CN101334338A - Health Monitoring Method of Cable System in Cable Structure Based on Spatial Coordinate Monitoring - Google Patents

Abstract

The health monitoring method of the cable system in the cable structure based on spatial coordinate monitoring performs several mechanical calculations on the basis of the mechanical calculation benchmark model of the structure, and the number of calculations is equal to the number of cables. Each calculation assumes that only one cable has unit damage, and each calculation result forms a calculation current coordinate vector; each calculation current coordinate vector subtracts the initial coordinate vector to obtain a coordinate change vector; all coordinate change vectors form a unit damage coordinate change matrix. According to the approximate linear relationship between the current coordinate vector (composed of the current measured coordinates of all specified points) and the initial coordinate vector, the unit damage coordinate change matrix, the unit damage scalar and the current cable damage vector (composed of the current damage of all cables), Appropriate algorithms such as multi-objective optimization algorithm can be used to quickly calculate the non-inferior solution of the current cable damage vector, based on which the location of the damaged cable and its damage degree can be determined more accurately.

Description

Health Monitoring Method of Cable System in Cable Structure Based on Spatial Coordinate Monitoring

technical field

The invention identifies damaged cables in cable systems (referring to all bearing cables) of cable structures (especially large cable structures, such as large cable-stayed bridges and suspension bridges) based on spatial coordinate monitoring, and belongs to the field of engineering structure health monitoring.

Background technique

The cable system is usually a key component of the cable structure, and its failure often leads to the failure of the entire structure. Based on structural health monitoring technology to identify cable systems (especially large cable structures, such as large cable-stayed bridges, suspension bridges) in the cable system The damaged cable is a method with great potential. At present, the structural health monitoring technology mainly monitors the cable force, and identifies the damaged cable and its damage degree according to the change of the cable force. However, as far as a single cable is concerned, the change of its cable force has a clear and monotonous relationship with its health status (damage degree). However, when the cable is a cable structure (especially a large cable structure, such as a large cable-stayed bridge, When one of the cable systems of a suspension bridge), since the change of the cable force of each specific cable is not only affected by its own health status, but also affected by the health status of other cables, the cable force of each specific cable is observed Even under the condition of the same health status of the cable (same degree of damage or no damage), it will be monitored that the change of its cable force is suddenly positive and negative, large and small, which is very important for the identification of damaged cables. Very unfavorable. At present, there is no public and effective health monitoring system and method to solve this problem. The health status of each cable will not only affect the cable force of all cables, but also affect the shape or spatial coordinates of the cable structure. There is no public report to realize the cable system by monitoring the shape or spatial coordinates of the cable structure. Systems and methods for health monitoring.

In order to be able to reliably monitor and judge the health status of the cable system of cable structures (especially large cable structures, such as large cable-stayed bridges and suspension bridges), there must be a change in the shape or spatial coordinates of the cable structure that can be reasonably and effectively established The method of the relationship between the health status of all cables in the same cable system, the health monitoring system established based on this method can give a more credible health assessment of the cable system.

Contents of the invention

Technical problem: the purpose of the present invention is aimed at the health monitoring problem of cable system in cable structure (particularly large-scale cable structure, such as large-scale cable-stayed bridge, suspension bridge), discloses a kind of reasonable and effective monitoring cable structure (especially large-scale cable structure) Structures, such as large cable-stayed bridges, suspension bridges), a health monitoring method for cable systems in cable structures based on spatial coordinate monitoring.

Technical solution: the present invention consists of three parts. They are respectively the method of establishing the knowledge base and parameters required for the health monitoring of the cable system, the evaluation method of the health status of the cable system based on the knowledge base (including parameters) and the spatial coordinates (or shape) of the measured cable structure, and the software and hardware of the health monitoring system. part.

The first part of the present invention: the method of establishing knowledge base and parameters for cable system health monitoring. Can be divided into the following three steps:

1. Establish a calculation benchmark model of the cable structure (such as a finite element benchmark model). According to the cable structure design drawing, as-built drawing and the measured data of the cable structure (including structural shape data, cable force data, structural modal data and other measured data, for cable-stayed bridges and suspension bridges, the bridge type data, cable force data, bridge modal data), using mechanical methods (such as finite element method) to establish the calculation (such as finite element) benchmark model of the structure, based on the calculation of the benchmark model (such as finite element benchmark model) to calculate the structural calculation data ( For cable-stayed bridges and suspension bridges, the bridge type data, cable force data, and bridge modal data) must be very close to the measured data, and the error is generally not greater than 5%. In this way, it can be ensured that the cable force calculation data, structural shape calculation data and spatial coordinate calculation data calculated on the calculation basis model in the simulation situation are reliably close to the actual measurement data when the simulation situation actually occurs.

