A gravity-oil pressure hybrid loading and holding welding test device and method

Abstract

The application discloses a kind of gravity-oil pressure mixed loading and holding load welding experimental device and method, it is related to steel member under load welding reinforcement technical field, including detachable lever component, detachable lever component in the power arm end of lever is connected with pulley block component, the resistance arm end of lever is connected with load transmission stability component, load transmission stability component is clamped with steel test piece, the upper side of steel test piece is abutted with test piece end plate, and test piece end plate is installed on counterforce frame by test piece fixing bolt;The reverse side of steel test piece welding is provided with temperature field-strain field synchronous coupling measurement component, and temperature field-strain field synchronous coupling measurement component detects temperature field and strain field synchronous change data in whole process of steel test piece loading stage and holding stage.The application has simple structure, reasonable layout, and improves the accuracy of measurement data in steel test piece welding process.

Description

Technical Field

[0001] This invention relates to the field of welding reinforcement technology for steel components under load, and particularly to a welding experimental apparatus and method for gravity-hydraulic hybrid loading and holding. Background Technology

[0002] Currently, social engineering construction is transitioning from a period of equal emphasis on new construction and renovation / reinforcement to a phase focused on the maintenance and renovation of existing buildings. According to engineering data, renovation saves approximately two-fifths of the cost and shortens the construction period by about 50% compared to new construction, making the reinforcement and renovation of existing buildings an urgent task. Reinforcement of existing steel structures mainly falls into two categories: unloading reinforcement and load reinforcement. The former is cumbersome and interrupts normal structural use, while the latter is simpler, more economical, and has minimal impact on structural functionality. On the other hand, welding reinforcement has become a primary technical method for steel structure reinforcement due to its convenience and speed. In summary, welding reinforcement of existing steel structures under load is widely accepted and highly anticipated in current reinforcement projects. However, in the actual welding reinforcement process of in-service structures, welding technology exhibits uncertainties such as localized high temperatures and rapid attenuation. Combined with the coupling effect of different load states on the in-service structure, the interaction mechanism between the load and the high welding temperature is unclear, leading to concerns about safety issues during the welding reinforcement process under load. Existing research on welded reinforced steel member tests under load often employs electro-hydraulic servo control systems and prestressed tendons to achieve the initial stress ratio. However, this approach has the following drawbacks: 1) The compressive potential energy stored in the pressure oil of the electro-hydraulic servo control system cannot provide a static constant load; 2) Power outages or equipment failures during the test can lead to unstable load levels on the specimen, affecting the accuracy of the test; 3) The high temperature during welding causes thermal expansion and contraction deformation of the member, resulting in unloading phenomena.

[0003] In the prior art, patent CN201716239U discloses a gravity loading test device, including a base and two columns symmetrically fixed on the base. A crossbeam is fixed to the upper part of the two columns by a crossbeam limiting nut. Three downward-facing concave fixing blocks are fixed at intervals on the crossbeam. A cantilever lever is fixed in each of the three concave fixing blocks. A loading limiting block is provided on each of the three cantilever levers. A pulley loading device is provided at the front end of the cantilever of each of the three cantilever levers, and a counterweight is provided at the rear end. This device can precisely control the load by adjusting the lever arm ratio, the number of pulleys, and the weight of the weights. It can accurately apply the load that changes in stages and provide a long-term constant load for rheological tests. Since no electric or hydraulic servo control system is used, it saves energy and ensures the precise constantness of the load. Its structure is simple, easy to manufacture, inexpensive, and reliable in use. The shortcomings of this technical solution are: using a rectangular cross-section steel column as a lever results in poor out-of-plane stability, which cannot meet the large force requirements of the test; using a nut to fix the crossbeam to limit the vertical displacement of the lever cannot meet the large force requirements of the test; after the self-weight load is amplified and transformed by the pulley block and lever, the force acting on the specimen lacks verification and validation; for welding reinforcement tests under load, there is a lack of full-field coupling measurement of strain field and temperature field and a secondary loading system.

[0004] In the prior art, patent CN111307598A discloses a gravity-amplified constant-pressure loading coal and rock creep test device and method, including a triaxial pressure chamber containing a coal and rock specimen for applying confining pressure; a closed water tank gravity loading system located above the triaxial pressure chamber for adjusting the overall weight required for the test by adjusting the mass of water, thereby adjusting the magnitude of the force applied to the coal and rock specimen; and a force amplification device located above the triaxial pressure chamber and connected to the closed water tank gravity loading system for amplifying the force applied by the closed water tank gravity loading system and applying axial loading to the coal and rock specimen in the triaxial pressure chamber. This invention is simple to operate, inexpensive, and provides stable test conditions for studying the creep properties of coal and rock under complex stress states. It can accurately grasp the relevant data on the increase of deformation of coal and rock over time under constant load, ensuring the scientific rigor, accuracy, and precision of the study on the deformation and instability of coal and rock. The shortcomings of this technical solution are: after the self-weight load is amplified and transformed by the pulley block and lever, the force acting on the specimen lacks verification and validation; for the axial static test of the reinforced specimen, it cannot meet the test requirements for larger forces; and there is a lack of temperature field and strain field measurement systems during the specimen welding process.

[0005] In the prior art, patent CN103983465A discloses a self-balancing gravity load loading device, including a "V"-shaped hanger, a series of pulleys, a hook, a steel wire rope, a steel wire rope fixing device, and a reaction base. The series of pulleys consists of two parallel pulley systems, upper and lower, with multiple pulleys arranged side-by-side and wound sequentially with a steel wire rope. By suspending the required weight on the hook, the load is amplified by the series of pulleys and then transferred to the distribution beam via the "V"-shaped hanger. The distribution beam then transfers the load to the test specimen. The specimen is placed on the reaction base, and the series of pulleys is connected to the reaction base via the steel wire rope, which is then secured with the steel wire rope fixing device. This invention, through the pulley system and a specific transfer device, can conveniently and stably achieve the loading of gravity loads. The shortcomings of this technical solution are: the pulley system is only connected by steel wire rope, resulting in low assembly efficiency; when the number of pulleys is large, the stability of the pulley system is poor; the force amplification is achieved solely through the pulley system, which cannot meet the large force requirements of the test; and the actual load acting on the specimen cannot be verified.

