T-shaped joint drop hammer impact test device and impact test method thereof

Abstract

The invention discloses a T-shaped joint drop hammer impact test device and an impact test method thereof.The device comprises a frame body, a fixed base is arranged at the bottom in the frame body, a T-shaped joint sample is connected to the fixed base, and an impact assembly, a locking assembly and a lifting assembly are arranged above the T-shaped joint sample; the lifting assembly is connected with the impact assembly through a locking assembly, and the locking assembly is provided with a locking position and a releasing position; when the locking assembly is located at the locking position, the lifting assembly is in locking linkage with the impact assembly, and when the locking assembly is located at the releasing position, the impact assembly is separated from the lifting assembly for impact; the impact assembly is provided with an acceleration sensor and a stress sensor, and the signal output end of the acceleration sensor and the signal output end of the stress sensor are both connected with the signal input end of the PLC. According to the invention, the drop hammer impact test of the T-shaped joint web can be realized, and the high-speed impact test of different positions of the T-shaped joint web under different impact loads can be realized.

Description

Technical Field

[0001] This invention belongs to the field of impact testing technology, and particularly relates to a T-joint drop hammer impact testing device and its impact testing method. Background Technology

[0002] T-joints are critical connection points in large fuel tanks. In the event of an arc fault explosion, they are susceptible to damage due to the immense explosive impact load, potentially leading to significant economic losses and safety hazards. Therefore, the impact performance of T-joints is crucial to the safety performance of large fuel tanks. However, the performance of T-joints obtained through different welding processes and parameters varies considerably. Thus, evaluating the impact performance of T-joints is essential. However, due to the varying stresses experienced by T-joints in different structural applications and their unique structure, evaluating T-joints is not as straightforward as evaluating the impact performance of butt joints.

[0003] The existing T-joint drop hammer impact testing device (announcement number CN114878370A) includes an impact machine with a frame structure. Impact components are slidably mounted vertically on the inner side of the impact machine, and fixing mechanisms are installed at intervals directly below the impact components. The impact components are pulled by chains from the top surface of the impact machine, and the impact machine's control system causes the impact components to descend freely. However, the above-mentioned testing device can only perform tensile impact tests on the flanges of the T-joint, and cannot perform impact tests on the web of the T-joint. When an arc fault occurs and the fuel tank explodes, both the flanges and web of the T-joint will be subjected to enormous explosive impact loads and fail. Therefore, it is essential to design a suitable testing device to evaluate the impact performance of the web of the T-joint. Summary of the Invention

[0004] To address the problems in existing technologies, this invention aims to provide a T-joint drop hammer impact testing device and method. By adjusting the height of the impact assembly and the weight of the counterweight, the total potential energy of the impact test is altered and converted into an impact load, which is then applied to the web of the T-joint specimen. Simultaneously, due to the fixed flanges of the T-joint specimen, the impact hammer also applies an impact tensile load to the weld of the T-joint. By adjusting the installation positions of the two impact hammers on the drop hammer plate, drop hammer impact tests with different spans can be achieved. High-speed impact tests under different impact loads can be performed on different locations of the complete T-joint web, thereby evaluating the high-speed impact resistance of the T-joint and the strength differences under different welding process parameters. This provides an optimized testing method for T-joints in devices that need to withstand high-speed impacts, thus verifying whether the impact performance of the T-joint and the corresponding welding process meet actual industrial requirements.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A T-joint drop hammer impact testing device includes a frame 1. A fixed base 6 is located at the bottom of the frame 1, and a T-joint sample 5 is connected to the fixed base 6. Above the T-joint sample 5, an impact assembly 4, a locking assembly 3, and a lifting assembly 2 are sequentially arranged inside the frame 1. The lifting assembly 2 is connected to the impact assembly 4 via the locking assembly 3, which has a locked position and a released position. When the locking assembly 3 is in the locked position, the lifting assembly 2 and the impact assembly 4 are locked together. When the locking assembly 3 is in the released position, the impact assembly 4 disengages from the lifting assembly 2 to perform the impact. The impact assembly 4 is equipped with an acceleration sensor and a stress sensor, and the signal output terminals of both the acceleration sensor and the stress sensor are connected to the signal input terminals of a PLC controller.

