A quality monitoring data collection method and apparatus

Abstract

The application discloses a kind of quality monitoring data acquisition method and device, by the application fast acquisition of workpiece data on assembly line is realized, equipment cost is low, efficiency is high, applicable to data batch acquisition processing, whether it is free deformation or the deformation caused under constraint state can be applicable, by calculating the influence of temperature and deformation respectively and highlighting stress concentration point is analyzed, and avoid the stress analysis result that cannot reflect actual situation caused by inconsistent change trend when considering temperature and deformation simultaneously in conventional model, realize reducing amount of calculation, the data result of acquisition is more accurate.The application can be widely applied to engineering quality monitoring field as a kind of quality monitoring data acquisition method and system device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engineering quality monitoring, and in particular to a quality monitoring data acquisition method and device. BACKGROUND

[0002] In engineering quality monitoring, the residual stress of the construction workpiece needs to be concerned, and fracture failure analysis is usually performed. Residual stress is the action and influence that remains in the component after the action and influence of various process factors and the like during the manufacturing process of the component, and the action and influence that remains in the component after the action and influence of various process factors and the like during the manufacturing process of the component.

[0003] Taking a welded workpiece as an example, the internal stress remaining in the welded structure due to the constraint of deformation during the welding heat process, among which the thermal stress generated by the constraint of the cooling shrinkage after the weld metal is melted and solidified is the most significant, is the main part of the residual stress. The internal stress generated when the internal metallographic structure changes during the welding cooling process is a secondary part of the residual stress. In the prior art, the residual stress is usually eliminated by post-weld heat treatment, overload treatment, vibration treatment and the like, or the generation of the residual stress is reduced by welding process, temperature control and the like during the welding process. In the prior art, the residual stress is usually calculated by finite element analysis, but the existing calculation model only establishes a model for temperature, deformation and the like, and it is difficult to meet the requirements when the quality monitoring precision requirement is high. For example, CN114528733A is a method for controlling residual stress of a multi-point distributed heat source for welding of a steel bridge deck, which is used to adjust the residual stress at different positions of the steel bridge deck weld to reduce the generation of residual stress during the welding process. However, this method is used for continuous control during the welding process, and it is difficult to apply to rapid data acquisition and monitoring of batch workpieces, and the final state of the workpiece after welding is not monitored and tested. SUMMARY

[0004] In order to solve the above technical problems, the purpose of the present application is to provide a quality monitoring data acquisition method and system with less calculation and more accurate data acquisition results.

[0005] One of the technical solutions adopted by the present application is a quality monitoring data acquisition method, comprising the following steps:

[0006] S1, acquiring first three-dimensional scanning data of a to-be-tested object at a first time and second three-dimensional scanning data of the to-be-tested object at a second time, and establishing a first three-dimensional finite element analysis model based on the second three-dimensional scanning data;

[0007] S2, acquire infrared image data of the to-be-tested object at at least two time points within a first time to a second time, and input the infrared image data to a first three-dimensional finite element analysis model to obtain a first stress field feature;

[0008] S3, adjust a grid node in the three-dimensional finite element analysis model based on the first three-dimensional scanning data and the second three-dimensional scanning data to obtain a third three-dimensional finite element analysis model, and input the first three-dimensional scanning data to the third three-dimensional finite element analysis model to obtain a second stress field feature;

[0009] S4, obtain third stress field feature data according to the first stress field feature and the second stress field feature.

[0010] Another technical solution adopted by the application is a quality monitoring data acquisition device, comprising:

[0011] An image data acquisition device is configured to acquire first three-dimensional scanning data of a to-be-tested object at a first time and second three-dimensional scanning data of the to-be-tested object at a second time.

[0012] An infrared data acquisition device is configured to acquire infrared image data of the to-be-tested object at at least two time points within a first time to a second time.

[0013] A data generation device is configured to

[0014] A first three-dimensional finite element analysis model is established based on the second three-dimensional scanning data.

[0015] The infrared image data of the to-be-tested object at at least two time points within a first time to a second time is input to the three-dimensional finite element analysis model to obtain a first stress field feature.

[0016] A third three-dimensional finite element analysis model is obtained by adjusting a grid node in the three-dimensional finite element analysis model based on the first three-dimensional scanning data and the second three-dimensional scanning data, and the first three-dimensional scanning data is input to the third three-dimensional finite element analysis model to obtain a second stress field feature.

[0017] Third stress field feature data is obtained according to the first stress field feature and the second stress field feature.

[0018] The application has the following advantages: the method and system can quickly acquire workpiece data on a production line, have low equipment cost and high efficiency, are suitable for batch data acquisition and processing, are applicable to deformation caused by free deformation or constraint state, can analyze stress concentration points by separately calculating the influence of temperature and deformation, and can avoid the situation that stress analysis results cannot reflect actual conditions due to inconsistent change trends when temperature and deformation are simultaneously considered in a conventional model, thereby reducing calculation amount and making the acquired data results more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 This is a flowchart illustrating the steps of a first specific embodiment of this application;

[0020] Figure 2 This is a flowchart illustrating the steps of a second specific embodiment of this application;

[0021] Figure 3 This is a schematic diagram of residual stress in a welded workpiece according to a specific embodiment of this application;

[0022] Figure 4 This is a schematic diagram of the mesh before division and merging in a specific embodiment of this application;

[0023] Figure 5 This is a schematic diagram of the segmented and merged mesh in a specific embodiment of this application;

[0024] Figure 6 This is a schematic diagram illustrating one method of dividing the merged mesh in a specific embodiment of this application;

[0025] Figure 7 This is a schematic diagram illustrating another method of dividing the merged grid in a specific embodiment of this application;

[0026] Figure 8 This is a schematic diagram of the first proportional division method of the grid cells in a specific embodiment of this application;

[0027] Figure 9 This is a schematic diagram of the second proportional division method of the grid cells in a specific embodiment of this application;

[0028] Figure 10 This is a schematic diagram of the third proportional division method of the grid cells in a specific embodiment of this application;

[0029] Figure 11 This is a temperature fitting curve for a specific embodiment of this application;

[0030] Figure 12 This is a temperature fitting curve of adjacent grid nodes in a specific embodiment of this application;

[0031] Figure 13 This is a schematic diagram of the architecture of the data acquisition device of this application. Detailed Implementation

[0032] In existing technical solutions, residual stress at different locations of the steel bridge deck weld is adjusted in a targeted manner to reduce the generation of residual stress during the welding process. However, the existing methods require continuous control of the welding process, and only one workpiece can be operated in a single welding process. This makes it difficult to apply to the rapid data acquisition and monitoring of batch workpieces. Furthermore, during the cooling process after welding, the internal metallographic structure changes or the presence of cracks can affect the final stress distribution, which may differ from the model prediction. Therefore, data must be collected for monitoring and analysis.

