, terminal and medium based on second-order difference of beam deflection difference

Abstract

The present invention provides a cable damage identification method, device, terminal and medium based on the second-order difference of beam deflection difference, which belongs to the technical field of cable damage identification method. AB A cable is provided on the top. k Before and after injury, injury k The change value of the bending moment at the anchor point is, and the change value of the bending moment at any section is, when x Value and k When the value is related, the bending moment change value is equal to the bending moment change value, and the cable is converted to k The present invention provides a cable damage identification method, device, terminal and medium based on the second-order difference of beam deflection difference. The relevant parameters are obtained by model calculation or actual measurement. The second-order derivative related to the deflection difference is used to judge the cable damage and determine the position of the damaged cable according to the positive or negative value. The method is simple and easy to implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable damage identification methods, and specifically relates to a cable damage identification method, device, terminal and medium based on second-order difference of beam deflection difference. Background Art

[0002] The cable-stayed bridge is one of the most important types of long-span bridges. It has a strong spanning capacity and is mainly composed of three parts: the main beam, the cable and the main tower. The cable is the most important load-bearing component. The cable can be regarded as multiple elastic supports within the span of the main beam. The main beam deadweight and live load are transmitted to the main tower through the cable, and then finally transmitted to the foundation by the main tower, which significantly reduces the bending moment of the main beam and reduces the deadweight of the beam. The cable is the component with the lowest fatigue life and the most vulnerable to damage in the entire bridge. During long-term use, the cable may be corroded under the influence of the external environment, and it is easy to suffer from pitting, wire breakage and other damages. When the damage reaches a certain extent, it may even be damaged and broken. After the cable is damaged or broken, it may cause the overall instability or destruction of the cable-stayed bridge, seriously affecting the safety of the bridge. Therefore, during the service of the cable, it is necessary to be able to detect the damaged cable in time and take corresponding measures.

[0003] At present, there are two main methods for cable damage identification: direct detection method and indirect detection method. Direct detection methods mainly include visual inspection method and cable force detection method. Visual inspection method has the disadvantages of long time consumption, low efficiency, high missed detection rate, large subjective influence, and large influence of detection environment. In addition, there is a lack of systematic demonstration of detection accuracy and stability. Cable force detection method is difficult to implement through automatic monitoring. Not only is the operation cumbersome and complicated, but the measured parameters are also easily contaminated, thus reducing the accuracy of damage identification. Summary of the invention

[0004] The purpose of the present invention is to provide a cable damage identification method, device, terminal and medium based on the second-order difference of beam deflection difference, aiming to solve the problems that the existing cable damage identification method is difficult to operate and has low identification accuracy.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a cable damage identification method based on the second-order difference of beam deflection difference, comprising the following steps:

[0006] Selected beam section on the main beam AB Set on n The cables are numbered 1, 2, ... from left to right. k-1 , k, k+ 1、 …、 n , the corresponding angles between each cable and the main beam are , any two adjacent cables and the selected beam segment AB The spacing between the anchor points onl , select the beam segment AB In the Razo k Concentrated load P The role of the cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB The upper part is subjected to uniform load q The role of;

[0007] When all cables are in an intact state, k With selected beam segment AB The bending moment at the anchor point on , a certain cable is damaged to form a damaged cable. k With selected beam segment AB The bending moment at the anchor point on , Lasso k The change in bending moment before and after damage is , The value of is related to the load, cable force and angle.

[0008] (1);

[0009] When all the cables are in an intact state, A The point distance is x The bending moment at the cross section is , a certain cable is damaged to form a damaged cable. k , the bending moment is , Lasso k The change in bending moment before and after damage is , The deflection difference The second-order derivative of

[0010] (2);

[0011] when x The value of k When the value is relevant, and Equal, that is, Formula 1 is equivalent to Formula 2,

[0012] (3),

[0013] The cable is obtained by converting it into formula 3 k Before and after the damage, the cable k The change of cable force The deflection difference The second-order derivative of the cablek The change of cable force The positive or negative value of the value can be used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable can be determined.

