Tank wall welding deformation automatic modeling and strength analysis method and system

Abstract

The invention discloses a tank wall welding deformation automatic modeling and strength analysis method and system, and belongs to the technical field of large storage tank structure safety evaluation. According to the method, full-process automation from actual measurement deformation to safety evaluation is achieved through automatic modeling and full-process analysis, the precision and engineering applicability of large storage tank wall structure analysis are remarkably improved, and a reliable basis is provided for storage tank design and safety evaluation.

Description

Technical Field

[0001] This invention belongs to the field of digital design and safety assessment technology for large welded steel structures. Specifically, it relates to an automatic modeling and strength analysis method for welding deformation of storage tank walls, which is particularly suitable for rapid geometric reconstruction of the initial irregular deformation of the tank walls caused by welding manufacturing in large vertical storage tanks and quantitative analysis of its impact on the structural service safety performance. Background Technology

[0002] In the safety assessment of large welded storage tanks, traditional methods rely on ideal geometric models, neglecting the actual initial deformation caused by welding during manufacturing. These irregular geometric defects can alter the local stiffness and stress distribution of the structure, affecting its mechanical response under service loads. Existing numerical simulations often struggle to integrate measured defect data, potentially leading to analyses that underestimate actual stress concentration and pose a risk of non-conservative approaches.

[0003] While high-precision 3D scanning technology makes it possible to obtain the true geometry of structures, there is still a lack of efficient and automated methods for converting measured point clouds into parametric models that can be used for finite element analysis. Current processes rely on manual processing, which is inefficient and inconsistent, hindering accurate safety assessments based on actual defect morphologies and impeding data correlation and lifecycle traceability during construction and operation. Therefore, an automated and systematic method is urgently needed to achieve a closed loop from measured deformation to quantitative safety assessment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an automatic modeling and strength analysis method, system, storage medium and equipment for welding deformation of storage tank walls, so as to overcome the defects of the prior art that the structural safety assessment is inaccurate due to ignoring the actual initial welding deformation, as well as the low efficiency of traditional manual modeling and the difficulty in realizing full life cycle data association.

[0005] The technical solution adopted by this invention to solve its technical problem is: an automatic modeling and strength analysis method for welding deformation of storage tank walls, comprising the following steps:

[0006] S1. Construct a parameterized tank wall geometric model containing initial welding deformation based on high-precision measured data;

[0007] S2. Automatically convert the parametric geometric model into a numerical calculation model that can be used for finite element analysis;

[0008] S3. Apply various preset service condition loads to the numerical calculation model and perform nonlinear finite element analysis.

[0009] S4. Extract and compare the mechanical responses of the deformable model and the ideal reference model under various working conditions;

[0010] S5. Based on the comparison results, quantitatively evaluate the specific impact of initial welding deformation on the structural strength and safety margin of the storage tank wall.

[0011] Furthermore, step S1 specifically includes:

[0012] Three-dimensional point cloud data of the tank wall surface is acquired using laser scanning or UAV photogrammetry technology; the point cloud data is preprocessed, including noise filtering, coordinate system normalization and data normalization; based on the preprocessed data, a parametric surface reconstruction algorithm is used to automatically reconstruct a geometric surface model of the tank wall that reflects irregular deformation features such as wavy and concave shapes caused by welding.

[0013] Furthermore, the parametric surface reconstruction algorithm employs non-uniform rational B-spline surface fitting technology and introduces the minimum bending energy criterion as an optimization constraint during the fitting process to ensure that the reconstructed surface maintains physically reasonable smoothness while conforming to the measured data, effectively suppressing the interference of measurement noise.

[0014] Furthermore, step S2 specifically includes:

[0015] Based on the reconstructed geometric surface, a structured quadrilateral mesh is automatically generated within the parameter domain of the surface according to the analysis accuracy requirements. The parameter coordinates of the mesh nodes are mapped to three-dimensional space to generate a shell element mesh that precisely fits the deformed surface. The shell elements are then assigned the mechanical properties of the tank wall material, thus completing the construction of the finite element sub-model of the tank wall containing the initial welding deformation.