[0033] In existing methods, stress data is typically obtained through finite element analysis (FEM). This analysis considers both elastic deformation and temperature distribution characteristics. However, in practice, it has been found that the sensitivity of FEM analysis for monitoring workpiece defects is too low, especially when there are open welds inside the weld while the surface remains intact. Often, only specialized equipment such as X-ray flaw detectors can detect these defects. Therefore, using FEM for quality monitoring poses significant safety risks. The main reason is that when there are open welds or cracks inside the weld, the temperature's influence on stress at these locations does not match the stress's influence on deformation. In other words, the stress at these locations affects temperature conduction differently than it affects stress conduction during deformation. Therefore, the stress data obtained through FEM is insufficient to reflect the actual situation. These open welds or cracks may be caused by incomplete welding or by contraction during cooling after welding.

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Reference Figure 1 The first specific embodiment of this application provides a method for collecting quality monitoring data, including the following steps:

[0036] S1. Obtain the first three-dimensional scanning data of the object under test at the first time and the second three-dimensional scanning data of the object under test at the second time, and establish the first three-dimensional finite element analysis model based on the second three-dimensional scanning data;

[0037] The first-time 3D scan data of the test object specifically refers to the 3D scan data of the test object (i.e., the welded workpiece) at the moment of welding completion; the second-time 3D scan data of the test object specifically refers to the 3D scan data of the test object after cooling and shaping. The basic model used for calculation is established based on the 3D scan data after cooling and shaping. The 3D scan data of the welded workpiece after cooling and shaping may differ from that of a standard workpiece. That is, the surface of some parts of the welded workpiece may be a plane with a certain degree of curvature due to cooling deformation. A typical modeling method is to pre-generate a uniform triangular mesh and then project it onto the surface of the welded workpiece to generate a triangular mesh model.

[0038] S2. Acquire infrared image data of the object under test at least two time points from the first time to the second time period, and input them into the first three-dimensional finite element analysis model to obtain the first stress field characteristics; the first stress field characteristics reflect the influence of temperature change on stress distribution during the cooling process of the welded workpiece.

[0039] In a specific implementation, infrared image data of the object under test should be acquired at least at two time points: the first time point and the second time point. Alternatively, the acquisition of infrared image data can be added at certain time points between the first and second time points, but this will correspondingly increase the amount of data processing or the cost of the acquisition equipment.

[0040] S3. Based on the first and second three-dimensional scanning data, adjust the mesh nodes in the three-dimensional finite element analysis model to obtain the third three-dimensional finite element analysis model. Input the first three-dimensional scanning data into the third three-dimensional finite element analysis model to obtain the second stress field characteristics. The second stress field characteristics reflect the influence of the deformation of the welded workpiece before and after cooling on the stress distribution.

[0041] The first and second three-dimensional scanning data are the corresponding data of the welded workpiece before and after cooling, respectively. Therefore, the deformation of the welded workpiece can be reflected by the two data. The stress caused by the larger deformation is greater. In particular, cracks may be generated inside the larger deformation. The stress transmission is often discontinuous here. Therefore, conventional finite element analysis models often cannot calculate the real data.

[0042] Finite element analysis software, such as ANSYS, typically provides error estimation and adaptive meshing functions to reduce errors introduced by mesh generation. For example, the predefined macro ADAPT.MAC can be used to implement adaptive meshing to minimize errors, such as avoiding excessively high mesh density near concentrated load regions and boundary constraints, which could lead to stress concentration in the calculation results. However, the adaptive meshing function still requires the user to manually select adaptive improvement regions in the initial mesh. Furthermore, the ADAPT process usually enlarges the mesh in concentrated load regions and near boundary constraints to eliminate certain stress singularities, which are typically larger than those in other regions, such as concentrated load regions.

[0043] In a specific embodiment of this application, since the influence of stress on temperature conduction and the influence on deformation stress conduction are inconsistent at the point of open weld or crack, it is necessary to increase the mesh density in the area with large deformation in order to capture stress singularities. When the welded workpiece is externally intact but may have internal cracks, the influence of temperature conduction and the influence on deformation stress conduction are calculated separately by finite element analysis using the three-dimensional data of the workpiece surface obtained by scanning, thereby discovering possible hidden internal cracks.

[0044] S4. Obtain the third stress field characteristic data based on the characteristics of the first and second stress fields;

[0045] When calculating the residual stress of a welded workpiece, it is often necessary to consider whether it is free deformation or deformation under constraint. If welding is under constraint, bending or torsional deformation may not occur. In this case, the stress is not released and is concentrated internally. In the finite element model, this is reflected as a partial stress increase when the first and second stress field characteristics are superimposed. The data here may reflect the presence of stress concentration points nearby. If it is free deformation, the stress acts on the workpiece to produce external deformation, thereby releasing some of the stress. In the finite element model, this is reflected as a partial stress cancellation when the first and second stress field characteristics are superimposed.

[0046] As a further preferred embodiment, step S3 specifically includes:

[0047] S31. Obtain the distribution characteristics of the deformed region based on the first three-dimensional scanning data and the second three-dimensional scanning data;

[0048] The second stress field characteristic reflects the influence of the deformation of the welded workpiece before and after cooling on the stress distribution. Therefore, the deformation region distribution characteristics are obtained by using the first and second three-dimensional scanning data as the basis for subsequent mesh adjustment.