[0006] Electro-hydraulic servo control technology can meet the precise force requirements of the load specimen, with stable and accurate load output. It is a mature technology that meets the initial stress ratio requirements for welded reinforcement of the load specimen. However, the equipment purchase and maintenance costs are high, and many laboratories lack the necessary facilities. Furthermore, electro-hydraulic servo systems exhibit a certain degree of hysteresis. When the welded specimen undergoes heating and cooling under load, localized thermal expansion and contraction deformation occurs, causing the load on the specimen to unload. The electro-hydraulic servo system then processes this deformation, replenishes the hydraulic cylinder, and finally restores the required load size. This process causes load fluctuations, reducing the reliability of the test results.

[0007] Based on the existing similar devices, the self-weight load amplification system mainly includes pulley blocks and lever blocks, with the latter often employing rod-like components. When the test requires a large load, this type of lever is prone to out-of-plane instability. Secondly, after multiple amplification and transfer of the load, the load value acting on the specimen lacks verification. When the test requires a large load, the levers are not securely fixed, failing to meet the requirements for simultaneous measurement of the temperature and strain fields during the load welding process and for secondary axial static loading after cooling.

[0008] Therefore, how to provide a welding experimental device and method with gravity-hydraulic hybrid loading and holding to accurately measure the temperature field and strain field changes over time during the entire welding process of steel specimens under stable holding conditions has become a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to provide a welding experimental device and method with gravity-hydraulic hybrid loading and holding, which solves the problems of existing welding experimental devices having small loads and being unable to accurately measure the temperature field and strain field changes over time during the entire welding process of steel specimens under stable holding conditions.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0011] This invention discloses a welding experimental device for gravity-hydraulic hybrid loading and holding, comprising a base and a truss lever assembly. The truss lever assembly is movably mounted on the base via prefabricated constraint supports. A pulley block is connected to the right end of the truss lever assembly, and a load transfer stabilizing component is connected to the upper left end of the truss lever assembly. A steel specimen from a welding fixture is clamped in the load transfer stabilizing component, and a specimen end plate abuts against the upper part of the steel specimen. The specimen end plate is mounted on a reaction frame via specimen fixing bolts. A hydraulic loading component abuts against the bottom left end of the truss lever assembly, and the hydraulic loading component is located directly below the load transfer stabilizing component. A temperature-strain field synchronous coupling measurement component is provided on the welded side of the steel specimen. The temperature-strain field synchronous coupling measurement component detects the synchronous changes in temperature and strain fields throughout the loading and holding stages of the steel specimen.

[0012] Preferably, the truss lever assembly is movably connected to the prefabricated constraint support and uses the connection point of the prefabricated constraint support as the rotation fulcrum. The right and left portions of the truss lever assembly on the prefabricated constraint support serve as the power arm and the resistance arm, respectively, and the length of the power arm of the truss lever assembly is greater than the length of the resistance arm.

[0013] Preferably, the truss lever assembly includes a lower chord of a steel pipe and an upper chord of a steel pipe, the lower chord of the steel pipe being parallel to the upper chord of the steel pipe; a vertical web member and a diagonal web member are connected between the lower chord of the steel pipe and the upper chord of the steel pipe; multiple vertical web members are provided and located on both sides, and the diagonal web members are located in the middle area;

[0014] A local reinforcing member is also connected between the lower chord of the steel pipe and the upper chord of the steel pipe. The local reinforcing member is located at the connection between the pulley block component and the truss lever assembly.

[0015] Preferably, the pulley block component includes a fixed pulley plate and a movable pulley plate. The fixed pulley plate is connected to the lower chord of the steel pipe, and the movable pulley plate is connected to the reaction frame via a rope. Multiple rotatable fixed pulleys are mounted on the fixed pulley plate, and multiple rotatable movable pulleys are mounted on the movable pulley plate. The number of fixed pulleys and the number of movable pulleys are determined by the magnification factor.

[0016] One end of the steel rope is connected to the reaction frame, and the other end passes through a plurality of adjacent fixed pulleys and movable pulleys in sequence before being connected to a weight, which is suspended in the air by the steel rope.

[0017] Preferably, the prefabricated constraint support includes a column support assembly, a fastening constraint assembly, and a rotating bearing component. Four rotating bearing components are placed on the opposite surfaces of the column support assembly and the fastening constraint assembly, and the truss lever assembly is clamped between the rotating bearing components.

[0018] The column support assembly includes a cylindrical steel column, a constrained lower crossbeam, and a first stiffening rib. The constrained lower crossbeam includes a first constrained plate and a first supporting column. The first supporting column is installed in the middle of the top surface of the first constrained plate. A first set of holes for assembling with the cylindrical steel column is opened at the center of the first constrained plate. The two first stiffening ribs are symmetrically distributed and their two ends are respectively connected to the bottom surface of the first constrained plate and the side wall of the cylindrical steel column.

[0019] The fastening and restraint assembly includes an assembled sleeve, a second stiffening rib, and a restraining upper crossbeam; the restraining upper crossbeam corresponds to the restraining lower crossbeam and is located directly above the restraining lower crossbeam; the restraining upper crossbeam includes a second restraining plate and a second receiving cylinder, the second receiving cylinder being installed in the middle of the bottom surface of the second restraining plate, and a second sleeve hole for assembling with the cylindrical steel column being opened at the center of the second restraining plate; two second stiffening ribs are symmetrically distributed and their two ends are respectively connected to the top surface of the second restraining plate and the assembled sleeve for assembling with the cylindrical steel column, and the assembled sleeve is fixed to the cylindrical steel column by sleeve fastening bolts;

[0020] The fastening and restraint assembly also includes a steel column nut. The outer peripheral wall of the cylindrical steel column is provided with an external thread that matches the internal thread of the steel column nut. The steel column nut is threadedly connected to the body of the cylindrical steel column and abuts against the top surface of the second restraint plate.

[0021] The first receiving cylinder and the second receiving cylinder are both corresponding to the rotating receiving component, which is rotatably connected to the first receiving cylinder and the second receiving cylinder. The rotating receiving component on the first receiving cylinder abuts against the lower chord of the steel pipe, and the rotating receiving component on the second receiving cylinder abuts against the upper chord of the steel pipe.

