Angle-controllable peeling clamp and low-medium-high speed peeling strength testing method

Abstract

The invention discloses an angle-controllable stripping clamp and a low-medium-high speed stripping strength test method, and relates to the field of stripping strength tests.The angle-controllable stripping clamp comprises a clamp base, a fixed loading end, a fixed turning shaft, a first movable base, a second movable base, a fastening part and a limiting column; the clamp base comprises a bottom plate, a side plate and a center plate, the side plate is arranged on the upper surface of the bottom plate, and the cross section of the side plate is L-shaped, so that a groove is formed between the bottom plate and the side plate; the cross section of the center plate is T-shaped, and the lower end of the center plate is detachably fixed on the upper surface of the bottom plate; the fixed loading end is arranged on the outer side surface of the side plate and is used for being connected with an external loading device; the fixed turning shaft is arranged on the upper surface of the center plate. According to the invention, the influence of the stripping angle on the stripping strength is fully considered, the stripping test of different angles is completed by using a single clamp, and the limitation that the single clamp can only realize the single-angle stripping test in the existing stripping method is solved.

Description

Technical Field

[0001] The present invention relates to the field of peel strength testing, and in particular to a controllable angle peeling fixture and a low, medium and high speed peel strength testing method. Background Art

[0002] According to the relevant requirements and regulations of national standards such as GB / T2790-1995 Adhesive 180° Peel Strength Test Method - Flexible Materials to Rigid Materials and GB / T2792-2014 Adhesive Tape Peel Strength Test Method, peel strength refers to the force required to peel a unit width of flexible material from a rigid material at a certain angle and rate, and the unit is N / mm.

[0003] In advanced manufacturing fields such as flexible electronic device stacking structures, biomedical coatings, and protective coatings, interfacial peel strength is a key indicator for evaluating the reliability of heterogeneous material bonding. Its test data directly determines the service life of the product under operating conditions.

[0004] Especially for aircraft coating materials, they are exposed to the coupling of multiple physical fields such as high-speed airflow scouring, mechanical vibration and particle impact for a long time. The actual service performance of the coating is highly dependent on the interface bonding strength between it and the substrate. If the interface bonding force is insufficient, the coating is prone to peeling failure under the action of high-speed airflow dynamic load, which in turn leads to substrate exposure, aerodynamic performance degradation and even structural damage, seriously threatening flight safety. Therefore, the interface bonding ability test of the coating / substrate material needs to be closely combined with its actual service environment. Traditional static / quasi-static tests cannot simulate real working conditions. Dynamic high-speed impact testing is a necessary means to evaluate the reliability of the interface between the coating and the substrate. Although the current mainstream peeling tester has a basic speed adjustment function, the speed is still relatively low, often less than 500mm / min, and it is impossible to build a peeling strength database with a wide speed range of low-speed, medium-speed and high-speed peeling, which restricts the establishment of a dynamic interface model of composite structures (such as adhesive structures, coated structures, etc.).

[0005] Currently, traditional peeling fixtures (such as 90° T-type peeling fixtures and 180° tape peeling fixtures) use a fixed geometric structure design, resulting in a single peeling fixture being able to perform peel tests only at specific angles. In actual applications, the direction of the peel force applied to the composite structure interface is not exactly 90° or 180°, and the peel strength varies at different peel angles. Therefore, it is necessary to develop a new fixture that can achieve arbitrary angle adjustment and cooperate with the loading system to realize peel strength testing at any angle. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a controllable angle peeling fixture and a low, medium and high speed peeling strength testing method, which solves the problem that the existing peeling fixture can only perform peeling tests at specific angles.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0008] Provided is a controllable angle peeling fixture, comprising a fixture base, a fixed loading end, a fixed turning shaft, a first movable base, a second movable base, a fastening component, and a limiting column;

[0009] The fixture base includes a bottom plate, side plates, and a center plate. The side plates are arranged on the upper surface of the bottom plate, and the cross-section of the side plates is L-shaped so that a groove is formed between the bottom plate and the side plates. The cross-section of the center plate is T-shaped, and the lower end of the center plate is detachably fixed to the upper surface of the bottom plate.

[0010] The fixed loading end is arranged on the outer side of the side plate and is used to be connected to the external loading device;

[0011] The fixed turning shaft is arranged on the upper surface of the center plate;

[0012] One end of the first movable base and the second movable base are both located in the groove formed by the bottom plate and the side plate, and the other end is located between the bottom plate and the center plate; the upper surfaces of the first movable base and the second movable base are both provided with limit columns located between the side plate and the center plate; the first movable base and the second movable base are both provided with fastening components, and when it is necessary to fix the first movable base and the second movable base, the first movable base and the second movable base are fixed to the clamp base by tightening the fastening components, and when it is necessary to adjust the positions of the first movable base and the second movable base, the first movable base and the second movable base are rotated relative to the clamp base by loosening the fastening components;

[0013] The limiting columns on the first movable base and the second movable base are used to fix the rigid base part of the peeled structure and allow the rigid base part of the peeled structure to slide back and forth, and the flexible part of the peeled structure bypasses the fixed turning axis and extends outside the clamp base; the peeling angle can be adjusted by adjusting the position of the first movable base and the second movable base.

[0014] Furthermore, the fixed turning axis is located at the center of the center plate.

