A multi-angle head drop hammer impact device and testing method

Abstract

The invention discloses a novel multi-angle head drop hammer impact device and a testing method. The device adopts a servo drive fixture to assemble the drop hammer, so as to avoid electromagnetic interference and friction of a motor shaft, and improve the repeatability and accuracy of the experimental results. The supporting arc plate and the bottom plate for clamping the head model are fastened by tooth meshing in two directions, so that the fastening effect is extremely high, and it is not easy to be swayed when subjected to the impact of the drop hammer, and the fastening method is simple and easy to operate, which is convenient for rapid repeated testing. An active mounting structure is provided between the hammer head and the impact plate, so that the position of the hammer head can be finely adjusted in all directions, so as to adjust the position deviation caused by the tooth meshing. In addition, a gel ice and snow plate is arranged around the head model, so as to control the actual temperature on the head model, and can simulate the impact effect under low temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of impact testing, and particularly relates to a new type of multi-angle head drop hammer impact device and a testing method. Background Art

[0002] As the most important part of the human body, the human brain is highly protected in daily life. People have taken various protective measures to prevent sudden external impacts. For example, wearing helmets when driving and safety helmets during construction. These protective measures are all aimed at resisting impacts from uncertain directions that may come from all directions, such as high-altitude falling objects, falling and colliding.

[0003] In order to better understand the situation of the head when suffering from various impact forces, it is crucial to develop a device that can simulate the sudden impacts that the head may receive. At present, although there are some drop hammer measurement devices, there are few devices that can be used to simulate head impacts, and these devices have many disadvantages in actual operation.

[0004] Current drop hammer measurement devices generally require manual installation of the drop hammer and manual adjustment of the height of the drop hammer. For example, patent CN118730765A. This method has the following problems in actual operation: when the drop hammer is heavy, manual installation will be very cumbersome. If the drop hammer needs to be adjusted to a high height, manual adjustment will become troublesome and dangerous, and the operator needs to use a ladder or other auxiliary tools to reach a high position for adjustment. On the other hand, it is difficult to guarantee the accuracy of manual adjustment, which may affect the accuracy of the experimental results.

[0005] There are also some devices that release the hammer head by the on-off of electricity magnetism, that is, adsorb the hammer head on the electromagnet and release the drop hammer by the power-off and demagnetization of the electromagnet. For example, patent CN118362384A. This release method will cause a large amount of electromagnetic interference from the electromagnet to the hammer head and surrounding sensors. During the drop hammer impact measurement process, the sensor is the core hardware, and its accuracy has a huge impact on the measurement results. Electromagnetic interference will cause inaccurate measurement data of the sensor, thus affecting the evaluation of the head's impact situation.

[0006] Another way of releasing for some devices is to release by the power-off of the motor, such as patent CN221765160A. This method also has some problems: there will be a certain resistance when the motor releases by the rotation of the motor shaft during power-off, thus unable to form the effect of free fall. The friction of the motor shaft will affect the falling speed, making the experimental results deviate from the actual situation. This release method will also shorten the life of the motor. Frequent power-off releases of the motor will cause wear to the motor, reduce the service life of the motor, and increase the maintenance cost of the equipment.

[0007] At present, almost all drop weight impact equipment uses clamps to clamp the two sides of the sample to fix the sample. This fixing method has the following limitations: it can only achieve single-angle impact. This fixing method is not suitable for measuring the situation where the simulated head is impacted at different angles.

[0008] In view of the above problems, a drop weight impact test device has been studied in the hope of designing a new drop weight impact test device and method that can solve the above problems. Summary of the invention

[0009] In order to overcome the above problems, a novel multi-angle head drop hammer impact device and testing method are designed. The device adopts a servo drive fixture to assemble the drop hammer, which avoids electromagnetic interference and friction of the motor shaft, thereby improving the repeatability and accuracy of the experimental results; the supporting arc plate and the bottom plate that clamp the head model are fastened by tooth engagement in two directions, so that the fastening effect is extremely high, and it is not easy to move when subjected to the impact of the drop hammer, and the fastening method is simple and easy to operate, which is convenient for rapid repeated testing; a movable mounting structure is provided between the hammer head and the impact plate, so that the position of the hammer head can be fine-tuned in all directions, so as to adjust the position deviation caused by tooth engagement, and in addition, a gel ice and snow plate is arranged around the head model to control the actual temperature on the head model, so as to simulate the impact effect at low temperature, thereby completing the present invention.

[0010] Specifically, the object of the present invention is to provide a novel multi-angle head drop hammer impact device, which includes a lifting platform located at the top and an impact platform located at the bottom;

[0011] The lifting platform comprises a lifting plate capable of moving up and down, a hammer head capable of falling freely is arranged on the lifting plate, and the falling starting height of the hammer head can be adjusted;

[0012] The impact platform includes a supporting arc plate, which can move in the horizontal direction; a groove is opened on the supporting arc plate along its circumference, a connecting rod mechanism is installed on the groove, and a head model is arranged at the end of the connecting rod mechanism. The angle of the head model is adjusted by controlling the connecting rod mechanism to rotate along the groove and the connecting rod mechanism itself.

