A method for controlling cracking at welding points of hoop reinforcement bars

Abstract

The present invention discloses a method for controlling cracking at the welding position of the reinforcing rib of a clamp, comprising: optimizing the cut angles at the rounded corners of the reinforcing rib plate and the clamp to obtain a drawing after the optimization process; establishing a finite element model, performing stress analysis and comparison between the optimized drawing and rib plates with different cut angle sizes on both sides of the clamp to obtain the stress distribution of the reinforcing rib plate in the clamp; and obtaining the optimal cut angle position based on the stress distribution of the reinforcing rib plate in the clamp. The present invention solves the difficult problem of cracking at the welding position of the reinforcing rib plate of the clamp, and provides a new method for stabilizing and improving the quality of clamp products.

Description

Technical Field

[0001] The present invention relates to the technical field of structural engineering, and in particular to a method for controlling cracking at welding locations of hoop reinforcement bars. Background Art

[0002] Structural engineering focuses on the design and construction of buildings and structures that can withstand various loads and environmental factors. The technical background in this field encompasses a wide range of disciplines, including materials science, mechanics, geology, computer-aided design (CAD), and project management. Within materials science, structural engineering relies on a deep understanding of the properties of various building materials, such as steel, concrete, wood, and composites. The selection and application of these materials are crucial to ensuring the strength, durability, and economic efficiency of structures. Mechanics is at the core of structural engineering, encompassing fields such as statics, dynamics, and the mechanics of materials. Engineers must be able to accurately calculate and analyze the behavior of structures under various loads (such as deadweight). With the advancement of computer technology, computer-aided design (CAD) and analysis software have become indispensable tools for structural engineers. These tools enable engineers to perform complex structural analysis, optimize designs, and generate construction drawings and models. With the promotion of sustainable development and green building concepts, the field of structural engineering is continuously incorporating new technologies, such as high-performance materials, intelligent monitoring systems, and sustainable design strategies, to improve the environmental performance of buildings and reduce their impact on the environment. In summary, the background technology in the field of structural engineering is a multidisciplinary and constantly evolving field, which requires engineers to not only have a solid theoretical foundation, but also be able to adapt to the development and application of new technologies.

[0003] For a long time, in order to control the problem of cracking at the weld corners of the clamp reinforcement plate, engineers usually use the distance between the bolt hole and the tube to increase the lever arm, thereby reducing the force. Due to the inconsistency of welding technology in different units and the different tightening torques applied, the problem of cracking of the clamp reinforcement plate has become increasingly prominent. At the same time, increasing the distance between the screw and the clamping tube will lengthen the clamp plate, seriously reducing the economic efficiency. Therefore, it is difficult to improve the problem of cracking of the clamp reinforcement plate while ensuring economic efficiency. Therefore, simply increasing the distance between the bolt and the tube is not a good solution. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a method for controlling cracking at the welding position of the hoop reinforcement bar to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides a method for controlling cracking at the weld of a hoop reinforcement bar, comprising:

[0006] Optimize the cut angles at the fillets of the stiffener plate and the hoop to obtain the optimized drawing;

[0007] Establish a finite element model, perform stress analysis and comparison between the optimized drawing and the ribs with different cut angle sizes on both sides of the clamp, and obtain the stress distribution of the ribs in the clamp;

[0008] The optimal cutting angle position is obtained based on the stress distribution of the reinforcing rib plate in the clamp.

[0009] Preferably, the cut angles at the fillets of the reinforcing ribs and the hoop are optimized, including:

[0010] Without considering the welding quality, a mechanical analysis is performed on the welds of the stirrup reinforcement plates to obtain mechanical analysis results. Based on the mechanical analysis results, the height of the reinforcement plate cut angle is increased to reduce the force on the inner reinforcement plate welds, and the side dimensions of the reinforcement plate are increased. The force generated by the bolt pretightening is dispersed through the stirrup itself.

[0011] Preferably, the optimized drawing is subjected to stress analysis and comparison with ribs with different cut angle sizes on both sides of the hoop, including:

[0012] Based on the optimized drawings, a finite element model is established for analysis, and stress comparison is performed on the ribs with different cut angle sizes on both sides of the clamp, and the comparison results are output.

[0013] Preferably, obtaining the optimal cutting angle position includes:

[0014] A stress diagram is drawn by using several similar cutting angles, and a threshold value of the relationship between the cutting angle and the stress height is obtained through the stress diagram, and the optimal cutting angle position is obtained through the threshold value.

