Shore crane cantilever track out-of-tolerance detection method based on strain measurement

Abstract

The invention provides a shore bridge cantilever track out-of-tolerance detection method based on strain measurement. The method comprises the following steps: constructing a unified coordinate system for two cantilever beams; dividing each cantilever beam into a plurality of monitoring units, and constructing an analysis unit in each monitoring unit; after strain information of each analysis unit is monitored and obtained, deformation information of each cantilever beam is calculated and obtained; and comparing the deformation information of the two cantilever beams, and analyzing and obtaining out-of-tolerance information of the cantilever track. According to the invention, each cantilever beam is divided into a plurality of monitoring units, the analysis units are respectively constructed, the strain mapping relation associated with actual deformation is constructed for each analysis unit, and after each analysis unit is monitored and analyzed, the strain information of each analysis unit can be obtained. Deformation information of each cantilever beam can be obtained after splicing analysis, whether the cantilever track is out of tolerance or not can be judged after the deformation information of the two cantilever beams and standard data are compared and analyzed, and the method has the advantages of being time-saving, labor-saving, stable, reliable and the like.

Description

Technical Field

[0001] The invention relates to the field of deformation monitoring of double tracks of a quay crane cantilever, and in particular to a method for detecting over-tolerance of a quay crane cantilever track based on strain measurement. Background Art

[0002] Shore container cranes are referred to as quay cranes. They are important equipment in port container loading and unloading operations. As quay cranes are operated under heavy loads for a long time, they are prone to structural deformation, which not only seriously affects the efficiency of mechanical operation, but also creates major safety hazards. Among them, track deviation caused by track deformation is one of the most common and most influential problems in loading and unloading operations.

[0003] The quay crane usually has two sets of tracks, namely the walking track and the cantilever track. The walking track is directly installed on the ground and bears the weight of the entire quay crane. Its deformation is mainly caused by the overall deformation of the foundation, especially the settlement of the sea side foundation; the deformation cycle of the walking track is relatively long, and long-term offline detection can be used to measure and adjust the deviation. The cantilever track is usually tens of meters higher than the shore foundation and is used to carry a trolley for lifting containers. Due to the short deformation cycle of the cantilever track and the difficulty of measurement, it currently mainly relies on personnel inspections, and it is impossible to detect track deviations in an unmanned operating environment in a timely manner. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention proposes a method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement.

[0005] A method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement comprises the following steps:

[0006] S100, constructing a unified coordinate system for two cantilever beams of the cantilever track;

[0007] S200, dividing the surface of each cantilever beam into a plurality of adjacent monitoring units, and constructing an analysis unit in each monitoring unit;

[0008] S300, after monitoring and acquiring the strain detection information of each analysis unit, calculate and acquire the deformation information of each cantilever beam;

[0009] S400: Compare deformation information of the two cantilever beams, analyze and obtain deviation information of the cantilever track.

[0010] Based on the above, in step S200, the analysis unit constructs a deformation field at any position corresponding to the monitoring unit, and constructs a theoretical strain corresponding to any point on the surface of the cantilever beam.

[0011] Based on the above, step S300 includes the following steps:

[0012] S310, setting a strain sensor on the monitoring unit, and obtaining strain detection information of the analysis unit through the strain sensor;

[0013] S320, acquiring a deformation mapping model of the analysis unit in combination with a theoretical strain corresponding to the analysis unit;

[0014] S330, constructing the relationship between the theoretical strain and the measured strain of the analysis unit through the least square variation principle, and obtaining the mapping relationship of a single analysis unit;

[0015] S340, uniformly construct an assembly matrix for all monitoring units of each cantilever beam, and after constructing the global deformation relationship of each cantilever beam according to the deformation mapping relationship in step S330, calculate the deformation information of each cantilever beam according to the strain information of each analysis unit obtained by monitoring.

[0016] Based on the above, the deformation field at any position in the monitoring unit is:

[0017]

[0018] u z (x,y,z)=w(x,y)

[0019] In the formula, u x (x,y,z),u y (x,y,z),u z (x, y, z) represent the deformation of any point of the plate structure along the three axial directions, u(x, y), v(x, y), w(x, y) represent the deformation of the neutral surface of the plate structure along the x, y, z directions, respectively, z represents the distance coordinate from any position to the neutral surface, They represent the rotation effects of the neutral plane along the x and y directions respectively.

[0020] Based on the above, the theoretical strain at any point P in the deformation field is expressed as:

[0021] ε(x,y,z)={ε x ,ε y ,ε z ,γ xy ,γ xz ,γ yz} T =Lu

[0022] Where ε(x, y, z) is the strain vector of any point in the analysis unit, u={u x (x,y,z),u y (x,y,z)} T represents the three-dimensional deformation vector of any point in the analysis unit, and L represents the differential operator.