[0015] Furthermore, the fastening component is a bolt that passes through the first movable base and the second movable base. By tightening the bolt to contact the bottom plate, the first movable base and the second movable base are raised until they are tightly attached to the side plate, thereby completing the fastening of the first movable base and the second movable base.

[0016] Furthermore, the extending end of the flexible portion of the peeled structure is in the opposite direction to the fixed loading end.

[0017] A low-speed peel strength test method based on a controllable angle peeling fixture is provided, wherein the external loading device is an electronic universal testing machine. The low-speed peel strength test method comprises the following steps:

[0018] A1. Move the first and second movable bases so that the angle between the rigid base portion of the stripped structure and the flexible portion of the stripped structure between the limiting posts on the two movable bases is a set angle, and tighten the fastening components to secure the first and second movable bases.

[0019] A2. Fix the fixed loading end in the upper pull head of the electronic universal testing machine, and fix the flexible part of the stripped structure in the lower pull head of the electronic universal testing machine;

[0020] A3. By setting the displacement speed of the upper pull head of the electronic universal testing machine, the peeling fixture is driven to move upward at a constant speed. The lower pull head is kept stationary, so that the flexible portion of the peeled structure is peeled away from the fixed rigid base portion of the peeled structure at a pre-designed peeling angle. At the same time, the rigid base portion of the peeled structure slides linearly according to its initial arrangement angle to ensure that the peeling angle remains unchanged during the peeling process.

[0021] A4. Use the load cell on the electronic universal testing machine to obtain the peeling force during the peeling process. Use the displacement of the crossbeam on the electronic universal testing machine as the peeling length to complete the low-speed peel strength test.

[0022] The peeling speed in the low-speed peel strength test is 0.001 to 500 mm / min.

[0023] A medium-speed peel strength test method based on a controllable angle peeling fixture is provided, wherein the external loading device is a Hopkinson pull-rod system, including an impact rod, an incident rod, a transmission rod, an air chamber, and a high-speed camera;

[0024] The impact rod is mounted on the incident rod, with one end of the incident rod being provided with a solid flange that bears the impact of the impact rod; the other end of the incident rod is used to connect to the fixed loading end; one end of the transmission rod is used to connect to the flexible part of the stripped structure; the transmission rod is provided with a strain gauge; the air chamber is used to store high-pressure nitrogen, which is used to push the impact rod to hit the solid flange on the incident rod;

[0025] The medium speed peel strength test method includes the following steps:

[0026] B1. Move the first movable base and the second movable base so that the angle between the rigid base portion of the stripped structure and the flexible portion of the stripped structure between the limiting columns on the two movable bases is a set angle, and tighten the fastening components to fix the first movable base and the second movable base;

[0027] B2. Connect the fixed loading end to the other end of the incident rod; connect the extended end of the flexible part of the stripped structure to one end of the transmission rod;

[0028] B3. Nitrogen is filled into the air chamber to reach a certain pressure. The high-pressure gas in the air chamber is released instantly, causing the impact rod to impact the solid flange on the incident rod at a certain impact speed, thereby generating a tensile stress wave in the incident rod. When the tensile stress wave propagates to the stripping fixture, the incident rod drives the stripping fixture to move toward the impact rod, thereby causing the flexible part of the stripped structure to be stripped from the rigid base part of the stripped structure at a set stripping angle. At the same time, the rigid base part of the stripped structure is caused to slide linearly according to its initial arrangement angle to ensure that the stripping angle remains unchanged during the stripping process;

[0029] B4. The time from the first transmission signal reaching the strain gauge on the transmission rod to the time it is reflected from the free end of the transmission rod and transmitted back to the strain gauge is taken as a measurement time;

[0030] B5. Use a high-speed camera to monitor the peeling length of the flexible portion of the peeled structure from the rigid base portion of the peeled structure. During each measurement time, the peeling force is calculated using the one-dimensional stress wave formula using the signal measured by the strain gauge on the transmission rod to complete the medium-speed peel strength test.

[0031] The peeling speed in the medium-speed peel strength test is 100,000 to 400,000 mm / min.

[0032] Furthermore, the transmission rod is a hollow organic glass rod, one end of the hollow organic glass rod is provided with an adapter, and the flexible part of the stripped structure is connected to the hollow organic glass rod through the adapter.

[0033] Furthermore, the fixed loading end and the flexible portion of the stripped structure are respectively connected to the other end of the incident rod and one end of the transmission rod by gluing.

[0034] A high-speed peel strength test method based on a controllable angle peeling fixture is provided, wherein the external loading device is a Hopkinson rod system, including an impact rod, a waveguide rod, an incident rod, a transmission rod and an air chamber;

[0035] The impact rod is mounted on the waveguide rod, one end of which is provided with a solid flange for bearing the impact of the impact rod; the other end of the waveguide rod is connected to one end of the incident rod; the other end of the incident rod is used to connect to the fixed loading end; one end of the transmission rod is used to connect to the flexible part of the stripped structure; strain gauges are provided on the incident rod and the transmission rod; the air chamber is used to store high-pressure nitrogen, which is used to push the impact rod to hit the solid flange on the waveguide rod;

[0036] The high-speed peel strength test method includes the following steps:

[0037] C1. Move the first movable base and the second movable base so that the angle between the rigid base portion of the stripped structure and the flexible portion of the stripped structure between the limiting columns on the two movable bases is a set angle, and tighten the fastening component to fix the first movable base and the second movable base;

[0038] C2. Connect the fixed loading end to the other end of the incident rod; connect the flexible part of the stripped structure to one end of the transmission rod;

[0039] C3. Nitrogen is filled into the air chamber to reach a certain pressure. The high-pressure nitrogen in the air chamber is released instantly, causing the impact rod to impact the flange on the waveguide rod at a certain impact speed, thereby generating a tensile stress wave in the waveguide rod. When the tensile stress wave propagates along the waveguide rod and the incident rod to the stripping fixture, the incident rod drives the stripping fixture to move toward the waveguide rod, thereby causing the flexible part of the stripped structure to be stripped from the rigid base part of the stripped structure at a set stripping angle. At the same time, the rigid base part of the stripped structure is caused to slide linearly according to its initial arrangement angle to ensure that the stripping angle remains unchanged during the stripping process.

[0040] C4. The peel length is calculated based on the one-dimensional stress wave formula using the signals measured by the strain gauges on the incident and transmission rods. The peel force is calculated based on the one-dimensional stress wave formula using the signals measured by the strain gauges on the transmission rods, completing the high-speed peel strength test.

[0041] The peeling speed in the high-speed peel strength test is 400,000 to 1,500,000 mm / min.

[0042] Furthermore, the transmission rod is a hollow organic glass rod, one end of the hollow organic glass rod is provided with an adapter, and the flexible part of the stripped structure is connected to the hollow organic glass rod through the adapter;

[0043] The fixed loading end and the flexible part of the stripped structure are respectively connected to the other end of the incident rod and one end of the transmission rod by gluing.

[0044] The beneficial effects of the present invention are:

[0045] 1. The present invention fully considers the influence of peeling angle on peeling strength, and realizes peeling tests at different angles using a single fixture, thus overcoming the limitation of existing peeling methods that a single fixture can only realize peeling tests at a single angle.

[0046] 2. This controllable angle peeling fixture has a compact and impact-resistant structure. During the test, the rigid base portion of the fixed structure to be peeled can slide linearly according to its initial arrangement angle, thereby ensuring that the peeling angle remains unchanged during the peeling process.

[0047] 3. The present invention fully considers the influence of peeling speed on peeling strength, and matches the controllable angle peeling fixture with the electronic universal testing machine (tensile mode) to realize low-speed peeling test.

[0048] 4. The present invention fully considers the influence of peeling speed on peeling strength, designs a Hopkinson pull rod for peeling test, and matches the controllable angle peeling fixture with the Hopkinson pull rod to realize medium and high speed peeling test. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural diagram of the controllable angle peeling angle;

[0050] Figure 2 Schematic diagram of the controllable peeling angle and the loading of the peeled structure during peeling at different angles;

[0051] Figure 3 Schematic diagram of the structure for low-speed peeling test;

[0052] Figure 4 Schematic diagram of the high-speed peeling test;

[0053] Figure 5 Displacement-force curve for a 180°, 700,000 mm / min high-speed peel test;

[0054] Figure 6 Schematic diagram of the structure of the medium-speed peeling test.

[0055] Among them: 1. Clamp base; 2. Fixed loading end; 3. Fixed turning axis; 4. First movable base; 5. Second movable base; 6. Fastening component; 7. Limiting column; 8. Bottom plate; 9. Side plate; 10. Center plate; 11. Rigid base part of the stripped structure; 12. Flexible part of the stripped structure; 13. Upper pull head; 14. Lower pull head; 15. Crossbeam; 16. Impact rod; 17. Waveguide rod; 18. Incident rod; 19. Transmission rod; 20. Air chamber; 21. Adapter; 22. High-speed camera. DETAILED DESCRIPTION

[0056] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0057] like Figure 1 and Figure 2As shown, the controllable angle peeling fixture includes a fixture base 1, a fixed loading end 2, a fixed turning shaft 3, a first movable base 4, a second movable base 5, a fastening component 6, and a limiting column 7;

[0058] The fixture base 1 includes a bottom plate 8, side plates 9, and a center plate 10. The side plates 9 are arranged on the upper surface of the bottom plate 8. The cross section of the side plates 9 is L-shaped, so that a groove is formed between the bottom plate 8 and the side plates 9. The cross section of the center plate 10 is T-shaped, and the lower end of the center plate 10 is detachably fixed to the upper surface of the bottom plate 8. The bottom plate 8 and the side plates 9 can be arranged in an integrated manner.

[0059] The fixed loading end 2 is provided on the outer side of the side plate 9 and is used to connect to an external loading device;

[0060] The fixed turning shaft 3 is arranged on the upper surface of the center plate 10;

[0061] One end of the first movable base 4 and the second movable base 5 are both located in the groove formed by the bottom plate 8 and the side plate 9, and the other end is located between the bottom plate 8 and the center plate 10; the upper surfaces of the first movable base 4 and the second movable base 5 are both provided with a limiting column 7 located between the side plate 9 and the center plate 10; the first movable base 4 and the second movable base 5 are both provided with a fastening component 6. When it is necessary to fix the first movable base 4 and the second movable base 5, the first movable base 4 and the second movable base 5 are fixed to the fixture base 1 by tightening the fastening component 6. When it is necessary to adjust the position of the first movable base 4 and the second movable base 5, the first movable base 4 and the second movable base 5 are rotated relative to the fixture base 1 by loosening the fastening component 6;

[0062] The limiting columns 7 on the first movable base 4 and the second movable base 5 are used to fix the rigid base part 11 of the peeled structure and allow the rigid base part 11 of the peeled structure to slide back and forth, and the flexible part 12 of the peeled structure bypasses the fixed turning axis 3 and extends outside the clamp base 1; the peeling angle can be adjusted by adjusting the position of the first movable base 4 and the second movable base 5.

