A method and system for deformation detection of steel structures based on thermal analysis

Abstract

The present application relates to the technical field of linear size measurement, and in particular to a steel structure deformation detection method and system based on thermal analysis. The method periodically collects three-dimensional point cloud data of the steel structure and temperature data corresponding to each point; for each cycle, according to the boundary line features of the two side weld plates on each corresponding local area, the angular deformation index is determined; according to the temperature data of each point in each local area, the temperature characteristic is calculated; according to the angular deformation index time series data and the temperature characteristic time series data of the target area with the highest temperature characteristic from the first cycle to the current cycle, the heat influence factor of the target area is determined; according to the angular deformation index of each butt joint area and the heat influence factor of the target area, the angular deformation characteristic parameter in the current cycle is determined; according to the thickness data of the weld plate and the angular deformation characteristic parameter, the angular deformation probability value of the steel structure in the current cycle is determined, thereby the possibility of angular deformation of the steel structure can be accurately detected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of linear size measurement, in particular to a deformation detection method and system for steel structure based on thermal analysis. BACKGROUND

[0002] The nodes are usually used to connect between the fabricated steel structures, and the connection between the nodes is mainly achieved by welding. In the process of welding the nodes by using the welding gun, the materials on both sides of the weld will be unevenly heated under the action of the heat generated by the welding gun, thereby causing the transverse shrinkage of the weld plate along the thickness direction of the plate, and finally causing the angular deformation of the weld plate, which results in the instability of the fabricated steel structure.

[0003] At present, in the prior art, the model simulation method is usually used to detect the change of the weld plate model in the welding process. By comparing the angle change amount between the two sides of the weld plate with the threshold value, it is detected whether the deformation of the fabricated steel structure occurs. However, with the continuous movement of the welding gun, the heating degree of each region on the weld plate is different under the action of the heat generated by the welding gun, so the degree of the slight deformation occurring in different regions is also inconsistent. The slight deformation occurring in these regions will eventually affect the stability of the overall structure of the fabricated steel structure. SUMMARY

[0004] In order to solve the technical problem that the heating degree of each region on the weld plate is different under the action of the heat generated by the welding gun, so the degree of the slight deformation occurring in different regions is also inconsistent, which eventually affects the deformation detection result of the fabricated steel structure, the present application provides a deformation detection method and system for steel structure based on thermal analysis, and the technical scheme adopted is as follows:

[0005] The present application provides a deformation detection method for steel structure based on thermal analysis, which comprises the following steps:

[0006] In the welding process of the steel structure, the three-dimensional point cloud data of the steel structure and the temperature data of each point corresponding to the three-dimensional point cloud data are periodically collected, wherein the steel structure comprises two weld plates, and the working surface of each weld plate is divided into a plurality of local regions;

[0007] For each cycle, the angular deformation index of each abutting region of the weld plates is determined according to the boundary line features of the two weld plates on each corresponding local region, wherein the abutting region is composed of the local regions on the two weld plates which are opposite to each other;

[0008] The temperature of each point in the boundary line of each local region is calculated to obtain the temperature of the abutting region. The heat influence factor of the target region is determined according to the time sequence data of the angular deformation index and the time sequence data of the temperature of the target region from the first cycle to the current cycle, wherein the abutting region with the highest temperature among the plurality of abutting regions is taken as the target region.

[0009] According to the angular deformation index of each docking area and the heat influencing factor of the target area, the angular deformation characteristic parameter in the current period is determined;

[0010] According to the thickness data of the welding plate and the angular deformation characteristic parameter, the angular deformation probability value of the steel structure in the current period is determined.

[0011] Further, in the case of the first period, the local area determination process comprises:

[0012] At the initial moment when the steel structure starts welding, the initial three-dimensional point cloud data of the un-welded steel structure is collected through the detection equipment preset at the preset detection point;

[0013] At the initial moment, the sum of the distances from each point in each edge contour line of the welding plate working surface to the preset detection point is calculated through the initial three-dimensional point cloud data, and the total distance corresponding to each edge contour line is obtained; the edge contour line with the shortest total distance in each edge contour line is taken as the target edge contour line of the welding plate working surface;

[0014] For each side welding plate working surface, the target edge contour line is taken as the reference line, and parallel contour lines perpendicular to the normal direction of the welding plate working surface are constructed at a preset interval distance along a direction parallel to the target edge contour line until they extend to the outer contour boundary of the welding plate working surface;

[0015] Based on the target edge contour line and the parallel contour line, the welding plate working surface is divided to form a plurality of strip areas, wherein the area between adjacent contour lines constitutes a strip area; each strip area is taken as a target local area of the welding plate working surface; the target edge contour line and the parallel contour line each constitute a boundary line of adjacent target local areas;

[0016] In the first period, the local area at the same position on the welding plate working surface as the target local area is obtained through the collected three-dimensional point cloud data.

[0017] Further, the local area determination process comprises:

[0018] For each period, based on the three-dimensional coordinate data and temperature data of the respective corresponding points on the welding plate working surface in the current period and in the previous period, the matching value between the respective corresponding points in the current period and in the previous period is calculated; the target points in the current period and in the previous period whose matching values exceed a preset matching threshold are determined.

[0019] For each boundary line, based on the target points in the boundary line in the previous period, the target points corresponding thereto in the current period are connected to determine the boundary line in the current period.

[0020] Determine a local area on the welding plate working surface based on the area between adjacent boundary lines in the current period.

[0021] Further, the corner deformation index determination process comprises:

[0022] For each side welding plate working surface, determine a length variation of each local area in the current period based on a difference between a boundary line length of each local area in the current period and a boundary line length of the same local area in the previous period.

[0023] Calculate a variation between an included angle between respective opposite boundary lines on the two side welding plate working surfaces in the current period and an included angle between the same pair of boundary lines in the previous period to determine an included angle variation of the butt joint area.

[0024] Determine a corner deformation index of the butt joint area based on the included angle variation of each butt joint area and the length variation of the local area in the butt joint area, wherein the length variation and the included angle variation are positively correlated with the corner deformation index.

[0025] Further, the representative temperature calculation process comprises:

[0026] Calculate a mean value of temperature data of each point in the boundary line of each local area to obtain a temperature mean value of each local area.