[0022] Preferably, the load transfer stabilizing component includes a load conversion component, the shape of which matches the upper chord of the steel pipe, the load conversion component being placed on the upper chord of the steel pipe and located at the resistance arm of the truss lever assembly; a ball joint support is installed on the load conversion component, a sensor conversion component is installed on the ball joint support, the load sensor is installed on the sensor conversion component, the top of the load sensor abuts against a specimen fixing plate, and the bottom of the steel specimen abuts against the top surface of the specimen fixing plate.

[0023] Preferably, the hydraulic loading component includes a load lowering conversion component, the shape of which matches the lower chord of the steel pipe, the load lowering conversion component abutting against the lower chord of the steel pipe, the load lowering conversion component being located directly below the load uppering conversion component, and a hydraulic jack being connected to the bottom of the load lowering conversion component, the hydraulic jack being mounted on a support component, and the support component being mounted on the base.

[0024] Preferably, the temperature field-strain field synchronous coupling measurement component includes a non-contact infrared thermometer and a non-contact optical measurement system, and the non-contact infrared thermometer and the non-contact optical measurement system achieve synchronous measurement through a simultaneous triggering device.

[0025] Preferably, the weight is a weight.

[0026] The present invention also provides a test method for a welding experimental apparatus applied to gravity-hydraulic hybrid loading and holding, comprising the following steps:

[0027] S1: Install the column support assembly, fix the cylindrical steel column near the reaction frame, and place the rotating support on the constrained lower beam. Use a crane to lift the truss lever assembly, and place the steel pipe lower chord in the truss lever assembly horizontally on the rotating support on the constrained lower beam. The contact position between the steel pipe lower chord and the rotating support is determined by a preset gravity amplification factor.

[0028] S2: Install the fastening and restraint assembly, take another rotating bearing and place it on the upper chord of the steel pipe, and the placement position of the rotating bearing on the upper chord of the steel pipe corresponds to the placement position of the rotating bearing on the lower chord of the steel pipe. Then, put the fastening and restraint assembly onto the cylindrical steel column and slide the fastening and restraint assembly down the cylindrical steel column until the second bearing cylinder in the fastening and restraint assembly contacts the rotating bearing on the upper chord of the steel pipe. At this time, tighten the steel column nut so that the steel column nut and the top of the restraint upper crossbeam abut together, and tighten the sleeve fastening bolt so that the assembled sleeve is clamped on the cylindrical steel column.

[0029] S3: Install the load transfer stabilizing component, place the load transfer component on the resistance arm of the upper chord of the steel pipe, then install the sensor transfer component on the ball joint support on the load transfer component, and finally place the specimen fixing plate on the load sensor on the sensor transfer component.

[0030] S4: Install the steel specimen, clamp the steel specimen on the top of the specimen fixing plate, place the specimen end plate on the top of the steel specimen, and then install the specimen end plate on the reaction frame through the specimen fixing bolts;

[0031] S5: Determine the number of fixed pulleys and movable pulleys according to the planned magnification factor, then install the pulley block components, suspend the fixed pulley disc on the lower chord of the steel pipe, and connect the movable pulley disc to the reaction frame through a rope. The movable pulley disc is located directly below the fixed pulley disc. Install multiple fixed pulleys and movable pulleys on the fixed pulley disc and the movable pulley disc respectively. Connect one end of the steel rope to the reaction frame, and pass the other end around the adjacent fixed pulleys and movable pulleys in sequence until it passes around the last fixed pulley to connect the weight.

[0032] S6: Weight preloading process. Weights are used to preload the load. After step S5, weights are slowly placed one by one. After placing the preset weights, the truss lever assembly is repositioned horizontally using a crane. At this time, the steel column nuts and sleeve fastening bolts are retightened.

[0033] S7: Weight loading process. The non-contact optical measurement system is activated. After each weight is loaded, the load is amplified by the combination of the truss lever assembly and the pulley block component. The load acting on the steel specimen is displayed by the load sensor, realizing the verification and calibration of the amplified load, until the steel specimen is loaded to the planned load level.

[0034] S8: Welding data measurement. Keeping the weight of the weight loaded in step S7 unchanged, turn on the non-contact infrared thermometer and perform welding reinforcement on the back side of the steel specimen. The non-contact infrared thermometer and the non-contact optical measurement system detect and record the temperature data and strain data of the steel specimen during the welding reinforcement process, so as to realize the coupled measurement of temperature and strain data under stable load of the specimen.

[0035] S9: Hydraulic loading measurement. After the steel specimen has cooled after welding, the support is placed below the truss lever assembly and directly below the load conversion component. The hydraulic jack is placed on the support and aligned using a laser calibrator to ensure that the hydraulic jack is directly below the load conversion component. At this time, the load conversion component is placed at the output end of the hydraulic jack. The weight of the load is kept constant. The hydraulic jack is used to apply axial static load to the steel specimen until the steel specimen fails. The strain data of the steel specimen during the hydraulic loading stage is recorded using the non-contact optical measurement system. The load transition from the initial loading stage to the secondary loading stage is smooth.

[0036] S10: Disassemble the experimental device. First, unload the hydraulic loading components, then remove the weights one by one, and then unload the pulley block components. After the pulley block components are unloaded, use the crane to lift the truss lever assembly, then loosen the sleeve fastening bolts and the steel column nuts, and remove the fastening constraint assembly. Then, use the crane to remove the truss lever assembly, and finally remove the load transmission stabilizing component to complete the disassembly of the experimental device.

[0037] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0038] This invention discloses a welding experimental apparatus and method for gravity-hydraulic hybrid loading and holding. The apparatus includes a detachable lever component comprising a truss lever assembly and an assembled constraint support for supporting the truss lever assembly. This invention utilizes a truss lever assembly instead of a traditional single steel pipe as a lever, which can meet the greater load requirements of the experiment. Furthermore, the assembled constraint support is designed with stiffening ribs to ensure that the assembled constraint support can stably support the truss lever assembly.