[0016] Furthermore, step S2 also includes overall structural assembly: automatically assembling the finite element sub-model of the tank wall with the ideal geometric component models such as the tank wall, reinforcing angle steel, and reinforcing ring from the design data, and achieving mechanical connection through node merging or defining binding constraints to generate a complete three-dimensional finite element model of the storage tank.

[0017] Furthermore, the various preset service conditions mentioned in step S3 include at least two or more of the following: design internal pressure condition, extreme wind load condition, seismic load condition, and uneven foundation settlement condition.

[0018] Furthermore, step S4 specifically includes:

[0019] Extract equivalent stress cloud maps, displacement cloud maps, and stress / displacement distribution data along preset paths (such as vertical and circumferential) for both the deformed model and the ideal reference model under various working conditions; calculate and compare the differences between the two in key indicators, including the maximum equivalent stress value, the maximum displacement value, and the range and amplitude of the stress concentration area.

[0020] Furthermore, step S5 specifically includes:

[0021] Based on the comparative data from step S4, the stress amplification factor and displacement amplification factor caused by welding deformation are calculated; combined with the allowable stress of the material and the allowable deformation in the specification, the safety margin of the structure under the current deformation state is assessed; high-stress areas that have become potential risks due to initial deformation are identified and located, providing a basis for targeted inspection and maintenance.

[0022] Furthermore, the method also includes step S6: automatically generating a structural safety assessment report. The report integrates and displays measured deformation morphology, analysis cloud maps for various working conditions, quantitative comparison charts, safety margin assessment conclusions, and maintenance recommendations.

[0023] In addition, the present invention also provides an automatic modeling and strength analysis system for welding deformation of storage tank walls, comprising:

[0024] The data acquisition and processing module is used to acquire and preprocess the three-dimensional point cloud data of the tank wall;

[0025] The Deformation Geometry Reconstruction and Meshing Module is used to automatically reconstruct parametric deformable surfaces and generate finite element meshes based on point cloud data.

[0026] The overall structural assembly module is used to integrate the tank wall sub-model with other components to construct a complete finite element model;

[0027] The multi-condition mechanical analysis module is used to configure loads and boundary conditions and perform nonlinear finite element calculations.

[0028] The safety energy assessment module is used to compare and analyze model responses, quantify the impact of deformation, and generate reports.

[0029] In addition, the present invention also provides a computer-readable storage medium storing a computer program adapted to be loaded by a processor and to execute the steps of the automatic modeling and strength analysis method for welding deformation of tank walls as described above.

[0030] In addition, the present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the steps of the automatic modeling and strength analysis method for welding deformation of storage tank walls as described above by calling the computer program stored in the memory.

[0031] The automatic modeling and strength analysis method and system for welding deformation of storage tank walls, as described in this invention, has the following beneficial effects: This invention establishes an automated, closed-loop workflow from measured data to safety assessment. For the first time, it systematically and directly and accurately integrates specific, measured initial welding deformation geometry into finite element analysis, achieving a quantitative assessment of the impact of "real defects" and significantly improving the accuracy and reliability of strength analysis and safety assessment of large storage tanks. Simultaneously, the digital model generated by this method, containing the actual deformation state, provides a precise digital foundation for state tracking, performance evolution analysis, and predictive maintenance throughout the entire life cycle of the storage tank, strongly supporting digital operation and maintenance and integrity management. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 This is a schematic diagram of the process for constructing a deformable wall panel provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the automatic modeling process for the overall finite element model of the tank wall structure provided in this embodiment of the invention; Detailed Implementation

[0035] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the invention are now described in detail with reference to the accompanying drawings. In the following description, it should be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements or an interaction between two elements. When an element is referred to as being "on" or "below" another element, the element can be located "directly" or "indirectly" on the other element, or there may be one or more intermediary elements. The terms "first," "second," and "third," etc., are used only for the convenience of describing the technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," and "third," etc., may explicitly or implicitly include one or more of that feature. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0036] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0037] An automatic modeling and strength analysis method for welding deformation of storage tank walls is proposed, the first step of which is to deploy a three-dimensional data acquisition system. In practice, a stationary ground-based three-dimensional laser scanner or an airborne lidar system from an unmanned aerial vehicle can be used to perform a full-coverage scan of the outer surface of the storage tank wall to be evaluated.