[0023] Based on the above, in step S320, the deformation mapping model includes a plane strain model and a transverse shear strain model. The plane strain model is represented by e (s) (u e )=m(θ)L1u e , the transverse shear strain model is expressed as g (s) (u e )=L2u e ,in:

[0024]

[0025] In the formula, ε e Represents the deformation degrees of freedom of the four nodes of the analysis unit The strain vector, Represented as a transformation matrix and a submatrix of L; and denote plane strain and transverse shear strain, respectively; Indicates any position (x i ,y i ) is at an angle θ with the x direction i The measured strain, represents the strain component at the measuring point, m(θ)={cos 2 θ i ,sin 2 θ i ,sinθ i cosθ i} is the vector representing the angle of the strain sensor.

[0026] Based on the above, in step S330, the relationship between the theoretical strain and the measured strain of the analysis unit is expressed as:

[0027]

[0028] in, represents the inverse proportional boundary finite element functional symbol, e (s) (u e ), g (s) (u e ) represent the theoretical plane strain and transverse shear strain of the analysis unit, represents the planar measured strain of the analysis unit, represents the transverse shear measurement strain of the analyzed unit, w e ,w g represent the least squares weight coefficients of plane strain and transverse shear strain respectively.

[0029] Based on the above, in step S330, the local and global mapping relationship of a single analysis unit is expressed as:

[0030]

[0031] in, represents the inverse-proportional boundary finite element-like stiffness matrix, represents the inverse-scale boundary finite element class load vector, Represents the deformation degrees of freedom of the inverse-proportional boundary finite element nodes.

[0032] Based on the above, in step S340, the assembly matrix is ​​expressed as:

[0033]

[0034] Among them, k nn represents the stiffness matrix, M, N and O represent the abbreviation of the stiffness matrix, u n represents the node displacement matrix, f n represents the strain matrix.

[0035] Based on the above, in step S340, after the deformation information of the two cantilever beams is obtained, the deformation information of the cantilever track is obtained, and then a comparative analysis is performed based on the standard data information of the cantilever track to determine whether the deformation of the cantilever track causes the track to exceed the tolerance.

[0036] The present invention has outstanding substantial features and significant progress compared with the prior art. Specifically, the present invention divides each cantilever beam into multiple monitoring units and constructs analysis units respectively, and constructs a strain mapping relationship associated with the actual deformation for each analysis unit. After monitoring and analyzing each analysis unit, the strain information of each analysis unit can be obtained. After assembling and analyzing the strain information of each analysis unit, the deformation information of each cantilever beam can be obtained. Then, after comparing and analyzing the deformation information of the two cantilever beams with the standard data, it can be determined whether the cantilever track has an out-of-tolerance problem. The present invention has the advantages of saving time and effort, being stable and reliable, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic block diagram of the process structure of the present invention;

[0038] Figure 2 It is a structural schematic diagram of the quay bridge of the present invention;

[0039] Figure 3 It is a structural schematic diagram of the monitoring unit of the present invention;

[0040] Figure 4 It is a three-dimensional structural configuration diagram based on the ratio boundary finite element of the present invention;

[0041] Figure 5 It is a schematic diagram of the installation of the plate structure and the strain sensor of the present invention;

[0042] Figure 6 It is a schematic diagram of the structure of the measuring surface of a single cantilever beam of the present invention.

[0043] Explanation of the reference numerals: 1. quay crane; 2. cantilever beam; 3. monitoring unit; 4. strain sensor; 5. inner surface of cantilever beam; 6. outer surface of cantilever beam; 7. neutral plane. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In reality, the cantilever track of the quay crane 1 includes two cantilever beams 2, on which the cantilever beams 2 are provided with tracks for the trolley for lifting containers, such as Figure 2 shown.

[0046] like Figure 1 As shown, a method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement is specifically as follows:

[0047] The cantilever beam of the quay crane is taken as the object to be measured. According to the characteristics of the cantilever beam structure of the quay crane, the cantilever beam structure is divided into multiple monitoring units 3. Each monitoring unit 3 is regarded as a pseudo plate unit / boundary surface unit / boundary surface structure. Each unit of the pseudo plate unit has four nodes (i.e., the four corner points n-1, n-2, n-3 and n-4 of the square), such as Figure 3 As shown, a node includes six degrees of freedom (two degrees of freedom along the x-axis, y-axis and z-axis respectively), and the proportional boundary finite element theory is used for analysis. The proportional boundary finite element method is a structural analysis method that describes the deformation field characteristics of the structural boundary domain by introducing a proportional factor. In this embodiment, it is associated with the boundary surface theoretical strain and deformation freedom.