[0006] The frame 1 includes two parallel, smooth, vertical guide rods 8, with the top ends of the two guide rods 8 fixedly connected by a connecting plate 7.

[0007] The lifting assembly 2 includes a first protective box 9 located at the bottom of the connecting plate 7. The first protective box 9 contains a lifting motor 10 and a drum 11. The power output shaft of the lifting motor 10 is connected to a drive wheel 12. A driven wheel 13 is connected to one side of the drum 11. A transmission belt 14 is sleeved between the drive wheel 12 and the driven wheel 13. A chain 15 is wound around the drum 11. The signal output terminal of the PLC controller is connected to the signal input terminal of the lifting motor 10.

[0008] The locking assembly 3 includes a second protective box 16 connected to the chain 15. A locking motor 17 is installed inside the second protective box 16. The power output shaft of the locking motor 17 is connected to the worm gear 19 through a coupling 18. Turbines meshing with the worm gear 19 are symmetrically arranged on both sides of the worm gear 19, namely a first turbine 21 and a second turbine 22. The first turbine 21 and the second turbine 22 are provided with L-shaped latches 23 having a locking position and a releasing position.

[0009] The impact assembly 4 includes a retaining ring 24. When the L-shaped latch 23 is in the locked position, the L-shaped latch 23 is locked to the retaining ring 24. When the L-shaped latch 23 is in the released position, the L-shaped latch 23 is disengaged from the retaining ring 24. The retaining ring 24 is connected to the counterweight 26 via a short screw 25. The counterweight 26 is connected to the drop hammer plate 28 via a long screw 27. Both ends of the drop hammer plate 28 are machined with guide holes 29. The guide rod 8 is slidably connected to the drop hammer plate 28 via the guide holes 29. At least two mounting positions are provided at the bottom of the drop hammer plate 28. The drop hammer plate 28 is detachably connected to two symmetrically arranged impact hammers 31 via fasteners.

[0010] The impact hammer head 31 is a longitudinally extending rod-shaped structure, which includes a connecting section 32, a transition section 33 and a working rod section 34 from top to bottom. The connecting section 32 is installed in the mounting position on the drop hammer plate 28. The top end of the transition section 33 is connected to the connecting section 32, and its bottom end is smoothly connected to the working rod section 34 through a diameter reduction transition. The working rod section 34 is a flat, long strip-shaped plate structure, and its bottom end is machined into an arc shape.

[0011] The T-joint sample 5 includes a wing plate 35, the bottom end of which is welded to the middle of the web plate 36, and a flat plate 38 is provided at the top end of the wing plate 35.

[0012] The fixed base 6 has a symmetrical split triangular truncated structure, including a first base 41 and a second base 42 with the same and symmetrical structure; the first base 41 or the second base 42 includes a clamping plate 43, the bottom end of the clamping plate 43 is connected to the clamping seat 44, the clamping seat 44 is provided with a support block 45 inside, and the clamping seat 44 extends out; the clamping plate 43 is connected to the flat plate 38 of the T-type joint sample 5, and the top of the support block 45 is connected to the web plate 36 of the T-type joint sample 5.

[0013] The two clamping seats 44 are provided with rubber buffer blocks located between the two support blocks 45.

[0014] A T-joint drop hammer impact test method includes: installing an acceleration sensor and a stress sensor on an impact assembly 4; lifting the impact assembly 4 to a preset test height; releasing the impact assembly 4 to allow it to fall freely; the impact hammer 31 of the impact assembly 4 falls freely and applies force to the web plate 36 of the T-joint specimen 5 fixed below, thus applying an impact load to the T-joint specimen 5; and calculating the impact energy when the T-joint specimen 5 deforms or breaks after being impacted by adjusting the overall mass of the impact assembly 4, the lifting height, and the span between the two impact hammers 31.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention optimizes the installation position of the T-joint specimen on the drop hammer plate to form a series of impact components with varying spans. This gradient of impact components allows for the study of the impact performance at different locations on the web of the T-joint specimen. This overcomes the limitation of existing technologies that cannot study the impact performance of the web of a T-joint specimen.