[0063] The fixed pivot axis 3 is located at the center of the center plate 10 and is bolted to the center plate 10. The flexible portion 12 of the peeled structure is oriented in the opposite direction to the fixed loading end 2. The loading direction is defined by the line between the fixed loading end 2 and the center of the fixture base 1. The loading device drives the fixed loading end 2, thereby moving the entire peeling fixture and the peeled structure to achieve the peel test.

[0064] In the specific implementation process, the implementation methods of fixing the first mobile base 4 and the second mobile base 5 by the fastening component 6 include the following three methods:

[0065] ①. The fastening member 6 is a bolt that penetrates the first and second movable bases 4 and 5. By tightening the bolt to contact the bottom plate 8, the first and second movable bases 4 and 5 are raised until they are in close contact with the side plates 9, thus completing the fastening of the first and second movable bases 4 and 5. This method only requires the fastening member 6 to be placed between the side plates 9 and the center plate 10.

[0066] ② The fastening member 6 is a bolt that penetrates the bottom plate 8. Tightening the bolt squeezes the first and second movable bases 4 and 5, forcing them to cling to the upper edges of the side plates 9 and secure them. This method requires an arc-shaped through-groove in the bottom plate 8 to allow the fastening member 6 to secure the two movable bases at different locations.

[0067] ③. The fastening member 6 is a bolt that penetrates the bottom plate 8 or the upper edge of the side plate 9. When the fastening member 6 is a bolt that penetrates the upper edge of the side plate 9, tightening the bolt can squeeze the first and second mobile bases 4 and 5, forcing them into close contact with the bottom plate 8 and thus securing them. This method requires an arc-shaped through-groove in the upper edge of the side plate 9 to enable the fastening member 6 to secure the two mobile bases at different positions.

[0068] In this embodiment, each limiting column 7 includes two parallel support shafts, and the rigid base portion 11 of the peeled structure and the flexible portion 12 of the peeled structure are half tightly fitted and half separated. The flexible portion 12 of the peeled structure can be freely bent to form any angle with the rigid base portion. The length of the rigid base portion 11 of the peeled structure and the flexible portion 12 of the peeled structure are both greater than 1.2 times the outer diameter of the clamp base 1, and the width is less than or equal to the height of the fixed turning axis 3 and the limiting column 7. The sum of the thicknesses is less than the distance between the two parallel limiting columns 7 on the same movable base, so that during the peeling strength test, the rigid base portion 11 of the peeled structure slides linearly according to its initial arrangement angle, ensuring that the peeling angle remains unchanged during the peeling process.

[0069] In this embodiment, the relative positions of the two mobile bases and the fixed turning axis 3 are adjusted so that the rigid base portion 11 of the stripped structure lies between the two limiting columns 7 on the two mobile bases, above the fixed turning axis 3, and in contact with the fixed turning axis 3. The separation point between the rigid base portion 11 of the stripped structure and the flexible portion 12 of the stripped structure is the point of intersection between the stripped structure and the fixed turning axis 3. The flexible portion 12 of the stripped structure is oriented toward the fixed turning axis 3 and is bent along the fixed turning axis 3 to be parallel to the fixed loading end 2. At this time, the angle formed by only the rigid base portion and only the flexible coating portion in the stripped structure is the stripping angle. After setting the stripping angle according to the pre-requirements, tighten the fastening component 6 to ensure that the two mobile bases are fixed during the stripping test.

[0070] Example 2:

[0071] This embodiment is a further extension of the first embodiment. Figure 3 As shown, in a low-speed peel strength test method based on a controllable angle peeling fixture, the external loading device is an electronic universal testing machine, and the low-speed peel strength test method includes the following steps:

[0072] A1. Move the first movable base 4 and the second movable base 5 so that the angle between the rigid base portion 11 of the stripped structure and the flexible portion 12 of the stripped structure between the limiting posts 7 on the two movable bases is the set angle. Tighten the fastening component 6 to fix the first movable base 4 and the second movable base 5.

[0073] A2. Fix the fixed loading end 2 in the upper pull head 13 of the electronic universal testing machine, and fix the flexible part 12 of the peeled structure in the lower pull head 14 of the electronic universal testing machine;

[0074] A3. By setting the displacement speed of the upper pull head 13 of the electronic universal testing machine, the peeling fixture is driven to move upward at a constant speed. The lower pull head 14 is kept stationary, so that the flexible portion 12 of the peeled structure is peeled off from the fixed rigid base portion 11 of the peeled structure at a pre-designed peeling angle. At the same time, the rigid base portion 11 of the peeled structure slides linearly according to its initial arrangement angle to ensure that the peeling angle remains unchanged during the peeling process.