[0013] The lifting platform further comprises a lifting motor, a main shaft of the lifting motor is connected with a sprocket, a chain connected with the lifting plate is arranged on the sprocket, and the lifting motor controls the lifting plate to move up and down through the sprocket and the chain;

[0014] Preferably, the lifting platform further comprises a longitudinal guide rail, and the lifting plate is provided with a guide sleeve sleeved on the outer side of the longitudinal guide rail, and the cooperation between the longitudinal guide rail and the guide sleeve provides a limit for the up and down movement of the lifting plate.

[0015] Among them, a fixture composed of two clamping rods is arranged on the lifting plate.

[0016] An impact plate is connected above the hammer head, and a head is arranged above the impact plate.

[0017] The fixture can clamp the head in an openable and closable manner. When the fixture releases the head, the hammer head, the impact plate and the head synchronously fall freely, and the hammer head impacts the head model.

[0018] Among them, a servo motor is arranged on the lifting plate 1, a cam is connected to the servo motor, the cam is arranged between the two clamping rods, and the cam is driven by the servo motor to rotate to open the fixture, so that the fixture releases the head.

[0019] Among them, a piezoelectric dynamic force sensor is connected between the impact plate and the hammer head. The hammer head can translate along the X-axis in the horizontal direction relative to the piezoelectric dynamic force sensor, and the piezoelectric dynamic force sensor can translate along the Y-axis in the horizontal direction relative to the impact plate. The X-axis is perpendicular to the Y-axis.

[0020] By rotating the piezoelectric dynamic force sensor, the height distance between the impact plate and the hammer head can be adjusted.

[0021] Among them, a lower groove with a T-shaped cross-section is opened along the X-axis direction at the top of the hammer head. The lower groove is narrow at the top and wide at the bottom. A T-shaped nut is installed in the lower groove, and the T-shaped nut can slide along the X-axis direction in the lower groove.

[0022] An upper groove with a T-shaped cross-section is opened along the Y-axis direction at the bottom of the impact plate. The upper groove is wide at the top and narrow at the bottom. A square nut is installed in the upper groove, and the square nut can slide along the Y-axis direction in the upper groove.

[0023] An upper bolt is arranged above the piezoelectric dynamic force sensor, and a lower bolt is arranged below the piezoelectric dynamic force sensor. The upper bolt and the lower bolt have opposite thread directions. The upper bolt is screwed into the square nut, and the lower bolt is screwed into the T-shaped nut.

[0024] Among them, the impact table further includes an X-axis tooth surface bottom plate at the bottom. The X-axis tooth surface bottom plate is provided with a dense arrangement of triangular cross-section racks extending along the X-axis direction. Horizontal guide rails extending along the Y-axis direction are arranged on both sides of the X-axis tooth surface bottom plate, and guide rail sliders capable of reciprocatingly sliding along the horizontal guide rails are arranged on the horizontal guide rails.

[0025] On the guide rail slider, a Y-axis tooth surface bottom plate is arranged along the length direction of the guide rail slider. The Y-axis tooth surface bottom plate is provided with a dense arrangement of triangular cross-section racks extending along the Y-axis direction.

[0026] An embedded slider capable of reciprocatingly sliding along the length direction of the guide rail slider is further provided on the guide rail slider, and the support arc plate is installed on the embedded slider, and the support arc plate is driven to move horizontally by sliding the guide rail slider and the embedded slider;

[0027] Preferably, a fixed rod capable of reciprocatingly sliding in the vertical direction is further provided on the embedded slider; a horizontal fixed locking knob screwed and matched with the embedded slider is arranged above the fixed rod, and a Y-axis tooth pattern insert block and an X-axis tooth pattern insert block are arranged below the fixed rod; when the horizontal fixed locking knob presses the fixed rod downward, the Y-axis tooth pattern insert block meshes with the Y-axis tooth surface bottom plate, and the X-axis tooth pattern insert block meshes with the X-axis tooth surface bottom plate, so as to lock the embedded slider and the support arc plate in the horizontal direction.

[0028] Wherein, the link mechanism includes a fixed bolt, the head model is screwed and fixed at the end of the fixed bolt, and an arc fixed locking knob, an inner slider of the arc plate and a fixed sleeve are arranged on the fixed bolt; the arc fixed locking knob is integrated with the fixed bolt and rotates synchronously, the inner slider 36 of the arc plate is integrally arc-shaped, and a rack with a triangular cross section is arranged thereon;

[0029] Inside the support arc plate, cavities integrally arc-shaped for accommodating the inner slider of the arc plate are arranged on both sides of the notch; a rack with a triangular cross section is arranged on the arc-shaped top surface of the cavity, and the inner slider of the arc plate can move in the cavity to facilitate adjusting the angle of the link mechanism and the head model;

[0030] The link mechanism is fixed and locked to the support arc plate by meshing the inner slider of the arc plate with the arc-shaped top surface of the cavity.

[0031] The present invention also provides a new multi-angle head drop hammer impact test method, which is realized by the new multi-angle head drop hammer impact device described above.