[0016] 2. This invention changes the total energy of the impact test by adjusting the height of the impact assembly and the weight of the counterweight, and converts it into an impact load that is applied to the web of the T-joint specimen. The web of the T-joint specimen is impacted, and the upper part of the flange and both ends of the web of the T-joint specimen are fixed by the fixed base, which restricts the degree of freedom of the T-joint specimen, so that the T-joint specimen can uniformly bear the impact load applied by the impact testing device. In addition, the impact hammer also applies an impact tensile load to the weld of the T-joint specimen.

[0017] 3. By adjusting the position of the impact hammer in the impact assembly, this invention can not only conduct impact tests on T-joint samples, but also fix the butt joint with a fixed base without clamps, and conduct impact tests on different fixed parts of the butt joint with a single impact hammer. The impact testing device of this invention has better versatility.

[0018] 4. This invention can combine an accelerometer and a stress sensor to obtain the acceleration curve of the T-joint specimen during the impact load test; and use a stress sensor to obtain the stress-time curve of the T-joint specimen during the impact process, so as to study the influence of welding process parameters on the impact performance of the T-joint specimen from an energy perspective, and to study and evaluate the impact resistance performance of the T-joint specimen through energy analysis at the critical impact fracture height.

[0019] In summary, the T-joint drop hammer test device disclosed in this invention is convenient to operate and highly feasible. It can perform high-speed impact tests on complete T-joints under different impact loads to evaluate the impact resistance of T-joints and the strength differences of different welding process parameters. It provides an optimized test method for T-joints for some devices that need to withstand high-speed impacts. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the T-joint drop hammer impact device.

[0021] Figure 2 This is a structural diagram of the frame.

[0022] Figure 3 A structural diagram of the component.

[0023] Figure 4 This is a schematic diagram of the locking assembly.

[0024] Figure 5 This is an assembly drawing of the impact component.

[0025] Figure 6 This is a schematic diagram of the impact assembly.

[0026] Figure 7This is a schematic diagram of the impact hammer head.

[0027] Figure 8 This is a schematic diagram of the structure of a T-type joint sample.

[0028] Figure 9 This is an assembly drawing for fixing the base.

[0029] Figure 10 This is a structural diagram of the fixed base.

[0030] In the diagram: 1-Frame; 2-Lifting assembly; 3-Locking assembly; 4-Impact assembly; 5-T-joint sample; 6-Fixed base; 7-Connecting plate; 8-Guide rod; 9-First protective box; 10-Lifting motor; 11-Drum; 12-Driving wheel; 13-Driven wheel; 14-Transmission belt; 15-Chain; 16-Second protective box; 17-Locking motor; 18-Coupling; 19-Worm gear; 20-Support frame; 21-First turbine; 22-Second turbine; 23-L-type lock; 24-Snap fastener 25-Ring; 26-Short screw; 27-Counterweight; 28-Long screw; 29-Falling hammer plate; 30-Guide through hole; 31-Threaded through hole; 32-Impact hammer head; 33-Connecting section; 34-Transition section; 35-Working rod section; 36-Wing plate; 37-Web plate; 38-Weld; 39-Flat plate; 40-Large bolt hole; 41-Small bolt hole; 42-Second base; 43-Clamping plate; 44-Clamping seat; 45-Support block; 46-Large bolt; 47-Small bolt; 48-Push block. Detailed Implementation