[0015] Preferably, after obtaining the optimal cutting angle position, the method further includes:

[0016] Symmetrically identical nodes are extracted from the dangerous cracking zone of the same stiffener before and after the improvement to perform stress comparison, and the change in the stress value is observed to obtain a comparison result, which is given to verify the control method.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] The present invention provides a method for controlling the cracking position at the welding portion of the clamp reinforcement plate, taking into account the adjustment of the structure of the reinforcement plate to achieve the effect of controlling cracking. When the clamp is clamped to the pipe fitting, bolts need to be installed on the wing plate. When the bolts are tightened, the tightening torque generated applies a clamping force to the clamp. At the same time, the clamp with the reinforcement plate will be subjected to a large load at the welded edge of the reinforcement plate. Therefore, the reasonable design of the reinforcement plate and the removal of its contact angle can improve the load transfer capacity of the structure, effectively share and bear the load, ensure the stability of the structure, and achieve the effect of preventing cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of an assembly clamp according to an embodiment of the present invention;

[0021] Figure 2 Dimensional diagrams of some different reinforcing ribs according to embodiments of the present invention;

[0022] Figure 3 This is a stress cloud diagram of the hoop reinforcement plate according to an embodiment of the present invention;

[0023] Figure 4 Comparison of stress magnitude at welding corners between the cutting angle dimensions of the reinforcing ribs and the cutting angle dimensions of the ribs according to an embodiment of the present invention, where (a) the cutting angle height is 10.2 mm and (b) the cutting angle height is 15 mm.

[0024] Figure 5 This is a comparison diagram of the stress magnitude at the welding corners of the reinforcing rib plate cutting angle dimensions and the rib plate cutting angle dimensions according to an embodiment of the present invention, wherein (a) the cutting angle height is 13 mm, and (b) the cutting angle height is 17 mm. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] The present invention proposes a method for controlling cracking at a welding location of a hoop reinforcement bar, comprising:

[0028] Optimize the cut angles at the fillets of the stiffener plate and the hoop to obtain the optimized drawing;

[0029] Establish a finite element model, perform stress analysis and comparison between the optimized drawing and the ribs with different cut angle sizes on both sides of the clamp, and obtain the stress distribution of the ribs in the clamp;

[0030] The optimal cutting angle position is obtained based on the stress distribution of the reinforcing rib plate in the clamp.

[0031] This embodiment proposes a method for controlling cracking at the welded portion of the ribbed plate of the clamp, considering adjusting the structure of the ribbed plate to achieve the desired effect. Bolts must be installed on the flanges when the clamp is clamped to the pipe. The tightening torque generated by tightening the bolts applies a clamping force to the clamp. Furthermore, the clamp with the ribbed plate is subject to significant load at the welded edge of the plate. Therefore, rationally designing the ribs and cutting off their contact angles can improve the structure's load transfer capacity, effectively share and bear the load, ensure structural stability, and ultimately prevent cracking.

[0032] Furthermore, the cut angles at the fillets of the reinforcing ribs and the hoop are optimized, including:

[0033] Without considering the welding quality, a mechanical analysis is performed on the welds of the stirrup reinforcement plates to obtain mechanical analysis results. Based on the mechanical analysis results, the height of the reinforcement plate cut angle is increased to reduce the force on the inner reinforcement plate welds, and the side dimensions of the reinforcement plate are increased. The force generated by the bolt pretightening is dispersed through the stirrup itself.

[0034] Specifically, to reduce the cracking of the ribs, the cut angle at the R corner (rounded corner) between the ribs and the clamp is optimized. Increasing the cut angle at the R corner can effectively prevent stress concentration at the contact part between the ribs and the clamp when the tightening torque is applied. The enlarged cut angle transfers part of the stress to the clamp itself, thereby increasing the area under stress and avoiding the occurrence of cracking. Figure 1-Figure 2 shown.

[0035] In this embodiment, the initial design angled cut height was 10.2mm. After commissioning, widespread cracking occurred in the welded hoop reinforcement plates. Without considering weld quality, a mechanical analysis of the welded hoop reinforcement plates revealed that during bolt pretightening, forces were applied to the hoop reinforcement plates. Forces were applied to both ends of the angled cut, creating a moment. Tension was applied to the inner side of the hoop reinforcement plates. This internal tension caused cracks to form along the inner edge of the reinforcement plates, leading to cracking. To reduce the forces acting there, the plate heights were raised to 13mm, 15mm, 17mm, and 20mm, respectively. This increased the distance between the two forces, thereby reducing the forces acting on the inner reinforcement plate welds and preventing cracking. The side edges of the reinforcement plates were also machined outward to 14.2mm, 20.3mm, 19.4mm, 21.2mm, and 22.6mm, respectively. This further increased the distance between the two stressed ends and allowed the hoop itself to distribute the forces generated during bolt pretightening.