[0032] Wherein, the method includes the following steps:

[0033] Step 1, control the steering gear to rotate 90°, and open the fixture; control the lifting plate to descend through the lifting motor, so that the fixture clamp can clamp the end; then control the steering gear to rotate 90°, so that the clamping rod clamps the clamping end;

[0034] Step 2, move the support arc plate to a predetermined position by moving the guide rail slider and the embedded slider, and then control the fixed rod to move downward through the horizontal fixed locking knob to lock the embedded slider and the support arc plate in the horizontal direction;

[0035] Step 3: Install the head model onto the fixing bolt and lock it through the fixing sleeve. The slider inside the arc plate slides in the cavity to a predetermined position. After adjusting the installation angle of the link mechanism, tighten the slider inside the arc plate through the arc fixing rotary lock knob, so that the slider inside the arc plate meshes with the arc-shaped top surface of the cavity, and lock the link mechanism to the supporting arc plate.

[0036] Step 4: Install a piezoelectric dynamic force sensor and a hammer head on the impact plate, and finely adjust the position of the hammer head in the horizontal direction to eliminate the error caused by the tooth meshing on the impact table. Fine-tune the height of the hammer head by rotating the piezoelectric dynamic force sensor.

[0037] Step 5: Embed the gel ice and snow board into the groove of the baffle frame, and then install the baffle frame into the support frame, so that the gel ice and snow board surrounds the head model.

[0038] Step 6: Control the servo motor to rotate and open the fixture. The impact plate falls freely along the falling wire, and the hammer head impacts the head model. The data information is obtained by measuring through the piezoelectric dynamic force sensor and the optical displacement sensor.

[0039] The beneficial effects of the present invention include:

[0040] (1) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, a servo motor is used to drive the fixture for the assembly of the drop hammer. This fixture has a simple structure, and the rapid installation of the drop hammer can be achieved only by controlling the rotation of the servo motor.

[0041] (2) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, the cooperation of the servo motor and the fixture is used to release the hammer head, avoiding the interference of the strong electromagnetic property of the electromagnet on the sensor; the measurement accuracy of the sensor can be guaranteed, and the reliability and repeatability of the experiment can be improved.

[0042] (3) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, the device uses a motor to drive a sprocket chain for lifting, which has no limitation on the lifting height and is very safe. The lifting height of the drop hammer can be controlled more precisely to meet different experimental requirements.

[0043] (4) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, a gel ice and snow board is installed around the support frame. The installation method of this gel ice and snow board is simple and fast, and it can be disassembled and installed at any time according to needs. It can effectively simulate the impact under low temperature conditions, and the low temperature lasts for a long time. There is no need for long-time refrigeration preparation before the experiment, which can greatly improve the experimental efficiency.

[0044] (5) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, the sample fixing table of this device adopts the cooperation of guide rails, chutes and sliders, which can impact the head and samples similar to the head model in all directions and at all angles; it can better simulate the impacts at various angles that the head receives in actual situations;

[0045] (6) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, the impact table only needs to be tightened twice to fix the movement of four degrees of freedom, and the disassembly and assembly are very convenient. This design can improve the experimental efficiency and reduce the operation time;

[0046] (7) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, the movement of four degrees of freedom such as the sliding and rotation of the impact table are fixed by gear meshing, which is more stable than the friction method and can withstand greater impact forces, ensuring the accuracy of the experimental results;

[0047] (8) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, nuts and grooves are provided between the hammer head and the impact plate for cooperation to eliminate the small errors caused by gear meshing fixation and improve the accuracy of the experiment;

[0048] (9) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, by installing the helmet on the impact table, the force-displacement change during the impact process can be measured in real time, so as to evaluate the safety performance indicators such as the anti-impact performance and buffering effect of the helmet;

[0049] (10) According to the novel multi-angle head drop hammer impact device and impact method provided by the present invention, by measuring the stress-strain parameters of different materials under the drop hammer impact, the most suitable materials for simulating the human head can be selected. Description of the Drawings

[0050] Figure 1 Shows the overall structural schematic diagram of the novel multi-angle head drop hammer impact device in this application;

[0051] Figure 2 Shows the structural schematic diagram of the lifting platform of the novel multi-angle head drop hammer impact device in this application;

[0052] Figure 3 Shows the structural schematic diagram of the bottom of the impact plate on the lifting platform of the novel multi-angle head drop hammer impact device in this application;

[0053] Figure 4 Shows the exploded view of the hammer head and the piezoelectric dynamic force sensor on the lifting platform of the novel multi-angle head drop hammer impact device in this application;

[0054] Figure 5Shows the structural schematic diagram of the impact table of the new multi-angle head drop hammer impact device in this application;

[0055] Figure 6 Shows a cross-sectional view of one side of the impact table of the new multi-angle head drop hammer impact device in this application;

[0056] Figure 7 Shows a cross-sectional view of the other side of the impact table of the new multi-angle head drop hammer impact device in this application;

[0057] Figure 8 Shows the structural schematic diagram of the support arc plate and the link mechanism on the impact table of the new multi-angle head drop hammer impact device in this application;

[0058] Figure 9 Shows the structural schematic diagram of the link mechanism on the impact table of the new multi-angle head drop hammer impact device in this application;

[0059] Figure 10 Shows the structural schematic diagram of the baffle frame of the new multi-angle head drop hammer impact device in this application.

