A method of eliminating steel bridge deck panel welding residual deformation by combining 3D scanning and distributed heat source

Abstract

The application discloses a method for eliminating welding residual deformation of a steel bridge deck plate by combining 3D scanning and distributed heat sources. A three-dimensional thermal elastic-plastic finite element model of the steel bridge deck plate is established to simulate a welding temperature field and a stress field; the obtained heating temperature and theoretical deformation value are transmitted to an intelligent data processing center; a heating area is demarcated according to the welding residual deformation distribution of different areas; the heating area is heated by using an oxyacetylene flame; after cooling, the welding residual deformation of the above measuring points is measured by using a 3D laser scanner; the measured data are transmitted to the intelligent data processing center through a WiFi network; the theoretical deformation value is compared with the measured deformation value for comparative analysis and adjustment by the intelligent data processing center; and the plastic deformation generated during heating makes the welding deformation area of the steel bridge deck plate shrink after cooling, so that the welding residual deformation is eliminated, the stability and fatigue life of the orthotropic steel bridge deck plate structure are improved, and the use quality of the steel bridge deck plate is improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically relating to a method for eliminating residual deformation from steel bridge deck welding by combining 3D scanning and distributed heat sources, which is particularly suitable for eliminating residual deformation from steel bridge deck welding. Background Technology

[0002] In recent years, with the continuous development of orthotropic steel bridge deck structures, orthotropic steel bridge decks have become widely used in large and medium-span steel bridge decks due to their advantages such as light weight, good integrity, high load-bearing capacity, fast construction speed, and wide applicability. However, steel bridge deck stiffening often adopts U-ribs. Since the U-ribs are set on one side and the out-of-plane stiffness of the deck is not high, in addition to longitudinal and transverse shrinkage deformation, the components also experience significant transverse bending deformation during welding. The residual deformation generated by U-rib welding seriously affects the manufacturing accuracy of the structure, increases the workload of post-weld straightening, reduces production efficiency, and also has an adverse effect on the fatigue resistance of the structure. In order to eliminate welding residual deformation as much as possible, we need to delineate the heating zone based on the stress field simulation results of the steel bridge deck. We can use the plastic deformation generated by local heating of the weldment with a flame to cause the longer metal to shrink after cooling, thereby eliminating the deformation and ensuring that the stiffness, strength, stability, and fatigue life of the orthotropic steel bridge deck are improved.

[0003] As a new high-tech product, 3D laser scanners have been successfully applied in fields such as cultural relic protection, urban building surveying, topographic mapping, mining, deformation monitoring, factories, large structures, pipeline design, aircraft and ship manufacturing, highway and railway construction, tunnel engineering, and bridge reconstruction. 3D laser scanning systems can densely and massively acquire data points of target objects, boasting advantages such as high scanning efficiency, high scanning accuracy, and high sampling rate. They can achieve the acquisition of information about scanned objects quickly, accurately, and efficiently. Due to their characteristics of speed, non-contact operation, real-time performance, dynamic operation, proactive operation, high density, high accuracy, high sampling rate, digitization, and automation, they are highly effective. Distributed heat sources employ local heating methods. By using multiple sets of oxy-acetylene flames with moving mechanisms as local heating sources, the same temperature can be applied to the required heating area over a large area with high efficiency, resulting in uniform temperature and forming a movable heating zone. Furthermore, the temperature can be controlled and adjusted flexibly. Therefore, this invention proposes a method combining 3D scanning and distributed heat sources to eliminate residual deformation from steel bridge deck welding. Summary of the Invention

[0004] In view of the above background technology, the present invention aims to propose a method for eliminating residual welding deformation of steel bridge decks by combining 3D scanning and distributed heat sources. The method involves using a 3D laser scanner to scan and measure the residual welding deformation value, and then using finite element numerical simulation to delineate the heating zone based on the finite element calculation results of the steel bridge deck. Local oxyacetylene heating is then applied to the weld deformation area in a targeted manner. The plastic deformation generated during heating causes the weld deformation area of ​​the steel bridge deck to shrink after cooling, thereby eliminating the residual welding deformation. This ensures improved structural stability and fatigue life of orthotropic steel bridge decks, and enhances the overall quality of the steel bridge deck.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method combining 3D scanning and distributed heat sources to eliminate residual deformation from steel bridge deck welding is described below:

[0007] Step 1: Pre-treat the steel by removing residual oxides from the steel surface using manual and mechanical methods, and remove surface grease and contaminants with solutions such as acetone to ensure the flatness of the surface to be pasted, and collect the welding parameters of the steel bridge deck.

[0008] Step 2: Based on the collected welding parameters of the steel bridge deck, establish a three-dimensional thermo-elastic-plastic finite element model of the steel bridge deck, simulate the welding temperature field, and transmit the obtained heating temperature to the intelligent data processing center via WiFi network.