[0075] A4. The peeling force during the peeling process is obtained by using a load sensor on the electronic universal testing machine. The displacement of the crossbeam 15 on the electronic universal testing machine is used as the peeling length to complete the low-speed peel strength test.

[0076] In this embodiment, the electronic universal testing machine's sliders consist of an upper slider 13 and a lower slider 14. The upper slider 13 is fixed to a crossbeam 15. By adjusting the displacement speed of the crossbeam 15, the upper slider 13 can be pulled to move the controllable peel angle. The low-speed peel strength achieved by the electronic universal testing machine is 0.001 to 500 mm / min.

[0077] Example 3:

[0078] This embodiment is a further extension of the first embodiment. This embodiment provides a method for testing the peel strength of a medium-speed peeling fixture with a controllable angle. Figure 6 As shown, the external loading device is a Hopkinson rod system, including an impact rod 16, an incident rod 18, a transmission rod 19, an air chamber 20 and a high-speed camera 22;

[0079] The impact rod 16 is sleeved on the incident rod 18. One end of the incident rod 18 is provided with a solid flange that withstands the impact of the impact rod 16. The other end of the incident rod 18 is used to connect to the fixed loading end 2. One end of the transmission rod 19 is used to connect to the flexible part 12 of the peeled structure. The transmission rod 19 is provided with a strain gauge. The air chamber 20 is used to store high-pressure nitrogen, which is used to push the impact rod 16 to impact the solid flange on the incident rod 18.

[0080] The medium speed peel strength test method includes the following steps:

[0081] B1. Move the first movable base 4 and the second movable base 5 so that the angle between the rigid base portion 11 of the stripped structure and the flexible portion 12 of the stripped structure between the limiting columns 7 on the two movable bases is the set angle, and tighten the fastening component 6 to fix the first movable base 4 and the second movable base 5;

[0082] B2. Connect the fixed loading end 2 to the other end of the incident rod 18; connect the extended end of the flexible portion 12 of the stripped structure to one end of the transmission rod 19;

[0083] B3. Nitrogen is filled into the air chamber 20 to reach a certain pressure. The high-pressure gas in the air chamber 20 is released instantly, causing the impact rod 16 to impact the solid flange on the incident rod 18 at a certain impact speed, thereby generating a tensile stress wave in the incident rod 18. When the tensile stress wave propagates to the stripping fixture, the incident rod 18 drives the stripping fixture to move toward the impact rod 16, thereby causing the flexible portion 12 of the stripped structure to be stripped from the rigid base portion 11 of the stripped structure at a set stripping angle. At the same time, the rigid base portion 11 of the stripped structure to slide linearly according to its initial arrangement angle, so as to ensure that the stripping angle remains unchanged throughout the stripping process;

[0084] B4. The time from when the first transmission signal reaches the strain gauge on the transmission rod 19 to when it is reflected from the free end of the transmission rod 19 and transmitted back to the strain gauge is taken as a measurement time;

[0085] B5. Monitor the peeling length of the flexible portion 12 of the peeled structure from the rigid base portion 11 of the peeled structure using a high-speed camera 22. During each measurement time, calculate the peeling force using the one-dimensional stress wave formula using the signal measured by the strain gauge on the transmission rod 19 to complete the medium-speed peel strength test.

[0086] In this embodiment, when a medium-speed peel strength test is performed using a Hopkinson rod, medium-speed (100,000 to 400,000 mm / min) peeling can be achieved by reducing the speed at which the impact rod 16 impacts the flange. However, since the loading displacement is positively correlated with the length and impact speed of the impact rod 16, the displacement generated by the medium-speed peel strength test using a traditional Hopkinson rod is limited and insufficient to produce effective peeling. Therefore, corresponding improvements to the traditional Hopkinson rod are required. Compared with the traditional Hopkinson rod system, the improved Hopkinson rod of this embodiment does not have a waveguide rod, the length of the incident rod 18 is only 1-1.05 times the length of the impact rod 16, and the length of the transmission rod 19 is greater than 4 times the length of the incident rod 18. Due to the small peeling force, the reflected wave on the incident rod 18 has basically no attenuation compared with the incident wave; since the length of the incident rod 18 and the impact rod 16 are close, the loading stress wave can be connected end to end in the incident rod 18. Based on the above two reasons, continuous constant amplitude loading can be achieved, and the loading displacement is no longer limited by the length of the impact rod 16. The measurement time of the entire system is from the first transmission signal reaching the strain gauge on the transmission rod 19 to its reflection from the free end of the transmission rod 19 and transmitting back to the strain gauge.

[0087] Since the impact rod 16 and the incident rod 18 are substantially the same length, and the stress wave circulates back and forth in the incident rod 18 and is connected end to end, it is impossible to stick a strain gauge on the incident rod 18 or to measure an effective strain signal using the strain gauge, that is, it is impossible to obtain real displacement data using the strain gauge. If non-contact digital image correlation technology (DIC) is used to obtain displacement information, the impact rod 16 will block the image of the peeling test section in the initial state before the experiment. Based on this, this embodiment improves the structural form of the impact rod 16 and the assembly position of the impact rod 16 and the incident rod 18. The impact rod 16 is designed as a cylindrical structure with an inner boss at one end, and is assembled in the opposite direction to the incident rod 18. This can not only meet the conditions for generating stress waves, but also use a high-speed camera combined with DIC testing technology to obtain the peeling length.

