Method for evaluating actual service state of coal gas holder based on laser point cloud surveying technology
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WISDRI ENG & RES INC LTD
- Filing Date
- 2023-03-07
- Publication Date
- 2026-06-02
Smart Images
Figure CN116127816B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building structure testing technology, and more specifically, relates to a method for evaluating the actual service status of a gas holder based on laser point cloud mapping technology. Background Technology
[0002] Gas holders typically employ a cylindrical steel frame structure, with internal piston plates and sealing rubber membranes to store the gas generated during metallurgical production. Gas safety is a key aspect of production safety control; an accident can disrupt the entire metallurgical production process, causing significant economic and property losses, and even casualties. Therefore, comprehensive and accurate methods for assessing actual service conditions are urgently needed to regularly inspect the gas holder structure, preventing shutdowns and production stoppages due to partial or overall structural failures, and eliminating the risk of gas leaks.
[0003] Surveying and mapping techniques such as theodolites, total stations, and video / audio recordings can quantitatively record changes in a specific area of a gas holder through point-to-point measurements. However, they cannot accurately assess the overall service status of the gas holder's structural system in a short period of time, requiring engineers to make judgments based on simplified models and experience. Furthermore, the routine maintenance plan for gas holders lacks scientific and systematic structural analysis guidance. Summary of the Invention
[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for assessing the actual service status of gas holders based on laser point cloud mapping technology. This method can provide a complete and quantitative description and assessment of the overall stress state and component deformation of the gas holder under actual service conditions. The assessment results can provide reliable solutions for the periodic maintenance and component repair and replacement of the gas holder.
[0005] To achieve the above objectives, this invention provides a method for assessing the actual service status of a gas holder based on laser point cloud mapping technology, comprising:
[0006] S1: Preprocess all laser point cloud data of the gas holder collected by the laser point cloud scanning equipment to remove redundant data such as human figures, debris, and natural landscapes that are not related to the gas holder system. Filter the data using the bilateral filtering method to remove outlier noise points caused by the acquisition equipment, actual site conditions, etc.
[0007] S2: Divide the pre-processed gas holder point cloud data into subsystems according to the structural system;
[0008] S3: Extract point cloud data at the component level from the main structural components of each subsystem. Component types include: structural columns, structural beams, structural supports, and structural slabs.
[0009] S4: Calculate the degree of deformation of structural components in each subsystem using component point cloud data;
[0010] S5: Using the extracted actual geometric shape and spatial positioning of the components, a finite element analysis model of the gas holder under actual deformation state is built.
[0011] S6: Calculate the overall modal state of the gas holder under actual deformation and the limit state stress under multiple working conditions using the finite element analysis model.
[0012] S7: Compare the finite element calculation results of the structural model under actual deformation with those of the original design model to evaluate the actual service status of the gas holder.
[0013] In some optional implementations, the preprocessing of all laser point cloud data of the gas holder acquired using a laser point cloud scanning device includes:
[0014] Interference data is removed from all laser point cloud data, including redundant point cloud data such as human figures, debris, and natural landscapes that are unrelated to the gas holder system, as well as outliers caused by acquisition equipment and actual site conditions. At the same time, the curvature, thin wall and other features of the gas holder structural system point cloud data are preserved, making it easy to identify structural objects.
[0015] In some alternative implementations, step S2 includes:
[0016] The pre-processed gas holder point cloud data is selected by manual intervention and divided into structural subsystems according to the spatial occupancy of the components within the subsystem. The integrity of the component data of each subsystem should be ensured at the boundary of the divided subsystems. The divided subsystems include: top plate system, side plate system, bottom plate system and piston system.
[0017] In some alternative implementations, step S3 includes:
[0018] The extraction of point cloud data for structural columns, structural beams and structural supports includes: based on the initially specified spatial range, reference end face and axial direction of the component, multiple cross-sectional slices are made of the component to determine the cross-sectional design parameters of the component. Through optimization, the final centroid of the end face, cross-sectional dimensions and axial direction of the component are determined, and all irrelevant data outside the geometric boundary range of the component are removed.