[0049] like Figure 3As shown, this illustrates the residual stress generated when two components are welded together with a butt weld. The shaded area represents the middle butt weld. The cooling and shrinkage of the weld causes the two components to tend to bend towards each other. Figure 3 As shown by the dashed line; and the closer to the center, the greater the tendency to bend. Figure 3 The arrow lengths are used to represent the corresponding components. However, since the two parts are now welded together, the shrinkage displacement along the XY axes around the weld in the diagram is difficult to represent using 3D scanning data. Instead, the shrinkage displacement along the Z-axis of the 3D Cartesian coordinate system can be represented by the deformation region distribution characteristics (i.e., the difference between the first and second 3D scanning data along the Z-axis). The shrinkage displacement along the XY axes is only visible at the edges, but the stress at the edges is often small and can be ignored. When the welded workpiece has a complex shape, the deformation region distribution characteristics are the set of differences between the first and second 3D scanning data along the normal direction of the corresponding scanning point. The principle is the same as the calculation of the difference along the Z-axis of the 3D Cartesian coordinate system, and will not be elaborated here.

[0050] S32. Based on the distribution characteristics of the deformation region, adjust the mesh nodes in the corresponding first three-dimensional finite element analysis model to obtain the third three-dimensional finite element analysis model;

[0051] S33. Input the first three-dimensional scanning data into the third three-dimensional finite element analysis model to obtain the second stress field characteristics.

[0052] As a further preferred embodiment, step S33 specifically includes:

[0053] S331. Calculate the change value of the corresponding grid cell in the model based on the distribution characteristics of the deformation region;

[0054] The change in mesh cell values ​​reflects the changes in mesh cells before and after the welded workpiece cools. For example, if the welded part shrinks after cooling, the mesh position corresponding to the shrunken part will shift more significantly compared to its position before cooling. Specific mesh cell change values ​​can be the average of the differences in position between nodes on the mesh before and after cooling, or the difference in position between the mesh center (e.g., the centroid of a triangular mesh) before and after cooling; anything that reflects the change in mesh cell position before and after cooling is acceptable.

[0055] S332. When the change value is greater than a preset threshold, divide the corresponding grid cell;

[0056] When the change value exceeds the preset threshold, it indicates that significant stress may be generated at this location and within the corresponding workpiece. Therefore, it is necessary to increase the mesh density to identify stress singularities in the acquired data. For example... Figure 4 , 5 As shown, the middle part corresponds to Figure 3 The shaded area shows the location of the weld.

[0057] As a further preferred embodiment, step S33 specifically includes:

[0058] S333. When the change value is less than the preset threshold, traverse the adjacent grid cells of the corresponding grid cell. If there is an adjacent grid cell whose change value is less than the preset threshold, merge the corresponding grid cell with the adjacent grid cell.

[0059] When the variation values ​​of adjacent mesh elements are all less than a preset threshold, the mesh elements can be merged to reduce the computational load in finite element analysis and improve computational speed. The effect of merging corresponding mesh elements is shown in the following diagram. Figure 5 As shown, its left and right ends correspond Figure 3 The shaded area refers to the location on both sides of the weld. Note that steps S2 and S3 both use [this method / method / technique]. Figure 4 and Figure 5 The principle is explained, but since the effects of temperature change and deformation change on stress are not the same, steps S2 and S3 are based on the same principle. Figure 4 The actual results of splitting and merging operations will not produce the same outcome. Figure 5 The results are shown.

[0060] As a further preferred embodiment, step S33 specifically includes:

[0061] S334. Divide the merged grid cells into multiple sub-grid cells, wherein the number of sub-grid cells is smaller than the number of grid cells before merging.

[0062] After merging mesh cells in step S333 above, irregular polygonal mesh cells may be formed, which are not conducive to analysis and calculation. Therefore, they need to be divided to be suitable for subsequent numerical calculations. Therefore, as a preferred embodiment, step S334 specifically involves:

[0063] The multiple sub-mesh units are triangular sub-mesh units and / or quadrilateral sub-mesh units. When dividing the merged mesh unit into multiple sub-mesh units, quadrilateral sub-mesh units are preferred.

[0064] like Figure 6 As shown, when multiple mesh cells are merged into a mesh cell as indicated by the solid line, it needs to be divided into triangular sub-mesh and / or quadrilateral sub-mesh, as shown in the following method. Figure 6 As shown by the dashed line. Besides this, other division methods include... Figure 7 As shown by the dashed line. Since the change values ​​of the merged adjacent grid cells are all less than the preset threshold, therefore... Figure 6 , Figure 7 The differences in calculation results caused by other different partitioning methods can be ignored.

[0065] As a further preferred embodiment, step S332 specifically includes:

[0066] S3321. When the change value is greater than the preset threshold T, determine the threshold range corresponding to the change value;

[0067] S3322. Divide the grid cells according to the division ratio corresponding to the threshold interval;

[0068] In actual implementation, the numerical range [T, +∞) exceeding a preset threshold can be divided into three intervals: [T, T1), [T1, T2), and [T2, +∞), with division ratios of 3, 4, and 6, respectively. These ratios represent the number of grid cells after each division, as shown below. Figures 8-10 As shown; the corresponding segmentation ratio can also be set according to the thresholds T1 and T2, and the value of the threshold interval is positively correlated with the segmentation ratio.

[0069] As a further preferred embodiment, step S2 specifically includes:

[0070] S2. Acquire infrared image data of the object under test at least two time points from the first time point to the second time point, interpolate the infrared image data of the object at the first time point to obtain infrared image data of multiple time points, and input them into the three-dimensional finite element analysis model to obtain the first stress field characteristics.

[0071] In a specific implementation, infrared image data of the object under test should be acquired at least at two time points, namely the first time point and the second time point. Alternatively, the acquisition of infrared image data can be added at some time points between the first and second time points, but this will correspondingly increase the amount of data processing or the cost of the acquisition equipment. Therefore, infrared image data at multiple time points between the first and second time points can also be generated by data interpolation. The specific interpolation method is not limited, and linear interpolation or nonlinear interpolation based on the temperature conduction model can be used. The former generates data faster, while the latter generates more accurate data. The appropriate interpolation method can be selected according to actual needs.