[0027] Perform a mean value operation on the temperature mean value of the local area in each butt joint area to determine a representative temperature of each butt joint area.

[0028] Further, the heat influence factor determination process comprises:

[0029] Arrange the corner deformation indexes of the target area in each period in a time sequence from the first period to the current period to obtain corner deformation index time sequence data.

[0030] Arrange the representative temperatures of the target area in each period in a time sequence from the first period to the current period to obtain representative temperature time sequence data.

[0031] Calculate a variation between each corner deformation index in the corner deformation index time sequence data and the smallest corner deformation index to determine a corner deformation variation of the target area in the current period.

[0032] Calculate a variation between each representative temperature in the representative temperature time sequence data and the lowest representative temperature to determine a representative temperature variation of the target area in the current period.

[0033] determine a heat influence factor of the target region in the current period based on a correlation between the angular deformation change amount and the temperature change amount in the target region in the current period, wherein the angular deformation change amount is positively correlated with the heat influence factor, and the temperature change amount is negatively correlated with the heat influence factor.

[0034] Further, the butt joints are classified into two categories, one category being welded and the other category being unwelded, and the angular deformation feature parameter determination process comprises:

[0035] determining the sequence of the butt joints in the order in which the welding torch is expected to pass through the butt joints;

[0036] classifying the butt joints in the current period to determine the category of each butt joint, wherein the category of the target region and the butt joints before the target region are welded, and the category of the butt joints after the target region are unwelded;

[0037] calculating the change amount between the temperature of the target region and the temperature of the butt joints in the current period, to obtain the temperature change value of the butt joints in the current period;

[0038] determining a second angular deformation feature parameter in the current period based on the correlation between the temperature change value, the angular deformation index, and the heat influence factor of the target region, wherein the temperature change value, the angular deformation index, and the heat influence factor of the target region are positively correlated with the second angular deformation feature parameter.

[0039] Further, the thickness data of the welding plates comprises the total thickness of the welding plates on both sides at the initial moment when the steel structure starts welding and the total thickness of the welding plates on both sides in each period, and the angular deformation probability value determination process comprises:

[0040] performing summation operation on the angular deformation index of the butt joints in the category of welded to determine a first angular deformation feature parameter in the current period;

[0041] determining a first summation value based on the sum of the first angular deformation feature parameter and the second angular deformation feature parameter;

[0042] calculating the difference between the total thickness of the welding plates on both sides in the current period and the total thickness of the welding plates on both sides at the initial moment to obtain a first difference value;

[0043] determining a welding completion index in the current period based on the quotient of the number of regions in which the target region is located in the current period and the total number of butt joints;

[0044] determining a thickness change amount in the current period based on the product between the welding completion index and the first difference value;

[0045] determine an angular deformation probability value of the steel structure in the current period based on the thickness change amount and the first sum value, wherein the thickness change amount and the first sum value are positively correlated with the angular deformation probability value.

[0046] Further, the method further comprises:

[0047] If the angular deformation probability value in the current period exceeds a preset abnormal threshold value, it is determined that the fabricated steel structure will have significant angular deformation under the heat action of the welding gun.

[0048] The present application provides a deformation detection system for steel structure based on thermal analysis, which comprises a memory, a processor and a computer program stored in the memory and running on the processor, wherein the processor implements the deformation detection method for steel structure based on thermal analysis disclosed in the embodiments of the present application when executing the computer program.

[0049] The present application has the following beneficial effects:

[0050] The present application first periodically collects three-dimensional point cloud data of multiple local areas on the working surface of the welding plate and temperature data corresponding to each point, divides the steel structure welding process into multiple periods, so as to subsequently pay attention to the deformation degree of the welding plate in different periods as the welding task continuously advances, divides the welding plate into multiple local areas, considers the influence of the heat generated by the welding gun on the heating degree of different local areas, so as to further analyze the subtle angular deformation phenomenon occurring in different local areas of the welding plate as the welding gun continuously moves, then detects the deformation degree of the welding plate in different periods through the angular deformation index of each butt joint area of the welding plate, then finds out the target area of the welding gun in the current period from multiple different butt joint areas through the temperature representing, it is known that the farther the area from the welding gun is, the lower the temperature in the area is, and the heating degree is also greatly different from that in other areas, so that the heating condition of each area on the welding plate under the action of the heat generated by the welding gun is further understood through the heat influence factor of the target area, and then the influence degree of the heat generated by the welding gun on the subtle angular deformation occurring in each butt joint area is analyzed according to the angular deformation index and the heat influence factor of the target area, the angular deformation characteristic parameter is determined, finally, the subtle angular deformation phenomenon occurring in the area through which the welding gun has passed is understood through the angular deformation characteristic parameter, and the subtle angular deformation phenomenon expected to occur in the area through which the welding gun has not passed is evaluated through the angular deformation characteristic parameter, the deformation degree of the welding plate in different periods is deeply detected, so that not only the possibility of angular deformation of the steel structure can be accurately detected, but also the degree of angular deformation of the local area caused by the heat generated by the welding gun is analyzed, so that the deformation phenomenon of the steel structure can be detected in time and repaired in time, and the structural stability of the fabricated steel structure is improved. Attached Figure Description

[0051] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A flowchart illustrating a deformation detection method for steel structures based on thermal analysis, provided in one embodiment of the present invention;

[0053] Figure 2 An example diagram illustrating the deployment of the welding station and testing equipment provided in one embodiment of the present invention;

[0054] Figure 3 An example diagram of a local area on the working surface of the solder plate at the initial moment, provided in an embodiment of the present invention;

[0055] Figure 4 This is a schematic diagram illustrating the process of determining angular deformation indices according to an embodiment of the present invention;

[0056] Figure 5 This is a schematic diagram illustrating the process of determining the heat influence factor according to an embodiment of the present invention;

[0057] Figure 6 This is a schematic diagram illustrating the process of determining angular deformation characteristic parameters according to an embodiment of the present invention;

[0058] Figure 7 This is an example diagram of temperature monitoring during the welding process of a steel structure, provided as an embodiment of the present invention.