[0060] 1 - lifting plate, 2 - hammer head, 3 - support arc plate, 4 - notch, 5 - link mechanism, 6 - head model, 7 - lifting motor, 8 - sprocket, 9 - chain, 10 - longitudinal guide rail, 11 - guide sleeve, 12 - clamping rod, 13 - impact plate, 14 - end, 15 - servo motor, 16 - cam, 17 - piezoelectric dynamic force sensor, 18 - lower groove, 19 - T-shaped nut, 20 - upper groove, 21 - square nut, 22 - upper bolt, 23 - lower bolt, 24 - through hole, 25 - X-axis tooth surface bottom plate, 26 - horizontal guide rail, 27 - guide rail slider, 28 - Y-axis tooth surface bottom plate, 29 - embedded slider, 30 - fixed rod, 31 - horizontal fixed locking knob, 32 - Y-axis tooth pattern inlay block, 33 - X-axis tooth pattern inlay block, 34 - fixed bolt, 35 - arc fixed locking knob, 36 - inner slider of arc plate, 37 - fixed sleeve, 38 - cavity, 39 - baffle frame, 40 - groove, 41 - support frame, 42 - mounting boss, 43 - mounting groove, 44 - optical displacement sensor, 45 - falling steel wire. Detailed implementation manners

[0061] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become more clearly defined.

[0062] The special term "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0063] The present invention provides a novel pendulum impact device. As shown in Figure 1 the device includes a lifting platform located above and an impact platform located below;

[0064] The lifting platform includes a lifting plate 1 capable of moving up and down. A hammer head 2 capable of freely falling is arranged on the lifting plate 1, and the starting height of the falling of the hammer head 2 can be adjusted.

[0065] The impact platform includes a supporting arc plate 3, and the supporting arc plate 3 can move in the horizontal direction; A notch 4 is formed along the circumferential direction of the supporting arc plate 3, a connecting rod mechanism 5 is installed on the notch 4, and a head model 6 is arranged at the end of the connecting rod mechanism 5. The angle of the head model 6 is adjusted by controlling the connecting rod mechanism 5 to rotate along the notch 4 and the connecting rod mechanism 5 itself to rotate.

[0066] In a preferred embodiment, as shown in Figure 1 the lifting platform further includes a lifting motor 7. A sprocket 8 is linked to the main shaft of the lifting motor 7, and a chain 9 connected to the lifting plate 1 is arranged on the sprocket 8. The lifting motor 7 controls the lifting plate 1 to move up and down through the sprocket 8 and the chain 9;

[0067] Preferably, the lifting platform further includes a longitudinal guide rail 10. A guide sleeve 11 sleeved outside the longitudinal guide rail 10 is arranged on the lifting plate 1, and the cooperation of the longitudinal guide rail 10 and the guide sleeve 11 provides a limit for the up and down movement of the lifting plate 1.

[0068] In a preferred embodiment, as shown in Figure 2 a fixture composed of two clamping rods 12 is arranged on the lifting plate 1.

[0069] An impact plate 13 is connected above the hammer head 2, and a head end 14 is arranged above the impact plate 13.

[0070] The fixture can clamp the head end 14 in an openable and closable manner. When the fixture releases the head end 14, the hammer head 2, the impact plate 13 and the head end 14 fall freely synchronously, and the hammer head 2 impacts the head model 6.

[0071] Preferably, a servo motor 15 is arranged on the lifting plate 1, a cam 16 is connected to the servo motor 15, and the cam 16 is arranged between the two clamping rods 12. The servo motor 15 drives the cam 16 to rotate to open the fixture, so that the fixture releases the head end 14.

[0072] Preferably, inside the impact plate 13 and outside the clamping rods 12, a spring is arranged. The spring presses the clamping rods 12 inward, so that the clamping rods 12 maintain an inwardly contracted state, thereby clamping the head end 14.

[0073] In a preferred embodiment, as Figure 2 , Figure 3 , Figure 4 shown, a piezoelectric dynamic force sensor 17 is connected between the impact plate 13 and the hammer head 2. The hammer head 2 can translate along the X-axis in the horizontal direction relative to the piezoelectric dynamic force sensor 17, and the piezoelectric dynamic force sensor 17 can translate along the Y-axis in the horizontal direction relative to the impact plate 13. In this application, both the X-axis direction and the Y-axis direction are directions parallel to the horizontal plane, and the X-axis is perpendicular to the Y-axis.

[0074] By rotating the piezoelectric dynamic force sensor 17, the height distance between the impact plate 13 and the hammer head 2 can be adjusted.

[0075] Preferably, a lower groove 18 with a T-shaped cross-section is formed in the top of the hammer head 2 along the X-axis direction. The lower groove 18 is narrow at the top and wide at the bottom. A T-shaped nut 19 is installed in the lower groove 18, and the T-shaped nut 19 can slide along the X-axis direction in the lower groove 18;

[0076] An upper groove 20 with a T-shaped cross-section is formed in the bottom of the impact plate 13 along the Y-axis direction. The upper groove 20 is wide at the top and narrow at the bottom. A square nut 21 is installed in the upper groove 20, and the square nut 21 can slide along the Y-axis direction in the upper groove 20; Through the piezoelectric dynamic force sensor 17 and the corresponding horizontal movement mechanism, the hammer head 2 can be finely adjusted in the horizontal direction to correct the position deviation caused by the fixed engagement of the lower supporting circular arc plate by teeth.