[0036] Furthermore, the optimized drawing is subjected to stress analysis and comparison with ribs with different cut angle sizes on both sides of the hoop, including:

[0037] Based on the optimized drawings, a finite element model is established for analysis, and stress comparison is performed on the ribs with different cut angle sizes on both sides of the clamp, and the comparison results are output.

[0038] Specifically, a finite element model is established for the drawing for analysis. In this embodiment, in order to enhance the contrast between the two stiffeners, stiffeners with different cut-angle sizes are used on both sides of the clamp to facilitate stress comparison and provide better intuitiveness for the output results.

[0039] like Figure 3 The stress contours shown in the figure show that stress is concentrated at the connection between the clamp and the rib plate. The clamp and rib plate are subjected to compressive stress on the inside and tensile stress on the outside, especially at the weld edge. The interaction of these two factors requires the rib to have a reasonable structure and good welding quality.

[0040] Furthermore, the stress distribution of the reinforcing rib in the hoop is as follows:

[0041] The effects of two different cutting angles on the stress of the stiffener are analyzed. Increasing the cutting angle of the stiffener reduces the stress concentration at the weld, and the stress distribution area also diffuses to the outside of the stiffener. Increasing the stress-bearing area effectively reduces the occurrence of the danger zone.

[0042] Furthermore, obtaining the optimal cutting angle position includes:

[0043] A stress diagram is drawn by using several similar cutting angles, and a threshold value of the relationship between the cutting angle and the stress height is obtained through the stress diagram, and the optimal cutting angle position is obtained through the threshold value.

[0044] Specifically, in this embodiment, the situation of the reinforcing rib in the hoop was preliminarily discovered, and its convergence range was determined to find its optimal and appropriate cutting angle position. Several groups of similar data were used for comparison, such as 10.2mm, 13mm, 15mm, 17mm, and 20mm. The stresses of different corners obtained from these five groups of data are shown in Table 1: Through the stress information obtained from Table 1, it was found that a threshold value of cutting angle and stress was near the cutting angle height of 15mm. The stress of the cutting angle at the height of 10.2mm was 525MPa, the stress of the cutting angle at the height of 13mm was 471MPa, the stress of the cutting angle at the height of 15mm was 422MPa, the stress of the cutting angle at the height of 17.m was 513MPa, and the stress of the cutting angle at the height of 20mm was 411MPa. From this data, it can be concluded that the value at or near 15mm is a coefficient peak. The stress will gradually increase below 15mm, and the stress will also gradually increase above this threshold. However, by comparing the stress at 20mmnm, it can be found that the corresponding stress at 20mm is 411MPa. This set of data shows that 20mm may be the second peak of the ratio of the cut angle to the corner stress. However, given that the stress of 20mm is only reduced by 2.6% compared with 15mm, the increase in the cut angle height to 20mm will lead to a reduction in the welding contact area. According to the stress formula σ=F / A, σ is the stress magnitude, F is the force, and A is the area, it can be found that the area is inversely proportional to the stress. Then, reducing the area by half will lead to an increase in stress at the entire weld, and the stress value of the cracking area of ​​the weld corner cannot be considered alone. Therefore, compared with the cut angles of 15mm and 20mm heights, the stress of 15mm is slightly higher than that of 20mm, but its overall welding area is much larger than 20mm. Therefore, the cut angle value of the hoop reinforcement plate in production should be around 15mm.

[0045] Table 1

[0046] Height of rib cutting angle / mm Welding edge stress / MPa 10.2mm 525 13mm 471 15mm 422 17mm 513 20mm 411

[0047] The above analysis is verified twice. It can be seen from the above description that the stress at the 15mm cutting angle height is more reasonable, and the stress value at the 17mm cutting angle height where the cutting angle height is only increased by 2mm does increase. Therefore, in order to further confirm whether the stress value comparison is accurate, the above is a simultaneous comparison of the 13mm cutting angle height and the 17mm cutting angle height. Now a secondary comparison is made with the 10mm cutting angle height and the 17mm cutting angle height, and this data result is compared one by one with the previous 10mm and 15mm data. The cutting angles of 10mm and 17mm are modeled and simulated in the same way. Stress analysis of the nodes at the two locations can produce stress history line diagrams of the two corner positions. The maximum stress of the ribbed plate corner with a cutting angle height of 10mm is 585MPa, and the maximum stress of 17mm is 521MPa. From these two sets of data, it can be further determined that the appropriate cutting angle selection range should be around 15mm but not exceed the range of 13mm-17mm, otherwise the stress will increase. The specific stress curve extracted in ABAQUS is as follows Figure 5 As shown in (a)-(b).