[0039] The device provided by this invention amplifies the gravity generated by the heavy object through a combination of truss lever assembly and pulley block components. It is low in cost, has a large load amplification factor, and can meet experimental requirements.

[0040] By combining prefabricated constraint supports and load transfer stabilizing components, load transfer stability is ensured, providing a stable load-bearing environment for welding experiments and guaranteeing the accuracy of the experiments. The load transfer stabilizing components are equipped with load sensors, which can reflect and verify the actual load acting on the specimen in real time.

[0041] The non-contact infrared thermometer and non-contact optical measurement system in this invention can achieve synchronous coupled measurement of the temperature field and strain field throughout the welding reinforcement process under stable load conditions of the specimen through a simultaneous triggering device;

[0042] The experimental method of the welding experimental device for gravity-hydraulic hybrid loading and holding provided by the present invention involves sequentially installing the column support assembly, fastening constraint assembly, load transfer stabilizing component, steel specimen, and pulley block assembly. Then, the steel specimen is subjected to welding reinforcement experimental data measurement and the steel specimen is destroyed by the hydraulic loading component. Afterwards, the hydraulic loading component, pulley block assembly, fastening constraint assembly, truss lever assembly, and load transfer stabilizing component are sequentially removed, so that the device provided by the present invention can be used repeatedly. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings.

[0044] Figure 1 This is a schematic diagram of the welding experimental device for gravity-hydraulic hybrid loading and holding according to the present invention;

[0045] Figure 2 This is a schematic diagram of the pulley block component structure of the present invention;

[0046] Figure 3 This is a schematic diagram of the prefabricated constraint support structure of the present invention;

[0047] Figure 4 This is a schematic diagram of the column support component structure of the present invention;

[0048] Figure 5 This is a schematic diagram of the fastening and restraint assembly structure of the present invention;

[0049] Figure 6 This is a schematic diagram of the assembly structure of the load transfer stabilization component of the present invention;

[0050] Figure 7 This is a schematic diagram of the hydraulic loading structure component of the present invention.

[0051] Explanation of reference numerals in the attached drawings: 1. Truss lever assembly; 2. Pulley block assembly; 3. Column support assembly; 4. Fastening and restraint assembly; 5. Rotating support component; 6. Welded fastener; 7. Load transfer and stabilizing component; 8. Hydraulic loading component; 9. Support component; 11. Steel pipe lower chord; 12. Vertical web member; 13. Diagonal web member; 14. Local reinforcement component; 15. Steel pipe upper chord; 21. Movable pulley; 22. Fixed pulley; 23. Weight; 24. Fixed pulley disc; 25. Steel rope; 26. Movable pulley disc; 27. Reaction frame; 31. Cylindrical steel column 32. Lower constrained crossbeam; 33. First stiffening rib; 41. Assembled sleeve; 42. Sleeve fastening bolt; 43. Second stiffening rib; 44. Upper constrained crossbeam; 45. Steel column nut; 61. Specimen end plate; 62. Specimen fixing bolt; 63. Steel specimen; 71. Load conversion component; 72. Ball joint support; 73. Specimen fixing plate; 74. Load sensor; 75. Sensor conversion component; 81. Load conversion component; 82. Hydraulic jack; 101. Non-contact infrared thermometer; 102. Non-contact optical measurement system. Detailed Implementation

[0052] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present 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 only used to explain the present invention and are not intended to limit the present invention.

[0053] like Figure 1-7 As shown, this invention provides a welding experimental device for gravity-hydraulic hybrid loading and holding, including a base 17 and a truss lever assembly 1. The truss lever assembly 1 is movably mounted on the base 17 via an assembled constraint support 16. A pulley block component 2 is connected to the right end of the truss lever assembly 1, and a load transfer stabilizing component 7 is connected to the upper left end of the truss lever assembly. A steel specimen 63 from a welding fixture 6 is clamped in the load transfer stabilizing component 7. A specimen end plate 61 abuts against the upper part of the steel specimen 63, and the specimen end plate 61 is mounted on a reaction frame via specimen fixing bolts 62. A hydraulic loading component 8 abuts against the bottom left end of the truss lever assembly 1, and the hydraulic loading component 8 is located directly below the load transfer stabilizing component 7. A temperature field-strain field synchronous coupling measurement component is provided on the welded side of the steel specimen 63. The temperature field-strain field synchronous coupling measurement component detects the synchronous changes in temperature field and strain field throughout the loading and holding stages of the steel specimen 63.

[0054] Specifically, the temperature field-strain field can be placed away from the welding position of the steel specimen 63 through the coupling measurement component to avoid damage to the temperature field-strain field through the coupling measurement component and interference from welding light.

[0055] The amplified gravity generated by pulley block component 2 is amplified by the lever and transmitted to load transfer stabilizing component 7, and then transmitted to the body of steel specimen 63 via load transfer stabilizing component 7. Load transfer stabilizing component 7 ensures the stability and accuracy of load transfer during the welding and reinforcement of steel specimen 63, while also verifying the amplified load force transmitted by the lever. The amplification factor of the gravity generated by the lever on pulley block component 2 is determined by the ratio of the length of the lever's effort arm to its resistance arm.

[0056] Specifically, the truss lever assembly 1 is movably connected to the prefabricated constraint support 16 and takes the connection point of the prefabricated constraint support 16 as the rotation fulcrum. The right and left parts of the truss lever assembly 1 serve as the power arm and the resistance arm, respectively. The length of the power arm of the truss lever assembly 1 is greater than the length of the resistance arm.

[0057] Specifically, the truss lever assembly 1 includes a steel pipe lower chord 11 and a steel pipe upper chord 15, with the steel pipe lower chord 11 parallel to the steel pipe upper chord 15; a vertical web member 12 and an oblique web member 13 are connected between the steel pipe lower chord 11 and the steel pipe upper chord 15; multiple vertical web members 12 are provided and located on both sides, and the oblique web members 13 are located in the middle area;

[0058] A local reinforcing member 14 is also connected between the lower chord 11 of the steel pipe and the upper chord 15 of the steel pipe. The local reinforcing member 14 is located at the connection between the pulley block component 2 and the truss lever assembly 1.