[0038] Before scanning, measurement planning is required. Typically, horizontal measurement zones are divided at fixed intervals along the height of the tank, and within each measurement zone, a 360-degree circumferential scanning path is planned to ensure that the point cloud data has sufficient density in both the circumferential and vertical directions to capture local wave deformation caused by welding.

[0039] Perform a scan to acquire raw point cloud data. Import the data into preprocessing software for initial noise removal and manual or semi-automatic segmentation of point clouds containing irrelevant objects, preserving the clean point cloud of the tank wall surface.

[0040] Establish a coordinate system for analysis. Typically, a global Cartesian coordinate system is established with the theoretical central axis of the tank as the Z-axis and the theoretical reference plane of the tank bottom as the XY plane. Using known reference points on the tank body or by fitting a cylindrical surface to the point cloud, all tank wall point cloud data are transformed to this unified coordinate system.

[0041] Point cloud data normalization processing is performed. The transformed point cloud is grouped according to pre-divided measurement zones. Within each measurement zone, the points are sorted according to their circumferential angles, and a regular sequence of 3D coordinate points is generated at fixed angular intervals using an interpolation algorithm, providing an ordered data foundation for subsequent surface reconstruction.

[0042] Core Step: Parametric Surface Reconstruction. Develop or utilize a script to read the normalized point cloud data. The algorithm treats the tank wall surface as a single-valued function of radial displacement R in a two-dimensional parametric domain of height Z and circumferential angle θ. A smooth surface model passing through or approximating these data points is constructed using a non-uniform rational B-spline surface fitting technique.

[0043] In the surface fitting process, "minimum bending energy" is introduced as one of the optimization objectives. This constraint ensures that the reconstructed surface conforms to the measured data while its curvature changes as smoothly as possible. This conforms to the physical law of deformation of thin plates under welding residual stress and can effectively suppress unreasonable and drastic fluctuations caused by data noise.

[0044] Based on the reconstructed NURBS surface, finite element meshes are automatically generated. Within the surface's parameter domain (Z, θ), a structured quadrilateral mesh is created at a user-specified density. Subsequently, the parametric coordinates of each mesh node are mapped back to three-dimensional space using the surface equations to obtain its precise three-dimensional coordinates, thereby generating a surface shell mesh that perfectly matches the measured deformation geometry.

[0045] The generated curved shell mesh is exported as a generic INP format and imported into the finite element analysis software ABAQUS. In the finite element software, actual material properties are assigned to the shell elements, including elastic modulus, Poisson's ratio, density, and plastic constitutive relations, thus completing the construction of the finite element sub-model of the tank wall including initial welding deformation.

[0046] Overall structural assembly. Ideal geometric information and their connection relationships with the tank wall are obtained from the tank design model for components such as the tank top, tank bottom, wind-resistant ring, and reinforcing ring. Using coordinate matching and contact search algorithms, the deformable tank wall sub-model is automatically aligned and assembled with other components.

[0047] At the assembly interface, node merging is used to define binding constraints to achieve mechanical connections between components. For bolted connections and similar situations, these can be simplified to coupling constraints or simulated using beam or rod elements to ensure effective load transfer and structural integrity.

[0048] Define the "design internal pressure condition". Apply a uniform normal pressure to the inner wall of the complete model, with the pressure value being the maximum allowable working pressure of the tank. Constrain all translational degrees of freedom (U1=U2=U3=0) at the bottom edge nodes of the model to simulate the fixed connection with the foundation.