[0014] In a possible implementation, when the cables are all in an intact state, cables 1, 2, ..., k-1 , k, k+1, …、 n The corresponding cable forces are , Lasso k With selected beam segment AB Bending moment at the anchor point on ,

[0015] ,

[0016] Cable k After the damage occurs, the cables 1, 2, ..., k-1 , k, k+1, …、 n The corresponding cable forces of each cable are , Lasso k With selected beam segment AB Bending moment at the anchor point on ,

[0017] ,

[0018] Definition of cable k Before and after the damage, the cable k The change of cable force is

[0019] (6),

[0020] Correspondingly, Lasso k The change in bending moment before and after damage is ,

[0021] .

[0022] In a possible implementation, when the cables are all in an intact state, A The point distance is x Bending moment at the cross section ,

[0023] (8),

[0024] Cable k After the injury occurs, A The point distance is x Bending moment at the cross section ,

[0025] (9),

[0026] definition 、 、 ，

[0027] (10),

[0028] Correspondingly, Lasso k Changes in bending moment before and after damage ,

[0029] (11).

[0030] In a possible implementation, when the cables are in an intact state, k With selected beam segment AB Bending moment at the anchor point on ,

[0031] ,

[0032] Cable k After the damage occurs, the cable k With selected beam segment AB Bending moment at the anchor point on ,

[0033] (13),

[0034] definition ,

[0035] (14),

[0036] Correspondingly, Lasso k The change in bending moment before and after damage is ,

[0037] (15).

[0038] In one possible implementation, according to Formula 11, the cable k Before and after the injury, x Value and k When relevant, select the beam segment AB In the cross section k-1, k, k+1 The change of bending moment at They are respectively,

[0039] (16),

[0040] According to formula 15, we can get k The change in bending moment before and after damage is ,

[0041] .

[0042] In a possible implementation, according to Formula 7 and Formula 17, the change in bending moment calculated by the two sets of formulas is exist k The values ​​are equivalent if they have the same value.

[0043] ,

[0044] According to formula 18, we can get k Before and after the damage, the cable k The change of cable force ,

[0045] .

[0046] In one possible implementation, the damage index is defined according to Formula 19: (Damage index of second-order difference) ,

[0047] ,

[0048] According to the damage index The positive or negative value of is used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable is determined.

[0049] A cable damage identification device based on the second-order difference of beam deflection difference is provided, comprising:

[0050] The first data acquisition module is used to obtain the data of the cables when all cables are in an intact state. k With selected beam segment AB Deflection value at the anchor point on the

[0051] The second data acquisition module is used to obtain the damage cable. k With selected beam segment AB Deflection value at the anchor point on the

[0052] Computing module, cable k The change of cable force The deflection difference The second-order derivative of k Deflection before and after damage Calculate the cable k The change of cable force The positive and negative, the cable k The change of cable force The positive and negative of the cable k In both cases, before and after the damage, the cable k The change of cable force;

[0053] Damage identification module, used to identify k The change of cable force The positive or negative value of the value can be used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable can be determined.

[0054] A terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the computer program.

[0055] A computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, wherein the computer program implements the steps of any of the above methods when executed by a processor.

[0056] The beneficial effects of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention are:

[0057] Compared with the prior art, the selected beam section on the main beam AB Perform analysis and select the beam segment AB Can be located in any area on the main beam, or the entire main beam can be selected as the selected beam segment AB Perform analysis and select the beam segment AB Set on n A cable, any cable n The angle with the main beam is , the two adjacent cables are in the selected beam segment AB The spacing of the anchor points on l， Cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB In the Raso k Concentrated load P The effect of concentrated load P Acting on the cable k Select the beam segment AB The upper part is subjected to uniform load q The effect of uniform load q For the selected beam segment AB When the deadweight of the cable is in an intact state, the cable k With selected beam segment ABThe bending moment at the anchor point on , Lasso k When in a damaged state, the damage line k With selected beam segment AB The bending moment at the anchor point on , Lasso k Changes in bending moment before and after damage For cable k Bending moment after damage With cable k Bending moment before damage The difference to A The point distance is x At the cross section, when the cables are in an intact state, the bending moment is , Lasso k In the damaged state, the bending moment is , Lasso k Changes in bending moment before and after damage , for the cable k Bending moment after damage With cable k Bending moment before damage The difference, when x Value and k When relevant, and Equal, get the cable k Cable before and after damage occurs k The change of cable force , Lasso k The change of cable force The deflection difference The second-order derivative of the cable k The change of cable force The positive and negative of the cable k The change of cable force can be used to determine whether the cable is damaged and determine the damage location when damage occurs. The data in the identification process is easy to calculate or measure and the data accuracy is high. The above method is simple and easy to implement, has high accuracy and reliability in judging the damage of the cable, and has good feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] Figure 1 The selected beam section used in the embodiment of the present invention AB Schematic diagram of force analysis of the endpoints;

[0060] Figure 2 Schematic diagram of the stress analysis of the isolation beam section used in the embodiment of the present invention Figure 1 ;

[0061] Figure 3 Schematic diagram of the stress analysis of the isolation beam section used in the embodiment of the present invention Figure 2 ;

[0062] Figure 4 Schematic diagram of the stress analysis of the isolation beam section used in the embodiment of the present invention Figure 3 ;

[0063] Figure 5 The beam segment selected in the non-cable damage state adopted in the embodiment of the present invention is AB Schematic diagram of force analysis;

[0064] Figure 6 The beam section selected in the state of cable damage adopted in the embodiment of the present invention AB Schematic diagram of force analysis. DETAILED DESCRIPTION

[0065] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0066] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or indirectly on the other element. It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0067] Please refer to Figures 1 to 4 , select the beam section on the main beam AB The upper part is subjected to uniform load q and oblique concentrated loadsP The effect of oblique concentrated load P The cable force comes from the cable, select the beam segment AB Set on n The cables are numbered 1, 2, ... from left to right. k-1 , k, k+1, …、 n , in Lasso k With selected beam segment AB Bending moment at the anchor point on for A The bending moment generated by the end force at the end point , uniform load q The bending moment generated here and oblique concentrated loads P The bending moment generated here The sum of

[0068] (twenty one);

[0069] Define the moment change offset , bending moment change offset Indicates cable k Bending moment at the anchor point Compared with the cable k The offset of the mean bending moment at the anchorage points of the adjacent cables on both sides is calculated by the bending moment change offset Judgment cable k Bending moment at the anchor point The offset of the bending moment at the anchorage points of the cables on both sides,

[0070] ;

[0071] Substituting Formula 21 into Formula 22, we obtain

[0072] (twenty three)

[0073] ; k With selected beam segment AB The anchor point on the selected beam segment is used as the isolation point. AB of A End point to cable k The beam segment with anchor points is used as the isolation beam segment. Select the beam segment AB of A End point to cable 1 and selected beam segment AB The distance between the anchor points on , select the beam segment B of AB End point to cable n With selected beam segment AB The distance between the anchor points on , in the selected beam segment AB of A The bending moment at the end point is , in the selected beam segment A of AB The vertical upward support force at the end point is , Cable 1 to Cable k The distance between ,

[0074] According to the mechanical formula, select the beam segment within the range of the isolated beam segment. AB of A The end force at the end point is in the cable k The bending moment generated at the anchor point ,

[0075] (twenty four);

[0076] According to the mechanical formula, select the beam segment within the range of the isolated beam segment. AB Uniform load q The bending moment generated here ,

[0077] (25);

[0078] According to the mechanical formula, within the range of the isolation beam section, cable 1 to cable k The sum of the cable forces is the oblique concentrated load P The bending moment generated here ,

[0079] (26);

[0080] Substituting formula 24, formula 25, and formula 26 into formula 23, we can obtain

[0081] .