The structural shape data is described by the spatial coordinates of K designated points on the structure and L designated directions of each designated point, and the change of the structural shape data is the change of all coordinate components of the K designated points. Each time there are M (M=K×L) coordinate measurements or calculation values to characterize the shape of the structure. K and M are generally not less than the number of cables. When the structural shape is mentioned later, it can be understood as structural space coordinates, and vice versa.

Assuming that there are N cables in the cable system, the vector C _o can be used to represent the initial coordinate vectors of all specified points in the cable structure (see formula (1)). Because under the above conditions, the initial coordinates of the specified point calculated based on the calculation benchmark model of the cable structure are reliably close to the measured data of the initial coordinates of the specified point, in the following description, the same symbol will be used to represent the calculated value and the measured value value.

C _o ＝[C _o1 C _o2 ...C _oi ...C _oM ] ^T (1)

In formula (1), C _oi (i=1, 2, 3,..., M; M≥N) is the i-th initial coordinate component in the cable structure (assuming that the cable is not damaged at this time), This component corresponds to a coordinate component of a particular point according to the numbering convention. T represents the transpose of the vector (the same below).

2. Establish the cable structure unit damage coordinate change matrix ΔC. Several calculations are performed on the basis of the mechanical calculation benchmark model of the cable structure, and the number of calculations is numerically equal to the number of all cables. Each calculation assumes that only one cable in the cable system has unit damage D _u (unit damage should be small, and the shape or coordinate changes caused by it can be accurately identified by sensors, for example, 10% damage is taken as unit damage), each The damaged cable in the calculation is different from the damaged cable in other calculations. Each calculation uses a mechanical method (such as the finite element method) to calculate all the current coordinate components of all specified points in the cable structure. Each calculation forms a set of all specified points. Calculate the current coordinate vector of the point (when it is assumed that the jth cable has unit damage, the formula (2) can be used to express the calculated current coordinate vector C _t ^j of all specified points); the calculated current coordinate vector obtained by each calculation minus the initial coordinate vector, the resulting vector is the coordinate change vector (marked by the position or number of the cable with unit damage) under this condition (when the jth cable has unit damage, use δC _j to represent the coordinate change vector, the definition is shown in the formula ( 3), formula (3) is obtained by subtracting formula (1) from formula (2), δC _j actually expresses the displacement of the specified point relative to the initial position, so δC _j can also be called the displacement vector), the coordinate change vector Each element represents the amount of change in the coordinates of the specified point corresponding to the element due to the unit damage of the cable that is assumed to have unit damage during calculation; there are N coordinate change vectors, Each coordinate change vector has M (M≥N) elements, and these N coordinate change vectors form a unit damage coordinate change matrix ΔC with M×N elements in turn. The definition of ΔC is shown in formula (4). Similar to δC _j can be called the current displacement vector, ΔC can also be called the unit damage displacement matrix.

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; ti</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; tM</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula (2), the element C _ti ^j (i=1, 2, 3, ..., j = 1, 2, 3, ..., N; M≥N) represents that due to When the jth cable has unit damage, calculate the current coordinates of a specified point, a certain direction, and number i according to the numbering rule.

${\mathrm{<span\; class="notranslate">\; \&delta;C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccccc}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1,1</span>}}& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1,2</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}\\ \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2,1</span>}}& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2,2</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}& <span\; class="notranslate">\; \&CenterDot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}\\ <span\; class="notranslate">\; \&CenterDot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&CenterDot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>\\ \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}\\ <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>& <span\; class="notranslate">\; \&Center\; Dot;</span>\\ \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}& <span\; class="notranslate">\; \&Center\; Dot;</span>& \mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In formula (4), ΔC _ij (i=1, 2, 3, ..., M; j = 1, 2, 3, ..., N; M≥N) means only The change (algebraic value) of the coordinates numbered i in a certain direction corresponding to a specified point according to the numbering rules due to the unit damage of the jth cable. The coordinate change vector δC _j is actually a column in the matrix ΔC, that is to say, formula (4) can also be written as formula (5).