[0059] Figure 8 This is an example diagram illustrating the variation trend of steel structure welded plate thickness according to an embodiment of the present invention;

[0060] Figure 9 This is an example diagram of a steel structure angular deformation risk assessment provided in one embodiment of the present invention;

[0061] Figure 10 This is an example diagram illustrating the correlation analysis process of steel structure welding parameters provided in one embodiment of the present invention. Detailed Implementation

[0062] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined inventive purpose, the specific implementation, structure, features and effects of a steel structure deformation detection method and system based on thermal analysis according to the present application are described in detail as follows in combination with the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0064] The specific scheme of a steel structure deformation detection method and system based on thermal analysis provided by the present application is described in detail below in combination with the drawings.

[0065] Please refer to Figure 1 , which shows a flow chart of a steel structure deformation detection method based on thermal analysis provided by one embodiment of the present application. The method comprises:

[0066] S101: During the welding process of the steel structure, periodically collect three-dimensional point cloud data of the steel structure and temperature data of each point corresponding to the three-dimensional point cloud data, wherein the steel structure comprises two side welding plates, and each welding plate working surface is divided into a plurality of local areas.

[0067] It should be noted that, in order to collect the three-dimensional point cloud data of the steel structure and the temperature data of each point corresponding to the three-dimensional point cloud data, detection equipment can be arranged at a suitable position. The detection equipment can be an infrared thermal imager and a laser scanner. The laser scanner is used to scan the steel structure to collect the three-dimensional point cloud data of the steel structure, and the infrared thermal imager can collect the temperature data of each point in the steel structure.

[0068] It should be noted that the specific position of the arrangement of the detection equipment can be determined according to the actual situation of the welding table, and the present embodiment does not make specific limitation, for example, the detection equipment can be deployed in front of the welding table plane.

[0069] For example, an example diagram of the welding table and the deployment of the detection equipment is shown in Figure 2 , wherein the detection equipment comprises an infrared thermal imager and a laser scanner. Through the infrared thermal imager and the laser scanner, the three-dimensional point cloud data of the steel structure on the welding table can be collected, and the temperature data of each point in the steel structure can also be collected.

[0070] It needs to be understood that the welding plate working surface is divided into multiple local areas, and as the welding process continues to advance, the welding plate gradually shrinks inward in the view of the detection device, and the three-dimensional coordinates of each point in the welding plate also change, so that if the three-dimensional coordinates of each point are directly used to determine the local area, the specific division of the local area on the welding plate working surface will not be consistent in different periods. However, in order to facilitate subsequent analysis of the change of the angular deformation occurring in the same local area on the welding plate working surface in different periods, it can be ensured that the specific positions of each local area on the welding plate working surface remain unchanged in different periods, which is of great significance to guarantee the reliability of the detection result.

[0071] It needs to be pointed out that since there is no previous period adjacent to the first period in the steel structure welding process, in order to determine the specific positions of each local area on the welding plate working surface in the first period, the specific positions of each local area on the welding plate working surface at the initial moment when the steel structure starts to weld can be referred to.

[0072] In this embodiment, at the initial moment when the steel structure starts to weld, the initial three-dimensional point cloud data of the un-welded steel structure is collected by the detection device preset at the preset detection point; at the initial moment, the sum of the distances from each point in the edge contour line of the welding plate working surface to the preset detection point is calculated based on the initial three-dimensional point cloud data to obtain the total distance corresponding to each edge contour line; the edge contour line with the shortest total distance in each edge contour line is taken as the target edge contour line of the welding plate working surface; for each side of the welding plate working surface, the target edge contour line is taken as the reference line, and parallel contour lines perpendicular to the normal direction of the welding plate working surface are constructed at a preset interval distance along a direction parallel to the target edge contour line until they extend to the outer contour boundary of the welding plate working surface; based on the target edge contour line and the parallel contour lines, the welding plate working surface is divided to form multiple strip areas, wherein the area between adjacent contour lines constitutes a strip area; each strip area is taken as a target local area of the welding plate working surface; the target edge contour line and the parallel contour lines each constitute a boundary line of adjacent target local areas; in the first period, the local area at the same position on the welding plate working surface as the target local area is obtained based on the collected three-dimensional point cloud data.

[0073] It needs to be pointed out that the specific value of the preset interval distance is determined according to actual needs, which is not limited in this embodiment, for example, the preset interval distance can be 0.5 centimeters.

[0074] It needs to be pointed out that the adjacent contour lines include the target edge contour line and the parallel contour lines, wherein if the interval distance between two contour lines does not exceed the preset interval distance, the two contour lines are adjacent contour lines.

[0075] For example, an example diagram of local regions on the work surface of the welding plate at the initial moment is shown in FIG. 1, where there are three local regions on each side of the work surface of the welding plate, and the local regions on the two sides of the work surface of the welding plate are opposite to each other. Figure 3

[0076] To determine the specific positions of the local regions on the work surface of the welding plate in each cycle, as a possible implementation, the target points in the current cycle whose matching values with the points in the boundary line in the previous cycle exceed a preset matching threshold are obtained based on the three-dimensional coordinate data and the temperature data of the points in the boundary line on the work surface of the welding plate, and the local regions on the work surface of the welding plate are determined based on the boundary line formed by connecting the target points in the current cycle.

[0077] As an example, for each cycle, the matching values between the points corresponding to each other in the current cycle and the previous cycle on the work surface of the welding plate are calculated based on the three-dimensional coordinate data and the temperature data of the points corresponding to each other in the current cycle and the previous cycle on the work surface of the welding plate; the target points in the current cycle whose matching values with the points in the previous cycle exceed a preset matching threshold are determined; for each boundary line, the target points in the current cycle corresponding to each target point in the previous cycle are connected to determine the boundary line in the current cycle; and the local regions on the work surface of the welding plate are determined based on the regions between the adjacent boundary lines in the current cycle.

[0078] It should be noted that the specific value of the preset matching threshold is determined according to actual requirements, and the present embodiment is not limited in specific, for example, the preset matching threshold can be 0.8.

[0079] For example, it is assumed that the three-dimensional point cloud data in the first cycle is collected in the process of welding the steel structure, where each point contains the position of the point, which can be represented by three-dimensional coordinate data , and the temperature data at the position, for example, a point in the first cycle, the matching value between the two points is calculated according to the three-dimensional point cloud data of the corresponding points in the initial moment, where the difference between the three-dimensional coordinates of the two points is , and the difference between the temperature data of the two points is , if the matching value exceeds a preset matching threshold, the two points are target points.