[0072] Since the mesh nodes in the second and third three-dimensional finite element analysis models are different, as a preferred embodiment, step S4 specifically includes:

[0073] A merged mesh node is generated based on the mesh nodes of the second and third 3D finite element analysis models; the merged mesh node includes all mesh nodes of the second and third 3D finite element analysis models.

[0074] Based on the correspondence between the first stress field characteristics and the mesh nodes of the second three-dimensional finite element analysis model, the first stress field characteristics corresponding to the merged mesh nodes are updated; that is, interpolation is performed to supplement the first stress field characteristic data corresponding to mesh nodes that are not in the second three-dimensional finite element analysis model among all merged mesh nodes. Since this data is interpolated and not calculated by increasing the mesh density, no additional stress singularity data is introduced.

[0075] Similarly, based on the correspondence between the second stress field characteristics and the mesh nodes of the third three-dimensional finite element analysis model, the second stress field characteristics corresponding to the mesh nodes are updated and merged.

[0076] The third stress field characteristic data is obtained by superimposing the first and second stress field characteristics. When the stress corresponding to a grid node in the third stress field characteristic data exceeds a set stress threshold, this data may indicate a problem with the quality of the welded workpiece.

[0077] Reference Figure 2 The second specific embodiment of this application provides a method for collecting quality monitoring data, including the following steps:

[0078] S1. Obtain the first three-dimensional scanning data of the object under test at the first time and the second three-dimensional scanning data of the object under test at the second time, and establish the first three-dimensional finite element analysis model based on the second three-dimensional scanning data;

[0079] The first-time 3D scan data of the test object specifically refers to the 3D scan data of the test object (i.e., the welded workpiece) at the moment of welding completion; the second-time 3D scan data of the test object specifically refers to the 3D scan data of the test object after cooling and shaping. The basic model used for calculation is established based on the 3D scan data after cooling and shaping. The 3D scan data of the welded workpiece after cooling and shaping may differ from that of a standard workpiece. That is, the surface of some parts of the welded workpiece may be a plane with a certain degree of curvature due to cooling deformation. A typical modeling method is to pre-generate a uniform triangular mesh and then project it onto the surface of the welded workpiece to generate a triangular mesh model.

[0080] S2. Acquire infrared image data of the object under test at least two time points from the first time point to the second time point. Based on the infrared image data of the at least two time points, interpolate to obtain infrared image data of multiple time points, and input them into the three-dimensional finite element analysis model to obtain the first stress field characteristics. The first stress field characteristics reflect the influence of temperature change on the stress distribution of the welded workpiece during the cooling process.

[0081] In a specific implementation, infrared image data of the object under test should be acquired at least at two time points, namely the first time point and the second time point. Alternatively, the acquisition of infrared image data can be added at some time points between the first and second time points, but this will correspondingly increase the amount of data processing or the cost of the acquisition equipment. Therefore, infrared image data at multiple time points between the first and second time points can also be generated by data interpolation. The specific interpolation method is not limited, and linear interpolation or nonlinear interpolation based on the temperature conduction model can be used. The former generates data faster, while the latter generates more accurate data. The appropriate interpolation method can be selected according to actual needs.

[0082] S3. Based on the first and second three-dimensional scanning data, adjust the mesh nodes in the three-dimensional finite element analysis model to obtain the third three-dimensional finite element analysis model. Input the first three-dimensional scanning data into the third three-dimensional finite element analysis model to obtain the second stress field characteristics. The second stress field characteristics reflect the influence of the deformation of the welded workpiece before and after cooling on the stress distribution.

[0083] The first and second three-dimensional scanning data are the corresponding data of the welded workpiece before and after cooling, respectively. Therefore, the deformation of the welded workpiece can be reflected by the two data. The stress caused by the larger deformation is greater. In particular, cracks may be generated inside the larger deformation. The stress transmission is often discontinuous here. Therefore, conventional finite element analysis models often cannot calculate the real data.

[0084] Finite element analysis software, such as ANSYS, typically provides error estimation and adaptive meshing functions to reduce errors introduced by mesh generation. This is achieved using the predefined macro ADAPT.MAC to reduce errors, for example, by avoiding excessively high mesh density near concentrated load regions and boundary constraints, which could lead to stress concentration in the analysis results. However, the adaptive meshing function still requires the user to manually select adaptive improvement regions in the initial mesh. Furthermore, the ADAPT process usually enlarges the mesh in areas of concentrated load regions and boundary constraints to eliminate certain stress singularities, which are typically larger than those in other regions, such as concentrated load regions.

[0085] In a specific embodiment of this application, since the influence of stress on temperature conduction and the influence on deformation stress conduction are inconsistent at the point of open weld or crack, it is necessary to increase the mesh density in the area with large deformation in order to capture stress singularities. When the welded workpiece is externally intact but may have internal cracks, the influence of temperature conduction and the influence on deformation stress conduction are calculated separately by finite element analysis using the three-dimensional data of the workpiece surface obtained by scanning, thereby discovering possible hidden internal cracks.

[0086] S4. Obtain the third stress field characteristic data based on the characteristics of the first and second stress fields;

[0087] When calculating the residual stress of a welded workpiece, it is often necessary to consider whether it is free deformation or deformation under constraint. If welding is under constraint, bending or torsional deformation may not occur. In this case, the stress is not released and is concentrated internally. In the finite element model, this is reflected as a partial stress increase when the first and second stress field characteristics are superimposed. The data here may reflect the presence of a stress concentration point nearby. If it is free deformation, the stress acts on the workpiece to produce external deformation, thereby releasing some of the stress. In the finite element model, this is reflected as a partial stress cancellation when the first and second stress field characteristics are superimposed.

[0088] As a further preferred embodiment, step S2 specifically includes:

[0089] S21. Acquire infrared image data of the object under test at least two time points from the first time point to the second time point, and obtain infrared image data of multiple time points by interpolation based on the infrared image data of the at least two time points.