ΔC＝[δC ₁ δC ₂ ... δC _j ... δC _N ] (5)

3. The approximate linear relationship between the current (calculated or measured) coordinate vector C of the cable system and the initial coordinate vector C _o , the unit damage coordinate change matrix ΔC, the unit damage scalar D _u and the current damage vector d, such as formula (6) or formula (7) shown.

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

The definition of the current coordinate vector C in formulas (6) and (7) is similar to the definition of the initial coordinate vector C _o , see formula (8); the definition of the current damage vector d of the cable system see formula (9); D _u is the unit The damage has been described above. The left side of formula (7) is C minus C _o , which is actually the current displacement vector, so it can also be said that formula (7) expresses the current displacement vector (defined as C minus C _o ) with the unit damage displacement matrix ΔC, unit The approximate linear relationship between the damage scalar D _u and the current damage vector d.

C＝[C ₁ C ₂ ...C _i ...C _M ] ^T (8)

In formula (8), C _i (i=1, 2, 3,..., M; M≥N) is the cable structure, corresponding to a certain designated point and a certain direction according to the numbering rules , the current coordinate numbered i.

d=[d ₁ d ₂ ...d _i ...d _N ] ^T (9)

In formula (9), d _i (i=1, 2, 3, ..., N) is the current damage of the i-th cable in the cable system; when d _i is 0, it means no damage, and when it is 100% It means that the cable completely loses its bearing capacity, and when it is between 0 and 100%, it means that it loses the corresponding proportion of bearing capacity.

If the cable damage is set as 100%, it means that the cable completely loses its bearing capacity, then when the actual damage is not too large (for example, the damage is not greater than 30%), since the cable structure material is still in the linear elastic stage, the deformation of the cable structure is also small , such a linear relationship represented by formula (6) or formula (7) has a small error with the actual situation. The error vector e defined by formula (10) represents the error of the linear relationship shown in formula (6) or formula (7).

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; abs</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In the formula (10), abs() is an absolute value function, and the absolute value is taken for each element of the vector obtained in the brackets.

The second part of the present invention: a cable system health status evaluation method based on the knowledge base (including parameters) and the current measured structure shape (coordinates of designated points). Since there is a certain error in the linear relationship represented by formula (6) and formula (7), the cable damage vector d cannot be obtained simply by directly solving formula (6) or formula (7) and the measured current coordinate vector C. If this is done, the elements in the obtained cable damage vector d will even have relatively large negative values, that is, negative damage, which is obviously unreasonable. Therefore, it is a reasonable solution to obtain an acceptable solution of the cable damage vector d (that is, with a reasonable error, but the location of the damaged cable and its damage degree can be determined more accurately from the cable system), and the formula (11) can be used to express this method.

$\mathrm{<span\; class="notranslate">\; abs</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In formula (11), abs() is an absolute value function, and the vector g describes the reasonable deviation from the ideal linear relationship (formula (6) or formula (7)), which is defined by formula (12).

g＝[g ₁ g ₂ ...g _i ...g _M ] ^T (12)

g _i (i=1, 2, 3, . . . , M) in formula (12) describes the maximum allowable deviation from the ideal linear relationship shown in formula (6) or formula (7). The vector g can be selected according to the error vector e defined by formula (10).

When the initial coordinate vector C _o (obtained from actual measurement), the cable structure unit damage coordinate change matrix ΔC (obtained by calculation), the measured current coordinate vector C and the unit damage D _u (set before calculation of ΔC) are known, an appropriate algorithm can be used (eg multi-objective optimization algorithm) to solve equation (11) to obtain an acceptable solution of the cable damage vector d, so as to determine the position and damage degree of the damaged cable.

The third part of the present invention: the software and hardware parts of the health monitoring system. The hardware part includes shape (coordinate) monitoring system, signal collector and computer. It is required to monitor the coordinates of all specified directions of each specified point in real time. The software should have the following functions: the software part first analyzes the data transmitted from the shape (coordinate) monitoring system in real time or quasi-real time to obtain the current coordinate vector C, and then reads the pre-stored cable system unit damage coordinate change matrix ΔC, initial coordinate vector C _o and the unit damage value D _u , according to the appropriate algorithm (such as multi-objective optimization algorithm) to solve the formula (11), the non-inferior solution of the cable damage vector d of the cable system is obtained, that is, there is a reasonable error, but it can be relatively accurate The location of the damaged cable and the solution of its damage degree can be accurately determined from the cable system.