[0019] The extraction of point cloud data for the structural panels in the gas holder side panel system includes: based on the initially determined spatial range of the structural panels, performing circular fitting of the outermost and innermost contours of the point cloud data, determining the radius and center of the outermost and innermost circles, and identifying all points whose X and Y coordinates fall within the XY plane range of this circle as the total point cloud data of the side panels in the gas holder side panel system, and removing all irrelevant data outside the geometric boundary range of the components; and dividing the gas holder side panels into sections based on the dimensions and spatial positioning information in the design drawings to obtain the point cloud data of each spliced panel.
[0020] The extraction of point cloud data for the structural plates in the gas holder top plate system, bottom plate system, and piston system includes: based on the initially determined spatial range of the structural plates, performing circular fitting of the outermost contour; points whose X and Y coordinates are all within the XY plane of this circle are all point cloud data belonging to the gas holder top plate, bottom plate, and piston plate, and all irrelevant data outside the geometric boundary range of the components are removed; based on the dimensions and spatial positioning information in the design drawings, the structural plates are divided into sections to obtain the point cloud data of each spliced plate.
[0021] In some alternative implementations, step S4 includes:
[0022] For the deformation degree of structural columns, structural beams, and structural supports, the component axis is fitted by the centroid coordinates of the cross-sectional slices along the component axis direction to calculate the actual length of the component. The displacement and inclination rate of the component in the X, Y, and Z directions are calculated by the deviation value of the centroid coordinates of the other end section from the centroid coordinates of the reference end face. The maximum deflection of the component in the X, Y, and Z directions is calculated by the deviation value of the centroid coordinates of each cross-sectional slice of the component from the centroid coordinates of the reference end face. The local maximum bending value of each plate surface of the component is calculated by comparing the cross-sectional slices with the standard design section.
[0023] To determine the degree of deformation of the structural plate, a spatial surface fitting is performed on the selected reference plane. The minimum distance from other points on the structural plate to this spatial surface is calculated. The maximum value of this distance for all points on the structural plate minus the design thickness of the plate is the maximum deflection value of the structural plate.
[0024] In some alternative implementations, step S5 includes:
[0025] In the finite element analysis model, all structural components of the top plate system, side plate system, bottom plate system, and piston system are constructed. The component types and quantities, end face positioning coordinates, and geometric shapes are consistent with the results extracted from the laser point cloud data. The component materials, end face boundary condition settings, and coupling condition settings at the connection between two components are consistent with the original design finite element model. The boundary conditions can be estimated and set according to the degree of node stiffness degradation.
[0026] In some alternative implementations, step S6 includes:
[0027] Limit states include ultimate limit state of bearing capacity, serviceability limit state, and durability limit state, and stress calculations are performed using linear elastic analysis.
[0028] In some alternative implementations, step S7 includes:
[0029] The structural model under actual deformation is compared with the finite element calculation results of the original design model, including the overall modal period value and mode shape change of the structure, the stress value of the component under the most unfavorable state, and the maximum stress difference of the component under different working conditions. Then, combined with the results of the component's tilt, deflection, and bending, an actual service status assessment report of the gas holder structural system is given.
[0030] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:
[0031] This invention classifies and extracts component-level data from laser point cloud mapping data of gas holders collected on-site, and calculates and analyzes the deformation degree of the main structural components of the gas holder. By building a finite element model with actual deformation characteristics in finite element analysis software, it performs overall structural modal calculations and stress calculations under limit states to assess the actual service condition of the gas holder, including changes in the overall structural stress characteristics, component stress-strain states, and deformation. This allows for a complete and quantitative description and assessment of the overall stress state and component deformation under actual service conditions of the gas holder. The assessment results can provide reliable solutions for the periodic maintenance and replacement of components of the gas holder. Attached Figure Description
[0032] Figure 1 This is a flowchart of a gas holder service status assessment method provided by an embodiment of the present invention;
[0033] Figure 2 This is a schematic diagram of a gas holder structure system provided in an embodiment of the present invention. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0035] like Figure 1 As shown, this invention provides a method for assessing the service status of a gas holder based on laser point cloud mapping technology, comprising the following steps:
[0036] Step 1: Preprocess all laser point cloud data of the gas holder collected by the ground-type laser point cloud scanning equipment. Through manual intervention, redundant data such as human figures, debris, and natural landscapes that are irrelevant to the gas holder system are removed. The point cloud data is filtered as a whole by bilateral filtering to remove outliers caused by the acquisition equipment and actual site conditions, while retaining the curvature, thin wall and other characteristics of the point cloud data.