[0080] S102: For each cycle, the angular deformation indicators of the abutment areas of the welding plates are determined according to the boundary line features of the local regions on the welding plates, where the abutment areas are composed of the local regions opposite to each other on the two welding plates.

[0081] ​​It is important to understand that, due to the heat generated by the welding torch, the degree of deformation varies across different areas on the working surface of the steel structure welding plate. In practice, areas that are heated more tend to shrink inwards, resulting in a smaller angle between these areas on either side of the weld, i.e., a smaller angle between the relative boundary lines. Furthermore, from the perspective of the inspection equipment, as the welding process progresses, the working surface of the welding plate gradually changes from an initially flat surface to a slightly sloping surface. Even within the same area on the working surface of the welding plate, the visible area gradually decreases. Consequently, from the perspective of the inspection equipment, the length of the boundary line of the area also gradually shortens. Therefore, by analyzing the changes in the length of the boundary line and the changes in the angle between the relative boundary lines within each cycle, the degree of angular deformation occurring on the working surface of the welding plate within each cycle can be comprehensively analyzed.

[0082] The process of determining angular deformation index is as follows: Figure 4 As shown, it includes:

[0083] S102-1: For the working surface of each side welding plate, based on the difference between the boundary line length of each local area in the current cycle and the boundary line length of the same local area in the previous cycle, determine the length change of each local area in the current cycle.

[0084] It is important to understand that since a local area is a region composed of two adjacent boundary lines, we can first analyze the quotient of the length of the two adjacent boundary lines and the length of their respective corresponding boundary lines in the previous period to determine the length ratio of the two adjacent boundary lines. Then, we can calculate the average length ratio of the two adjacent boundary lines in each local area to determine the length change of each local area.

[0085] As the welding process of steel structures progresses, angular deformation inevitably occurs. From the perspective of the inspection equipment, the visible boundary line on the working surface of the weld plate will shrink. The greater the shrinkage, the greater the degree of shrinkage and angular deformation. Therefore, the change in length of each local area can be expressed by the following formula:

[0086]

[0087] in, This represents the length change of the kth local region on the working surface of each side welding plate; This represents the length of the j-th boundary line on the working surface of the welding plate during the i-th cycle. Indicates the first The length of the j-th boundary line on the working surface of the welding plate within each cycle (previous cycle); Indicates the first The first on the working surface of the welding plate within the cycle The length of each boundary line; denotes the length of the jth boundary line on the working surface of the welding plate in the current period. denotes the length of the jth boundary line on the working surface of the welding plate in the current period.

[0088] wherein, the jth boundary line and the ith boundary line are adjacent boundary lines, and the jth boundary line and the ith boundary line constitute the kth local region on the working surface of the welding plate. wherein, the jth boundary line and the ith boundary line are adjacent boundary lines, and the jth boundary line and the ith boundary line constitute the kth local region on the working surface of the welding plate.

[0089] wherein, the difference relationship represents the ratio between the length of the boundary line in the current period and the length of the boundary line of the same local region in the previous period.

[0090] denotes the average value of the difference between the length of the adjacent two boundary lines of each local region in the current period and the length of the respective opposite boundary line in the previous period.

[0091] wherein, it should be noted that since there is no previous period adjacent to the first period in the steel structure welding process, the length change amount of each local region in the first period can be determined based on the difference between the length of the boundary line of each local region in the first period and the length of the boundary line of the same local region at the initial time when the steel structure starts welding. The specific method of determining the length change amount is similar to the method of determining the length change amount in the current period, and will not be described herein.

[0092] S102-2: Calculate the change amount between the included angle between the respective opposite boundary lines on the working surfaces of the two welding plates in the current period and the included angle between the same pair of boundary lines in the previous period, and determine the included angle change amount of the butt joint area.

[0093] It should be noted that since the local region is a region constituted by two adjacent boundary lines, for each adjacent boundary line, the difference between the included angle between the respective opposite boundary lines on the working surfaces of the two welding plates in the current period and the included angle between the same pair of boundary lines in the previous period is calculated to determine the included angle difference of the boundary line, and then the average value of the included angle difference of the two pairs of opposite boundary lines in the butt joint area is calculated to determine the included angle change amount of the butt joint area.

[0094] denotes the average value of the difference between the included angle of each pair of opposite boundary lines in the current period and the included angle of the same pair of boundary lines corresponding thereto in the previous period.

[0095] S102-3: Determine the angular deformation index of the butt joint area based on the included angle change amount of each butt joint area and the length change amount of the local region in the butt joint area, wherein the length change amount and the included angle change amount are positively correlated with the angular deformation index.

[0096] ​​It should be noted that, since the butt joint area is composed of the mutually opposite local areas on the two side weld plates, the total number of the mutually opposite local areas on the working surfaces of the two side weld plates is the total number of the butt joint areas.

[0097] Since, with the continuous advancement of the steel structure welding process, the angle between the opposite boundary lines on the working surface of the weld plate will decrease under the perspective of the detection equipment, the change amount between the angle between the respective opposite boundary lines in the current period and the angle between the same pair of boundary lines in the previous period will increase, and if the change amount of the angle is increasingly large, the degree of the change in the angle is larger, which indicates that the degree of the angular deformation is higher, therefore, the angular deformation index of the butt joint area can be represented by the following formula:

[0098]

[0099] wherein, represents the angular deformation index of the kth butt joint area in the ith period; represents the length change amount of the kth local area; represents the angle change amount.

[0100] It should be noted that the angle change amount is determined based on the average value of the difference between the angle of each pair of opposite boundary lines in the current period and the angle of the same pair of boundary lines in the previous period, and it can be known that the material of the steel structure itself has higher strength and hardness, and if no other unexpected situation causes damage to the steel structure, only due to the heat generated by the welding gun, the region on the steel structure will not shrink significantly in a short period of time even if it shrinks inward, and the angle change amount will not be too large in the adjacent two periods, i.e., the angle change amount will not exceed 90 degrees, and therefore cannot be equal to 0.