[0031] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1As shown, a T-joint drop hammer impact testing device includes a frame 1, with a fixed base 6 at the bottom of the frame 1, and a T-joint sample 5 connected to the fixed base 6. An impact assembly 4 is disposed inside the frame 1, and a locking assembly 3 is disposed above the impact assembly 4. A lifting assembly 2 is disposed above the locking assembly 3 and located at the bottom inner side of the frame 1. The lifting assembly 2 and the impact assembly 4 are connected by the locking assembly 3, which has a locked position and a released position. When the locking assembly 3 is in the locked position, the lifting assembly 2 and the impact assembly 4 are locked together, allowing the lifting assembly 2 to drive the impact assembly 4 to lift. When the locking assembly 3 is in the released position, the impact assembly 4 disengages from the lifting assembly 2 to impact, the locking assembly 3 releases its lock on the impact assembly 4, and the impact assembly 4 disengages from the lifting assembly 2 and impacts. The impact assembly 4 is equipped with an acceleration sensor and a stress sensor. The signal output terminals of the acceleration sensor and the stress sensor are connected to the signal input terminal of the PLC controller installed on the impact assembly 4. The PLC controller is wirelessly connected to a computer through a wireless network module.

[0033] like Figure 2 and Figure 3 As shown, the frame 1 includes two parallel, smooth, vertical guide rods 8. The top ends of the two guide rods 8 are fixedly connected by a connecting plate 7. A lifting assembly 2 is located at the bottom center of the connecting plate 7. The lifting assembly 2 includes a first protective box 9 located at the bottom of the connecting plate 7. A lifting motor 10 and a drum 11 are located inside the first protective box 9. The drum 11 is fixed inside the first protective box 9 by a drum fixing bracket. The power output shaft of the lifting motor 10 is connected to a drive wheel 12. A driven wheel 13 is connected to one side of the drum 11. A transmission belt 14 is sleeved between the drive wheel 12 and the driven wheel 13. A chain 15 is wound around the drum 11. The other end of the chain 15 is connected to a locking assembly 3. The signal output terminal of the PLC controller is connected to the signal input terminal of the lifting motor 10. The computer transmits the signal to the PLC controller, which controls the lifting motor 10 to rotate forward or backward, thereby driving the drive wheel 12 to rotate. The drive wheel 12 drives the driven wheel 13 to rotate via the transmission belt 14, which in turn drives the drum 11 to rotate forward or backward, thereby lifting or lowering the locking assembly 3.

[0034] like Figure 4As shown, the locking assembly 3 includes a second protective box 16 connected to the chain 15. A locking motor 17 is installed inside the second protective box 16. The locking motor 17 is fixed inside the second protective box 16 by a support frame 20. The power output shaft of the locking motor 17 is connected to the worm gear 19 through a coupling 18. Symmetrically arranged on both sides of the worm gear 19 are turbines that mesh with the worm gear 19, namely a first turbine 21 and a second turbine 22. The turbine shafts of the first turbine 21 and the second turbine 22 are rotatably mounted on the second protective box 16 through bearings. L-shaped latches 23 are provided on the first turbine 21 and the second turbine 22. The signal output terminal of the PLC controller is connected to the signal input terminal of the locking motor 17. The signal is transmitted to the PLC controller through the computer. The PLC controller controls the locking motor 17 to rotate forward, driving the worm gear 19 to rotate, which in turn drives the first turbine 21 and the second turbine 22 to rotate, so that the L-shaped latches 23 are closed and in the locked position. Similarly, when the PLC controller controls the locking motor 17 to rotate in reverse, the L-shaped latches 23 are opened and in the released position.

[0035] like Figure 5 and Figure 6 As shown, the impact assembly 4 includes a retaining ring 24. When the L-shaped latch 23 is in the locked position, the L-shaped latch 23 is locked to the retaining ring 24. When the L-shaped latch 23 is in the released position, the L-shaped latch 23 is disengaged from the retaining ring 24. The retaining ring 24 is connected to the counterweight 26 via a short screw 25. The counterweight 26 is connected to the drop hammer plate 28 via a long screw 27. Both ends of the drop hammer plate 28 are machined with guide holes 29. The guide rod 8 is slidably connected to the drop hammer plate 28 via the guide holes 29. At least two threaded through holes 30 are machined at the bottom of the drop hammer plate 28. The drop hammer plate 28 is connected to two symmetrically arranged impact hammers 31 via screws. The loading force of the impact assembly 4 on the T-joint sample 5 is converted from the gravitational potential energy of the impact assembly 4.