[0090] S22. Based on the grid nodes, calculate the temperature fitting curve of each node in the time dimension;

[0091] Mesh nodes are the grid nodes established in the finite element model. Each mesh node corresponds to a point in the infrared image data, and each point has corresponding temperature data. Since the temperature data corresponding to each mesh node changes continuously over time, the data can be interpolated based on the time-temperature curve to simulate the temperature change over time at each mesh node, which can then be used for subsequent calculations. Figure 11 As shown, each point in the infrared image has corresponding temperature data. The temperatures corresponding to the first time t1 and the second time t2 for each point are Ti1 and Ti2, respectively. Since the temperature difference between the welded workpiece and the ambient temperature is large when the temperature is high, the heat dissipation efficiency is higher. Temperature changes are usually not linear. Therefore, nonlinear interpolation methods and nonlinear fitting methods are commonly used to fit the temperature curve, such as the most basic least squares method.

[0092] Theoretically, since temperature changes may cause deformation, the points corresponding to the mesh nodes may also experience displacement. Ignoring the displacement of mesh nodes would introduce calculation errors. However, in practice, firstly, the high thermal conductivity of welded metal workpieces in engineering construction means that the influence of welds on temperature conduction can be ignored. Secondly, the displacement in actual welding is usually not large, and the effect of deformation is calculated independently in subsequent step S3. Therefore, the error in the actual displacement of mesh nodes can be ignored. Furthermore, the above-mentioned defects are compensated for by adjusting the mesh node density established in the finite element model.

[0093] S23. Calculate the integral of the temperature change rate difference between each two adjacent nodes per unit time based on the three-dimensional finite element analysis model, and calculate the directional characteristics of the first stress field.

[0094] like Figure 12 As shown, suppose there are two adjacent grid nodes A and B. During the first time interval [t1, t2] from the first time interval t1 to the second time interval t2, ... m The temperature change rate at node A is greater. Since both are cooling processes, the contraction at point A is greater than that at point B, and the stress direction is from B to A; after a certain period of time [t m The temperature change rate at node B is greater, and the contraction at point B is greater than at point A, with the stress direction pointing from A to B. Therefore, from a macroscopic perspective, the final direction of the accumulated stress over each time period is determined by the integral of the difference in the temperature change rates between nodes A and B.

[0095] S24. Calculate the integral of the difference in temperature change rate per unit time between each two adjacent nodes based on the three-dimensional finite element analysis model, and calculate the stress change characteristics of the first stress field.

[0096] At the same time, due to the previous period of [t1,t] m The stress direction is from B to A, and after a certain period of time [t] m The stress direction [t2] is from A to B, which may cause stress cancellation. However, from a microscopic perspective, since there is interlayer stress in the workpiece in three-dimensional space, the model used can only reflect the surface condition based on the three-dimensional data of the workpiece surface. If solid elements are used for simulation, at least three layers of mesh in the thickness direction are needed to capture the stress gradient in the thickness direction, and the number of meshes will be very large. Therefore, simplifying it to a single layer of mesh on the workpiece surface will greatly reduce the number of meshes and improve the solution efficiency. However, the stress generated by interlayer slip needs to be considered. The change in stress direction over different time periods may lead to stress accumulation rather than stress cancellation at the microscopic level. Therefore, the three-dimensional finite element analysis models (first three-dimensional finite element analysis model, second three-dimensional finite element analysis model, and third three-dimensional finite element analysis model) of the specific embodiments of this application are all single-layer mesh-based models based on the three-dimensional data of the workpiece surface. Therefore, in step S24, it is necessary to calculate the integral of the difference in the unit time temperature change rate between each two adjacent nodes. The difference in the unit time temperature change rate between each two adjacent nodes is positively correlated with the absolute value of the difference in the unit time temperature change rate between each two adjacent nodes, thereby obtaining the stress accumulation brought about at the microscopic level under extreme conditions.

[0097] As a further preferred embodiment, step S22 specifically includes:

[0098] S221. Based on the grid nodes, calculate the temperature fitting curve of each node in the time dimension;

[0099] The mesh nodes here are the initial mesh nodes, that is, the mesh nodes established in the first three-dimensional finite element analysis model;

[0100] S222. Calculate the temperature change rate per unit time between each pair of adjacent nodes, and calculate the absolute value of the difference in temperature change rate per unit time. When the mean M of the absolute value of the difference in temperature change rate per unit time between two adjacent nodes is within the corresponding change rate threshold range, add nodes to the mesh corresponding to the two adjacent nodes to perform mesh division or merging operations, and obtain the second three-dimensional finite element analysis model.

[0101] In actual implementation, the rate of change threshold interval can be divided into three intervals: [0, M1], (M1, M2), and [M2, +∞), with corresponding segmentation ratios of 3, 4, and 6, respectively. These represent the number of grid cells after each grid cell is segmented, as shown below. Figures 8-10 As shown; alternatively, the corresponding segmentation ratio can be set according to the threshold range, and the value corresponding to the threshold range is positively correlated with the segmentation ratio.

[0102] The absolute value of the difference in temperature change rate per unit time reflects the stress impact caused by temperature changes during cooling. If the average value is within a relatively small threshold range, it indicates that the temperature difference between two adjacent nodes is small, and the stress change can be ignored. Mesh merging can be used to reduce mesh density and computational load. If the average value is within a relatively large threshold range, it indicates that the temperature difference between two adjacent nodes is large, potentially leading to stress concentration. Mesh splitting to increase mesh density is necessary for analysis and to capture stress singularities. For nodes with a moderate threshold range, no change in mesh density is required. Figures 3-5 As shown, Figure 3 The image illustrates the residual stress generated when two components are welded together via a butt weld. However, since the two components are now welded as a single unit, the contraction displacement along the X and Y axes around the weld in this state is difficult to represent using 3D scanning data. Temperature changes at the mesh nodes, however, can reflect this. Figure X Stress in the Y-axis direction, therefore for example Figure 4 The grid cells are divided or merged, as shown in the following figure. Figure 5 As shown.

[0103] S223. Calculate the temperature fitting curve of the added node in the time dimension; for the newly added grid node, it is necessary to calculate and generate its corresponding temperature fitting curve.

[0104] As a further preferred embodiment, the three-dimensional finite element analysis model in steps S23 and S24 is a second three-dimensional finite element analysis model;

[0105] The first stress field direction characteristics and first stress field stress variation characteristics are calculated using the second three-dimensional finite element analysis model after updating the mesh nodes. The first stress field characteristics include the first stress field direction characteristics and the first stress field stress variation characteristics.