[0082] According to the material mechanics formula, the bending moment and deflection The relationship is

[0083] (28),

[0084] (29),

[0085] in, is the beam deflection The second-order derivative of E is the elastic modulus of the main beam, I is the section moment of inertia of the main beam, For cross section xThe curvature at

[0086] Substituting Formula 28 into Formula 29, we obtain

[0087] (30),

[0088] Ignore Selected Segments AB Bending deformation, select the beam segment AB The deflection curve is a flat curve. is very small compared to 1, so The value of can be ignored, and Formula 30 is simplified to

[0089] (31),

[0090] According to the second-order central difference formula, the beam deflection The second derivative of Expressed as

[0091] (32),

[0092] Substituting formula 31 into formula 32, we obtain

[0093] (33).

[0094] Please refer to Figures 1 to 6 Now, a specific implementation of a cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention is described, which includes the following steps:

[0095] Selected beam section on the main beam AB Set on n The cables are numbered 1, 2, ... from left to right. k-1 , k, k+ 1、 …、 n , the corresponding angles between each cable and the main beam are , any two adjacent cables and the selected beam segment AB The spacing between the anchor points on l , select the beam segment AB In the Razo k Concentrated load P The role of the cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB The upper part is subjected to uniform load q The role of;

[0096] When all cables are in an intact state,k With selected beam segment AB The bending moment at the anchor point on , a certain cable is damaged to form a damaged cable. k With selected beam segment AB The bending moment at the anchor point on , Lasso k The change in bending moment before and after damage is , The value of is related to the load, cable force and angle.

[0097] (1);

[0098] When all the cables are in an intact state, A The point distance is x The bending moment at the cross section is , a certain cable is damaged to form a damaged cable. k , the bending moment is , Lasso k The change in bending moment before and after damage is , according to formula 33, The deflection difference The second-order derivative of

[0099] (2);

[0100] when x The value of k When the value is relevant, and Equal, that is, Formula 1 is equivalent to Formula 2,

[0101] (3),

[0102] The cable is obtained by converting it into formula 3 k Before and after the damage, the cable k The change of cable force The deflection difference The second-order derivative of the cable k The change of cable force The positive or negative value of the value can be used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable can be determined.

[0103] The cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention is more accurate than the prior art in identifying the damage of the selected beam section on the main beam. AB Perform analysis and select the beam segment AB Can be located in any area on the main beam, or the entire main beam can be selected as the selected beam segment AB Perform analysis and select the beam segment AB Set on n A cable, any cable n Angle with main beam , the two adjacent cables are in the selected beam segment AB The spacing of the anchor points on l， Cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB In the Raso k Concentrated load P The effect of concentrated load P Acting on the cable k Select the beam segment AB The upper part is subjected to uniform load q The effect of uniform load q For the selected beam segment AB When the deadweight of the cable is in an intact state, the cable k With selected beam segment AB The bending moment at the anchor point on k When in a damaged state, the damage line k With selected beam segment AB The bending moment at the anchor point on , Lasso k Changes in bending moment before and after damage For cable k Bending moment after damage With cable k Bending moment before damage The difference to A The point distance is x At the cross section, when the cables are in an intact state, the bending moment is , Lasso k In the damaged state, the bending moment is , Lasso k Changes in bending moment before and after damage , for the cable k Bending moment after damage With cable k Bending moment before damage The difference, when x Value and k When relevant, and Equal, get the cable k Cable before and after damage occurs k The change of cable force , Lasso k The change of cable force The deflection difference The second-order derivative of the cable k The change of cable force The positive and negative of the cable k The change of cable force can be used to determine whether the cable is damaged and determine the damage location when damage occurs. The data in the identification process is easy to calculate or measure and the data accuracy is high. The above method is simple and easy to implement, has high accuracy and reliability in judging the damage of the cable, and has good feasibility.