[0101] It should be noted that the kth butt joint area is composed of the mutually opposite kth local areas on the two side weld plates.

[0102] S103: According to the temperature data of each point in the boundary line on each local area, the characteristic temperature of the butt joint area is calculated; according to the time sequence data of the angular deformation index and the time sequence data of the characteristic temperature of the target area from the first period to the current period, the heat influence factor of the target area is determined, wherein the butt joint area with the highest characteristic temperature in the plurality of butt joint areas is taken as the target area.

[0103] It should be understood that the main reason for the angular deformation of the steel structure is the heat generated by the welding gun, and the welding gun is constantly moving, and the position of the welding gun in different periods is also different, which can cause the heating condition in the local area of the working surface of the welding plate to change. However, the uneven heating can cause different degrees of deformation in different local areas of the steel structure, and ultimately cause the occurrence of angular deformation of the steel structure. It can be known that the welding gun is a heat output source, and the area where the welding gun is located and passes through has a higher heat. Therefore, the position of the welding gun in each period can be determined, and the heating condition in different areas in the current period can be analyzed, so that the influence of temperature on the deformation change in different areas can be determined.

[0104] In the embodiment, the average value of the temperature data of each point in the boundary line of each local area is calculated to obtain the temperature average value of each local area. The temperature average value of the local area in each butt joint area is subjected to a mean operation to determine the representative temperature of each butt joint area.

[0105] It should be understood that since the local area includes a plurality of points, and even on the same local area, the temperature at different positions is not the same. The closer to the welding point, i.e. the weld, the higher the temperature at the position. Therefore, in order to accurately analyze the representative temperature that can comprehensively reflect the heating condition of the local area, it is known that the local area is a region composed of two adjacent boundary lines. The temperature average value can be obtained by focusing on the average value of the temperature data of all points in the two adjacent boundary lines, and the heating condition of the local area can be reflected by the temperature average value.

[0106] The heat influence factor determination process is as shown in Figure 5 , including:

[0107] S103-1: Arrange the angular deformation indicators of the target area in the corresponding period in the time order of each period from the first period to the current period to obtain angular deformation indicator time sequence data.

[0108] S103-2: Arrange the representative temperature of the target area in the corresponding period in the time order of each period from the first period to the current period to obtain the representative temperature time sequence data.

[0109] It should be understood that since the welding gun is a heat output source, the area where the welding gun is located and passes through has a higher heat. The representative temperature of the target area in the current period can determine the area where the welding gun is located in the current period as the target area. Therefore, from the time when the welding gun has not passed through the target area to the time when the welding gun has passed through the target area in the current period, the change of the representative temperature in the target area and the change of the degree of angular deformation in the target area can be analyzed, and the influence of the change of the representative temperature in the target area on the change of the angular deformation can be further analyzed.

[0110] S103-3: Calculate the change amount between each angular distortion index and the smallest angular distortion index in the angular distortion index time series data, and determine the angular distortion change amount of the target region in the current period.

[0111] S103-4: Calculate the change amount between each characteristic temperature and the lowest characteristic temperature in the characteristic temperature time series data, and determine the characteristic temperature change amount of the target region in the current period.

[0112] Wherein, it can be understood that, since the welding torch is a heat output source, the closer the local area is to the position where the welding torch is located, the higher the temperature becomes, and the greater the influence of temperature on the degree of angular distortion. Therefore, conversely, if the angular distortion index of the target region is the smallest and the characteristic temperature is the lowest in a certain period, it indicates that the change of the target region caused by the heat generated by the welding torch is the smallest in the period. From the period to the current period, the change of the target region caused by the heat generated by the welding torch gradually becomes significant. The period can be represented as the Lth period, which is used to represent that the angular distortion index in the target region is the smallest and the characteristic temperature is the lowest in the period.

[0113] S103-5: Determine the heat influence factor of the target region in the current period based on the correlation between the angular distortion change amount and the characteristic temperature change amount of the target region in the current period, wherein the angular distortion change amount is positively correlated with the heat influence factor, and the characteristic temperature change amount is negatively correlated with the heat influence factor.

[0114] Since the core heat in the region that has been welded gradually decreases as the welding torch moves, the position of the welding torch changes over time, and even the heat in the same region changes, the smaller the characteristic temperature change amount in the target region, the more significant the degree of angular distortion, and the greater the influence of temperature change on the change of angular distortion. Therefore, it is assumed that the characteristic temperature time series data is represented as Wherein, s represents the order of the period from the first period to the current period, and the th docking area is represented as the target region; the angular distortion index time series data is represented as The heat influence factor can be represented by the following formula:

[0115]

[0116] Wherein, Y represents the heat influence factor; represents the angular distortion index of the target region in the s th period from the first period to the current period; represents the angular distortion index of the target region in the L th period from the first period to the current period, i.e. the smallest angular distortion index; represents the characteristic temperature of the target region in the s th period from the first period to the current period; represents the characterization temperature of the target region in the Lth cycle from the first cycle to the current cycle, i.e., the lowest characterization temperature.

[0117] It should be noted that in the actual working scenario, the welding torch moves forward regularly according to the preset direction, and it can be known that the region where the welding torch is located in the current cycle is the target region. If the welding torch is located farther away from the target region in a certain cycle, the target region is less affected by the heat generated by the welding torch at this time, i.e., the characterization temperature is lower, which is represented as in the example. Therefore, in other cycles except the Lth cycle, the position where the welding torch is located is closer to the target region than the position where the welding torch is located in the Lth cycle, and are all greater than It should be noted that analyzing the change of the characterization temperature of the target region in the same cycle does not have reference significance, so s is not equal to L.

[0118] S104: Determine the angular deformation characteristic parameter of the butt joint zone according to the angular deformation index of each butt joint zone and the heat influence factor of the target region.

[0119] It should be understood that the temperature in the region where the welding torch has passed will gradually decrease as the welding torch leaves, and the angular deformation degree in the subsequent region will not change much. The region where the welding torch has not passed will also be passed subsequently as the welding process continues. Therefore, by focusing on the temperature change that will occur subsequently in the region where the welding torch has not passed, the angular deformation change that will occur subsequently in the region where the welding torch has not passed can be further analyzed. Thus, the angular deformation degree of the whole steel structure in the current cycle can be comprehensively judged based on the angular deformation degree in the butt joint zone that has been passed by the welding torch and the angular deformation change that will occur subsequently in the butt joint zone that has not been passed by the welding torch.