[0048] Depend on Figure 4 Based on the three-dimensional structure configuration diagram of the proportional boundary finite element, the position of any point X on the geometric boundary domain can be expressed as:

[0049]

[0050] Among them, x(ξ,η), y(ξ,η), z(ξ,η) are the position coordinates of the structure boundary along the three axial directions, ζ is the scaling factor coordinate along the radial direction, (ξ,η) is the isoparametric coordinate of the boundary element plane, x a ={x1,x2...,x4} T ,y a={y1,y2...,y4} T , z a ={z1,z2...,z4} T Respectively represent the coordinates of the four nodes of the boundary surface unit in the global coordinate system, (x0, y0, z0) represents the position coordinates of the scaling center, and N(ξ,η) is the unit shape function interpolation matrix, which can be expressed as:

[0051]

[0052] Where N i (ξ,η), (i=1,2...m) represents the element shape function of m nodes.

[0053] Based on the classic Kirchhoff plate structure theory, the deformation field at any position in the plate structure of the pseudo-plate element is:

[0054]

[0055] u z (x,y,z)=w(x,y)

[0056] In the formula, u x (x,y,z),u y (x,y,z),u z (x, y, z) represent the deformation of any point of the plate structure along the three axial directions, u(x, y) and v(x, y) represent the deformation of the neutral surface 7 of the plate structure along the x and y directions, w(x, y) represents the deformation of the neutral surface 7 of the plate structure along the z direction, and z represents the distance coordinate from any position to the neutral surface 7. They represent the rotation effects of the neutral plane 7 along the x and y directions respectively. The plate structure is as follows Figure 5 shown.

[0057] According to the elastic assumption of cantilever beam structure deformation and strain, the theoretical strain of any point P on the cantilever beam surface is expressed as:

[0058] ε(x,y,z)={ε x ,ε y ,ε z ,γ xy ,γ xz ,γ yz} T =Lu

[0059] where ε(x, y, z) is the strain vector at any point on the cantilever beam surface, u = {u x (x,y,z),u y (x,y,z)} T represents the three-dimensional deformation vector of any point on the plate structure, and L represents the differential operator.

[0060] According to the method of describing the three-dimensional deformation field of the cantilever beam structure by using the proportional boundary finite element, the inner surface 5 of the cantilever beam or the outer surface 6 of the cantilever beam structure is selected as the structural boundary surface, and the scaling center coincides with the origin of the global coordinate system. The geometric position of the point P inside the boundary surface unit of the cantilever beam can be expressed as:

[0061]

[0062] Where N i (ξ,η), (i=1,2…4) represents the cubic isoparametric element shape function. By constructing the Jacobian matrix J, the differential operator L is transformed by Jacobian, and the conversion relationship between the partial differential under the global coordinate system (x, y, z) and the local coordinate system (ξ,η,ζ) can be expressed as:

[0063]

[0064] In the formula, They represent the partial derivatives along the three axial directions of x, y, and z, respectively, and J -1 represents the inverse of the Jacobian matrix, Denote the partial derivatives along the global coordinate system ξ, η, ζ respectively. It can be obtained that the differential operator L can be expressed as where |J| represents the determinant of the Jacobian matrix, b 1 ,b 2 ,b 3 Represents the matrix associated with the derivatives of the shape functions for the boundary surface elements.

[0065] The strain sensor 4 is used to detect the strain of the boundary surface unit of the cantilever beam, and the deformation mapping model is obtained by combining the corresponding theoretical strain. The strain vector based on the unit form can be expressed as

[0066]

[0067] In the formula, ε e Denotes the degree of freedom of deformation of the unit node The strain vector, Represents the transformation matrix and the submatrix of L; and denote plane strain and transverse shear strain, respectively.

[0068] The strain at any position in the xy plane within the monitoring unit can be expressed as:

[0069]

[0070] In the formula, Indicates any position (x i ,y i ) is at an angle θ with the x directioni The measured strain, represents the strain component at the measuring point, m(θ)={cos 2 θ i ,sin 2 θ i ,sinθ i cosθ i} is the vector representing the angle of the strain sensor.