[0037] Step 2: The pre-processed gas holder point cloud data is manually divided into subsystems according to the structural system. The division of data for each subsystem is based on the spatial occupancy of its components. During data segmentation, the integrity of the component data within each subsystem should be ensured at the subsystem boundaries. For example... Figure 2 As shown, the subsystem includes a top plate system, side plate system, bottom plate system, and piston system. The component systems of each subsystem are as follows: the gas holder top plate system consists of a top beam, a top plate, a top ventilation cap, and a leveling bracket; the gas holder side plate system consists of columns, side plates, and wind-resistant trusses; the gas holder bottom plate system consists of a bottom plate; and the piston system consists of a piston plate, piston bracket, piston support, T-shaped baffle bracket, and lower T-shaped baffle bracket.
[0038] Step 3: Extract point cloud data at the component level from the main structural components of each subsystem. Component types include structural columns, structural beams, structural supports, and structural slabs. Within each subsystem, the main component types for the top slab system are: structural columns, structural beams, structural supports, and structural slabs; for the side slab system, they are: structural columns, structural supports, and structural slabs; for the bottom slab system, the main component type is structural slabs; and for the piston system, they are: structural columns, structural beams, structural supports, and structural slabs. The extraction steps for each type of component include:
[0039] (1) Extract point cloud data of structural columns, structural beams and structural supports: (a) Initially define the spatial range of the component and use bilateral filtering to initially filter out point cloud noise data that does not belong to the component; (b) Specify one end section of the component as the initial reference plane and obtain the initial axis normal of the component in the length direction; (c) Obtain the average value and root mean square error of the outer contour shape and size of the component through multiple cross-sectional slices in the length direction of the component, and compare it with the standard component library to confirm the design cross-sectional parameters of the component; (d) Using the minimum error of the geometric size and design parameters of the cross-sectional slices in the length direction of the axis as the optimization standard, adjust the reference plane and axis direction of the component end face to determine the final direction of the two end faces and axis of the component; (e) Using the determined centroid of the component end face, cross-sectional size and axis spatial direction, use a clustering algorithm to remove all irrelevant data outside the geometric boundary of the component.
[0040] (2) Extract point cloud data of structural panels in the gas holder side panel system: (a) Remove point cloud data of structural columns and structural supports from the point cloud data belonging to the side panel system; (b) Perform circular fitting of the outermost and innermost contours on the remaining data in the subsystem to determine the radius and center of the outermost and innermost circles. All points whose X and Y coordinates are within the XY plane range of the circle are the point cloud data of the side panel belonging to the gas holder side panel system. Remove all irrelevant data outside the geometric boundary range of the components; (c) Divide the gas holder side panel into sections according to the dimensions and spatial positioning information in the design drawings to obtain the point cloud data of each splicing plate.
[0041] (3) Extract point cloud data of structural plates in the gas holder top plate system, bottom plate system, and piston system: (a) Remove point cloud data of structural columns, structural beams, and structural supports from the point cloud data belonging to the top plate system, bottom plate system, and piston system; (b) Perform circular fitting of the outermost contour to determine the radius and center of the outermost circle. All points whose X and Y coordinates are within the XY plane of this circle are the point cloud data belonging to the structural plates. Remove all irrelevant data outside the geometric boundary of the components; (c) Divide the structural plates into sections according to the dimensions and spatial positioning information in the design drawings to obtain the point cloud data of each splicing plate.