[0104] For details, please refer to Figures 1 to 6 , select the beam segment along the length direction of the main beam, select the beam segment AB It can be located in any area on the main beam, or the entire main beam can be selected as a beam segment for analysis. n Cable, selected beam segment AB of A Point is located on the selected beam segment AB , select the beam segment AB of B Point is located on the selected beam segment AB The right end of n The cables are numbered 1, 2, ... from left to right. k-1 , k, k+1, …、 n , 1, 2, ..., k-1 , k, k+1, …、 n The angles between the cables and the main beam are The cable has different inclination directions depending on the location of the cable. The cable is inclined toward the left side of the selected beam segment, or toward the right side of the selected beam segment. At the end of the selected beam segment, the left end of the selected beam segment A The bending moment at a point is (When the cable is intact, the bending moment is , when the cable is damaged, the bending moment is ), the vertical force is (When the cable is intact, the vertical force is , when the cable is damaged, the vertical force is ), the axial force is , select the left end of the beam segment B The bending moment at a point is (When the cable is intact, the bending moment is , when the cable is damaged, the bending moment is ), the vertical force is (When the cable is intact, the vertical force is , when the cable is damaged, the vertical force is ), the axial force is , ignoring the axial deformation of the selected beam segment, that is, not considering the horizontal axial force at the left and right ends of the selected beam segment, and analyzing the vertical component of the cable force. AB The distance between the anchor points of any two adjacent cables is equal. l , concentrated load P Acting on the cable k Define the selected beam segment AB of A The end is the origin, the cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB The effect of self-gravity on the selected beam segment AB The load is equivalent to a uniform load. q , Lasso k The value of the bending moment before and after the damage changes. Two methods are used to calculate the difference between the bending moment before and after the damage. The first method is calculated according to formula 1. k The change in bending moment before and after damage is , the change of bending moment For cable k Bending moment after damage With cable k Bending moment before damage The difference between k Bending moment before damage , Cable k Bending moment after damage With cable k In the selected beam segment AB The load at the anchor point on the cable, the cable force and the angle, so the change in the bending moment is For the cable k In the selected beam segment AB The second method is to calculate the load at the anchor point on the cable, the cable force and the angle according to formula 2. k The change in bending moment before and after damage is , the change of bending moment For Lasso k Bending moment after damage With cable k Bending moment before damage The difference between k Bending moment before damage , Cable k Bending moment after damage With A Distance of points xFormula 1 and Formula 2 are the calculation methods for the change values ​​of the two bending moments. x The value of k The change of bending moment The change of bending moment Equal, we get formula 3, which is the same as the cable k In the selected beam segment AB Loads, cable forces, angles, and cable tension at anchor points on k Anchor point to A Distance of points x The relevant formula is transformed to obtain the cable k The change of cable force The deflection difference The second-order derivative of the cable force is When it is positive or zero, there is no cable damage and the cable force change value When it is a negative value, the cable is damaged. If the cable is damaged, the position of the damaged cable is determined. During the identification process, the data is easy to calculate or measure, and the data accuracy is high. The above method is simple and easy, and has high accuracy and reliability in judging the damage of the cable, and has good feasibility.

[0105] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 According to Formula 27, when all cables are in a non-destructive state, cables 1, 2, ..., k-1 , k, k+ 1、 …、 n The corresponding cable forces of each cable are , Lasso k With selected beam segment AB Bending moment at the anchor point on ,

[0106] ,

[0107] According to Formula 27, the cable k After the damage occurs, the cables 1, 2, ..., k-1 , k, k+1, …、 n The corresponding cable forces of each cable are , Lasso k With selected beam segment AB Bending moment at the anchor point on ,

[0108] ,

[0109] Definition of cable k Before and after the damage, the cable kThe change of cable force is

[0110] (6),

[0111] Correspondingly, Lasso k The change in bending moment before and after damage is ,

[0112] .