[0120] It should be noted that the butt joint zone can be divided into two categories of butt joint zones, one category being welded and the other category being unwelded.

[0121] The butt joint zone of the welded category indicates the butt joint zone that has been passed by the welding torch from the first cycle to the current cycle.

[0122] The butt joint zone of the unwelded category indicates the butt joint zone that has not been passed by the welding torch from the first cycle to the current cycle.

[0123] The angular deformation characteristic parameter determination process is shown in Figure 6 , which includes:

[0124] S104-1: Determine the front and rear order between the butt joint zones according to the order in which the welding torch is expected to pass through each butt joint zone.

[0125] It should be noted that the specific order in which the welding gun is expected to pass through each joint area is determined according to actual needs, and the present embodiment does not make specific limitations. For example, under the visual angle of the detection device, the welding gun passes through the joint areas in sequence from left to right along the weld.

[0126] S104-2: Classify each joint area in the current period to determine the category of each joint area, wherein the target area and the joint areas before the target area are all welded, and the joint areas after the target area are all unwelded.

[0127] S104-3: Perform a summation operation on the angular deformation indicators of each joint area with the category of welded to determine the first angular deformation feature parameter in the current period.

[0128] Since the temperature in the area that has been passed through by the welding gun will gradually decrease as the welding gun leaves, the degree of angular deformation in the subsequent area will not change much. Therefore, the greater the angular deformation indicator of a joint area with the category of welded, the greater the possibility of angular deformation of the entire steel structure in the current period. Therefore, the first angular deformation feature parameter can be represented by the following formula:

[0129]

[0130] wherein the target area is located in the jth joint area; represents the first angular deformation feature parameter in the ith period; represents the angular deformation indicator of the kth joint area (with the category of welded) in the ith period. The first angular deformation feature parameter represents the degree of angular deformation that has occurred in all joint areas with the category of welded in the ith period.

[0131] The first angular deformation feature parameter represents the degree of angular deformation that has occurred in all joint areas with the category of welded in the ith period.

[0132] S104-4: Calculate the change between the representative temperature of each joint area with the category of unwelded and the representative temperature of the target area to obtain the temperature change value of each joint area with the category of unwelded.

[0133] S104-5: Determine the second angular deformation feature parameter in the current period based on the correlation between the temperature change value, the angular deformation indicator of each joint area with the category of unwelded, and the heat influence factor of the target area, wherein the temperature change value, the angular deformation indicator, and the heat influence factor of the target area are all positively correlated with the second angular deformation feature parameter.

[0134] ​Since, if the temperature change of a certain category of butt joint area after the subsequent will be larger, it reflects that the subsequent butt joint area is affected by the heat of the welding gun more, the degree of angular deformation will be more significant, therefore, the second angular deformation characteristic parameter can be represented by the following formula:

[0135]

[0136] wherein, represents the temperature change value of the kth butt joint area (category: not welded) in the ith cycle; Y represents the heat influence factor of the target area; represents the angular deformation index of the kth butt joint area (category: not welded) in the ith cycle; represents the second angular deformation characteristic parameter in the ith cycle; n represents the total number of all butt joint areas.

[0137] The second angular deformation characteristic parameter represents the degree of angular deformation of all butt joint areas of the category not welded in the ith cycle after the subsequent.

[0138] S105: According to the thickness data of the welding plate and the angular deformation characteristic parameters of each butt joint area, the angular deformation probability value of the steel structure in the current cycle is determined.

[0139] It should be noted that the thickness data of the welding plate includes the total thickness of the two side welding plates at the initial moment when the steel structure starts welding, and the total thickness of the two side welding plates in each cycle.

[0140] In this embodiment, based on the sum of the first angular deformation characteristic parameter and the second angular deformation characteristic parameter, a first sum value is determined; the difference between the total thickness of the two side welding plates in the current cycle and the total thickness of the two side welding plates at the initial moment is calculated to obtain a first difference value; based on the quotient of the number of regions where the target area is located in the current cycle and the total number of all butt joint areas, a welding completion index in the current cycle is determined; based on the product between the welding completion index and the first difference value, a thickness change amount in the current cycle is determined; based on the thickness change amount and the first sum value, the angular deformation probability value of the steel structure in the current cycle is determined, wherein the thickness change amount and the first sum value are positively correlated with the angular deformation probability value.

[0141] Since, if a certain category is the greater the angular deformation index of the welded butt joint, and if a certain category is the greater the degree of subsequent angular deformation of the non-welded butt joint, the greater the possibility of the overall angular deformation of the steel structure, it can be known that the deformation degree of each region on the working surface of the steel structure welding plate is inconsistent under the influence of the heat generated by the welding gun. In actual situations, the more the heat received by the region, the greater the tendency of the region to shrink inward. The shrinkage of the region inward will lead to the reduction of the thickness of the welding plate. Therefore, as the thickness of the welding plate gradually decreases, if the difference between the total thickness of the welding plate on both sides in a certain period and the total thickness at the initial moment is large, it reflects that the degree of thickness reduction in the period is greater, and further indicates that the tendency of the region to shrink inward in the period is greater, and the greater the possibility of the overall angular deformation of the steel structure in the period. Therefore, the angular deformation probability value can be represented by the following formula:

[0142]

[0143] wherein, = ; represents the thickness change amount in the i th period; represents the welding completion index; represents the first difference value in the i th period; represents the mapping of the angular deformation probability value to [0, 1]; represents the exponential function with the natural constant e as the base; represents the first angular deformation feature parameter in the i th period; represents the second angular deformation feature parameter in the i th period; represents the angular deformation probability value in the i th period.

[0144] The first difference value is the difference between the total thickness of the welding plate on both sides in the i th period and the total thickness of the welding plate on both sides at the initial moment, wherein the initial moment represents the moment when the steel structure starts to be welded.

[0145] The welding completion index is the quotient of the number of regions (the number of butt joints) in which the target region is located in the i th period and the total number n of all butt joints.