[0077] As Figure 3 , Figure 4 shown, an upper bolt 22 is arranged above the piezoelectric dynamic force sensor 17, and a lower bolt 23 is arranged below the piezoelectric dynamic force sensor 17. The rotation directions of the upper bolt 22 and the lower bolt 23 are opposite; the upper bolt 22 is screwed into the square nut 21, and the lower bolt 23 is screwed into the T-shaped nut 19. Based on such a design, the distance between the hammer head and the impact head model 6 can be finely adjusted by screwing the piezoelectric dynamic force sensor 17 to correct the height error caused by tooth engagement.

[0078] Preferably, as Figure 3 , Figure 4 and Figure 5 shown, a through hole 24 is formed at the end of the impact plate 13. The lifting platform further includes a vertically arranged falling steel wire 45. The falling steel wire 45 passes through the through hole 24, and the free fall of the impact plate is guided by the cooperation of the falling steel wire 45 and the through hole 24 to ensure that the hammer head 2 impacts vertically downward.

[0079] A photoelectric displacement sensor 44 is provided near the bottom of the falling wire 45 for real-time measurement of the displacement change during the impact process.

[0080] In a preferred embodiment, as Figure 5 , Figure 6 and Figure 7 shown, the impact table further includes an X-axis toothed surface bottom plate 25 at the bottom. The X-axis toothed surface bottom plate 25 is provided with densely arranged racks with a triangular cross-section and extending along the X-axis direction; horizontal guide rails 26 extending along the Y-axis direction are provided on both sides of the X-axis toothed surface bottom plate 25, and a guide rail slider 27 capable of reciprocatingly sliding along the horizontal guide rail 26 is provided on the horizontal guide rail 26;

[0081] On the guide rail slider 27, a Y-axis toothed surface bottom plate 28 is provided along the length direction of the guide rail slider 27. The Y-axis toothed surface bottom plate 28 is provided with densely arranged racks with a triangular cross-section and extending along the Y-axis direction;

[0082] An embedded slider 29 capable of reciprocatingly sliding along the length direction of the guide rail slider 27 is further provided on the guide rail slider 27. The support arc plate 3 is installed on the embedded slider 29, and the support arc plate 3 is driven to move horizontally by sliding the guide rail slider 27 and the embedded slider 29;

[0083] Preferably, a fixing rod 30 capable of reciprocatingly sliding in the vertical direction is further provided on the embedded slider 29; a horizontal fixing lock knob 31 screwed and matched with the embedded slider 29 is provided above the fixing rod 30, and a Y-axis toothed pattern embedded block 32 and an X-axis toothed pattern embedded block 33 are provided below the fixing rod 30; when the horizontal fixing lock knob 31 presses the fixing rod 30 downward, the Y-axis toothed pattern embedded block 32 meshes with the Y-axis toothed surface bottom plate 28, and the X-axis toothed pattern embedded block 33 meshes with the X-axis toothed surface bottom plate 25, so as to lock the embedded slider 29 and the support arc plate 3 in the horizontal direction. The two meshing and locking mechanisms of the Y-axis toothed pattern embedded block 32 and the X-axis toothed pattern embedded block 33 are controlled by a single horizontal fixing lock knob 31. Only one screwing is required to lock two degrees of freedom in the horizontal direction, completing the fixing of the support arc plate, improving the working efficiency and convenience of the experimental test.

[0084] In a preferred embodiment, as Figure 8 and Figure 9 shown, the link mechanism 5 includes a fixing bolt 34. The head model 6 is screwed and fixed to the end of the fixing bolt 34. An arc fixing lock knob 35, an arc plate inner slider 36 and a fixing sleeve 37 are provided on the fixing bolt 34; the arc fixing lock knob 35 is integrated with the fixing bolt 34 and rotates synchronously. The arc plate inner slider 36 is integrally arc-shaped and is provided with a rack with a triangular cross-section;

[0085] Inside the supporting arc plate 3, on both sides of the notch 4, there are cavities 38 which are integrally arc-shaped and used to accommodate the slider 36 inside the arc plate; on the arc-shaped top surface of the cavity 38, there is a rack with a triangular cross-section, and the slider 36 inside the arc plate can move in the cavity 38 to facilitate the adjustment of the angle of the link mechanism 5 and the head model 6.

[0086] The link mechanism 5 is fixed and locked to the supporting arc plate 3 by the engagement of the slider 36 inside the arc plate with the arc-shaped top surface of the cavity 38.

[0087] Preferably, the fixing bolt 34 and the arc fixing rotary lock knob 35 are of an integral structure. By turning the arc fixing rotary lock knob 35 externally, the rotation of the fixing bolt 34 is controlled. The slider 36 inside the arc plate is provided with internal threads and cooperates with the fixing bolt 34. By screwing the fixing bolt 34, the slider 36 inside the arc plate is controlled to move along the axis direction of the fixing bolt 34, so that the slider 36 inside the arc plate can both engage with the top surface of the cavity 38 and move in the cavity 38; the fixing sleeve 37 is provided with internal threads that cooperate with the fixing bolt 34 and can be screwed and moved on the fixing bolt 34, so as to be able to abut against the head model, and then the head model 6 is locked by the fixing bolt 34 to prevent the head model 6 from rotating by itself; the head model 6 is also provided with internal threads that cooperate with the fixing bolt 34, so that by screwing the head model 6, the angular direction and elongation of the head model 6 can be controlled to facilitate setting the desired impact angle and position.