[0088] In this embodiment, since the peeling force is generally small (often less than 100N), a more accurate peeling force measurement can be achieved by properly configuring the transmission rod 19. Therefore, a hollow plexiglass rod is selected, and in-situ calibration of the sensitivity coefficient of a semiconductor strain gauge is used to achieve precise measurement of the transmission signal. However, the hollow plexiglass rod cannot be slotted to adhere to the flexible portion 12 of the structure to be peeled. Therefore, before connecting the peeling fixture end to the transmission rod 19, an plexiglass adapter 21 is first connected. The adapter 21 has a slot for adhering to the flexible portion 12 of the structure to be peeled.

[0089] The fixed loading end 2 and the flexible portion 12 of the stripped structure are respectively connected to the other end of the incident rod 18 and one end of the transmission rod 19 by gluing.

[0090] Two pairs of strain gauges (a low-voltage semiconductor strain gauge and a metal strain gauge, enabling in-situ calibration of the semiconductor strain gauge sensitivity coefficient) are affixed to the surface of the transmission rod 19, approximately 10 times the rod diameter from the end of the stripping fixture. This innovative design can be used to test the dynamic tensile mechanical properties of any material with low wave impedance (the product of the density of the medium and the wave velocity).

[0091] Example 4:

[0092] This embodiment is a further extension of the first embodiment. Since there is no effective high-speed peel strength test solution in this field, this embodiment designs the following high-speed peel strength test method based on a controllable angle peeling fixture: Figure 4 The external loading device shown is based on the Hopkinson rod system, which includes an impact rod 16, a waveguide rod 17, an incident rod 18, a transmission rod 19 and a gas chamber 20;

[0093] The impact rod 16 is sleeved on the waveguide rod 17. One end of the waveguide rod 17 is provided with a solid flange that withstands the impact of the impact rod 16. The other end of the waveguide rod 17 is connected to one end of the incident rod 18. The other end of the incident rod 18 is used to connect to the fixed loading end 2. One end of the transmission rod 19 is used to connect to the flexible part 12 of the stripped structure. Strain gauges are provided on the incident rod 18 and the transmission rod 19. The air chamber 20 is used to store high-pressure nitrogen, which is used to push the impact rod 16 to impact the solid flange on the waveguide rod 17.

[0094] The high-speed peel strength test method includes the following steps:

[0095] C1. Move the first movable base 4 and the second movable base 5 so that the angle between the rigid base portion 11 of the stripped structure and the flexible portion 12 of the stripped structure between the limiting columns 7 on the two movable bases is the set angle, and tighten the fastening component 6 to fix the first movable base 4 and the second movable base 5;

[0096] C2, connect the fixed loading end 2 to the other end of the incident rod 18; connect the flexible part 12 of the stripped structure to one end of the transmission rod 19;

[0097] C3. Nitrogen is filled into the air chamber 20 to reach a certain pressure. The high-pressure nitrogen in the air chamber 20 is instantly released, causing the impact rod 16 to impact the flange on the waveguide rod 17 at a certain impact speed, thereby generating a tensile stress wave in the waveguide rod 17. When the tensile stress wave propagates along the waveguide rod 17 and the incident rod 18 to the stripping fixture, the incident rod 18 drives the stripping fixture to move toward the waveguide rod 17, thereby causing the flexible portion 12 of the stripped structure to be stripped from the rigid base portion 11 of the stripped structure to be stripped according to the set stripping angle. At the same time, the rigid base portion 11 of the stripped structure to slide linearly according to its initial arrangement angle, so as to ensure that the stripping angle remains unchanged throughout the stripping process;

[0098] C4. The peel length is calculated based on the signals measured by the strain gauges on the incident rod 18 and the transmission rod 19 according to the one-dimensional stress wave formula; the peel force is calculated based on the signals measured by the strain gauges on the transmission rod 19 according to the one-dimensional stress wave formula, completing the high-speed peel strength test;

[0099] The peeling speed in the high-speed peel strength test is 400,000 to 1,500,000 mm / min.

[0100] In this embodiment, since the peeling force is generally small (often less than 100N), a more accurate peeling force measurement can be achieved by properly configuring the transmission rod 19. Therefore, a hollow plexiglass rod is selected, and in-situ calibration of the sensitivity coefficient of a semiconductor strain gauge is used to achieve precise measurement of the transmission signal. However, the hollow plexiglass rod cannot be slotted to adhere to the flexible portion 12 of the structure to be peeled. Therefore, before connecting the peeling fixture end to the transmission rod 19, an plexiglass adapter 21 is first connected. The adapter 21 has a slot for adhering to the flexible portion 12 of the structure to be peeled.

[0101] The fixed loading end 2 and the flexible portion 12 of the stripped structure are respectively connected to the other end of the incident rod 18 and one end of the transmission rod 19 by gluing.

[0102] Two pairs of strain gauges (a low-voltage semiconductor strain gauge and a metal strain gauge, enabling in-situ calibration of the semiconductor strain gauge sensitivity coefficient) are affixed to the surface of the transmission rod 19, approximately 10 times the rod diameter from the end of the stripping fixture. This innovative design can be used to test the dynamic tensile mechanical properties of any material with low wave impedance (the product of the density of the medium and the wave velocity).