[0106] As a further preferred embodiment, step S222 specifically includes:

[0107] S2221. Calculate the rate of temperature change per unit time between any two adjacent nodes, and calculate the absolute value of the difference in the rate of temperature change per unit time.

[0108] S2222: When the mean absolute value of the difference in temperature change rate per unit time between two adjacent nodes is greater than the change rate threshold, add nodes to the grid corresponding to the two adjacent nodes to divide the grid.

[0109] S2223. When the mean absolute value of the difference in temperature change rate per unit time between two adjacent nodes is less than the change rate threshold, the meshes corresponding to the two adjacent nodes are merged to obtain the second three-dimensional finite element analysis model.

[0110] Since merging mesh cells may result in irregular polygonal mesh cells, which are not conducive to analysis and calculation, it is necessary to divide them to make them suitable for subsequent numerical calculations. Therefore, as a preferred implementation method, step S2223 specifically includes:

[0111] S2223. When the mean absolute value of the difference in temperature change rate per unit time between two adjacent nodes is less than the change rate threshold, the grids corresponding to the two adjacent nodes are merged, and the merged grid cells are divided into multiple sub-grid cells. The number of sub-grid cells is less than the number of grid cells before merging, thus obtaining the second three-dimensional finite element analysis model.

[0112] As a further preferred embodiment, in step S2223, the multiple sub-mesh units are triangular sub-mesh units and / or quadrilateral sub-mesh units, and when dividing the merged mesh unit into multiple sub-mesh units, it is preferred to divide it into quadrilateral sub-mesh units.

[0113] like Figure 6 As shown, when multiple mesh cells are merged into a mesh cell as indicated by the solid line, it needs to be divided into triangular sub-mesh and / or quadrilateral sub-mesh, as shown in the following method. Figure 6 As shown by the dashed line. Besides this, other division methods include... Figure 7 As shown by the dashed line. Since the change values ​​of the merged adjacent grid cells are all less than the preset threshold, therefore... Figure 6 , Figure 7 The differences in calculation results caused by other different partitioning methods can be ignored.

[0114] As a further preferred embodiment, step S3 specifically includes:

[0115] S31. Obtain the distribution characteristics of the deformed region based on the first three-dimensional scanning data and the second three-dimensional scanning data;

[0116] The second stress field characteristic reflects the influence of the deformation of the welded workpiece before and after cooling on the stress distribution. Therefore, the deformation region distribution characteristics are obtained by using the first and second three-dimensional scanning data as the basis for subsequent mesh adjustment.

[0117] like Figure 3 As shown, this illustrates the residual stress generated when two components are welded together with a butt weld. The shaded area represents the middle butt weld. The cooling and shrinkage of the weld causes the two components to tend to bend towards each other. Figure 3 As shown by the dashed line; and the closer to the center, the greater the tendency to bend. Figure 3 The arrow lengths are used to represent the corresponding components. However, since the two parts are now welded together, the shrinkage displacement along the XY axes around the weld in the diagram is difficult to represent using 3D scanning data. Instead, the shrinkage displacement along the Z-axis of the 3D Cartesian coordinate system can be represented by the deformation region distribution characteristics (i.e., the difference between the first and second 3D scanning data along the Z-axis). The shrinkage displacement along the XY axes is only visible at the edges, but the stress at the edges is often small and can be ignored. When the welded workpiece has a complex shape, the deformation region distribution characteristics are the set of differences between the first and second 3D scanning data along the normal direction of the corresponding scanning point. The principle is the same as the calculation of the difference along the Z-axis of the 3D Cartesian coordinate system.

[0118] S32. Based on the distribution characteristics of the deformation region, adjust the mesh nodes in the corresponding first three-dimensional finite element analysis model to obtain the third three-dimensional finite element analysis model;

[0119] S33. Input the first three-dimensional scanning data into the third three-dimensional finite element analysis model to obtain the second stress field characteristics.

[0120] As a further preferred embodiment, step S33 specifically includes:

[0121] S331. Calculate the change value of the corresponding grid cell in the model based on the distribution characteristics of the deformation region;

[0122] The change in mesh element values ​​reflects the changes in mesh elements before and after the welded workpiece cools. For example, if the welded part shrinks after cooling, the mesh position corresponding to the shrunken part will shift more significantly compared to its position before cooling. Specific mesh element change values ​​can be the average of the differences in position between nodes on the mesh before and after cooling, or the difference in position between the mesh center (e.g., the centroid of a triangular mesh) before and after cooling; anything that reflects the change in mesh element position before and after cooling is acceptable.

[0123] S332. When the change value is greater than a preset threshold, divide the corresponding grid cell;

[0124] When the change value exceeds the preset threshold, it indicates that significant stress may be generated at this location and within the corresponding workpiece. In this case, the mesh density needs to be increased to identify stress singularities in the acquired data. For example... Figure 4 , 5 As shown, the middle part corresponds to Figure 3 The shaded area shows the location of the weld.

[0125] As a further preferred embodiment, step S33 specifically includes:

[0126] S333. When the change value is less than the preset threshold, traverse the adjacent grid cells of the corresponding grid cell. If there is an adjacent grid cell whose change value is less than the preset threshold, merge the corresponding grid cell with the adjacent grid cell.

[0127] When the variation values ​​of adjacent mesh elements are all less than a preset threshold, the mesh elements can be merged to reduce the computational load in finite element analysis and improve computational speed. The effect of merging corresponding mesh elements is shown in the following diagram. Figure 5 As shown, its left and right ends correspond Figure 3 The shaded area refers to the location on both sides of the weld. Note that steps S2 and S3 both use [this method / method / technique]. Figure 4 and Figure 5 The principle is explained, but since the effects of temperature change and deformation change on stress are not the same, steps S2 and S3 are based on the same principle. Figure 4 The actual results of splitting and merging operations will not produce the same outcome. Figure 5 The results are shown.

[0128] As a further preferred embodiment, step S33 specifically includes:

[0129] S334. Divide the merged grid cells into multiple sub-grid cells, wherein the number of sub-grid cells is smaller than the number of grid cells before merging.