[0036] like Figure 7 As shown, the impact hammer head 31 is a longitudinally extending rod-shaped structure, which includes a connecting section 32, a transition section 33, and a working rod section 34 from top to bottom. The top connecting section 32 is a long screw structure, which is connected to the threaded through hole 30 on the drop hammer plate 28. The transition section 33 is a square column, with its top end connected to the top connecting section 32 and its bottom end smoothly connected to the working rod section 34 through a diameter reduction transition. The working rod section 34 is a flat, long strip plate-shaped structure, and its bottom end is machined into an arc shape to avoid damage to the T-joint sample 5 by the hammer head during the impact. The diameter reduction transition of the transition section 33 adopts an arc surface transition to disperse the impact force and reduce stress concentration.

[0037] like Figure 8As shown, the T-joint specimen 5 includes a flange 35, the bottom end of which is welded to the middle of the web 36 to form a T-joint specimen 5 with a weld 37; a protruding flat plate 38 is machined at the top of the flange 35, and four large bolt holes 39 are machined on the flat plate 38; small bolt holes 40 are machined at both ends of the web 36; the transition section between the flange 35 and the flat plate 38 adopts an arc surface transition to reduce stress concentration at the protruding part and the T-joint specimen 5.

[0038] like Figure 9 and Figure 10 As shown, the fixed base 6 has a symmetrical split triangular frustum structure, including a first base 41 and a second base 42 with identical and symmetrical structures. The first base 41 or the second base 42 includes a clamping plate 43, the bottom of which is connected to a clamping seat 44. The clamping seat 44 includes two parallel right-angled trapezoidal plates, whose upper base edges are connected by a connecting plate to form a hollow frustum structure. Lateral openings are provided on one side of the corresponding hypotenuse of the two right-angled trapezoidal plates for inserting the T-joint sample 5. The lower base edges of the right-angled trapezoidal plates of the clamping seat 44 of the first base 41 and the second base 42 are arranged in close contact with each other. A support block 45 is provided inside the clamping seat 44 and extends outwards to connect with the T-joint sample 5. The clamping plate 43 has four large bolt holes 39, and the clamping plate 43 is connected to the flat plate 38 of the T-joint sample 5 by large bolts 46. The support block 45 has a small bolt hole 40 in the middle of its top, and the pad block 48, the web plate 36 of the T-joint sample 5, and the support block 45 are fixedly connected by small bolts 47, thereby fixing both ends of the T-joint sample 5. During the test, after the impact hammer 31 breaks the T-joint sample 5, it will collide with the fixed base 6, which will damage the impact hammer 31 and the fixed base 6, affecting the use of the entire impact testing device. Therefore, a rubber buffer block is provided inside the two clamping seats 44 between the two support blocks 45 to avoid collision between the rigid bodies.

[0039] The working principle of the T-joint drop hammer impact testing device of the present invention is as follows: During the test, the T-joint specimen 5 is clamped between the first base 41 and the second base 42 and fixed with bolts to form a fixed support. This clamping method allows the impact load to be directly applied to the web 36 of the T-joint specimen 5 and transmitted to the weld 37 area between the flange 35 and the web 36, which can test the overall impact resistance of the T-joint specimen 5. The guide rod 8 ensures that the impact hammer 31 remains vertical during free fall, allowing the two impact hammers 31 to simultaneously and vertically impact the web 36 of the lower T-joint specimen 5. The computer transmits control signals to the PLC controller, which controls the locking motor 17 to rotate forward, closing the L-shaped latch 23, thereby connecting and fixing the L-shaped latch 23 with the buckle 24; at this time, the PLC controller controls the lifting motor 10 to rotate forward, thereby lifting the impact assembly 4 to the required test height; then the PLC controller controls the locking motor 17 to rotate in reverse, opening the L-shaped latch 23, thereby releasing the impact assembly 4 and allowing it to fall downwards in free fall.