[0009] Step 3: Perform finite element analysis. Based on the inherent strain theory, calculate the inherent deformation in each direction in the calculation results, and then apply the obtained inherent strain to the elastic element to obtain the distribution of welding residual deformation in different areas. Delineate the heat source control area at a reasonable position on the cover plate and U-rib and mark it.

[0010] Step 4: Further refine the heat source control zone, and determine the heating zone by combining numerical simulation. The cover plate heating zone is located in the middle of two adjacent U-ribs, and the U-rib heating zone is located in the middle of the side wall of the U-rib. The range of the heating zone is adjusted according to the actual situation.

[0011] Step 5: Perform numerical simulation calculations to obtain the theoretical value of welding residual deformation, and transmit the theoretical deformation value to the intelligent data processing center via WiFi network;

[0012] Step 6: Based on the heating temperature calculated in Step 2, the heating zone is heated using an oxyacetylene flame. After cooling, the steel bridge deck is measured using a 3D laser scanner, and the measured deformation value is transmitted to the intelligent data processing center via WiFi network.

[0013] Step 7: The intelligent data processing center compares and analyzes the theoretical deformation value from Step 5 with the measured deformation value from Step 6 to obtain the data analysis results;

[0014] Step 8: Analyze whether the measured deformation value and the theoretical deformation value are within the allowable range. If they are, the process ends. If not, return to Step 2 to correct the model. After correction, reheat the model and use a 3D laser scanner to measure and compare the residual deformation of the steel bridge deck welding until the error requirements are met. The process ends then.

[0015] As a preferred technical solution, the temperature field in step 2 belongs to the standard three-dimensional nonlinear unsteady-state heat conduction, and the three-dimensional heat conduction control equation for the welding process is:

[0016]

[0017] Where p is the material density (kg*m) -3 c is the specific heat capacity of the material (J / (kg*k)); λ is the thermal conductivity of the material (W / (m*k)); t is the heat transfer time (s); T is the temperature field distribution function; To solve for the intensity of the internal heat source in the region (W / m3); in the formula, p, c, and λ are all functions of temperature T.

[0018] Heat dissipation on the surface of the weldment mainly considers convection and radiation, and its expression is as follows:

[0019]

[0020] In the formula, q loss For total heat loss, h c ε represents the convective heat transfer coefficient, σ is the thermal radiation coefficient, σ is the Stephen-Boltzmann constant, and T0 is the room temperature.

[0021] As a preferred technical solution, the numerical simulation of the temperature field in the spatial model established in step 2 adopts a Gaussian distributed heat convection density model. The following equation is in the form of a Gaussian heat source function, representing the heat flux density at any point from the heating center:

[0022]

[0023] In the formula: qm is the maximum heat flux density at the center of the heating range; R is the effective heating radius of the heat source; r is the distance of any point P from the heating center O. Furthermore, it is easy to obtain that the integral of the heat flux density over the entire heating area equals the total heat input qf0 for a moving heat source;

[0024]

[0025] In the formula: qf is the total heat input; η is the acetylene flow rate (L / h); A is the calorific value of acetylene combustion (kJ / mol); η is the thermal efficiency; R is the effective heating radius of the heat source (m);

[0026] The maximum heat flux density (J·m) at the center of the heat source can be calculated using the above formula. -2 ·s -1 )for:

[0027]

[0028] As a preferred technical solution, the method for determining the heating zone in step 4 is as follows: based on the numerical simulation calculation results and the distribution of welding residual deformation in different areas, the cover plate heating zone is set in the middle of two adjacent U-ribs, and the U-rib heating zone is set in the middle of the side wall of the U-rib, while measuring points are arranged.

[0029] As a preferred technical solution, the 3D laser scanner in step 6, as the main component of the three-dimensional laser scanning system, consists of a laser emitter, receiver, time counter, motor-controlled rotatable filter, control circuit board, microcomputer, CCD machine, and software.

[0030] As a preferred technical solution, the principle of laser ranging used by the 3D laser scanner in step 6 is to record the three-dimensional coordinates, reflectivity, and texture information of a large number of dense measurement points on the surface of the steel bridge deck. This allows for the rapid reconstruction of the three-dimensional model of the steel bridge deck and various graphic data such as lines, surfaces, and volumes, thereby measuring the actual welding residual deformation value.

[0031] As a preferred technical solution, in step 8, the intelligent data processing center needs to analyze whether the measured deformation value and the theoretical deformation value are within the allowable range of 5% based on the data results. If they are, the process ends; otherwise, it returns to correct the model. After correction, an oxyacetylene flame is applied again, and then a 3D laser scanner is used to measure and compare the residual deformation of the steel bridge deck welding until the error requirements are met, at which point the process ends.