[0146] In the embodiment, if the angular deformation probability value in the current period exceeds the preset abnormal threshold value, it is determined that the assembled steel structure will subsequently have significant angular deformation under the action of the welding gun heat.

[0147] ​It should be noted that the specific value of the preset abnormal threshold is determined according to actual needs, and the present embodiment is not limited specifically, for example, it is found that if the preset abnormal threshold is 0.7, it can be determined that if the steel structure is continuously welded according to the welding strategy used in the current period, the subsequent assembly type steel structure will have significant angular deformation.

[0148] It should be noted that if the angular deformation probability value in the current period exceeds the preset abnormal threshold, it can be determined that if the steel structure is continuously welded according to the welding strategy used in the current period, the subsequent assembly type steel structure will have significant angular deformation, so the welding strategy can be adjusted in time, for example, the welding temperature is reduced or the movement path of the welding gun is changed, etc. Welding strategy to reduce the degree of angular deformation of the assembly type steel structure and save subsequent repair costs.

[0149] For example, the steel structure welding deformation monitoring data table is shown in Table 1, for example, for the same target area 2, due to the influence of heat generated by the welding gun, it can be found that the greater the heat radiated to the target area 2, the higher the average temperature, and the more significant the degree of angular deformation, reflecting that the greater the heat influence factor, the greater the influence of temperature change on angular deformation. For the same target area 1, it can be found that the higher the average temperature of the target area 1, the more significant the inward contraction of the steel structure, reflecting that the greater the thickness change rate, the greater the influence of temperature change on the thickness of the steel structure, and the greater the thickness change rate, the greater the possibility of angular deformation of the steel structure as a whole. It can be found by comparing period 1 and period 2.

[0150] Table 1 Steel structure welding deformation monitoring data table

[0151]

[0152] For example, the steel structure welding deformation monitoring is as follows: the steel structure welding process temperature monitoring example diagram is shown in Figure 7 , the steel structure plate thickness change trend example diagram is shown in Figure 8 , the steel structure angular deformation risk assessment example diagram is shown in Figure 9 , and the steel structure welding parameter correlation analysis process example diagram is shown in Figure 10 , wherein the time axis values in examples Figure 7 , 8 , 9 and 10 are used to represent the specific time of each period, and the examples Figure 7 , 8, 9 and 10, at all times before time 6, it can be found that the area affected by the heat generated by the welding torch is more prone to shrink inward, and the area shrinks inward, and the welding plate thickness is also significantly reduced. As the welding plate thickness gradually decreases, it further indicates that the area is more prone to shrink inward during this period, and it can be found that as the temperature changes, the angular deformation also changes, and the heat influence factor also gradually increases, so the possibility of overall angular deformation of the steel structure is also greater.

[0153] It should be noted that the effectiveness verification of the steel structure deformation detection scheme is as follows:

[0154] 1. Physical law consistency verification: temperature distribution characteristics: the monitoring data shows that the temperature of the welding area increases significantly (the peak value of target area 5 can reach 312.6°C), which is consistent with the heat source distribution law of the welding torch; thickness change trend: the welding plate thickness decreases from the initial 20.00mm to 18.73mm (change rate 6.33%), which is consistent with the physical properties of heat deformation leading to material shrinkage; deformation development process: the angular deformation probability value continuously rises (0.421→0.832) with the welding progress, which is consistent with the welding heat accumulation effect.

[0155] 2. Early warning mechanism effectiveness verification: the risk early warning is triggered for the first time at time 3 (0.718>0.7), and the actual detection data shows that significant deformation characteristics appear at this stage: the angular deformation index of target area 5 reaches 18.73 (peak value in the whole cycle); the thickness change rate reaches 6.33% (exceeding the safety threshold of 5%); early warning for 2 cycles provides a key time window for adjusting the welding strategy.

[0156] 3. Multi-factor correlation analysis: the heat influence factor and the welding completion degree show strong correlation (r=0.92), r represents the correlation between the heat influence factor and the welding completion degree; the angular deformation probability value comprehensively reflects the multiple influences of temperature (weight 0.38), thickness change (weight 0.32) and welding progress (weight 0.30); in the simulation of the overrun accident in cycle 10, the angular deformation risk can also be accurately predicted.

[0157] 4. Actual application verification: when the system issues a warning at cycle 8, take timely cooling measures: reduce the welding torch power by 15%

[0158] , increase the welding speed by 20%, and the final product is detected by a three-coordinate measuring instrument: the angular deformation is controlled within 0.05° (the standard requires ≤0.1°), and the product pass rate is also improved to 99.3% (originally 97.6%).

[0159] In summary: this deformation detection scheme effectively predicts the angular deformation risk of steel structures through multi-parameter fusion analysis, with an early warning accuracy of more than 95%, significantly improving the product quality control level.

[0160] One embodiment of the present application provides a steel structure deformation detection system based on thermal analysis, the system comprises a memory, a processor and a computer program stored in the memory and running on the processor, wherein the processor implements the steel structure deformation detection method based on thermal analysis disclosed by the embodiment of the present application when executing the computer program.

[0161] It should be noted that the above-mentioned embodiment sequence of the present application is only for description, not representing the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0162] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment mainly describes the difference from other embodiments.