[0103] In one embodiment of the present invention, the displacement-force curve of the 180°, 700,000 mm / min high-speed peel test is as follows: Figure 5 As shown in the figure, the effectiveness of the high-speed peel strength test method can be demonstrated.

[0104] In summary, the controllable angle peeling fixture and low, medium and high speed peeling strength testing method provided by the present invention lay the foundation for building a peeling strength database for low, medium and high speed peeling at different angles.

Claims

1. A controllable angle peeling fixture, characterized in that: It comprises a clamp base (1), a fixed loading end (2), a fixed turning shaft (3), a first movable base (4), a second movable base (5), a fastening component (6) and a limiting column (7); The fixture base (1) includes a bottom plate (8), a side plate (9) and a center plate (10), wherein the side plate (9) is arranged on the upper surface of the bottom plate (8), and the cross section of the side plate (9) is L-shaped so that a groove is formed between the bottom plate (8) and the side plate (9); the cross section of the center plate (10) is T-shaped, and the lower end of the center plate (10) is detachably fixed to the upper surface of the bottom plate (8); The fixed loading end (2) is arranged on the outer side surface of the side plate (9) and is used to be connected to an external loading device; The fixed turning shaft (3) is arranged on the upper surface of the center plate (10); One end of the first movable base (4) and the second movable base (5) are both located in the groove formed by the bottom plate (8) and the side plate (9), and the other end is located between the bottom plate (8) and the center plate (10); the upper surfaces of the first movable base (4) and the second movable base (5) are both provided with a limiting column (7) located between the side plate (9) and the center plate (10); the first movable base (4) and the second movable base (5) are both provided with a fastening component (6); when it is necessary to fix the first movable base (4) and the second movable base (5), the first movable base (4) and the second movable base (5) are fixed to the clamp base (1) by tightening the fastening component (6); when it is necessary to adjust the position of the first movable base (4) and the second movable base (5), the first movable base (4) and the second movable base (5) are rotated relative to the clamp base (1) by loosening the fastening component (6); The limiting columns (7) on the first movable base (4) and the second movable base (5) are used to fix the rigid base portion (11) of the stripped structure and allow the rigid base portion (11) of the stripped structure to slide back and forth, and the flexible portion (12) of the stripped structure bypasses the fixed turning axis (3) and extends outside the clamp base (1); the stripping angle can be adjusted by adjusting the positions of the first movable base (4) and the second movable base (5).

2. The controllable angle peeling fixture according to claim 1, characterized in that: The fixed turning shaft (3) is located at the center of the center plate (10).

3. The controllable angle peeling fixture according to claim 1, characterized in that: The fastening component (6) is a bolt that passes through the first movable base (4) and the second movable base (5). By screwing the bolt to contact the bottom plate (8), the first movable base (4) and the second movable base (5) are raised until they are in close contact with the side plate (9), thereby completing the fastening of the first movable base (4) and the second movable base (5).

4. The controllable angle peeling fixture according to claim 1, characterized in that: The extending end of the stripped structure flexible portion (12) is in the opposite direction to the fixed loading end (2).

5. A low-speed peel strength test method based on a controllable angle peeling fixture according to any one of claims 1 to 4, characterized in that: The external loading device is an electronic universal testing machine, and the low-speed peel strength test method includes the following steps: A1. Move the first movable base (4) and the second movable base (5) so that the angle between the rigid base portion (11) of the stripped structure and the flexible portion (12) of the stripped structure between the limiting columns (7) on the two movable bases is a set angle, and tighten the fastening component (6) to fix the first movable base (4) and the second movable base (5); A2. Fix the fixed loading end (2) in the upper pull head (13) of the electronic universal testing machine, and fix the flexible part (12) of the stripped structure in the lower pull head (14) of the electronic universal testing machine; A3. By setting the displacement speed of the upper pull head (13) of the electronic universal testing machine, the peeling fixture is driven to move upward at a constant speed; the lower pull head (14) is kept stationary, so that the flexible portion (12) of the peeled structure is peeled off from the fixed rigid base portion (11) of the peeled structure at a pre-designed peeling angle, and at the same time, the rigid base portion (11) of the peeled structure is made to slide linearly according to its initial arrangement angle, so as to ensure that the peeling angle remains unchanged during the peeling process; A4. The peeling force during the peeling process is obtained by a load sensor on an electronic universal testing machine, and the displacement of the crossbeam (15) on the electronic universal testing machine is used as the peeling length to complete the low-speed peeling strength test; The peeling speed in the low-speed peel strength test is 0.001 to 500 mm / min.