[0071] The relationship between the deformation freedom of the xy plane and the unit node can be obtained from the strain vector based on the unit form and the strain at any position on the surface, which is expressed as e (s) (u e )=m(θ)L1u e .e (s) (u e ) is the plane strain of the boundary surface element; the relationship between the transverse shear strain and the deformation freedom of the element node can be expressed as g (s) (u e )=L2u e , g (s) (u e ) represents the transverse shear strain of the boundary surface unit. Therefore, the strain field of the cantilever beam structure can be calculated by simply measuring the strain detection information of the structure boundary surface. The installation method of the strain sensor is as follows: Figure 5 As shown, the measurement surface of the cantilever beam structure is as follows Figure 6 shown.

[0072] Through the least square variation principle, the relationship between the theoretical strain and the measured strain of the cantilever beam structure boundary surface is constructed and expressed as:

[0073]

[0074] in, represents the inverse proportional boundary finite element functional symbol, e (s) (u e ), g (s) (u e ) represent the theoretical plane strain and transverse shear strain of the boundary surface, represents the measured strain on the boundary surface element plane, represents the transverse shear measurement strain of the boundary surface element, w e ,w g represent the least squares weight coefficients of plane strain and transverse shear strain respectively.

[0075] Find the node degree of freedom u e The partial derivative of , based on the proportional boundary finite element theory, can be expressed as in, represents the inverse-scale boundary finite element-like stiffness matrix, represents the inverse-scale boundary finite element-like load vector, Represents the inverse proportional boundary finite element node deformation degrees of freedom.

[0076] Substituting the initial boundary conditions, the solution can be directly obtained as U = K -1 F, U represent the displacement matrix, K -1 represents the inverse matrix of the stiffness matrix, and F represents the vector strain matrix. The operation form is similar to the stiffness matrix operation in the finite element theory. In order to facilitate the overall operation of the cantilever beam structure, it is necessary to assemble all the monitoring unit relationship matrices of the cantilever beam into a total matrix, so that the deformation data of the cantilever beam as a whole can be obtained at one time.

[0077] Assembly matrix calculation and track deviation detection: Assemble each monitoring unit of a single cantilever beam structure to form an assembly matrix. By calculating the deformation of the cantilever beam structure in the assembly matrix, the deformation of the single cantilever beam structure is obtained, and the deformation of the single track is obtained accordingly. By comparing the deformation data generated by the two tracks, it can be determined whether the track exceeds the allowable deformation range, that is, whether there is a deviation.

[0078] According to the structure of a single track, it is only necessary to find out the matrix conversion relationship of a monitoring unit, and then simply assemble the whole unit. in is a 24×24 square matrix, is a 24×1 column vector, which can be obtained by coordinate transformation

[0079]

[0080] Among them, T moment is a transformation matrix of order 24, and The matrix dimensions correspond.

[0081] The stiffness matrix for monitoring unit 1 is as follows

[0082]

[0083] When assembling according to the common nodes later, each unit matrix needs to be expanded to the overall matrix dimension and then superimposed. Taking unit 1 as an example, its expansion form is as follows:

[0084]

[0085] Among them, the A matrix is ​​a sixth-order zero matrix, k ij The (i,j=1,2,3,4) matrix is ​​a sixth-order matrix. The matrix for monitoring unit n (when n is an even number) is as follows

[0086]

[0087] Among them, kij (i=(n-3),(n-2),(n-1),nj=1,2,3,4.),u i (i=(n-3),(n-2),(n-1),n.) and f i (i=(n-3),(n-2),(n-1),n.) is a six-dimensional vector, and the node order is the counterclockwise order of the unit nodes. The final assembly matrix is ​​as follows:

[0088]

[0089] Among them, M, N and O represent the abbreviation of the stiffness matrix, k ij (i=1,2,…,nj=1,2,3,4.) represents the stiffness matrix, u i (i=1,2,…,n.) represents the node displacement matrix, f i (i=1,2,…,n.) represents the strain matrix. The expanded form is

[0090]

[0091] Construct a unified coordinate system for the two cantilever beams of the cantilever track, assemble the single monitoring unit in the coordinate system, assemble the monitoring units into an overall matrix according to the common nodes (the common nodes of two adjacent monitoring units), first expand each unit matrix into the overall dimension, and then superimpose. It is important to pay attention to the order of the nodes, and adjust the unit order as needed. After the assembled units are assembled into the overall structural matrix, they are generally singular, and boundary adjustment needs to be added to solve. The fixed end needs to be determined, and then brought into the equation to solve, and the displacement data of other nodes can be obtained. The superimposed assembly matrix is ​​converted to the global coordinate system to obtain the deformation of the single-sided cantilever beam. Perform the same calculation on the cantilever beams on both sides to obtain the deformation of the cantilever beams on both sides, that is, the deformation of the cantilever track, and then compare the deformation of the two tracks according to the standard data to see if it causes the track to exceed the tolerance.