Claims

1. A deformation detection method for steel structures based on thermal analysis, characterized in that, The method includes: During the steel structure welding process, the three-dimensional point cloud data of the steel structure and the temperature data of each corresponding point are periodically collected. The steel structure includes welding plates on both sides, and the working surface of each welding plate is divided into multiple local areas. For each cycle, the angular deformation index of each mating area of ​​the welding plates is determined based on the boundary line characteristics of the two welding plates in their respective local areas. The mating area is composed of the local areas that are opposite to each other on the two welding plates. Based on the temperature data of each point within the boundary line of each local area, the characterization temperature of the docking zone is calculated; based on the time series data of the angular deformation index and the characterization temperature of the target area from the first cycle to the current cycle, the heat influence factor of the target area is determined, wherein the docking zone with the highest characterization temperature among multiple docking zones is taken as the target area. Based on the angular deformation index of each docking zone and the heat influence factor of the target area, determine the angular deformation characteristic parameters in the current cycle; Based on the thickness data of the welded plate and the angular deformation characteristic parameters, determine the angular deformation probability value of the steel structure in the current period; In the case of the first cycle, the local region determination process includes: At the initial moment before welding of the steel structure begins, the initial three-dimensional point cloud data of the unwelded steel structure is collected by the detection equipment pre-positioned at the preset detection points; At the initial moment, using the initial three-dimensional point cloud data, the sum of the distances from each point within each edge contour line of the working surface of the welding plate to the preset detection point is calculated to obtain the total distance corresponding to each edge contour line; the edge contour line with the shortest total distance among all edge contour lines is taken as the target edge contour line of the working surface of the welding plate. For each side of the working surface of the welding plate, taking the target edge contour line as the reference line, parallel contour lines perpendicular to the normal direction of the working surface of the welding plate are constructed along the direction parallel to the target edge contour line at preset intervals until they extend to the outer contour boundary of the working surface of the welding plate. Based on the target edge contour line and the parallel contour line, the working surface of the welding plate is divided into multiple strip regions, wherein the area between adjacent contour lines constitutes one strip region; each strip region serves as a target local area on the working surface of the welding plate; the target edge contour line and the parallel contour line each constitute the boundary line of adjacent target local areas; In the first cycle, by collecting three-dimensional point cloud data, a local area on the working surface of the welding plate that is in the same position as the target local area is obtained.

2. The deformation detection method for steel structures based on thermal analysis according to claim 1, characterized in that, The local region determination process includes: For each cycle, based on the three-dimensional coordinate data and temperature data of the points corresponding to each point on the working surface of the soldering plate in the current cycle and the previous cycle, the matching value between the points corresponding to each point in the current cycle and the previous cycle is calculated; and the target point in the current cycle whose matching value with the previous cycle exceeds the preset matching threshold is determined. For each boundary line, based on the target points within the boundary line in the previous period, connect the corresponding target points in the current period to determine the boundary line in the current period; Based on the region between adjacent boundary lines within the current cycle, a local region on the working surface of the welding plate is determined.

3. The deformation detection method for steel structures based on thermal analysis according to claim 2, characterized in that, The process for determining the angular deformation index includes: For the working surface of each side welding plate, the length change of each local area in the current cycle is determined based on the difference between the boundary line length of each local area in the current cycle and the boundary line length of the same local area in the previous cycle. Calculate the change in the angle between the relative boundary lines on the working surfaces of the two welding plates in the current cycle and the angle between the same pair of boundary lines in the previous cycle, and determine the change in the angle of the docking area. Based on the change in the included angle of each docking zone and the change in the length of a local area within the docking zone, the angular deformation index of the docking zone is determined, wherein the change in length and the change in included angle are both positively correlated with the angular deformation index.

4. The deformation detection method for steel structures based on thermal analysis according to claim 1, characterized in that, The process of calculating the characterization temperature includes: Calculate the mean temperature data of each point within the boundary line of each local region to obtain the mean temperature of each local region; A mean averaging operation is performed on the local temperature averages within each docking zone to determine the characterization temperature of each docking zone.

5. The deformation detection method for steel structures based on thermal analysis according to claim 4, characterized in that, The process for determining the heat impact factor includes: Arrange the angular deformation indices of the target area in the corresponding period according to the time sequence of each period from the first period to the current period, and obtain the time series data of the angular deformation indices. Arrange the characterization temperatures of the target region within the corresponding period according to the time sequence of each period from the first period to the current period to obtain the time series data of the characterization temperatures. Calculate the changes between each angular deformation index and the smallest angular deformation index in the time series data of angular deformation index to determine the angular deformation change of the target area in the current period; Calculate the change between each characterization temperature and the lowest characterization temperature in the characterization temperature time series data, and determine the change in characterization temperature of the target region in the current period; Based on the correlation between the change in angular deformation and the change in temperature of the target region within the current cycle, the thermal influence factor of the target region within the current cycle is determined, wherein the change in angular deformation is positively correlated with the thermal influence factor, and the change in temperature is negatively correlated with the thermal influence factor.

6. The deformation detection method for steel structures based on thermal analysis according to claim 1, characterized in that, The docking area is divided into two categories: welded and unwelded. The process for determining the angular deformation characteristic parameters includes: Determine the order of each docking zone according to the expected sequence of the welding torch passing through each docking zone; The docking areas within the current cycle are classified and processed to determine the category of each docking area. The target area and the docking areas before the target area are classified as welded, while the docking areas after the target area are classified as unwelded. The change in temperature between the characterization temperature of each unwelded docking area and the characterization temperature of the target area is calculated to obtain the temperature change value of each unwelded docking area. Based on the correlation between the temperature change value, angular deformation index, and heat influence factor of the target area for each unwelded docking zone, the second angular deformation characteristic parameter in the current cycle is determined, wherein the temperature change value, angular deformation index, and heat influence factor of the target area are all positively correlated with the second angular deformation characteristic parameter.

7. The deformation detection method for steel structures based on thermal analysis according to claim 6, characterized in that, The thickness data of the welding plates includes the total thickness of the welding plates on both sides at the initial moment before welding of the steel structure begins, and the total thickness of the welding plates on both sides in each period. The process of determining the angular deformation probability value includes: Perform a summation operation on the angular deformation indices of each welded area to determine the first angular deformation characteristic parameter in the current cycle; A first summation value is determined based on the sum of the first angular deformation characteristic parameter and the second angular deformation characteristic parameter; Calculate the difference between the total thickness of the two welding plates in the current cycle and the total thickness of the two welding plates in the initial time, and obtain the first difference; The welding completion index for the current period is determined by the quotient of the number of regions where the target area is located and the total number of all docking areas in the current period; the thickness change in the current period is determined by the product of the welding completion index and the first difference. Based on the thickness change and the first summation value, the angular deformation probability value of the steel structure in the current period is determined, wherein the thickness change and the first summation value are both positively correlated with the angular deformation probability value.

8. The deformation detection method for steel structures based on thermal analysis according to claim 1, characterized in that, The method further includes: If the probability value of angular deformation in the current cycle exceeds the preset abnormal threshold, it is determined that the prefabricated steel structure will undergo significant angular deformation under the action of the welding torch heat.

9. A deformation detection system for steel structures based on thermal analysis, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that the processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 8.

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