[0113] For details, please refer to Figures 1 to 6 , when the cables are in an intact state, select the beam segment under uniform load q and cable k Soli Under the action of k With selected beam segment AB Bending moment at the anchor point on , when Lasso k In the damaged state, the selected beam segment is under uniform load. q and cable k Soli Under the action of k With selected beam segment AB Bending moment at the anchor point on , Substitute Formula 4, Formula 5, and Formula 6 into Formula 1 to obtain Formula 7, which is the cable k Changes in bending moment before and after damage With cable k The change of cable force is The functional relationship of .

[0114] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 , when the cables are intact, A The point distance is x Bending moment at the cross section ,

[0115] (8),

[0116] Cable k After the injury occurs, A The point distance is x Bending moment at the cross section ,

[0117] (9),

[0118] definition 、 、 ，

[0119] (10),

[0120] Correspondingly, Lasso k Changes in bending moment before and after damage ,

[0121] (11).

[0122] For details, please refer to Figures 1 to 6 , according to formula 8, When the cables are intact, the cross section at a distance x from point A Deflection for ,arrive A The point distance is x Bending moment at the cross section For deflection The relevant function, according to formula 9, when the cable k When in a damaged state, A The point distance is x The deflection at the cross section is ,arrive A The point distance is x Bending moment at the cross section For deflection Related functions, define the cable k Before and after the injury A The point distance is x The deflection change at the cross section is , deflection change value For cable k Deflection after damage With cable k Deflection before damage Substituting formula 8, formula 9, and formula 10 into formula 2, we get formula 11, which is the cable k Before and after the injury A The point distance is x The change of bending moment at the cross section and deflection change The functional relationship of the bending moment is is the change value of deflection The functional relationship related to the second-order derivative of .

[0123] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 , when the cables are intact, k With selected beam segment AB Bending moment at the anchor point on ,

[0124] ,

[0125] Cable k After the damage occurs, the cable k With selected beam segment AB Bending moment at the anchor point on ,

[0126] (13),

[0127] definition ,

[0128] (14),

[0129] Correspondingly, Lasso k The change in bending moment before and after damage is ,

[0130] (15).

[0131] For details, please refer to Figures 1 to 6 According to formula 22, when the cables are in a non-destructive state, we can get k With selected beam segment AB Bending moment at the anchor point on , when Lasso k While in the damaged state, gain the Cable k With selected beam segment AB Bending moment at the anchor point on , define the cable k Before and after the damage, the cable k With selected beam segment AB The change in the bending moment at the anchor point is The change of bending moment is For cable k Bending moment after damage With cable k Bending moment before damage The difference between

[0132]

[0133] Substituting Equation 14 into Equation 34, the result is simplified to obtain Equation 15.

[0134] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 According to formula 11, the cable kBefore and after the injury, x Value and k When relevant, select the beam segment AB In the cross section k-1, k, k+1 The change of bending moment at They are respectively,

[0135] (16),

[0136] According to formula 15, we can get k The change in bending moment before and after damage is ,

[0137] .

[0138] For details, please refer to Figures 1 to 6 , Lasso k Before and after damage occurs, select the beam segment AB In the Raso k The change in the bending moment of the section at , select the beam segment AB In the Raso k-1 The change in the bending moment of the section at , select the beam segment AB In the Raso k+1 The change in the bending moment of the section at , according to formula 11, we can get formula 16, and substitute formula 16 into formula 15 to get the cable k Before and after the damage, the cable k With selected beam segment AB The change in the bending moment at the anchor point is , Lasso k With selected beam segment AB Changes in the bending moment at the anchor point on is the change value of deflection The functional relationship related to the second-order derivative of .

[0139] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 According to Formula 7 and Formula 17, the change in bending moment calculated by the two sets of formulas is exist k The values ​​are equivalent if they have the same value.

[0140] ,

[0141] According to formula 18, we can get k Before and after the damage, the cable k The change of cable force ,

[0142] .