[0130] After merging mesh cells in step S333 above, irregular polygonal mesh cells may be formed, which are not conducive to analysis and calculation. Therefore, they need to be divided to be suitable for subsequent numerical calculations. Therefore, as a preferred embodiment, step S334 specifically involves:

[0131] The multiple sub-mesh units are triangular sub-mesh units and / or quadrilateral sub-mesh units. When dividing the merged mesh unit into multiple sub-mesh units, quadrilateral sub-mesh units are preferred.

[0132] like Figure 6 As shown, when multiple mesh cells are merged into a mesh cell as indicated by the solid line, it needs to be divided into triangular sub-mesh and / or quadrilateral sub-mesh, as shown in the following method. Figure 6 As shown by the dashed line. Besides this, other division methods include... Figure 7 As shown by the dashed line. Since the change values ​​of the merged adjacent grid cells are all less than the preset threshold, therefore... Figure 6 , Figure 7 The differences in calculation results caused by other different partitioning methods can be ignored.

[0133] As a further preferred embodiment, step S332 specifically includes:

[0134] S3321. When the change value is greater than the preset threshold T, determine the threshold interval corresponding to the change value; S3322. Divide the grid cells according to the division ratio corresponding to the threshold interval;

[0135] In actual implementation, the numerical range [T, +∞) greater than the preset threshold can be divided into three intervals [T, T1), [T1, T2), and [T2, +∞), with division ratios of 2, 4, and 6, respectively, as shown in the figure. Alternatively, the corresponding division ratio can be set according to the thresholds T1 and T2, and the numerical value corresponding to the threshold interval is positively correlated with the division ratio.

[0136] Since the mesh nodes in the second and third three-dimensional finite element analysis models are different, as a preferred embodiment, step S4 specifically includes:

[0137] A merged mesh node is generated based on the mesh nodes of the second and third 3D finite element analysis models; the merged mesh node includes all mesh nodes of the second and third 3D finite element analysis models.

[0138] Based on the correspondence between the first stress field characteristics and the mesh nodes of the second three-dimensional finite element analysis model, the first stress field characteristics corresponding to the merged mesh nodes are updated; that is, interpolation is performed to supplement the first stress field characteristic data corresponding to mesh nodes that are not in the second three-dimensional finite element analysis model among all merged mesh nodes. Since this data is interpolated and not calculated by increasing the mesh density, no additional stress singularity data is introduced.

[0139] Similarly, based on the correspondence between the second stress field characteristics and the mesh nodes of the third three-dimensional finite element analysis model, the second stress field characteristics corresponding to the mesh nodes are updated and merged.

[0140] The third stress field characteristic data is obtained by superimposing the first and second stress field characteristics. When the stress corresponding to a grid node in the third stress field characteristic data exceeds a set stress threshold, this data may indicate a problem with the quality of the welded workpiece.

[0141] Reference Figure 13 The third embodiment of this application provides a quality monitoring data acquisition device, which corresponds to the image processing-based quality monitoring method provided in the first and second embodiments described above. The device includes:

[0142] Image data acquisition devices 11 and 12 are used to acquire first three-dimensional scan data of the object under test 60 at a first time and second three-dimensional scan data of the object under test 60 at a second time.

[0143] Infrared data acquisition devices 21 and 22 are used to acquire infrared image data of the object under test 60 at at least two time points from the first time to the second time period;

[0144] Data generation device 30, for

[0145] A first three-dimensional finite element analysis model was established based on the second three-dimensional scanning data;

[0146] Infrared image data of the object under test at least two time points from the first time to the second time period are input into the three-dimensional finite element analysis model to obtain the first stress field characteristics;

[0147] Based on the first and second three-dimensional scanning data, the mesh nodes in the three-dimensional finite element analysis model are adjusted to obtain the third three-dimensional finite element analysis model. The first three-dimensional scanning data is then input into the third three-dimensional finite element analysis model to obtain the second stress field characteristics.

[0148] The third stress field characteristic data are obtained based on the characteristics of the first and second stress fields.

[0149] like Figure 13As shown, in a further preferred embodiment, the device further includes a test object conveying device 50. The image data acquisition device includes at least a first image data acquisition device 11 and a second image data acquisition device 12. The infrared data acquisition device includes at least a first infrared data acquisition device 21 and a second infrared data acquisition device 22. The first image data acquisition device 11 and the first infrared data acquisition device 21 are disposed at a first conveying point of the test object conveying device 50, and the second image data acquisition device 12 and the second infrared data acquisition device 22 are disposed at a second conveying point of the test object conveying device 50.

[0150] The first image data acquisition device and the first infrared data acquisition device are set at the first conveying point of the object under test conveying device to acquire the first three-dimensional scanning data and the first infrared image data of the welded workpiece at the first time when the welding is completed.

[0151] The welded workpiece is transported from the first conveying point to the second conveying point on the conveying equipment for a period of time and is cooled during this period. The second image data acquisition device and the second infrared data acquisition device are set at the second conveying point of the object to be tested conveying equipment to acquire the second three-dimensional scanning data and the second infrared image data of the welded workpiece after welding and cooling for a period of time at the second time.

[0152] The quality monitoring data acquisition device in the specific embodiment of this application does not require equipment interruption when acquiring data, and can continuously acquire data from batches of welded workpieces, resulting in high processing efficiency.

[0153] Further, as a preferred embodiment, a data generation device is used for

[0154] A first three-dimensional finite element analysis model was established based on the second three-dimensional scanning data;

[0155] Infrared image data at multiple time points are obtained by interpolation based on infrared image data at at least two time points, and then input into a three-dimensional finite element analysis model to obtain the first stress field characteristics;

[0156] Based on the first and second three-dimensional scanning data, the mesh nodes in the three-dimensional finite element analysis model are adjusted to obtain the third three-dimensional finite element analysis model. The first three-dimensional scanning data is then input into the third three-dimensional finite element analysis model to obtain the second stress field characteristics.

[0157] The third stress field characteristic data are obtained based on the characteristics of the first and second stress fields.