[0042] Step 4: Using the component point cloud data, calculate the deformation degree of the main structural components extracted from each subsystem. The component types include: structural columns, structural beams, structural supports, and structural slabs. The steps for calculating the deformation degree of each type of component include:
[0043] (1) Calculation of deformation degree of structural columns, structural beams, and structural supports: (a) Select the end with the smaller Z-axis coordinate of the two ends of the member as the reference end face, and slice the member in the axial length direction. The number and spacing of the slices should be adjusted according to the sampling density. The interval between the slices should not be less than 5cm and not more than 30cm, and the number of slices should not be less than 8; (b) Connect the centroid coordinates of each slice of the member and fit the axis of the member. The axis fitting should sample the Bézier curve at least twice; (c) Calculate the actual length of the member based on the fitted axis; d) Calculate the displacement and inclination rate of the component in the X, Y, and Z directions based on the deviation between the centroid coordinates of the other end section and the centroid coordinates of the reference end face; (e) Calculate the maximum deflection of the component in the X, Y, and Z directions based on the deviation between the centroid coordinates of each section slice and the centroid coordinates of the reference end face; (f) Project each section slice onto the reference end face along the axial direction, align the centroids and correct the angles with the standard design section, project the section point cloud data onto the nearest edge of the standard design section, and determine the local maximum bending value of each plate surface of the component based on the projection distance.
[0044] (2) Calculation of the deformation degree of the structural plate: (a) For the structural plate in the gas holder side plate system, the plate surface located on the inner side of the gas holder is selected as the reference surface. For the structural plates in the gas holder top plate, bottom plate and piston system, the side with the larger Z-axis coordinate is selected as the reference surface. Spatial surface fitting is performed on the point cloud on the reference surface; (b) Calculate the minimum distance from other points on the plate to the spatial surface. The maximum value of the distance corresponding to all points on the plate minus the design thickness value of the plate is the maximum deflection value of the structural plate.
[0045] Step 5: Construct a finite element analysis model of the gas holder under actual deformation state using the extracted actual geometric shape and spatial positioning of the components. The components in the finite element analysis model include all components in the top plate system, side plate system, bottom plate system, and piston system that have undergone point cloud data processing. For the finite element model under actual deformation state, the component type and quantity, the end face positioning coordinates, and the geometric shape of the components are consistent with the results of the laser point cloud data extraction: this condition can be guaranteed by converting the component-level point cloud data processed in Step 4 into a triangular mesh and importing it into the finite element analysis software. The component material, the boundary condition settings of the end faces, and the coupling condition settings at the connection between two components can be consistent with the original design finite element model. The boundary conditions can be estimated and set according to the degree of nodal stiffness degradation.
[0046] Step 6: Utilize the constructed finite element analysis model to perform overall modal calculations of the gas holder and limit state stress calculations under multiple operating conditions. Limit states include the ultimate limit state of bearing capacity, the serviceability limit state, and the durability limit state, and linear elastic analysis is used for stress calculations.
[0047] Step 7: Compare the finite element calculation results of the structural model under actual deformation with those of the original design model to assess the actual service status of the gas holder. This includes the overall actual service status of the structure and the stress and strain levels of the components, including: the overall modal period value and mode shape changes of the structure, identifying regions and subsystems with significant mode shape changes; the stress values of the components under the most unfavorable conditions, comparing them with the standard design values, and calculating the percentage of the maximum stress value to the standard design value; calculating the maximum stress difference of the components under different working conditions, comparing it with the minimum stress value, and calculating the multiple relationship between the maximum stress difference and the minimum stress value. Based on the above analysis results, combined with the tilt, deflection, and bending results of various components, a report on the actual service status assessment of the gas holder structural system is provided.
[0048] This invention proposes a method for assessing the actual service status of gas holders based on laser point cloud mapping technology. The assessment results obtained by this method can provide a reliable solution for the periodic overall maintenance and component repair and replacement of gas holders, and have broad application prospects in the field of existing industrial building structure inspection.
[0049] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.