[0143] For details, please refer to Figures 1 to 6 , Formula 7 and Formula 17 are both cable k The change in bending moment before and after damage is The calculation formula for the same cable k At this point, Formula 7 is equivalent to Formula 17, so Formula 18 is obtained. By converting Formula 18, we can get the cable k Cable before and after damage k The change of cable force and deflection change The functional relationship related to the second-order derivative of .

[0144] Further, Lasso k Deflection change before and after damage The second difference of for

[0145] (35)

[0146] As a specific implementation of the cable damage identification method based on the second-order difference of beam deflection difference provided by the present invention, please refer to Figures 1 to 6 , according to formula 19, the damage index is defined (Damage index of second-order difference) ,

[0147] ,

[0148] According to the damage index The positive or negative value of is used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable is determined.

[0149] For details, please refer to Figures 1 to 6 According to formula 19, for the same cable k , , All are fixed values, cable k Cable before and after damage k The change of cable force Changes and

[0150] Directly related, so the damage index is defined for

[0151] , damage index The value change of

[0152] About, when the rope k The change in deflection at Larger than cable k Changes in the deflection of the cables on both sides When the average value of k The change of deflection value is greater than that of cable k The change in the deflection value of the cables on both sides. is positive, the cable k Cable force changes before and after damage is a negative value, the cable k The cable force on ， Cable k There is damage, on the contrary, when the cable k The change in deflection at Less than or equal to cable k Changes in the deflection of the cables on both sides When the average value of k The change in deflection value is less than or equal to the cable k The changes of the cables on both sides of is a negative or zero value, the cable k Cable force changes before and after damage is a positive or zero value, the cable k The cable force on the cable increases or remains unchanged ， Cable k No damage.

[0153] Further, Lasso k The change in deflection at , by measuring the cable k With selected beam segment AB The displacement at the anchor point on the cable is obtained. k With selected beam segment AB A displacement sensor is provided at the anchor point on the vehicle.

[0154] Based on the same inventive concept, the embodiment of the present application further provides a cable damage identification device based on the second-order difference of beam deflection difference. Now, a specific implementation of the cable damage identification device based on the second-order difference of beam deflection difference is described, including:

[0155] The first data acquisition module is used to obtain the data of the cables when all cables are in an intact state. k With selected beam segment AB Deflection value at the anchor point on the

[0156] The second data acquisition module is used to obtain the damage cable. k With selected beam segment AB Deflection value at the anchor point on the

[0157] Computing module, cable k The change of cable force The deflection difference The second-order derivative of the cable k Deflection difference before and after damage Calculate the cable k The change of cable force The positive and negative, the cable k The change of cable force The positive and negative of the cable k In both cases, before and after the damage, the cable k The change of cable force;

[0158] Damage identification module, used to identify k The change of cable force The positive or negative value of the value can be used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable can be determined.

[0159] Specifically, the device can intuitively obtain the state of the damaged cables when all cables are in an intact state and the damaged cables when there are damaged cables. k Deflection difference at , calculate the change in cable force The positive or negative value of the cable force changes according to the value of The positive and negative judgment of the cable damage can quickly obtain various parameters, improve the judgment efficiency of the damaged cable, and can accurately determine the position of the damaged cable, improve the judgment accuracy, simplify the judgment process, and has good practicality.

[0160] Based on the same inventive concept, an embodiment of the present application also provides a terminal. A specific implementation of a terminal is now described, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of any of the methods described above when executing the computer program.

[0161] Specifically, in this embodiment, the terminal may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal may include, but is not limited to, a processor and a memory, and may include more components than the above structure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0162] The processor may be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, field programmable gate arrays, or other programmable logic device discrete gates or discrete hardware components of transistor logic devices. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor. The memory may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. The memory may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card, or a flash memory card equipped on the terminal.

[0163] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium. A specific implementation of a computer-readable storage medium is now described. The computer-readable storage medium stores a computer program, characterized in that when the computer program is executed by a processor, the steps of any of the methods described above are implemented.