[0158] The above provides a detailed description of preferred embodiments of the present invention. However, it should be noted that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although the present application has been described in detail through the above embodiments, this application is not limited to the above embodiments. More other equivalent embodiments may be included without departing from the concept of this application, and the scope of this application is determined by the scope of the appended claims.

Claims

1. A method for collecting quality monitoring data, characterized in that, It includes the following steps: S1. Obtain the first three-dimensional scanning data of the object under test at the first time and the second three-dimensional scanning data of the object under test at the second time, and establish the first three-dimensional finite element analysis model based on the second three-dimensional scanning data; S21. Acquire infrared image data of the object under test at least two time points from the first time point to the second time point, and obtain infrared image data of multiple time points by interpolation based on the infrared image data of the at least two time points. S22. Based on the grid nodes, calculate the temperature fitting curve of each node in the time dimension; S23. Calculate the integral of the temperature change rate difference between each two adjacent nodes per unit time based on the three-dimensional finite element analysis model, and calculate the directional characteristics of the first stress field; S24. Based on the three-dimensional finite element analysis model, calculate the integral of the difference in temperature change rate per unit time between each pair of adjacent nodes, and calculate the stress change characteristics of the first stress field; S31. Obtain the distribution characteristics of the deformed region based on the first three-dimensional scanning data and the second three-dimensional scanning data; S32. Based on the distribution characteristics of the deformation region, adjust the mesh nodes in the corresponding first three-dimensional finite element analysis model to obtain the third three-dimensional finite element analysis model; S33. Input the first three-dimensional scanning data into the third three-dimensional finite element analysis model to obtain the second stress field characteristics. S4. Generate merged mesh nodes based on the mesh nodes of the second three-dimensional finite element analysis model and the mesh nodes of the third three-dimensional finite element analysis model; The merged mesh nodes include all mesh nodes of the second 3D finite element analysis model and the mesh nodes of the third 3D finite element analysis model; Based on the correspondence between the first stress field characteristics and the mesh nodes of the second three-dimensional finite element analysis model, update the first stress field characteristics corresponding to the merged mesh nodes. Based on the correspondence between the second stress field characteristics and the mesh nodes of the third three-dimensional finite element analysis model, the second stress field characteristics corresponding to the mesh nodes are updated and merged. The third stress field characteristic data is obtained by superimposing the first stress field characteristics and the second stress field characteristics.

2. The quality monitoring data acquisition method according to claim 1, characterized in that: Step S33 specifically involves: S331. Calculate the change value of the corresponding grid cell in the model based on the distribution characteristics of the deformation region; S332. When the change value is greater than the preset threshold, the corresponding grid cell is divided.

3. The quality monitoring data acquisition method according to claim 2, characterized in that: Step S33 specifically also includes: S333. When the change value is less than the preset threshold, traverse the adjacent grid cells of the corresponding grid cell. If there is an adjacent grid cell whose change value is less than the preset threshold, merge the corresponding grid cell with the adjacent grid cell.

4. The quality monitoring data acquisition method according to claim 3, characterized in that: Step S33 specifically also includes: S334. Divide the merged grid cells into multiple sub-grid cells, wherein the number of sub-grid cells is smaller than the number of grid cells before merging.

5. The quality monitoring data acquisition method according to claim 4, characterized in that: Step S334 specifically involves: The multiple sub-mesh units are triangular sub-mesh units and / or quadrilateral sub-mesh units. When dividing the merged mesh unit into multiple sub-mesh units, quadrilateral sub-mesh units are preferred.

6. The quality monitoring data acquisition method according to claim 2, characterized in that: The specific steps of S332 are as follows: S3321. When the change value is greater than a preset threshold, determine the threshold range corresponding to the change value; S3322. Divide the grid cells according to the division ratio corresponding to the threshold interval.

7. A quality monitoring data acquisition device, characterized in that, include: An image data acquisition device is used to acquire first three-dimensional scan data of the object under test at a first time and second three-dimensional scan data of the object under test at a second time. Infrared data acquisition equipment is used to acquire infrared image data of the object under test at least two time points between a first time and a second time. Data generation equipment, used for A first three-dimensional finite element analysis model was established based on the second three-dimensional scanning data; Infrared image data at multiple time points are obtained by interpolation based on infrared image data at at least two time points; Based on the grid nodes, calculate the temperature fitting curve for each node in the time dimension; The integral of the temperature change rate difference per unit time between each two adjacent nodes is calculated based on a three-dimensional finite element analysis model, and the directional characteristics of the first stress field are also calculated. The integral of the difference in temperature change rate per unit time between each two adjacent nodes is calculated based on a three-dimensional finite element analysis model, and the stress change characteristics of the first stress field are calculated. The distribution characteristics of the deformed region are obtained based on the first and second three-dimensional scan data; The third three-dimensional finite element analysis model is obtained by adjusting the mesh nodes in the first three-dimensional finite element analysis model based on the distribution characteristics of the deformation region. The first three-dimensional scan data is input into the third three-dimensional finite element analysis model to obtain the second stress field characteristics. A merged mesh node is generated based on the mesh nodes of the second three-dimensional finite element analysis model and the mesh nodes of the third three-dimensional finite element analysis model. The merged mesh nodes include all mesh nodes of the second 3D finite element analysis model and the mesh nodes of the third 3D finite element analysis model; Based on the correspondence between the first stress field characteristics and the mesh nodes of the second three-dimensional finite element analysis model, update the first stress field characteristics corresponding to the merged mesh nodes. Based on the correspondence between the second stress field characteristics and the mesh nodes of the third three-dimensional finite element analysis model, the second stress field characteristics corresponding to the mesh nodes are updated and merged. The third stress field characteristic data is obtained by superimposing the first stress field characteristics and the second stress field characteristics.

8. A quality monitoring data acquisition device according to claim 7, characterized in that, It also includes a device for conveying the object under test. The image data acquisition device includes at least a first image data acquisition device and a second image data acquisition device. The infrared data acquisition device includes at least a first infrared data acquisition device and a second infrared data acquisition device. The first image data acquisition device and the first infrared data acquisition device are located at a first conveying point of the device for conveying the object under test. The second image data acquisition device and the second infrared data acquisition device are located at a second conveying point of the device for conveying the object under test.

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