[0032] The advantages and positive effects of this invention are:

[0033] This invention combines a 3D laser scanner to scan and measure the residual deformation value of welding. Through calculation methods that combine finite element numerical simulation and inherent strain theory, a heating zone is delineated based on the calculation results. Then, local heat sources are applied to the weld deformation area in a targeted manner. The plastic deformation generated during heating causes the weld deformation area of ​​the steel bridge deck to shrink after cooling, thereby eliminating the residual welding deformation. This ensures improved stability and fatigue life of the orthotropic steel bridge deck structure and enhances the quality of the steel bridge deck in use. Attached image description:

[0034] Figure 1This is a system diagram of the present invention;

[0035] Figure 2 This is a schematic diagram illustrating the control of residual deformation during welding of the U-rib steel bridge deck according to the present invention.

[0036] Figure 3 This is a step diagram of the present invention;

[0037] Figure 4 This is a flowchart of the present invention.

[0038] In the diagram: 1. U-rib steel bridge deck; 2. Cover plate - U-rib; 21. Cover plate heating zone; 22. U-rib heating zone; 3. Oxy-acetylene flame; 4. Intelligent data processing center; 5. 3D laser scanner; Detailed implementation method:

[0039] The following description, in conjunction with the accompanying drawings of the embodiments of the present invention, will provide a detailed and complete description of the technical solutions in the embodiments of the present invention. Of course, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0040] like Figure 1-4 As shown, the present invention provides a method for eliminating residual deformation from steel bridge deck welding by combining 3D scanning and distributed heat sources, comprising the following steps:

[0041] Step 1: Pre-treat the steel by removing residual oxides from the steel surface using manual and mechanical methods, and remove surface grease and contaminants with solutions such as acetone to ensure the flatness of the surface to be pasted, and collect the welding parameters of the steel bridge deck.

[0042] Step 2: Based on the collected welding parameters of the steel bridge deck, establish a three-dimensional thermo-elastic-plastic finite element model of the steel bridge deck, simulate the welding temperature field, and transmit the obtained heating temperature to the intelligent data processing center via WiFi network.

[0043] Step 3: Perform finite element analysis. Based on the inherent strain theory, calculate the inherent deformation in each direction in the calculation results, and then apply the obtained inherent strain to the elastic element to obtain the distribution of welding residual deformation in different areas. Delineate the heat source control area at a reasonable position on the cover plate and U-rib and mark it.

[0044] Step 4: Further refine the heat source control zone, and determine the heating zone by combining numerical simulation. The cover plate heating zone is located in the middle of two adjacent U-ribs, and the U-rib heating zone is located in the middle of the side wall of the U-rib. The range of the heating zone is adjusted according to the actual situation.

[0045] Step 5: Perform numerical simulation calculations to obtain the theoretical value of welding residual deformation, and transmit the theoretical deformation value to the intelligent data processing center via WiFi network;

[0046] Step 6: Based on the heating temperature calculated in Step 2, the heating zone is heated using an oxyacetylene flame. After cooling, the steel bridge deck is measured using a 3D laser scanner, and the measured deformation value is transmitted to the intelligent data processing center via WiFi network.

[0047] Step 7: The intelligent data processing center compares and analyzes the theoretical deformation value from Step 5 with the measured deformation value from Step 6 to obtain the data analysis results;

[0048] Step 8: Analyze whether the measured deformation value and the theoretical deformation value are within the allowable range. If they are, the process ends. If not, return to Step 2 to correct the model. After correction, reheat the model and use a 3D laser scanner to measure and compare the residual deformation of the steel bridge deck welding until the error requirements are met. The process ends then.

[0049] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. Any similar changes and improvements made in accordance with the claims of the present invention should be considered as within the scope of protection of the concept of the present invention and the claims.