[0049] Define the "extreme wind load case". Calculate the design wind pressure according to the load specifications, and decompose it into static pressure distribution acting on the outer surface of the tank wall and uplift pressure acting on the tank top. Apply these pressure loads to the corresponding surfaces of the model. Meanwhile, the constraints are the same as those for the design internal pressure case.

[0050] Define the "seismic load case". When using the response spectrum analysis method, apply seismic acceleration response spectra in three directions to the model base; when using the time history analysis method, input the seismic acceleration time history curve to the base. Under this load case, all translational degrees of freedom of the base nodes are constrained, but rotational degrees of freedom are released or set according to the actual foundation conditions.

[0051] Define the "uneven settlement condition". Based on the measured or assumed settlement mode (such as plane tilting, basin settlement), calculate the settlement displacement value at each node of the bottom ring plate of the tank, and apply it directly to the corresponding node as a forced displacement load, while constraining the remaining degrees of freedom.

[0052] Submit finite element calculations. For all defined load cases, submit nonlinear static analysis jobs separately. In the analysis step settings, enable the geometric nonlinearity option to account for large deformation effects. For seismic load cases, submit either a dynamic implicit or explicit analysis.

[0053] After the calculations are completed, the results are extracted and post-processed. The focus is on extracting the Mises equivalent stress contour map, principal stress contour map, and displacement contour map along the wall thickness of the tank wall. Simultaneously, for quantitative comparison, several vertical paths from the bottom to the top of the tank, as well as circumferential paths around the tank wall, need to be defined in the model.

[0054] Extract the distribution data of equivalent stress, first principal stress, and normal displacement along each path. This data will be used for point-by-point comparison with the results of a benchmark model based on ideal geometry under the same working conditions and along the same path.

[0055] Implement safety energy assessment. Calculate key indicators: (1) the ratio of the maximum equivalent stress value of the deformable model to the maximum equivalent stress value of the ideal model (stress amplification factor); (2) the ratio of the maximum displacement value of the deformable model to the maximum displacement value of the ideal model (displacement amplification factor); (3) identify the areas where the stress exceeds the material yield strength or the allowable stress specified in the standard and their area proportion.

[0056] Based on the quantitative assessment results, a structural safety assessment conclusion is generated. For example, if the stress amplification factor is less than 1.1 under the main working conditions and no area exceeds the allowable stress, the existing welding deformation is considered to have an acceptable impact on structural safety; if the amplification factor is significant or there are areas exceeding the limit, it is determined to be risky, and the risk area is located.

[0057] This method can be extended to historical data comparison. By comparing the deformation patterns obtained from this analysis with the deformation patterns reconstructed from historical detection data, the changes in deformation in a specific area can be calculated, enabling the tracking of deformation evolution and trend prediction.

[0058] Finally, the system automatically generates a comprehensive analysis report containing the following: (1) a comparison of measured deformation cloud map and model; (2) stress / displacement cloud maps and comparisons under various working conditions; (3) a comparison of critical path data curves; (4) a quantitative evaluation index table; and (5) safety conclusions and maintenance recommendations. The report is output in electronic document form, completing the entire technical process from data to decision.