The inventive method specifically comprises:

a. Determine the numbering rule of the cable, according to this rule, all the cables in the cable structure are numbered, and the numbering will be used to generate vectors and matrices in subsequent steps;

b. Determine the designated measured points, which are all designated points that represent the shape of the structure, and number all designated points; determine the measured coordinate direction of the measured points, and number them; the above numbers will also be used in subsequent steps Used to generate vectors and matrices; the number of measurement points generally cannot be less than the number of cables; the sum of the numbers of all specified coordinate directions of all measured specified points cannot be less than the number of cables;

c. Under the condition that the cable structure has no damage or can be regarded as no damage, the initial coordinates of all designated points of the cable structure are obtained by direct measurement and calculation, and the initial coordinate vector C _o is formed;

d. Under the condition that the cable structure has no damage or can be considered as no damage, while the initial coordinate vector is obtained by actual measurement, the initial cable force data of all cables of the cable structure are obtained by actual measurement;

e. Based on the cable structure design drawing, as-built drawing and the actual measurement data of the cable structure, establish the mechanical calculation benchmark model of the cable structure. The actual measurement data of the cable structure includes at least the initial cable force data and initial coordinate vectors of all cables of the structure;

f. Carry out several mechanical calculations on the basis of the mechanical calculation benchmark model, and obtain the unit damage coordinate change matrix ΔC through calculation;

g. Obtain the current measured coordinates of all specified points of the cable structure through actual measurement, and form the current coordinate vector C;

h. Define the current damage vector d of the cable system. The number of elements of the current damage vector is equal to the number of cables. There is a one-to-one correspondence between the elements of the current damage vector and the cables. The value of the elements of the current damage vector represents the damage degree of the corresponding cable or health status;

i. According to the approximate linear relationship between the current coordinate vector C and the initial coordinate vector C _o , the unit damage coordinate change matrix ΔC, the unit damage scalar D _u and the current damage vector d of the cable system to be obtained, the approximate linear relationship can be expressed as Formula 1, other quantities except d in formula 1 are known, and the current damage vector d can be calculated by solving formula 1;

$C=C_o+\frac{1}{{\mathrm{D.}}_u}\mathrm{\&Delta;C}\&Center\; Dot;d$ Formula 1

j. Since the element value of the current damage vector d represents the damage degree of the corresponding cable, it is determined which cables are damaged and the damage degree according to the current damage vector, that is, the health monitoring of the cable system in the cable structure is realized; if the current cable damage vector If the value of an element of 0 is 0, it means that the cable corresponding to this element is intact without damage; if its value is 100%, it means that the cable corresponding to this element has completely lost its bearing capacity; if its value is between Between 0 and 100%, it means that the cable has lost a corresponding proportion of its bearing capacity.

In step f, the specific method for obtaining the unit damage coordinate change matrix is:

f1. Carry out several mechanical calculations on the basis of the mechanical calculation benchmark model. The number of calculations is numerically equal to the number of all cables. There are N calculations for N cables. Each calculation assumes that only one cable in the cable system has unit damage. , the damaged cable in each calculation is different from the damaged cable in other calculations, and each calculation obtains all the current coordinate components of all specified points in the cable structure, and all the current coordinates obtained in each calculation form a calculation current coordinate vector ;

f2. The calculated current coordinate vector obtained by each calculation subtracts the initial coordinate vector to obtain a coordinate change vector; if there are N cables, there are N coordinate change vectors;

f3. A unit damage coordinate change matrix with N columns is sequentially formed by the N coordinate change vectors; or each column of the unit damage coordinate change matrix corresponds to a coordinate change vector.

Beneficial effects: the system and method disclosed in the present invention can very accurately monitor and evaluate the health status of the cable system (including all affected The location and damage degree of the damaged cable, because the deformation of the cable structure is small at this time, and the linear relationship is better). When there are many damaged cables (for example, more than 30 cables or more than 50% of the cables are simultaneously damaged), the positions and damage degrees of most of the damaged cables can be monitored and evaluated quite accurately. Considering that the cable damage of the cable system is usually non-equilibrium and non-synchronous damage of a large number of cables, the system and method disclosed in the present invention are very beneficial to the effective health monitoring of the cable system.