Claims

1. A method for eliminating residual deformation from welding of steel bridge decks by combining 3D scanning and distributed heat sources, characterized in that, Includes the following steps: Step 1: Pre-treat the steel by removing residual oxides from the steel surface using manual and mechanical methods, and remove surface grease and contaminants with acetone and other solutions to ensure the flatness of the surface to be pasted, and collect the welding parameters of the steel bridge deck. Step 2: Based on the collected welding parameters of the steel bridge deck, establish a three-dimensional thermo-elastic-plastic finite element model of the steel bridge deck, simulate the welding temperature field, and transmit the obtained heating temperature to the intelligent data processing center via WiFi network. Step 3: Perform finite element analysis. Based on the inherent strain theory, calculate the inherent deformation in each direction in the calculation results, and then apply the obtained inherent strain to the elastic element to obtain the distribution of welding residual deformation in different areas. Delineate the heat source control area at a reasonable position on the cover plate and U-rib and mark it. Step 4: Further refine the heat source control zone, and determine the heating zone by combining numerical simulation. The cover plate heating zone is located in the middle of two adjacent U-ribs, and the U-rib heating zone is located in the middle of the side wall of the U-rib. The range of the heating zone is adjusted according to the actual situation. Step 5: Based on numerical simulation calculations, the theoretical value of welding residual deformation is obtained, and the theoretical deformation value is transmitted to the intelligent data processing center via WiFi network. Step 6: Based on the heating temperature calculated in Step 2, the heating zone is heated using an oxyacetylene flame. After cooling, the steel bridge deck is measured using a 3D laser scanner, and the measured deformation value is transmitted to the intelligent data processing center via WiFi network. Step 7: The intelligent data processing center compares and analyzes the theoretical deformation value from Step 5 with the measured deformation value from Step 6 to obtain the data analysis results; Step 8: Analyze whether the measured deformation value and the theoretical deformation value are within the allowable range. If they are, the process ends. If not, return to Step 2 to correct the model. After correction, reheat the model and use a 3D laser scanner to measure and compare the residual deformation of the steel bridge deck welding until the error requirements are met. The process ends then.

2. The method for eliminating residual deformation from steel bridge deck welding by combining 3D scanning and distributed heat sources as described in claim 1, characterized in that, The temperature field in step 2 belongs to standard three-dimensional nonlinear unsteady-state heat conduction. The three-dimensional heat conduction control equation for the welding process is: Where ρ is the material density (kg*m) -3 c is the specific heat capacity of the material (J / (kg*k)); λ is the thermal conductivity of the material (W / (m*k)); t is the heat transfer time (s); T is the temperature field distribution function; To solve for the intensity of the internal heat source in the region (W / m3); ρ, c, and λ in the formula are all functions of temperature T; Heat dissipation on the surface of the weldment mainly considers convection and radiation, and its expression is as follows: In the formula, q loss For total heat loss, h c ε represents the convective heat transfer coefficient, σ is the thermal radiation coefficient, σ is the Stephen-Boltzmann constant, and T0 is the room temperature.

3. The method for eliminating residual deformation from steel bridge deck welding by combining 3D scanning and distributed heat sources as described in claim 1, characterized in that, The spatial model temperature field numerical simulation established in step 2 uses a Gaussian distributed heat convection density model. The following equation is in the form of a Gaussian heat source function, representing the heat flux density at any point from the heating center: In the formula: q m Let P be the maximum heat flux density at the center of the heating range; R be the effective heating radius of the heat source; and r be the distance from any point P to the heating center O. Furthermore, it is easy to see that the integral of the heat flux density over the entire heating region equals the total heat input q. f0 For mobile heat sources; In the formula: q f This represents the total heat input. η is the acetylene flow rate (L / h); A is the calorific value of acetylene combustion (kJ / mol); η is the thermal efficiency; R is the effective heating radius of the heat source (m); The maximum heat flux density (J·m) at the center of the heat source can be calculated using the above formula. -2 ·s -1 )for:

4. The method for eliminating residual welding deformation of steel bridge decks by combining 3D scanning and distributed heat sources as described in claim 1, characterized in that, In step 3, the inherent strain is obtained through the inherent strain theory. In general thermoforming, the total strain ε is derived from the elastic strain ε. e Plastic strain ε p Thermal strain ε T Phase transition strain ε tr and creep strain ε c Composition, inherent strain ε after removing elastic strain * The inherent strain formula can be obtained by calculating the following: e * =e-e e =e p +e T +e c +e tr The four main types of welding deformation: longitudinal shrinkage δ L * Horizontal contraction δ T * Longitudinal bending θ L * Lateral bending θ T *It can be defined by the following equation: In the formula, x is the welding direction and z is the direction perpendicular to the welding surface.

5. The method for eliminating residual welding deformation of steel bridge decks by combining 3D scanning and distributed heat sources as described in claim 1, characterized in that, The method for determining the heating zone in step 4 is as follows: Based on the numerical simulation calculation results and the distribution of welding residual deformation in different areas, the cover plate heating zone is set in the middle of two adjacent U-ribs, and the U-rib heating zone is set in the middle of the side wall of the U-rib. Measurement points are also arranged at the same time.

6. The method for eliminating residual welding deformation of steel bridge decks by combining 3D scanning and distributed heat sources as described in claim 1, characterized in that, In step 8, the intelligent data processing center needs to analyze whether the measured deformation value and the theoretical deformation value are within the 5% allowable range based on the data results. If they are, the process ends; otherwise, it returns to correct the model. After correction, an oxyacetylene flame is applied again, and then a 3D laser scanner is used to measure and compare the residual deformation of the steel bridge deck welding until the error requirements are met, at which point the process ends.

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