[0059] The design of the vertical web member 12, the diagonal web member 13, and the local reinforcement member 14 effectively improves the structural strength of the truss lever assembly 1. The truss lever assembly 1 replaces the traditional single steel pipe as a lever, enabling the present invention to test larger load forces.

[0060] Specifically, the pulley block component 2 includes a fixed pulley plate 24 and a movable pulley plate 26. The fixed pulley plate 24 is connected to the lower chord of the steel pipe 11, and the movable pulley plate 26 is connected to the reaction frame 27 via ropes. The fixed pulley plate 24 is equipped with multiple rotatable fixed pulleys 22, and the movable pulley plate 26 is equipped with multiple rotatable movable pulleys 21. The number of fixed pulleys 22 and the number of movable pulleys 21 are determined by the magnification factor.

[0061] One end of the steel rope 25 is connected to the reaction frame 27, and the other end passes through a plurality of adjacent fixed pulleys 22 and movable pulleys 21 in sequence, and is connected to a weight 23, which is suspended in the air by the steel rope 25.

[0062] Among them, installing multiple rotatable fixed pulleys on the fixed pulley plate can make the fixed pulley plate bear force evenly. The uniform force on the fixed pulley plate can make the lower chord of the steel pipe 11 connected to it bear force evenly. The uniform force on the lower chord of the steel pipe 11 ensures that the force transmitted from the truss lever assembly 1 to the load transmission stabilizing component 7 is evenly distributed, further ensuring that the steel specimen 63 bears force evenly.

[0063] Specifically, the prefabricated constraint support 16 includes a column support assembly 3, a fastening constraint assembly 4, and a rotating bearing 5. Four rotating bearings are placed on the opposite surfaces of the column support assembly 3 and the fastening constraint assembly 4, and the truss lever assembly 1 is clamped between the rotating bearings.

[0064] The column support assembly 3 includes a cylindrical steel column 31, a constrained lower crossbeam 32, and a first stiffening rib 33. The constrained lower crossbeam 32 includes a first constrained plate and a first supporting column. The first supporting column is installed in the middle of the top surface of the first constrained plate. A first set of holes for assembly with the cylindrical steel column 31 is opened at the center of the first constrained plate. The two first stiffening ribs 33 are symmetrically distributed and their two ends are respectively connected to the bottom surface of the first constrained plate and the side wall of the cylindrical steel column 31.

[0065] The fastening and restraining assembly 4 includes an assembled sleeve 41, a second stiffening rib 43, and a restraining upper crossbeam 44; the restraining upper crossbeam 44 corresponds to the restraining lower crossbeam 32 and is located directly above the restraining lower crossbeam 32; the restraining upper crossbeam 44 includes a second restraining plate and a second receiving cylinder, the second receiving cylinder being installed in the middle of the bottom surface of the second restraining plate, and a second sleeve hole for assembly with the cylindrical steel column 31 being opened at the center of the second restraining plate; two second stiffening ribs 43 are symmetrically distributed and their two ends are respectively connected to the top surface of the second restraining plate and the assembled sleeve 41 for assembly with the cylindrical steel column 31, and the assembled sleeve 41 is fixed to the cylindrical steel column 31 by sleeve fastening bolts 42;

[0066] The fastening and restraint assembly 4 also includes a steel column nut 45. The outer peripheral wall of the cylindrical steel column 31 is provided with an external thread that matches the internal thread of the steel column nut 45. The steel column nut 45 is threadedly connected to the body of the cylindrical steel column 31 and abuts against the top surface of the second restraint plate.

[0067] The first receiving cylinder and the second receiving cylinder are both corresponding to the rotating receiving member 5. The rotating receiving member 5 is rotatably connected to the first receiving cylinder and the second receiving cylinder. The rotating receiving member 5 on the first receiving cylinder abuts against the lower chord of the steel pipe 11, and the rotating receiving member 5 on the second receiving cylinder abuts against the upper chord of the steel pipe 15.

[0068] The design of the first stiffening rib 33 and the second stiffening rib 43 effectively improves the structural strength of the prefabricated restraint support, ensuring that the prefabricated restraint support can support a large load. The rotating bearing 5 provides a fixing function for the truss lever assembly 1, while also providing a rotation function for the truss lever assembly 1, ensuring that the truss lever assembly 1 can rotate between the column support assembly 3 and the fastening restraint assembly 4.

[0069] Specifically, the load transfer stabilizing component 7 includes a load conversion component 71, the shape of which matches the upper chord of the steel pipe 15. The load conversion component 71 is placed on the upper chord of the steel pipe 15 and located at the resistance arm of the truss lever assembly 1. A ball joint support 72 is installed on the load conversion component 71, a sensor conversion component 75 is installed on the ball joint support 72, and a load sensor 74 is installed on the sensor conversion component 75. The top of the load sensor 74 abuts against a specimen fixing plate 73, and the bottom of the steel specimen 63 abuts against the top surface of the specimen fixing plate 73.

[0070] The ball joint support 72 is used to eliminate the influence caused by the rotation of the truss lever assembly 1 during the loading and holding stages. The sensor conversion component 75 not only fixes and transmits the load sensor 74, but also further fixes and constrains the ball joint support 72. The load sensor 74 is used to verify the actual load applied to the steel specimen 63. The specimen fixing plate 73 is used to fix the steel specimen 63. The specimen fixing plate 73 has various specifications and can be adjusted and replaced according to the cross-sectional dimensions of the steel specimen 63.

[0071] Specifically, the hydraulic loading component 8 includes a load lowering conversion component 81, the shape of which matches the lower chord of the steel pipe 11. The load lowering conversion component 81 abuts against the lower chord of the steel pipe 11 and is located directly below the load uppering conversion component 71. A hydraulic jack 82 is connected to the bottom of the load lowering conversion component 81. The hydraulic jack 82 is mounted on a support component 9, and the support component 9 is mounted on the base 17.

[0072] Specifically, the temperature field-strain field synchronous coupling measurement component includes a non-contact infrared thermometer 101 and a non-contact optical measurement system 102. The non-contact infrared thermometer 101 and the non-contact optical measurement system 102 achieve synchronous measurement through a simultaneous triggering device.