[0088] In a preferred embodiment, as Figure 1 and Figure 10 shown, a support frame 41 is provided on the outside of the lifting table and the impact table. A detachable baffle frame 39 is provided on the outside of the support frame 41. A groove 40 for installing a gel ice and snow board is provided on the baffle frame 39, and the temperature near the head model 6 inside the support frame 41 is controlled by the gel ice and snow board.

[0089] In this application, the gel ice and snow board has unique physical properties. More than ninety percent of its components are water, so it has a refrigeration function almost the same as that of natural ice and snow and will not melt like ordinary ice cubes. By refrigerating it into an ice and snow state and then installing it on the baffle frame 39 and placing it around the sample to be tested, it can effectively simulate the impact under low temperature conditions. In traditional low temperature impact experiments, it is usually necessary to freeze the sample in advance or use complex refrigeration equipment to maintain a low temperature environment. However, the gel ice and snow board and the baffle frame 39 in this application perfectly solve these problems. Without freezing the sample in advance, a stable low temperature environment can be provided for the experiment at the moment of impact, greatly improving the experimental efficiency and convenience.

[0090] Preferably, asFigure 1 , Figure 5 and 10 As shown in Figure 5 , 10 and , multiple baffle frames 39 are provided and distributed around the sample 6 to be measured. An outwardly protruding mounting boss 42 is provided at the edge of the baffle frame 39. Correspondingly, an inwardly recessed mounting groove 43 is formed on the support frame 41. The baffle frame 39 is quickly and firmly mounted on the support frame 41 by embedding the mounting boss 42 into the mounting groove 43.

[0091] The present invention also provides a new multi-angle head drop hammer impact test method, which is realized by the new multi-angle head drop hammer impact device described above.

[0092] Preferably, the method includes the following steps:

[0093] Step 1: Control the servo 15 to rotate 90° to open the fixture; control the lifting plate 1 to descend through the lifting motor 7 so that the fixture can clamp the end 14; then control the servo 15 to rotate 90° so that the clamping rod 12 clamps the clamping end 14.

[0094] Step 2: Move the support arc plate 3 to a predetermined position through the moving guide rail slider 27 and the embedded slider 29, and then control the fixed rod 30 to descend through the horizontal fixing lock knob 31. The Y-axis tooth pattern insert 32 meshes with the Y-axis tooth surface bottom plate 28, and the X-axis tooth pattern insert 33 meshes with the X-axis tooth surface bottom plate 25, so as to lock the embedded slider 29 and the support arc plate 3 in the horizontal direction.

[0095] Step 3: Install the head model 6 on the fixing bolt 34 and lock it through the fixing sleeve 37; the inner slider 36 of the arc plate slides to a predetermined position in the cavity 38. After adjusting the installation angle of the link mechanism 5, tighten the inner slider 36 of the arc plate through the arc fixing lock knob 35 so that the inner slider 36 of the arc plate meshes with the arc-shaped top surface of the cavity 38, and lock the link mechanism 5 to the support arc plate 3.

[0096] Step 4: Install the piezoelectric dynamic force sensor 17 and the hammer head 2 on the impact plate 13, and finely adjust the position of the hammer head 2 in the horizontal direction to eliminate the error caused by the tooth meshing on the impact table; finely adjust the height of the hammer head 2 by rotating the piezoelectric dynamic force sensor 17.

[0097] Step 5: Embed the gel ice and snow plate into the groove 40 of the baffle frame 39, and then install the baffle frame 39 into the support frame 41 so that the gel ice and snow plate surrounds the head model 6; after 3-5 minutes of installation, the subsequent operation steps can be performed, that is, the temperature at the head model 6 can be reduced from room temperature to 5-8 °C at this time.

[0098] Step 6: Control the servo to rotate and expand the fixture. The impact plate falls freely along the falling wire, and the hammer head 2 impacts the head model 6. The piezoelectric dynamic force sensor 17 and the optical displacement sensor 44 are used to measure and obtain data information.

[0099] After the first impact is completed, prepare for the second impact. For the second impact, the positions of the nuts on the punch and the impact plate can be adjusted, or the rotary lock knob on the impact table can be adjusted to achieve a more accurate impact.

[0100] Select, for example Figures 1 to 10 the new multi-angle head drop hammer impact device in

[0101] to conduct impact tests on the bionic head model. For the same part of the head model, use the same impact force and conduct 5 impact tests at different angular directions in order to obtain the motion and force data of the head model when it is impacted at 6 degrees Celsius.

[0102] Step 1: Control the servo 15 to rotate 90°, and expand the fixture. Control the lifting plate 1 to descend through the lifting motor 7 so that the fixture can clamp the end 14. Then control the servo 15 to rotate 90° so that the clamping rod 12 clamps the clamping end 14.

[0103] Step 2: Move the support arc plate 3 to the predetermined position through the moving guide rail slider 27 and the embedded slider 29. Then control the fixed rod 30 to descend through the horizontal fixed rotary lock knob 31 to lock the embedded slider 29 and the support arc plate 3 horizontally.