6. A medium-speed peel strength test method based on a controllable angle peeling fixture according to any one of claims 1 to 4, characterized in that: The external loading device is a Hopkinson rod system, including an impact rod (16), an incident rod (18), a transmission rod (19), an air chamber (20) and a high-speed camera (22); The impact rod (16) is sleeved on the incident rod (18), and one end of the incident rod (18) is provided with a solid flange for bearing the impact of the impact rod (16); the other end of the incident rod (18) is used to be connected to the fixed loading end (2); one end of the transmission rod (19) is used to be connected to the flexible part (12) of the stripped structure; the transmission rod (19) is provided with a strain gauge; the air chamber (20) is used to store high-pressure nitrogen, and the high-pressure nitrogen is used to push the impact rod (16) to impact the solid flange on the incident rod (18); The medium speed peel strength test method includes the following steps: B1. Move the first movable base (4) and the second movable base (5) so that the angle between the rigid base portion (11) of the stripped structure and the flexible portion (12) of the stripped structure between the limiting columns (7) on the two movable bases is a set angle, and tighten the fastening component (6) to fix the first movable base (4) and the second movable base (5); B2, connecting the fixed loading end (2) to the other end of the incident rod (18); connecting the extended end of the flexible portion (12) of the stripped structure to one end of the transmission rod (19); B3. Nitrogen is filled into the air chamber (20) to reach a certain pressure, and the high-pressure gas in the air chamber (20) is released instantly to make the impact rod (16) impact the solid flange on the incident rod (18) at a certain impact speed, thereby generating a tensile stress wave in the incident rod (18). When the tensile stress wave propagates to the stripping fixture, the incident rod (18) drives the stripping fixture to move toward the impact rod (16), so that the flexible part (12) of the stripped structure is stripped from the rigid base part (11) of the stripped structure according to the set stripping angle, and at the same time, the rigid base part (11) of the stripped structure slides linearly according to its initial arrangement angle, so as to ensure that the stripping angle remains unchanged during the stripping process; B4. The time from when the first transmission signal reaches the strain gauge on the transmission rod (19) to when it is reflected from the free end of the transmission rod (19) and transmitted back to the strain gauge is taken as a measurement time; B5. Monitor the peeling length of the flexible portion (12) of the peeled structure from the rigid base portion (11) of the peeled structure by a high-speed camera (22); calculate the peeling force according to the one-dimensional stress wave formula using the signal measured by the strain gauge on the transmission rod (19) during each measurement time, and complete the medium-speed peeling strength test; The peeling speed in the medium-speed peel strength test is 100,000 to 400,000 mm / min.

7. The medium-speed peel strength testing method according to claim 6, wherein: The transmission rod (19) is a hollow organic glass rod. One end of the hollow organic glass rod is provided with an adapter (21). The flexible part (12) of the stripped structure is connected to the hollow organic glass rod through the adapter (21).

8. The medium-speed peel strength testing method according to claim 6, wherein: The fixed loading end (2) and the stripped structure flexible portion (12) are respectively connected to the other end of the incident rod (18) and one end of the transmission rod (19) by gluing.

9. A high-speed peel strength testing method based on a controllable angle peeling fixture according to any one of claims 1 to 4, characterized in that: The external loading device is a Hopkinson rod system, comprising an impact rod (16), a waveguide rod (17), an incident rod (18), a transmission rod (19) and an air chamber (20); The impact rod (16) is sleeved on the waveguide rod (17), and one end of the waveguide rod (17) is provided with a solid flange for bearing the impact of the impact rod (16); the other end of the waveguide rod (17) is connected to one end of the incident rod (18); the other end of the incident rod (18) is used to be connected to the fixed loading end (2); one end of the transmission rod (19) is used to be connected to the flexible part (12) of the stripped structure; strain gauges are provided on the incident rod (18) and the transmission rod (19); the air chamber (20) is used to store high-pressure nitrogen, and the high-pressure nitrogen is used to push the impact rod (16) to impact the solid flange on the waveguide rod (17); The high-speed peel strength test method includes the following steps: C1. Move the first movable base (4) and the second movable base (5) so that the angle between the rigid base portion (11) of the stripped structure and the flexible portion (12) of the stripped structure between the limiting columns (7) on the two movable bases is a set angle, and tighten the fastening component (6) to fix the first movable base (4) and the second movable base (5); C2, connecting the fixed loading end (2) to the other end of the incident rod (18); connecting the flexible portion of the stripped structure (12) to one end of the transmission rod (19); C3. Nitrogen is filled into the air chamber (20) to reach a certain pressure, and the high-pressure nitrogen in the air chamber (20) is released instantly to make the impact rod (16) impact the flange on the waveguide rod (17) at a certain impact speed, thereby generating a tensile stress wave in the waveguide rod (17). When the tensile stress wave propagates along the waveguide rod (17) and the incident rod (18) to the stripping fixture, the incident rod (18) drives the stripping fixture to move toward the waveguide rod (17), so that the flexible part (12) of the stripped structure is stripped from the rigid base part (11) of the stripped structure according to the set stripping angle, and at the same time, the rigid base part (11) of the stripped structure slides linearly according to its initial arrangement angle, so as to ensure that the stripping angle remains unchanged during the stripping process; C4. The peeling length is calculated based on the signal measured by the strain gauge on the incident rod (18) and the transmission rod (19) according to the one-dimensional stress wave formula; the peeling force is calculated based on the signal measured by the strain gauge on the transmission rod (19) according to the one-dimensional stress wave formula, thereby completing the high-speed peeling strength test; The peeling speed in the high-speed peel strength test is 400,000 to 1,500,000 mm / min.

10. The high-speed peel strength testing method according to claim 9, characterized in that: The transmission rod (19) is a hollow organic glass rod, one end of which is provided with an adapter (21), and the flexible portion (12) of the stripped structure is connected to the hollow organic glass rod via the adapter (21); The fixed loading end (2) and the stripped structure flexible portion (12) are respectively connected to the other end of the incident rod (18) and one end of the transmission rod (19) by gluing.

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