Detailed ways

Aiming at the health monitoring of cable systems of cable structures (especially large cable structures, such as large cable-stayed bridges and suspension bridges), the present invention discloses a method that can reasonably and effectively monitor the health status of each cable in the cable system in the cable structure. systems and methods. The following descriptions of embodiments of the invention are merely exemplary in nature, and are in no way intended to limit the application or uses of the invention.

The present invention employs an algorithm for monitoring the health status of the cable system (all cables) in cable structures, especially large cable structures, such as large cable-stayed bridges, suspension bridges. During specific implementation, the following steps are one of various steps that may be taken.

The first step: Determine the numbering rule of the cable, and number all the cables according to this rule. This number will be used in subsequent steps to generate vectors and matrices. Determine the points to be measured (that is, all designated points that characterize the shape of the structure) and the coordinate components to be measured, and number them. Each specified point can be the fixed end point of each cable (for example, the fixed end of the cable on the bridge deck of a cable-stayed bridge); this number will also be used to generate vectors and matrices in subsequent steps; the number of measurement points Must not be less than the number of claims. At each specified point, the coordinates of only one direction can be measured, and the coordinates of multiple directions can also be measured.

Step 2: Obtain the initial coordinates of all specified directions of all specified points of the cable structure by direct measurement or calculation after measurement, and the initial coordinate values of all specified points form the initial coordinate vector C _o . At the same time, the initial cable force of all cables of the cable structure is obtained by direct measurement or calculation after measurement.

Step 3: Establish the mechanical calculation benchmark model of the cable structure. According to the cable structure design drawing, as-built drawing and the measured data of the cable structure (including the initial shape or coordinate data of the structure, the initial cable force of all cables, the structural modal data and other data), it is a bridge for cable-stayed bridges and suspension bridges. model data, coordinate data, cable force data, and bridge modal data), use mechanical methods (such as the finite element method) to establish the mechanical calculation benchmark model of the structure (such as the finite element benchmark model), and calculate the structure based on the benchmark model The calculated data (for cable-stayed bridges and suspension bridges, at least the cable force data and bridge type data, that is, coordinate data) of the bridge must be very close to the measured data, and the error is generally not greater than 5%.

Step 4: Establish the cable structure unit damage coordinate change matrix ΔC. Several calculations are performed on the basis of the mechanical calculation benchmark model of the cable structure, and the number of calculations is numerically equal to the number of all cables. Each calculation assumes that there is only one cable in the cable system with unit damage D _u (the unit damage should be small and the coordinate changes caused by it can be accurately identified by the sensor, for example, 10% damage is taken as the unit damage). The damaged cable is different from the damaged cable in other calculations. Each calculation uses mechanical methods (such as finite element method) to calculate the current coordinates of all specified directions of all specified points in the cable system in the cable structure. Each calculation Compose a calculated current coordinate vector C; subtract the initial coordinate vector from the calculated current coordinate vector obtained by each calculation, and the obtained vector is the coordinate change vector under this condition (marked by the position or number of the cable with unit damage), and the coordinate Each element of the change vector represents the amount of coordinate change in the specified direction of the specified point corresponding to the element due to the unit damage of the cable assumed to have unit damage during calculation; there are N coordinate change vectors , each coordinate change vector has M elements (there are K specified points, and each specified point is specified to measure the coordinates of L directions, M=K×L; or different specified points have not necessarily the same number of measurement directions, M is the sum of the number of measured coordinate components), and the N coordinate change vectors are sequentially composed of a unit damage coordinate change matrix ΔC with M×N elements, or each column of the unit damage coordinate change matrix ΔC corresponds to a coordinate change vector.