[0050] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for evaluating the actual service state of a gasholder based on laser point cloud mapping technology, characterized in that, include: S1: Preprocess all laser point cloud data collected from the gas holder, remove data that is irrelevant to the gas holder system, and filter the data to remove outliers and noise. S2: Divide the pre-processed gas holder point cloud data into subsystems according to the structural system; S3: Extract component-level point cloud data from the main structural components in each subsystem to obtain component point cloud data. The component types include: structural columns, structural beams, structural supports, and structural slabs. S4: Calculate the degree of deformation of structural components in each subsystem using component point cloud data; S5: Using the extracted actual geometric shape and spatial positioning of the components, a finite element analysis model of the gas holder under actual deformation state is built. S6: Utilize the finite element analysis model to perform overall modal calculations and limit state stress calculations under multiple working conditions in the actual deformation state of the gas holder; S7: Compare the finite element analysis model under actual deformation with the finite element calculation results of the original design model to evaluate the actual service status of the gas holder. Step S4 includes: For the deformation degree of structural columns, structural beams, and structural supports, the component axis is fitted by the centroid coordinates of the cross-sectional slices along the component axis direction to calculate the actual length of the component. The displacement and inclination rate of the component in the X, Y, and Z directions are calculated by the deviation value of the centroid coordinates of the other end section from the centroid coordinates of the reference end face. The maximum deflection of the component in the X, Y, and Z directions is calculated by the deviation value of the centroid coordinates of each cross-sectional slice of the component from the centroid coordinates of the reference end face. The local maximum bending value of each plate surface of the component is calculated by comparing the cross-sectional slices with the standard design section. For the degree of deformation of the structural plate, the selected reference plane is fitted with a spatial surface of the plate, and the minimum distance from other points on the structural plate to the spatial surface is calculated. The maximum value of the distance corresponding to all points on the structural plate minus the design thickness of the plate is the maximum deflection value of the structural plate. Step S5 includes: In the finite element analysis model, all structural components of the top plate system, side plate system, bottom plate system, and piston system were constructed. The component types and quantities, end face positioning coordinates, and geometric shapes of the components were consistent with the results extracted from the laser point cloud data. The component materials, boundary conditions of the end faces, and coupling conditions at the connection between two components were consistent with the original design finite element model. The boundary conditions were estimated and set according to the degree of node stiffness degradation. Step S7 includes: The structural model under actual deformation is compared with the finite element calculation results of the original design model, including the overall modal period value and mode shape change of the structure, the stress value of the component under the most unfavorable state, and the maximum stress difference of the component under different working conditions. Then, combined with the results of the component's tilt, deflection, and bending, an actual service status assessment report of the gas holder structural system is given.
2. The method according to claim 1, characterized in that, The preprocessing of all laser point cloud data collected from the gas holder includes: Interference data is removed from all laser point cloud data, including point cloud data that is not related to the gas holder system and outliers. At the same time, the curvature and thin-wall characteristics of the gas holder structure, including the point cloud data, are preserved, making it easy to identify the structural objects.
3. The method according to claim 2, characterized in that, Step S2 includes: The pre-processed gas holder point cloud data is selected by manual intervention and divided into structural subsystems according to the spatial occupancy of the components within the subsystem. The integrity of the component data of each subsystem should be ensured at the boundary of the divided subsystems. The divided subsystems include: top plate system, side plate system, bottom plate system and piston system.
4. The method according to claim 3, characterized in that, Step S3 includes: The extraction of point cloud data for structural columns, structural beams and structural supports includes: based on the initially specified spatial range, reference end face and axial direction of the component, multiple cross-sectional slices are made of the component to determine the cross-sectional design parameters of the component. Through optimization, the final centroid of the end face, cross-sectional dimensions and axial direction of the component are determined, and all irrelevant data outside the geometric boundary range of the component are removed. The extraction of point cloud data for the structural panels in the gas holder side panel system includes: based on the initially determined spatial range of the structural panels, performing circular fitting of the outermost and innermost contours of the point cloud data, determining the radius and center of the outermost and innermost circles, and identifying all points whose X and Y coordinates fall within the XY plane range of this circle as the total point cloud data of the side panels in the gas holder side panel system, and removing all irrelevant data outside the geometric boundary range of the components; and dividing the gas holder side panels into sections based on the dimensions and spatial positioning information in the design drawings to obtain the point cloud data of each spliced panel. The extraction of point cloud data for the structural plates in the gas holder top plate system, bottom plate system, and piston system includes: based on the initially determined spatial range of the structural plates, performing circular fitting of the outermost contour; points whose X and Y coordinates are all within the XY plane of this circle are all point cloud data belonging to the gas holder top plate, bottom plate, and piston plate, and all irrelevant data outside the geometric boundary range of the components are removed; based on the dimensions and spatial positioning information in the design drawings, the structural plates are divided into sections to obtain the point cloud data of each spliced plate.
5. The method according to claim 4, characterized in that, In step S6, the limit states include the ultimate limit state of bearing capacity, the serviceability limit state, and the durability limit state, and the stress calculation is performed using the linear elastic analysis method.