[0040] The impact testing method for the T-joint described in this invention includes the following steps: Step 1: Install an acceleration sensor and a stress sensor on the impact assembly 4. After the lifting assembly 2 is raised to the preset test height by the PLC controller, the impact assembly 4 is released and allowed to fall freely. The impact hammer 31 of the impact assembly 4 falls freely and applies force to the web plate 36 of the T-joint specimen 5 fixed below, thereby applying an impact load to the T-joint specimen 5. The impact load is converted from the gravitational potential energy of the impact component 4. By selecting counterweights 26 of different weights and adjusting the rising height of the impact component 4, the impact load applied to the T-joint sample 5 can be adjusted. The critical impact load and the corresponding displacement can be obtained by the deformation or fracture state of the T-joint sample 5 after being impacted. The acceleration sensor is installed on the counterweight 26 of the impact assembly 4. The acceleration sensor can provide the acceleration curve of the T-joint sample 5 during the impact process, and integrate the acceleration-time curve to obtain the actual velocity curve at the time of impact. Integrate the velocity curve to obtain the displacement after the impact collision. The stress sensor is installed on the lower surface of the web 36 of the T-joint sample 5. The stress sensor can provide the stress-time curve of the impact load on the T-joint sample 5 during the impact, which is convenient for capturing the characteristics of the impact load. Step 2: Record the height of the bottom of the impact hammer 31 from the upper surface of the web plate 36 after it is lifted. The overall mass of impact component 4 The gravitational acceleration of the test site Let the impact energy required for the T-joint specimen 5 to fracture after being subjected to impact be... Then we have: in, It is the velocity of the impact component 4 when it continues to fall after breaking through the web plate 36, which can be obtained by integrating the acceleration; This is the deformation value of the web 36 after the bottom end of the impact hammer 31 collides with the upper surface of the web 36, which can be obtained by the second integral of the acceleration; if the web 36 is not broken, but only deformed and the process stops, then... =0 m / s, at this time for: in, It is the total energy of deformation of T-joint specimen 5, including the energy of deformation of web 36 and the energy of impact tensile deformation at weld 37, and is an overall energy assessment.

[0041] Furthermore, the connection between the drop hammer plate 28 and the impact hammer head 31 can be adjusted through multiple threaded through holes 30 at the bottom of the drop hammer plate 28 to form a series of impact components 4 with different spans. For reference, there are symmetrical impact hammer heads 31 with spans of 80mm, 160mm, and 320mm. The impact performance of different positions of the web plate 36 can be studied using this gradient of impact components 4.

[0042] During the test, the impact component 4 will roughly go through three main stages during its fall: the free fall stage at height H, the deceleration stage at height d, and the continued fall stage of the impact component 4 after the T-joint sample 5 breaks; the three stages can be distinguished from the detection data of the acceleration sensor.

Claims

1. A T-joint drop hammer impact testing device, comprising a frame (1), characterized in that: The frame (1) has a fixed base (6) at its bottom. A T-shaped connector sample (5) is connected to the fixed base (6). An impact component (4), a locking component (3), and a lifting component (2) are arranged sequentially above the T-shaped connector sample (5) inside the frame (1). The lifting component (2) and the impact component (4) are connected by the locking component (3). The locking component (3) has a locking position and a releasing position. When the locking component (3) is in the locking position, the lifting component (2) and the impact component (4) are locked together. When the locking component (3) is in the releasing position, the impact component (4) is disengaged from the lifting component (2) to impact. An acceleration sensor and a stress sensor are provided on the impact component (4). The signal output terminals of the acceleration sensor and the stress sensor are connected to the signal input terminal of the PLC controller.

2. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The frame (1) includes two parallel smooth vertical guide rods (8), and the top ends of the two guide rods (8) are fixedly connected by a connecting plate (7).

3. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The lifting assembly (2) includes a first protective box (9) located at the bottom of the connecting plate (7). The first protective box (9) contains a lifting motor (10) and a drum (11). The power output shaft of the lifting motor (10) is connected to a drive wheel (12). A driven wheel (13) is connected to one side of the drum (11). A transmission belt (14) is sleeved between the drive wheel (12) and the driven wheel (13). A chain (15) is wound around the drum (11). The signal output terminal of the PLC controller is connected to the signal input terminal of the lifting motor (10).

4. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The locking assembly (3) includes a second protective box (16) connected to the chain (15). A locking motor (17) is installed inside the second protective box (16). The power output shaft of the locking motor (17) is connected to the worm (19) through a coupling (18). Turbines that mesh with the worm (19) are symmetrically arranged on both sides of the worm (19), namely a first turbine (21) and a second turbine (22). The first turbine (21) and the second turbine (22) are provided with L-shaped latches (23) having a locking position and a releasing position.

5. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The impact assembly (4) includes a retaining ring (24). When the L-shaped latch (23) is in the locked position, the L-shaped latch (23) is locked to the retaining ring (24). When the L-shaped latch (23) is in the released position, the L-shaped latch (23) is disengaged from the retaining ring (24). The retaining ring (24) is connected to the counterweight (26) through a short screw (25). The counterweight (26) is connected to the drop hammer plate (28) through a long screw (27). Both ends of the drop hammer plate (28) are machined with guide holes (29). The guide rod (8) of the frame (1) is slidably connected to the drop hammer plate (28) through the guide holes (29). At least two mounting positions are provided at the bottom of the drop hammer plate (28). The drop hammer plate (28) is detachably connected to two symmetrically arranged impact hammers (31) through fasteners.

6. The T-joint drop hammer impact testing device according to claim 5, characterized in that: The impact hammer (31) is a longitudinally extending rod-shaped structure, which includes a connecting section (32), a transition section (33) and a working rod section (34) from top to bottom. The connecting section (32) is installed in the mounting position on the drop hammer plate (28). The top end of the transition section (33) is connected to the connecting section (32), and its bottom end is smoothly connected to the working rod section (34) through a diameter reduction transition. The working rod section (34) is a flat, long strip plate-shaped structure, and its bottom end is machined into an arc shape.

7. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The T-joint sample (5) includes a wing plate (35), the bottom end of which is welded to the middle of the web plate (36), and a flat plate (38) is provided at the top end of the wing plate (35).

8. The T-joint drop hammer impact testing device according to claim 1, characterized in that: The fixed base (6) is a symmetrical split triangular truncated structure, including a first base (41) and a second base (42) with the same structure and symmetrical. The first base (41) or the second base (42) includes a clamping plate (43), the bottom end of which is connected to the clamping seat (44). The clamping seat (44) is provided with a support block (45) inside and extends out of the clamping seat (44). The clamping plate (43) is connected to the flat plate (38) of the T-type connector sample (5), and the top of the support block (45) is connected to the web plate (36) of the T-type connector sample (5).

9. The T-joint drop hammer impact testing device according to claim 8, characterized in that: The two clamping seats (44) are provided with rubber buffer blocks located between the two support blocks (45).

10. A method for drop hammer impact testing of a T-joint, characterized in that, include: An acceleration sensor and a stress sensor are installed on the impact assembly (4). After the impact assembly (4) is raised to the preset test height, the impact assembly (4) is released and allowed to fall freely. The impact hammer (31) of the impact assembly (4) falls freely and applies force to the web plate (36) of the T-joint specimen (5) fixed below, thus applying an impact load to the T-joint specimen (5). By adjusting the overall mass of the impact assembly (4), the lifting height, and the span between the two impact hammers (31), the impact energy when the T-joint specimen (5) deforms or breaks after being impacted is calculated.

Images