[0073] The non-contact optical measurement system 102 is an existing measurement system.

[0074] Specifically, the weight 23 is a weight.

[0075] This invention discloses a welding experimental apparatus and method for gravity-hydraulic hybrid loading and holding. The apparatus includes a detachable lever component comprising a truss lever assembly and an assembled constraint support for supporting the truss lever assembly. This invention utilizes a truss lever assembly instead of a traditional single steel pipe as a lever, which can meet the greater load requirements of the experiment. Furthermore, the assembled constraint support is designed with stiffening ribs to ensure that the assembled constraint support can stably support the truss lever assembly.

[0076] The device provided by this invention amplifies the gravity generated by the heavy object through a combination of truss lever assembly and pulley block components. It is low in cost, has a large load amplification factor, and can meet experimental requirements.

[0077] By combining prefabricated constraint supports and load transfer stabilizing components, load transfer stability is ensured, providing a stable load-bearing environment for welding experiments and guaranteeing the accuracy of the experiments; among them, load sensors are installed in the load transfer stabilizing components, which can reflect the real load acting on the specimen in real time.

[0078] The non-contact infrared thermometer and non-contact optical measurement system in this invention can achieve synchronous coupled measurement of the temperature field and strain field throughout the welding reinforcement process under stable load conditions of the specimen through a simultaneous triggering device.

[0079] The present invention also provides a test method for a welding experimental apparatus applied to gravity-hydraulic hybrid loading and holding, comprising the following steps:

[0080] S1: Install the column support assembly 3, fix the cylindrical steel column 31 near the reaction frame, and place the rotating support 5 on the constrained lower beam 32. Use a crane to lift the truss lever assembly 1, and place the steel pipe lower chord 11 in the truss lever assembly 1 horizontally on the rotating support 5 on the constrained lower beam 32. The contact position between the steel pipe lower chord 11 and the rotating support 5 is determined by a preset gravity amplification factor.

[0081] S2: Install the fastening and restraint assembly 4, take another rotating support piece 5 and place it on the upper chord of the steel pipe 15, and the placement position of the rotating support piece 5 on the upper chord of the steel pipe 15 corresponds to the placement position of the rotating support piece 5 on the lower chord of the steel pipe 11. Then, put the fastening and restraint assembly 4 onto the cylindrical steel column 31 and slide the fastening and restraint assembly 4 down the cylindrical steel column 31 until the second support cylinder in the fastening and restraint assembly 4 contacts the rotating support piece 5 on the upper chord of the steel pipe 15. At this time, tighten the steel column nut 45 so that the steel column nut 45 and the top of the restraint upper crossbeam 44 abut together, and tighten the sleeve fastening bolt 42 so that the assembled sleeve 41 is clamped on the cylindrical steel column 31.

[0082] S3: Install the load transfer stabilizing component 7, place the load transfer component 71 on the resistance arm of the upper chord of the steel pipe 15, then install the sensor transfer component 75 on the ball joint support 72 on the load transfer component 71, and finally place the specimen fixing plate 73 on the load sensor 74 on the sensor transfer component 75.

[0083] S4: Install steel specimen 63, clamp the steel specimen 63 on the top of specimen fixing plate 73, place specimen end plate 61 on the top of steel specimen 63, and then install specimen end plate 61 on the reaction frame through specimen fixing bolt 62.

[0084] S5: Determine the number of fixed pulleys 22 and movable pulleys 21 according to the planned magnification factor, then install the pulley block component 2, suspend the fixed pulley plate 24 on the lower chord of the steel pipe 11, and connect the movable pulley plate 26 to the reaction frame 27 through a rope. The fixed pulley plate 26 is located directly below the movable pulley plate 24. Install multiple fixed pulleys 22 and movable pulleys 21 on the fixed pulley plate 24 and the movable pulley plate 26 respectively. Connect one end of the steel rope 25 to the reaction frame 27, and the other end passes around the adjacent fixed pulleys 22 and 21 in sequence until it passes around the last fixed pulley 22 and connects to the weight 23.

[0085] S6: Weight preloading process. Weights are used for weight 23. After step S5, weights are placed one by one slowly to perform weight preloading process. After placing the preset weights, the truss lever assembly 1 is re-lifted to the horizontal position using a crane. At this time, the steel column nut 45 and the sleeve fastening bolt 42 are tightened again.

[0086] S7: Weight loading process, the non-contact optical measurement system 102 is turned on, and after each weight is loaded, the load is amplified by the combination of the truss lever assembly 1 and the pulley block assembly 2. The load acting on the steel specimen 63 is displayed by the load sensor 74 to realize the verification and calibration of the amplified load until the steel specimen 63 is loaded to the planned load level.

[0087] S8: Welding data measurement. Keeping the weight of the weight loaded in step S7 unchanged, turn on the non-contact infrared thermometer 101 and perform welding reinforcement on the back side of the steel specimen 63; the non-contact infrared thermometer 101 and the non-contact optical measurement system 102 detect and record the temperature data and strain data of the steel specimen 63 during the welding reinforcement process, so as to realize the coupled measurement of temperature and strain data under stable load of the specimen;

[0088] S9: Hydraulic loading measurement. After the steel specimen 63 has cooled after welding, the support 9 is placed below the truss lever assembly 1 and directly below the load conversion component 71. The hydraulic jack 82 is placed on the support 9 and aligned using a laser calibrator to ensure that the hydraulic jack 82 is directly below the load conversion component 71. At this time, the load conversion component 81 is placed at the output end of the hydraulic jack 82. The weight of the load remains constant. The hydraulic jack 82 is used to apply axial static load to the steel specimen 63 until the steel specimen 63 is damaged. The strain data of the steel specimen 63 during the hydraulic loading stage is recorded using the non-contact optical measurement system 102 to achieve a smooth load connection from the specimen loading stage to the secondary loading stage.

[0089] S10: Disassemble the experimental device. First, unload the hydraulic loading component 8, then remove the weights one by one, and then unload the pulley block component 2. After unloading the pulley block component 2, use the crane to lift the truss lever assembly 1, then loosen the sleeve fastening bolt 42 and the steel column nut 45, and remove the fastening constraint component 4. Then, use the crane to remove the truss lever assembly 1, and finally remove the load transmission stabilizing component 7 to complete the disassembly of the experimental device.