Step 5: Establish linear relationship error vector e and vector g. Using the data in the first four steps (initial coordinate vector C _o , unit damage coordinate change matrix ΔC), while performing each calculation in the fourth step, that is, in "Each calculation assumes that only one cable in the cable system has unit damage D _u , the damaged cable in each calculation is different from the damaged cable in other calculations, each calculation uses mechanical methods (such as finite element method) to calculate the For the current coordinates, each calculation forms a calculation of the current coordinate vector C", and at the same time, each calculation forms a damage vector d. Among all the elements of the damage vector d, the value of only one element is D _u , and the value of other elements is 0. The element whose value is D _u in the damage vector d corresponds to the unit damage degree D _u of the only damaged cable in this calculation; put C, C _o , ΔC, D _u , d into formula (10) to obtain a linear relationship Error vector e, a linear relationship error vector e is obtained for each calculation; if there are N cables, there are N calculations, and there are N linear relationship error vectors e, and these N linear relationship error vectors e are added to obtain a vector , the new vector obtained after dividing each element of this vector by N is the final linear relationship error vector e. The vector g is equal to the final error vector e.

Step 6: Install the hardware part of the cable structure health monitoring system. The hardware part includes at least: a coordinate monitoring system (such as sensors, signal conditioners, etc.), a signal collector, a computer and communication alarm equipment. The coordinates of each specified direction of each specified point must be monitored by the coordinate monitoring system; the coordinate monitoring system monitors the coordinates of each specified direction of each specified point and transmits the signal to the signal (data) collector; the signal It is transmitted to the computer through the signal collector; the computer is responsible for running the health monitoring software of the cable system in the cable structure, including recording the signal transmitted by the signal collector; and (or) designated personnel to call the police.

Step 7: Save parameters such as initial coordinate vector C _o , cable structure unit damage coordinate change matrix ΔC and unit damage D _u in the form of data files on the hard disk of the computer running the health monitoring system software.

Step 8: Compile and install the software of the health monitoring system of the cable system in the cable structure on the computer. The software includes the following functional modules: 1. Read the initial coordinate vector C _o , cable structure unit damage coordinate change matrix ΔC, unit damage _Du and all necessary parameters from the data files stored on the computer hard disk. 2. Timing (or random trigger) recording of the signal transmitted through the signal collector. 3. Carry out signal processing on the recorded signal, calculate and obtain the current coordinates of all designated directions of each designated point, and all the current coordinates form the current coordinate vector C. 4. According to the approximate linear relationship between the current coordinate vector C and the initial coordinate vector C _o , the unit damage coordinate change matrix ΔC, the unit damage scalar D _u and the current damage vector d of the cable system (composed of the current damage of all cables) (formula (6)), calculate the non-inferior solution of the current damage vector d of the cable system according to the multi-objective optimization algorithm, that is, the solution with reasonable error, but can accurately determine the position of the damaged cable and its damage degree from all the cables .

There are many kinds of multi-objective optimization algorithms that can be used, such as: multi-objective optimization based on genetic algorithm, multi-objective optimization based on artificial neural network, multi-objective optimization algorithm based on particle swarm, multi-objective optimization based on ant colony algorithm, constraint method (Constrain Method), Weighted Sum Method, Goal Attainment Method and so on. Since various multi-objective optimization algorithms are conventional algorithms, they can be implemented conveniently. This implementation step only uses the objective programming method as an example to give the process of solving the current damage vector d. The specific implementation process of other algorithms can be based on the requirements of their specific algorithms implemented in a similar manner.

According to the objective programming method, Equation (6) can be transformed into the multi-objective optimization problem shown in Equation (13) and Equation (14). In Equation (13), γ is a real number, R is a real number field, and the spatial region Ω limits the vector The value range of each element of d (this embodiment requires that each element of vector d is not less than 0 and not greater than 1). Equation (13) means to find a minimum real number γ, so that Equation (14) is satisfied. G(d) in formula (14) is defined by formula (15), the product of weighted vector W and γ in formula (14) represents the allowable deviation between G(d) and vector g in formula (14), the definition of g See formula (12), its value has been calculated in the fifth step. The vector W may be the same as the vector g during actual calculation. The specific programming implementation of the goal programming method already has a general program that can be directly adopted. According to the goal programming method, the current cable damage vector d can be obtained.

minimize ¶

(13)

γ∈R,d∈Ω

G(d)-Wγ≤g (14)

$\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; abs</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

If the value of an element of the current cable damage vector d is 0, it means that the cable corresponding to this element is intact and has no damage; if its value is 100%, it means that the cable corresponding to this element has been completely damaged. Loss of bearing capacity; if its value is between 0 and 100%, it means that the cable has lost a corresponding proportion of its bearing capacity. 5. Data generation function. The health status report of the cable system can be generated periodically or by personnel operating the health monitoring system. 6. Alarm function. Under the specified conditions, the automatic operation of the communication alarm equipment will alarm the monitoring personnel, the owner and (or) the designated personnel.