[0164] Specifically, each functional unit in each embodiment of the present invention may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit. If the integrated module or unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium.

[0165] Based on this understanding, the present invention implements all or part of the processes in the above-mentioned implementation method, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned identification method can be implemented.

[0166] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cable damage identification method based on the second-order difference of beam deflection difference, characterized in that: The following steps are involved: Selected beam section on the main beam AB Set on n The cables are numbered 1, 2, ... from left to right. k-1 , k, k+1, …、 n , the corresponding angles between each cable and the main beam are Any two adjacent cables in the selected beam segment AB The spacing of the anchor points on l , select the beam segment AB In the Raso k Concentrated load P The role of the cable k To the selected beam segment AB of A The distance between the endpoints is x , select the beam segment AB The upper part is subjected to uniform load q The role of; When all cables are in an intact state, k With selected beam segment AB The bending moment at the anchor point on , a certain cable is damaged to form a damaged cable. k With selected beam segment AB The bending moment at the anchor point on , Lasso k The change in bending moment before and after damage is , The value of is related to the load, cable force and angle. （1）； When all the cables are in an intact state, A The point distance is x The bending moment at the cross section is , a certain cable is damaged to form a damaged cable. k , the bending moment is , Lasso k The change in bending moment before and after damage is , The deflection difference The second-order derivative of （2）； when x The value of k When the value is relevant, and Equal, that is, Formula 1 is equivalent to Formula 2, （3）， When the cables are all intact, cables 1, 2, ..., k-1 , k, k+1, …、 n The corresponding cable forces are , Lasso k With selected beam segment AB Bending moment at the anchor point on , ， Cable k After the damage occurs, the cables 1, 2, ..., k-1 , k, k+1, …、 n The corresponding cable forces are , Lasso k With selected beam segment AB Bending moment at the anchor point on , ， Definition of cable k Before and after the damage, the cable k The change of cable force is （6）， Correspondingly, Lasso k The change in bending moment before and after damage is , The cable is obtained by converting it into formula 3 k Before and after the damage, the cable k The change of cable force The deflection difference The second-order derivative of the cable k The change of cable force The positive or negative value of the value can be used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable can be determined.

2. The cable damage identification method based on the second-order difference of beam deflection difference according to claim 1 is characterized in that: When the cables are intact, A The point distance is x Bending moment at the cross section , （8）， Cable k After the injury occurs, A The point distance is x Bending moment at any cross-sectional location , （9）， definition 、 、 ， （10）， Correspondingly, Lasso k Changes in bending moment before and after damage , （11）。 3. The cable damage identification method based on the second-order difference of beam deflection difference according to claim 2 is characterized in that: When the cables are intact, k With selected beam segment AB Bending moment at the anchor point on , ， Cable k After the damage occurs, the cable k With selected beam segment AB Bending moment at the anchor point on , （13）， definition , （14）， Correspondingly, Lasso k The change in bending moment before and after damage is , （15）。 4. The cable damage identification method based on the second-order difference of beam deflection difference according to claim 3 is characterized in that: According to formula 11, the cable k Before and after the injury, x Value and k When relevant, select the beam segment AB In the cross section k-1, k, k+1 The change of bending moment at They are respectively, （16）， According to formula 15, we can get k The change in bending moment before and after damage is , 。 5. The cable damage identification method based on the second-order difference of beam deflection difference according to claim 4 is characterized in that: According to Formula 7 and Formula 17, the change in bending moment calculated by the two sets of formulas is exist k The values ​​are equivalent if they have the same value. ， According to formula 18, we can get k Before and after the damage, the cable k The change of cable force , 。 6. A cable damage identification method based on second-order difference of beam deflection difference according to claim 5, characterized in that: According to formula 19, the damage index is defined as , ， According to the damage index The positive or negative value of is used to determine whether the cable is damaged. If the cable is damaged, the location of the damaged cable is determined.

7. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

8. A computer-readable storage medium storing a computer program, characterized in that When the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 6 are implemented.

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