[0104] Step 3: Install the head model 6 on the fixing bolt 34 and lock it through the fixing sleeve 37. The inner slider 36 of the arc plate slides to the predetermined position in the cavity 38. After adjusting the installation angle of the linkage mechanism 5, tighten the inner slider 36 of the arc plate through the arc fixing rotary lock knob 35 so that the inner slider 36 of the arc plate meshes with the arc-shaped top surface of the cavity 38, and lock the linkage mechanism 5 to the support arc plate 3.

[0105] Step 4: Install the piezoelectric dynamic force sensor 17 and the hammer head 2 on the impact plate 13, and finely adjust the position of the hammer head 2 horizontally to eliminate the error caused by the tooth engagement on the impact table. Fine-tune the height of the hammer head 2 by rotating the piezoelectric dynamic force sensor 17.

[0106] Step 5: Embed the gel ice and snow board into the groove 40 of the baffle frame 39, and then install the baffle frame 39 into the support frame 41 so that the gel ice and snow board surrounds the head model 6. Start the impact test when the temperature at the head model 6 drops to 6 degrees Celsius.

[0107] Step 6: Control the servo to rotate and expand the fixture. The impact plate falls freely along the descending steel wire, and the head model 6 is impacted by the hammer head 2. The data information is obtained by measuring through the piezoelectric dynamic force sensor 17 and the optical displacement sensor 44.

[0108] The specific data in the 5 impact tests are shown in Table 1 below:

[0109] Table 1 Data of 5 impact tests

[0110]

[0111] The total time taken to complete the above 5 impact tests is 10 minutes;

[0112] As can be seen from the above embodiments, the novel multi-angle head drop hammer impact device and test method provided by the present application can accurately obtain the key data in the impact test, and can quickly and efficiently give exactly the same impact force during multiple repeated tests, improving the reliability of the test results. In addition, the novel multi-angle head drop hammer impact device and test method can greatly improve the test efficiency, not only shortening the time interval between multiple tests, but also being able to maintain the ideal test temperature by itself, saving the time for adjusting the test temperature.

[0113] The present invention has been described in conjunction with the preferred embodiments, but these embodiments are only exemplary and only serve an illustrative purpose. On this basis, various substitutions and improvements can be made to the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A multi-angle head hammer impact device, characterized in that: The device includes a lifting table located at the top and an impact table located at the bottom; The lifting platform comprises a lifting plate (1) that can move up and down, a hammer head (2) that can fall freely is arranged on the lifting plate (1), and the falling starting height of the hammer head (2) can be adjusted; The impact platform comprises a supporting circular arc plate (3), wherein the supporting circular arc plate (3) is movable in a horizontal direction; a slot (4) is provided on the supporting circular arc plate (3) along its circumference, a connecting rod mechanism (5) is mounted on the slot (4), a head model (6) is arranged at the end of the connecting rod mechanism (5), and the angle of the head model (6) is adjusted by controlling the connecting rod mechanism (5) to rotate along the slot (4) and the connecting rod mechanism (5) itself to rotate; A clamp consisting of two clamping rods (12) is provided on the lifting plate (1). An impact plate (13) is connected above the hammer head (2), and an end head (14) is arranged above the impact plate (13). The clamp can open and close to clamp the end head (14); when the clamp releases the end head (14), the hammer head (2), the impact plate (13) and the end head (14) are synchronously freed, and the hammer head (2) impacts the head model (6); The impact plate (13) and the hammer head (2) are connected via a piezoelectric dynamic force sensor (17); the hammer head (2) can translate along an X-axis in a horizontal direction relative to the piezoelectric dynamic force sensor (17); the piezoelectric dynamic force sensor (17) can translate along a Y-axis in a horizontal direction relative to the impact plate (13); the X-axis is perpendicular to the Y-axis; The height distance between the impact plate (13) and the hammer head (2) can be adjusted by rotating the piezoelectric dynamic force sensor (17).

2. The multi-angle head drop hammer impact device according to claim 1, characterized in that: The lifting platform further comprises a lifting motor (7), a main shaft of which is connected to a sprocket (8), a chain (9) connected to the lifting plate (1) is arranged on the sprocket (8), and the lifting motor (7) controls the lifting plate (1) to move up and down via the sprocket (8) and the chain (9); The lifting platform further comprises a longitudinal guide rail (10), and the lifting plate (1) is provided with a guide sleeve (11) sleeved on the outside of the longitudinal guide rail (10), and the cooperation between the longitudinal guide rail (10) and the guide sleeve (11) provides a limit for the lifting plate (1) to move up and down.

3. The multi-angle head drop hammer impact device according to claim 1, characterized in that: A steering gear (15) is arranged on the lifting plate (1), and a cam (16) is connected to the steering gear (15). The cam (16) is arranged between two clamping rods (12). The steering gear (15) drives the cam (16) to rotate to open the clamp, so that the clamp releases the end head (14).

4. The multi-angle head drop hammer impact device according to claim 1, characterized in that: A lower groove (18) with a T-shaped cross section is provided on the top of the hammer head (2) along the X-axis direction, the lower groove (18) being narrow at the top and wide at the bottom, a T-shaped nut (19) being installed in the lower groove (18), and the T-shaped nut (19) being able to slide in the lower groove (18) along the X-axis direction; An upper groove (20) with a T-shaped cross section is provided at the bottom of the impact plate (13) along the Y-axis direction. The upper groove (20) is wide at the top and narrow at the bottom. A square nut (21) is installed in the upper groove (20). The square nut (21) can slide in the upper groove (20) along the Y-axis direction. An upper bolt (22) is arranged above the piezoelectric dynamic force sensor (17), and a lower bolt (23) is arranged below the piezoelectric dynamic force sensor (17), wherein the upper bolt (22) and the lower bolt (23) have opposite rotation directions; the upper bolt (22) is screwed into the square nut (21), and the lower bolt (23) is screwed into the T-shaped nut (19).