[0090] The experimental method of the welding experimental device for gravity-hydraulic hybrid loading and holding provided by the present invention involves sequentially installing the column support assembly, fastening constraint assembly, load transfer stabilizing component, steel specimen, and pulley block assembly. Then, the steel specimen is subjected to welding reinforcement experimental data measurement and the steel specimen is destroyed by the hydraulic loading component. Afterwards, the hydraulic loading component, pulley block assembly, fastening constraint assembly, truss lever assembly, and load transfer stabilizing component are sequentially removed, so that the device provided by the present invention can be used repeatedly.

[0091] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0092] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A welding test device for gravity-hydraulic hybrid loading and holding, characterized in that: The assembly includes a base (17) and a truss lever assembly (1). The truss lever assembly (1) is movably mounted on the base (17) via a prefabricated constraint support (16). A pulley block assembly (2) is connected to the right end of the truss lever assembly (1), and a load transfer stabilizing component (7) is connected above the left end of the truss lever assembly (1). A steel specimen (63) from a welded fastener (6) is clamped in the load transfer stabilizing component (7). A specimen end plate (61) abuts above the steel specimen (63). The end plate (61) is installed on the reaction frame (27) by the specimen fixing bolts (62); the bottom left end of the truss lever assembly (1) is abutted against the hydraulic loading component (8), and the hydraulic loading component (8) is located directly below the load transfer stabilizing component (7); a temperature field-strain field synchronous coupling measurement component is provided on one side of the steel specimen (63), and the temperature field-strain field synchronous coupling measurement component detects the synchronous change data of temperature field and strain field during the entire process of loading stage and holding stage of the steel specimen (63); The truss lever assembly (1) includes a steel pipe lower chord (11) and a steel pipe upper chord (15), the steel pipe lower chord (11) being parallel to the steel pipe upper chord (15); a vertical web member (12) and a diagonal web member (13) are connected between the steel pipe lower chord (11) and the steel pipe upper chord (15); multiple vertical web members (12) are provided and located on both sides, and the diagonal web member (13) is located in the middle area; A local reinforcing member (14) is also connected between the lower chord (11) and the upper chord (15) of the steel pipe. The local reinforcing member (14) is located at the connection between the pulley block component (2) and the truss lever assembly (1). The assembled constraint support (16) includes a column support assembly (3), a fastening constraint assembly (4) and a rotating bearing (5). Four rotating bearings (5) are placed on the opposite surfaces of the column support assembly (3) and the fastening constraint assembly (4). The truss lever assembly (1) is clamped between the rotating bearings (5). The column support assembly (3) includes a cylindrical steel column (31), a constrained lower crossbeam (32), and a first stiffening rib (33). The constrained lower crossbeam (32) includes a first constrained plate and a first receiving column. The first receiving column is installed in the middle of the top surface of the first constrained plate. A first set of holes for assembling with the cylindrical steel column (31) is opened at the center of the first constrained plate. The two first stiffening ribs (33) are symmetrically distributed and their two ends are respectively connected to the bottom surface of the first constrained plate and the side wall of the cylindrical steel column (31). The fastening and restraint assembly (4) includes an assembled sleeve (41), a second stiffening rib (43), and a restraining upper crossbeam (44); the restraining upper crossbeam (44) corresponds to the restraining lower crossbeam (32) and is located directly above the restraining lower crossbeam (32); the restraining upper crossbeam (44) includes a second restraining plate and a second receiving cylinder, the second receiving cylinder is installed in the middle of the bottom surface of the second restraining plate, and a second sleeve hole for assembling with the cylindrical steel column (31) is opened at the center of the second restraining plate; two second stiffening ribs (43) are symmetrically distributed and their two ends are respectively connected to the top surface of the second restraining plate and the assembled sleeve (41) for assembling with the cylindrical steel column (31), and the assembled sleeve (41) is fixed to the cylindrical steel column (31) by sleeve fastening bolts (42); The fastening and restraint assembly (4) also includes a steel column nut (45). The outer peripheral wall of the cylindrical steel column (31) is provided with an external thread that matches the internal thread of the steel column nut (45). The steel column nut (45) is threadedly connected to the body of the cylindrical steel column (31) and abuts against the top surface of the second restraint plate. The first receiving cylinder and the second receiving cylinder are both corresponding to the rotating receiving component (5). The rotating receiving component (5) is rotatably connected to the first receiving cylinder and the second receiving cylinder. The rotating receiving component (5) on the first receiving cylinder abuts against the lower chord of the steel pipe (11), and the rotating receiving component (5) on the second receiving cylinder abuts against the upper chord of the steel pipe (15). The load transfer stabilizing component (7) includes a load transfer member (71), the shape of which matches the upper chord of the steel pipe (15). The load transfer member (71) is placed on the upper chord of the steel pipe (15) and located at the resistance arm of the truss lever assembly (1). A ball joint support (72) is installed on the load transfer member (71), a sensor transfer member (75) is installed on the ball joint support (72), a load sensor (74) is installed on the sensor transfer member (75), the top of the load sensor (74) abuts against a specimen fixing plate (73), and the bottom of the steel specimen (63) abuts against the top surface of the specimen fixing plate (73).

2. The welding test apparatus for gravity-hydraulic hybrid loading and holding according to claim 1, characterized in that: The truss lever assembly (1) is movably connected to the prefabricated constraint support (16) and takes the connection point of the prefabricated constraint support (16) as the rotation fulcrum. The right and left parts of the truss lever assembly (1) are respectively the power arm and the resistance arm. The length of the power arm of the truss lever assembly (1) is greater than the length of the resistance arm.

3. The welding test apparatus for gravity-hydraulic hybrid loading and holding according to claim 2, characterized in that: The pulley block component (2) includes a fixed pulley plate (24) and a movable pulley plate (26). The fixed pulley plate (24) is connected to the lower chord of the steel pipe (11), and the movable pulley plate (26) is connected to the reaction frame (27) by a rope. The fixed pulley plate (24) is equipped with a plurality of rotatable fixed pulleys (22), and the movable pulley plate (26) is equipped with a plurality of rotatable movable pulleys (21). One end of the steel rope (25) is connected to the reaction frame (27), and the other end passes through a plurality of adjacent fixed pulleys (22) and movable pulleys (21) in sequence before being connected to a weight (23), which is suspended in the air by the steel rope (25).