[0092] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement, characterized in that: Includes steps: S100, constructing a unified coordinate system for two cantilever beams of the cantilever track; S200, dividing the surface of each cantilever beam into a plurality of adjacent monitoring units, and constructing an analysis unit in each monitoring unit; S300, after monitoring and acquiring the strain detection information of each analysis unit, calculate and acquire the deformation information of each cantilever beam; S400: Compare deformation information of the two cantilever beams, analyze and obtain deviation information of the cantilever track.

2. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 1, characterized in that: In step S200, the analysis unit constructs a deformation field at any position corresponding to the monitoring unit, and constructs a theoretical strain corresponding to any point on the surface of the cantilever beam.

3. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 2 is characterized in that: Step S300 includes the steps of: S310, after a strain sensor is provided on the monitoring unit and strain detection information of the analysis unit is acquired through the strain sensor; S320, acquiring a deformation mapping model of the analysis unit in combination with a theoretical strain corresponding to the analysis unit; S330, constructing the relationship between the theoretical strain and the measured strain of the analysis unit through the least square variation principle, and obtaining the mapping relationship of a single analysis unit; S340, uniformly construct an assembly matrix for all monitoring units of each cantilever beam, and after constructing the global deformation relationship of each cantilever beam according to the deformation mapping relationship in step S330, calculate the deformation information of each cantilever beam according to the strain information of each analysis unit obtained by monitoring.

4. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 2 is characterized in that: The deformation field at any position within the monitoring unit is: u z (x,y,z)=w(x,y) In the formula, u x (x,y,z),u y (x,y,z),u z (x, y, z) represent the deformation of any point of the plate structure along the three axial directions, u(x, y), v(x, y), w(x, y) represent the deformation of the neutral surface of the plate structure along the x, y, z directions, respectively, z represents the distance coordinate from any position to the neutral surface, They represent the rotation effects of the neutral plane along the x and y directions respectively.

5. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 2, characterized in that: The theoretical strain at any point P on the cantilever beam surface is expressed as: ε(x,y,z)={ε x ,he y ,he z ,c xy ,c xz ,c yz } T =Lu Where ε(x, y, z) is the strain vector of any point in the analysis unit, u={u x (x,y,z),u y (x,y,z)} T represents the three-dimensional deformation vector of any point in the analysis unit, and L represents the differential operator.

6. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 3 is characterized in that: In step S320, the deformation mapping model includes a plane strain model and a transverse shear strain model. The plane strain model is represented by e (s) (u e )=m(θ)L1u e , the transverse shear strain model is expressed as g (s) (u e )=L2u e ,in: In the formula, ε e Represents and analyzes the deformation degrees of freedom of the four nodes of the unit i=1,2…4 related strain vector, Represented as a transformation matrix and a submatrix of L; and denote plane strain and transverse shear strain, respectively; Indicates any position (x i ,y i ) is at an angle θ with the x direction i The measured strain, represents the strain component at the measuring point, m(θ)={cos 2 θ i ,sin 2 θ i ,sinθ i cosθ i } is the vector representing the angle of the strain sensor.

7. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 3 is characterized in that: In step S330, the relationship between the theoretical strain and the measured strain of the analysis unit is expressed as: in, represents the inverse proportional boundary finite element functional symbol, e (s) (u e ), g (s) (u e ) represent the theoretical plane strain and transverse shear strain of the analysis unit, represents the planar measured strain of the analysis unit, represents the transverse shear measurement strain of the analyzed unit, w e ,w g represent the least squares weight coefficients of plane strain and transverse shear strain respectively.

8. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 3 is characterized in that: In step S330, the local and global mapping relationship of a single analysis unit is expressed as: in, represents the inverse-proportional boundary finite element-like stiffness matrix, represents the inverse-scale boundary finite element class load vector, Represents the deformation degrees of freedom of the inverse-proportional boundary finite element nodes.

9. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 3, characterized in that: In step S340, the assembly matrix is ​​expressed as: Among them, k nn represents the stiffness matrix, M, N and O represent the abbreviation of the stiffness matrix, u n represents the node displacement matrix, f n represents the strain matrix.

10. The method for detecting out-of-tolerance of a quay crane cantilever track based on strain measurement according to claim 3, characterized in that: In step S340, after the deformation information of the two cantilever beams is obtained, the deformation information of the cantilever track is obtained, and then a comparative analysis is performed based on the standard data information of the cantilever track to determine whether the deformation of the cantilever track causes the track to exceed the tolerance.

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