5. The multi-angle head drop hammer impact device according to claim 1, characterized in that: The impact table further comprises an X-axis tooth surface bottom plate (25) located at the bottom, on which racks having a triangular cross section and extending along the X-axis direction are densely arranged; horizontal guide rails (26) extending along the Y-axis direction are arranged on both sides of the X-axis tooth surface bottom plate (25), and guide rail sliders (27) capable of reciprocatingly sliding along the horizontal guide rails (26) are arranged on the horizontal guide rails (26); A Y-axis tooth surface bottom plate (28) is arranged on the guide rail slider (27) along the length direction of the guide rail slider (27), and the Y-axis tooth surface bottom plate (28) is provided with densely arranged racks with triangular cross-sections and extending along the Y-axis direction; An embedded slider (29) capable of reciprocating along the length direction of the guide rail slider (27) is also provided on the guide rail slider (27); the support circular arc plate (3) is mounted on the embedded slider (29); and the support circular arc plate (3) is driven to move in the horizontal direction by sliding the guide rail slider (27) and the embedded slider (29); A fixed rod (30) capable of reciprocating in a vertical direction is also provided on the embedded slider (29); a horizontal fixed rotary lock knob (31) screwed together with the embedded slider (29) is provided above the fixed rod (30); a Y-axis toothed insert block (32) and an X-axis toothed insert block (33) are provided below the fixed rod (30); when the fixed rod (30) is pressed downward by the horizontal fixed rotary lock knob (31), the Y-axis toothed insert block (32) meshes with the Y-axis toothed bottom plate (28), and the X-axis toothed insert block (33) meshes with the X-axis toothed bottom plate (25), thereby locking the embedded slider (29) and the supporting arc plate (3) in the horizontal direction.

6. The multi-angle head drop hammer impact device according to claim 1, characterized in that: The connecting rod mechanism (5) comprises a fixing bolt (34), the head model (6) is screwed and fixed to the end of the fixing bolt (34), and the fixing bolt (34) is provided with an arc fixing rotary lock button (35), an arc plate inner slider (36) and a fixing sleeve (37); the arc fixing rotary lock button (35) and the fixing bolt (34) are integrated and rotate synchronously, and the arc plate inner slider (36) is in an arc shape as a whole and is provided with a rack with a triangular cross section; In the supporting arc plate (3), a cavity (38) having an overall arc shape for accommodating an arc plate inner slider (36) is provided on both sides of the slot (4); a rack having a triangular cross section is provided on the arc-shaped top surface of the cavity (38); the arc plate inner slider (36) can move in the cavity (38) to facilitate adjustment of the angles of the connecting rod mechanism (5) and the head model (6); The connecting rod mechanism (5) is fixed and locked onto the supporting circular arc plate (3) by engaging the slider (36) in the circular arc plate with the arc-shaped top surface of the cavity (38).

7. A multi-angle head drop hammer impact test method, characterized in that: The method is implemented by a multi-angle head drop hammer impact device as claimed in any one of claims 1 to 6; The method comprises the following steps: Step 1, control the steering engine (15) to rotate 90 degrees to open the clamp; control the lifting plate (1) to descend through the lifting motor (7) so that the clamp can clamp the end (14); and then control the steering engine (15) to rotate 90 degrees so that the clamping rod (12) clamps the clamping end (14); Step 2, by moving the guide rail slider (27) and the embedded slider (29), the support arc plate (3) is moved to a predetermined position, and then the fixing rod (30) is controlled to move downward by the horizontal fixing lock knob (31), so as to lock the embedded slider (29) and the support arc plate (3) in the horizontal direction; Step 3, the head model (6) is mounted on the fixing bolt (34) and locked by the fixing sleeve (37); the slider (36) in the arc plate slides to a predetermined position in the cavity (38), that is, after the installation angle of the connecting rod mechanism (5) is adjusted, the slider (36) in the arc plate is tightened by the arc fixing locking knob (35), so that the slider (36) in the arc plate is engaged with the arc-shaped top surface of the cavity (38), and the connecting rod mechanism (5) is locked to the supporting arc plate (3); Step 4, installing a piezoelectric dynamic force sensor (17) and a hammer head (2) on the impact plate (13), fine-adjusting the position of the hammer head (2) in the horizontal direction to eliminate the error caused by the tooth meshing on the impact table; and fine-adjusting the height of the hammer head (2) by rotating the piezoelectric dynamic force sensor (17); Step 5, embedding the gel ice snow board into the groove (40) of the baffle frame (39), and then installing the baffle frame (39) into the support frame (41), so that the gel ice snow board surrounds the head model (6); Step 6, control the steering gear to rotate and open the clamp, and the impact plate falls freely along the falling wire, and the hammer head (2) impacts the head model (6), and data information is obtained by measuring through the piezoelectric dynamic force sensor (17) and the optical displacement sensor (44).

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