Claims (2)

1. health monitor method based on cable system in the Cable Structure of space coordinate monitoring is characterized in that described method comprises:

A. determine the coding rule of rope, with rope numberings all in the Cable Structure, this numbering will be used to generate the vector sum matrix in subsequent step by this rule;

B. determine the measured point of appointment, measured point promptly characterizes all specified points of planform, and gives all specified point numberings; Determine the measured coordinate direction of measured point, and numbering; Above-mentioned numbering will be used to generate the vector sum matrix equally in subsequent step; The quantity of measurement point generally must not be less than the quantity of rope; The quantity sum of all specified coordinate directions of the specified point that all are measured must not be less than the quantity of rope;

C. under Cable Structure not damaged conditioned disjunction can be thought the not damaged condition, directly measure the initial coordinate of all specified points that calculate Cable Structure, form initial coordinate vector C _o

D. under Cable Structure not damaged conditioned disjunction can be thought the not damaged condition, when actual measurement obtained the initial coordinate vector, actual measurement obtained the initial rope force data of all ropes of Cable Structure;

E. according to the measured data of design drawing, as-constructed drawing and the Cable Structure of Cable Structure, set up the Mechanics Calculation benchmark model of Cable Structure, the measured data of Cable Structure comprises the initial rope force data and the initial coordinate vector of all ropes of structure at least;

F. on the basis of Mechanics Calculation benchmark model, carry out the several times Mechanics Calculation, obtain unit injury coordinate variation matrix Δ C by calculating;

G. actual measurement obtains the current actual measurement coordinate of all specified points of Cable Structure, forms current coordinate vector C;

H. define the vectorial d of the current damage of cable system, the element number of current damage vector equals the quantity of rope, is one-to-one relationship between the element of current damage vector and the rope, and the element numerical value of current damage vector is represented the degree of injury or the health status of corresponding rope;

I. the current coordinate vector C of foundation is with initial coordinate vector C _o, unit injury coordinate variation matrix Δ C, unit damage scalar D _uAnd the linear approximate relationship that exists between the vectorial d of the current damage of cable system to be asked, this linear approximate relationship can be expressed as formula 1, and other amount in the formula 1 except that d is known, finds the solution formula 1 and just can calculate the vectorial d of current damage;

$C=C_o+\frac{1}{D_u}\mathrm{\&Delta;C}\&CenterDot;d$ Formula 1

J. because the element numerical value of current damage vector is represented the degree of injury of corresponding rope,, promptly realized the health monitoring of cable system in the Cable Structure so just can define the impaired and degree of injury of which rope according to current damage vector; If the numerical value of a certain element of current cable damage vector is 0, represent that the pairing rope of this element is intact, do not damage; If its numerical value is 100%, represent that then the pairing rope of this element has completely lost load-bearing capacity; If its numerical value between 0 and 100%, is then represented this rope and has been lost the load-bearing capacity of corresponding proportion.

2. the health monitor method based on cable system in the Cable Structure of space coordinate monitoring according to claim 1 is characterized in that in step f, and the concrete grammar that obtains unit injury coordinate variation matrix is:

F1. on the basis of Mechanics Calculation benchmark model, carry out the several times Mechanics Calculation, equal the quantity of all ropes on the calculation times numerical value, there is N root rope that N calculating is just arranged, calculating each time in the hypothesis cable system has only a rope that unit damage is arranged, the rope that occurs damage in calculating each time is different from the rope that occurs damage in other time calculating, calculate all current coordinate components of all specified points in the Cable Structure each time, the current coordinate of all that calculate is formed a current coordinate vector of calculating each time;

F2. that calculates each time calculates current coordinate vector and deducts the initial coordinate vector and obtain a coordinate variation vector; There is N root rope that N coordinate variation vector just arranged;

F3. form the unit injury coordinate variation matrix that the N row are arranged successively by this N coordinate variation vector; Each row of unit injury coordinate variation matrix are corresponding to a coordinate variation vector in other words.