[0048] According to the analysis of the above experimental data, it can be found that the improved reinforcing rib plate can effectively overcome the phenomenon of stress concentration at the welding position, so that the stress at the welding position is diffused to the edge of the rib plate, thereby increasing the stress area and reducing the maximum value of local stress concentration. By extracting the stress conditions in the dangerous area, it can be found that the stress of the improved reinforcing rib plate at the welding corner is reduced by 19.6%. Therefore, it can be concluded that increasing the cutting angle can reduce the local stress of the welding and avoid the risk of cracking. Secondly, in order to further verify the accuracy of the influence of the cutting angle height on stress, 5 groups of cutting angle height data were taken out, such as 10.2mm (initial), 13mm, 15mm, 17mm, and 20mm. After comparison, it was found that the stress on the welding corners at 15mm and 20mm was slightly different. However, due to the increase in the cutting angle height, the welding area will be reduced, thereby affecting the overall stress. If the welding area of ​​the hoop reinforcement plate is reduced and the overall stress is expanded, the entire reinforcement plate will be affected. It was verified again, and 10mm and 17mm were selected for comparison again to confirm whether the threshold of 15mm exists. The data verified that the cutting angle height of 15mm is the minimum stress within the nearby size range. Therefore, choosing a reinforcement plate cutting angle with a height of 15mm is a better solution.

[0049] Furthermore, after obtaining the optimal cutting angle position, the following steps are also included:

[0050] Symmetrically identical nodes are extracted from the dangerous cracking zone of the same stiffener before and after the improvement to perform stress comparison, and the change in the stress value is observed to obtain a comparison result, which is given to verify the control method.

[0051] Specifically, after the stress analysis of the stiffener is completed, nodes on the edge of the component, i.e., the dangerous cracking area, are extracted for precise analysis. Stress comparison is performed on the symmetrically identical nodes extracted from the same stiffener before and after improvement to observe the magnitude of their stress values.

[0052] Extract the stress at the crack and analyze it. Figure 4 (a) shows the stress amplitude of the dangerous area of ​​the rib plate with a cutting angle height of 10.2 mm. Figure 4 (b) is the stress amplitude of the dangerous area of ​​the rib plate with a cut-off height of 15 mm. Figure 4 It can be seen that the stress on the corners of the improved stiffener plate is significantly improved. The maximum stress on the original stiffener plate is 525MPa, while the maximum stress on the improved stiffener plate is 422MPa. The stress on the edge of the improved stiffener plate is reduced by about 19.6%. Therefore, the improved stiffener plate has played an improvement role in preventing the stiffener from cracking.

[0053] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for controlling cracking at the welding position of a hoop reinforcement, characterized in that: include: Optimize the cut angles at the fillets of the stiffener plate and the hoop to obtain the optimized drawing; Establish a finite element model, perform stress analysis and comparison between the optimized drawing and the ribs with different cut angle sizes on both sides of the clamp, and obtain the stress distribution of the ribs in the clamp; Obtaining an optimal cutting angle position based on the stress distribution of the reinforcing rib plate in the clamp; Optimize the cut corners of the stiffener plate and the hoop fillet, including: Without considering the welding quality, a mechanical analysis is performed on the welds of the stirrup reinforcement plates to obtain mechanical analysis results. Based on the mechanical analysis results, the height of the reinforcement plate cut angle is increased to reduce the force on the inner reinforcement plate welds, and the side dimensions of the reinforcement plate are increased. The force generated by the bolt pretightening is dispersed through the stirrup itself.

2. The method for controlling cracking at the weld of the hoop reinforcement according to claim 1, characterized in that: The optimized drawing is compared with the ribs with different cut angle sizes on both sides of the hoop for stress analysis, including: Based on the optimized drawings, a finite element model is established for analysis, and stress comparison is performed on the ribs with different cut angle sizes on both sides of the clamp, and the comparison results are output.

3. The method for controlling cracking at the weld of the hoop reinforcement according to claim 1, characterized in that: Obtaining the optimal cutting angle position includes: A stress diagram is drawn by using several similar cutting angles, and a threshold value of the relationship between the cutting angle and the stress height is obtained through the stress diagram, and the optimal cutting angle position is obtained through the threshold value.

4. The method for controlling cracking at the weld of the hoop reinforcement according to claim 3, characterized in that: After obtaining the optimal cutting angle position, the method further includes: Symmetrically identical nodes are extracted from the dangerous cracking zone of the same stiffener before and after the improvement to perform stress comparison, and the change in the stress value is observed to obtain a comparison result, which is given to verify the control method.

Images