[0059] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method of automatic modeling and strength analysis of weld distortion in a tank shell, characterized by, The method comprises the following steps: S1, data acquisition and processing: obtaining dense three-dimensional point cloud data of the tank wall by a laser scanner or a UAV equipped with a photogrammetry system; dividing the tank wall into several measurement zones along the height direction, and uniformly arranging measurement points in each measurement zone along the ring direction to form a point cloud acquisition network of the system; cleaning and filtering the point cloud data to remove noise and abnormal points, establishing a coordinate system, and extracting the coordinates of each measurement point to construct a three-dimensional deformation dataset; S2, automatic reconstruction of deformation geometry: based on the three-dimensional deformation dataset, a point-line-surface topological relationship is constructed, a quadrilateral mesh is formed by connecting nodes using the minimum distance principle, and a surface fitting is performed using the minimum bending energy criterion while introducing topological continuity constraints to automatically reconstruct the tank wall shell element mesh model with initial irregular deformation and wavy undulating topography caused by welding; S3, parameterized assembly of overall structure: automatically identifying and connecting the nodes between the tank wall and the reinforcing angle steel and reinforcing ring based on parameterized design rules according to the structure design, automatically assembling the deformed tank wall with other structures to generate a complete three-dimensional finite element model of the tank; S4, multi-working-condition mechanical modeling and analysis: at least two service working conditions including design internal pressure, extreme wind load, seismic load and uneven foundation settlement are applied to the model; the extreme wind load working condition includes non-uniform ring pressure distribution calculated from wind pressure standard and wind-induced drag force generated on the tank wall accessories, and geometric nonlinear static and dynamic analysis is performed; S5, quantitative comparison and safety evaluation: comparing the stress, displacement and buckling response of the deformed model with the ideal model, calculating and comparing the maximum equivalent stress, stress concentration coefficient, maximum displacement and displacement distribution uniformity, and buckling safety coefficient of both models under the same working condition, quantitatively evaluating the specific influence of welding deformation on local stress concentration, overall stability and safety margin of the tank wall, and automatically generating a structure safety evaluation report including stress and displacement contour maps, dangerous area identification and comparison results with specification allowable values.

2. The method of claim 1, wherein, The method is applied to tank design optimization, which optimizes the plate thickness distribution, weld arrangement or reinforcement structure design of the tank wall by iteratively analyzing the influence of welding deformation under different design parameters to predict and control the deformation mode that is unfavorable to service safety at the manufacturing stage.

3. The method of claim 1, wherein, The method is applied to tank operation and maintenance based on digital twinning, specifically including: establishing a high-fidelity digital twin of the tank containing the initial deformation model; updating the geometric deformation state in the twin by periodically scanning the latest point cloud data of the tank wall, and using the updated twin for real-time or periodic reanalysis to realize dynamic evaluation and predictive maintenance of the structure safety state.

4. A system for automatic modeling and strength analysis of welding distortion of a tank shell wall, characterized by, The system for implementing the method of any one of claims 1-3 comprises: a data acquisition and processing module for acquiring and processing three-dimensional point cloud data of the tank wall, which includes a point cloud data cleaning and filtering submodule for removing measurement noise and abnormal points; a deformation geometry automatic reconstruction module for generating a tank wall finite element submodel containing welding deformation; The whole structure automatic assembly module is used for automatically identifying and connecting nodes between the tank wall, the tank top, the tank bottom, the reinforcing ring and the opening connecting pipe based on the parameterized design rules, and integrating to form a complete finite element model. The multi-working condition mechanical analysis module is used for configuring the load and the boundary condition and performing the finite element calculation. The safety performance quantitative evaluation module is used for comparative analysis of the model response, and outputs the evaluation report including the stress nephogram, the displacement nephogram, the dangerous area identification and the comparison result with the specification allowable value. The historical data comparison module can compare the current analysis deformation and stress state with the previous historical detection and analysis results in different periods, and realizes the trend analysis and prediction of the storage tank wall structure performance degradation.

5. The system of claim 4, wherein, The system is integrated in a data processing device, which includes an interface in data communication with a three-dimensional scanning device, for processing data on site or remotely and completing the automatic modeling and analysis process.

6. A method for tank wall safety assessment and maintenance decision support, characterized in that The modeling and analysis method is applied to obtain a quantitative safety evaluation report of a specific storage tank wall under a target working condition, and a decision-making scheme for detection, maintenance or reinforcement is made based on the report.

7. A computer readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to realize the method of any one of claims 1-3.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the method of any one of claims 1-3.

9. A computer program product comprising computer instructions, characterized in that, The computer program is executed by the processor to realize the method of any one of claims 1-3.

10. A data processing apparatus, characterized by, The computer program is executed by the processor to realize the method of any one of claims 1-3. The computer program is executed by the processor to realize the method of any one of claims 1-3. The system is integrated in a data processing device, which includes an interface in data communication with a three-dimensional scanning device, for processing data on site or remotely and completing the automatic modeling and analysis process.

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