4. The welding test apparatus for gravity-hydraulic hybrid loading and holding according to claim 3, characterized in that: The hydraulic loading component (8) includes a load lowering conversion component (81), the shape of which matches the lower chord of the steel pipe (11), the load lowering conversion component (81) abuts against the lower chord of the steel pipe (11), the load lowering conversion component (81) is located directly below the load uppering conversion component (71), and a hydraulic jack (82) is connected to the bottom of the load lowering conversion component (81). The hydraulic jack (82) is installed on the support component (9), and the support component (9) is installed on the base (17).

5. The welding test apparatus for gravity-hydraulic hybrid loading and holding according to claim 4, characterized in that: The temperature field-strain field synchronous coupling measurement component includes a non-contact infrared thermometer (101) and a non-contact optical measurement system (102). The non-contact infrared thermometer and the non-contact optical measurement system achieve synchronous measurement through a simultaneous triggering device.

6. The welding test apparatus for gravity-hydraulic hybrid loading and holding according to claim 5, characterized in that: The weight (23) is a weight.

7. A test method for a welding test apparatus using the gravity-hydraulic hybrid loading and holding method as described in claim 6, characterized in that, Includes the following steps: S1: Install the column support assembly (3), fix the cylindrical steel column (31) near the reaction frame (27), and place the rotating support (5) on the constrained lower beam (32). Use a crane to lift the truss lever assembly (1), and place the steel pipe lower chord (11) in the truss lever assembly (1) horizontally on the rotating support (5) on the constrained lower beam (32). The contact position between the steel pipe lower chord (11) and the rotating support (5) is determined by the preset gravity amplification factor. S2: Install the fastening and restraint assembly (4), take another rotating bearing (5) and place it on the upper chord of the steel pipe (15), and the placement position of the rotating bearing (5) on the upper chord of the steel pipe (15) corresponds to the placement position of the rotating bearing (5) on the lower chord of the steel pipe (11). Then, put the fastening and restraint assembly (4) onto the cylindrical steel column (31) and slide the fastening and restraint assembly (4) down the cylindrical steel column (31) until the second bearing cylinder in the fastening and restraint assembly (4) contacts the rotating bearing (5) on the upper chord of the steel pipe (15). At this time, tighten the steel column nut (45) so that the top of the steel column nut (45) and the restraint upper crossbeam (44) abut together, and tighten the sleeve fastening bolt (42) so that the assembled sleeve (41) is clamped on the cylindrical steel column (31). S3: Install the load transfer stabilizing component (7), place the load transfer component (71) on the resistance arm of the upper chord of the steel pipe (15), then install the sensor transfer component (75) on the ball joint support (72) on the load transfer component (71), and finally place the specimen fixing plate (73) on the load sensor (74) on the sensor transfer component (75); S4: Install the steel specimen (63), clamp the steel specimen (63) on the top of the specimen fixing plate (73), place the specimen end plate (61) on the top of the steel specimen (63), and then install the specimen end plate (61) on the reaction frame (27) through the specimen fixing bolt (62); S5: Determine the number of fixed pulleys (22) and movable pulleys (21) according to the planned magnification factor, then install the pulley block component (2), suspend the fixed pulley plate (24) on the lower chord of the steel pipe (11), and connect the movable pulley plate (26) to the reaction frame (27) by rope. The movable pulley plate (26) is located directly below the fixed pulley plate (24). Install multiple fixed pulleys (22) and movable pulleys (21) on the fixed pulley plate (24) and the movable pulley plate (26) respectively. Connect one end of the steel rope (25) to the reaction frame (27), and the other end passes around the adjacent fixed pulleys (22) and movable pulleys (21) in sequence until it passes around the last fixed pulley (22) to connect the weight (23). S6: Weight preloading process. The weight (23) is preloaded by placing weights one by one after step S5. After placing the preset weights, the truss lever assembly (1) is re-lifted to a horizontal position using a crane. At this time, the steel column nut (45) and sleeve fastening bolt (42) are tightened again. S7: Weight loading process, turn on the non-contact optical measurement system (102), after each weight is loaded, the load is amplified by the combination of the truss lever assembly (1) and the pulley block assembly (2), and the load acting on the steel specimen (63) is displayed by the load sensor (74) to realize the verification and check of the amplified load until the steel specimen (63) is loaded to the planned load level; S8: Welding data measurement. Keeping the weight of the weight in step S7 unchanged, turn on the non-contact infrared thermometer (101) and weld and reinforce the back side of the steel specimen (63). The non-contact infrared thermometer (101) and the non-contact optical measurement system (102) detect and record the temperature data and strain data of the steel specimen (63) during the welding and reinforcement process, so as to realize the coupled measurement of temperature and strain data under stable load of the specimen. S9: Hydraulic loading measurement. After the steel specimen (63) is welded and cooled, the support (9) is placed below the truss lever assembly (1) and directly below the load conversion component (71). The hydraulic jack (82) is placed on the support (9) and aligned using a laser calibrator to ensure that the hydraulic jack (82) is directly below the load conversion component (71). At this time, the load conversion component (81) is placed at the output end of the hydraulic jack (82). The weight of the load is kept constant. The hydraulic jack (82) is used to apply axial static load to the steel specimen (63) until the steel specimen (63) is destroyed. The strain data of the steel specimen (63) during the hydraulic loading stage is recorded using the non-contact optical measurement system (102) to achieve a smooth connection between the load stage and the secondary loading stage of the specimen. S10: Disassemble the test device. First, unload the hydraulic loading component (8), then remove the weights one by one, and then unload the pulley block component (2). After the pulley block component (2) is unloaded, use the crane to lift the truss lever assembly (1), then loosen the sleeve fastening bolt (42) and the steel column nut (45), remove the fastening constraint component (4), then use the crane to remove the truss lever assembly (1), and finally remove the load transfer stabilizing component (7) to complete the disassembly of the test device.

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