A high-speed tensile experiment and mechanical testing device and method for flexible materials

Abstract

This invention relates to the field of materials mechanics testing technology, and discloses a high-speed tensile test and mechanical testing device and method for flexible materials. The device includes a rigid support frame with a tension sensor, a two-stage pneumatic clamp, a tension rod, and a screw drive device. A rubber band is connected to the bottom of the tension rod, and the traction seat of the screw drive device can pull the rubber band to store energy. A buffer mechanism consisting of a deceleration spring, a traction rope, and a movable pulley is provided on both sides of the frame. The tension rod is equipped with a semiconductor strain gauge and a guide structure, and a camera is used to collect signals and images. The testing method includes clamping and positioning, pre-tensioning and energy storage, high-speed tensioning, buffering and limiting, and data acquisition steps: the pneumatic clamp holds the sample, the rubber band stores energy and then releases to drive the tension rod to stretch the sample at high speed, the buffer mechanism ensures stability, and the tension, strain signals, and deformation images are collected simultaneously. This enables simultaneous testing of mechanical parameters and deformation behavior of flexible materials under high-speed tension, and is suitable for evaluating the dynamic mechanical properties of thin-film flexible materials.

Description

Technical Field

[0001] This invention relates to the field of materials mechanics testing technology, specifically to a high-speed tensile testing and mechanical testing device and method for flexible materials. Background Technology

[0002] Flexible thin-film materials are widely used in OLED flexible screens, wearable devices, flexible sensors, and other fields. Their moduli range from kPa to GPa. The mechanical response under dynamic loads is a key indicator determining the reliability and lifespan of these devices, and high-speed tensile testing is the core technical means to evaluate such performance. Given the characteristics of flexible materials—low modulus, easy deformation, and strong instantaneous dynamic response—high-speed tensile equipment must meet three core requirements: First, the tensile speed must simulate high strain rate scenarios to accurately reproduce the material's behavior under extreme conditions such as impact; second, the sensor must have wide range adaptability to accurately capture force signals during the tensile process of materials with different moduli; and third, data acquisition must simultaneously capture mechanical signals and deformation images to ensure the completeness and accuracy of the test results.

[0003] However, current mainstream commercial high-speed stretching equipment has significant technical shortcomings, making it difficult to adapt to the testing needs of flexible film materials: First, the driving method is limited to servo or hydraulic drive, which limits the maximum stretching speed and cannot meet the stringent requirements of high strain rate testing, thus restricting the research on the ultimate performance of materials; Second, it relies on a complex hydraulic system to achieve speed control, which is cumbersome to operate and requires professional personnel for debugging; Third, it lacks a stable guiding and buffering mechanism adapted to the high-speed stretching of flexible materials, which can easily lead to problems such as sample swaying and impact overload, affecting the reliability of test data.

[0004] Existing technologies suffer from insufficient stretching speed, poor sensor compatibility, complex operation, and poor testing stability, making it difficult to meet the requirements for high-speed, accurate, and stable dynamic mechanical property testing of flexible thin film materials. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed tensile testing and mechanical testing device and method for flexible materials, in order to solve the technical problems in the prior art, which are insufficient tensile speed, poor sensor compatibility, complex operation and poor test stability, making it difficult to meet the requirements of high-speed, accurate and stable dynamic mechanical property testing of flexible film materials.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0007] A high-speed tensile testing and mechanical testing device for flexible materials includes a tensile sensor mounted on a rigid support frame from top to bottom, a first pneumatic clamp for thin film samples, a second pneumatic clamp for thin film samples, a tensile rod clamped by a clamping guide device, and a screw drive device. The first pneumatic clamp for thin film samples is connected to the tensile sensor, and the second pneumatic clamp for thin film samples is connected to the top end of the tensile rod. The first and second pneumatic clamps for thin film samples respectively clamp both ends of the thin film sample.

[0008] A rubber band is connected to the bottom end of the tension rod near the bottom of the screw drive device;

[0009] A traction seat is provided on the screw drive device. The screw drive device is used to drive the traction seat to move up and down along the length direction of the rigid support frame. The traction seat is configured to connect the end of the rubber band away from the tension rod when it is driven to move downward by the screw drive device until the rubber band is pulled to the target length.

[0010] A deceleration spring is provided on the rigid support frame on both sides of the screw drive device. One end of the deceleration spring is fixed to the rigid support frame, and the other end is connected to a traction rope. The end of the traction rope away from the deceleration spring is wound around the tension rod radially through a movable pulley and connected to the side wall of the tension rod.

[0011] A semiconductor strain gauge is provided on the rod body of the tension rod near the pneumatic clamp of the second thin film sample;

[0012] In this process, after the rubber band is stretched downward to the target length by the traction seat, the clamping guide device releases the stretching rod. The elastic recovery of the rubber band pulls the stretching rod downward, thereby causing the second film sample pneumatic clamp to stretch the film sample, and an image of the stretched film sample is captured by a camera.

[0013] In a preferred embodiment of the present invention, a position adjustment device is provided at the top of the rigid support frame. The position adjustment device is connected to the tension sensor and is used to adjust the initial height position of the tension sensor.

[0014] As a preferred embodiment of the present invention, a fixed seat is provided on both sides of the rigid support frame near the top of the screw drive device, and an adjusting rod is mounted on the fixed seat. The adjusting rod is installed on the fixed seat along the length direction of the rigid support frame, and the bottom end of the deceleration spring away from the traction rope is connected to the end of the adjusting rod.

[0015] The adjusting rod, the deceleration spring, and the traction rope are coaxial and located in the same horizontal and vertical plane as the tension rod.

[0016] As a preferred embodiment of the present invention, a guide ring is movably fitted on the rod body of the tension rod near the top of the screw drive device, and the ends of the two traction ropes are connected to the outer wall of the guide ring, and the positions where the two traction ropes are connected to the guide ring are symmetrically arranged with the tension rod as the axis of symmetry.

[0017] Multiple guide grooves are evenly distributed on the circumferential surface of the tension rod, and the guide grooves extend along the axial direction of the tension rod; guide blocks corresponding to the multiple guide grooves are provided on the inner surface of the guide ring, and the guide blocks can move along the guide grooves.

[0018] During the process of using the elastic recovery of the rubber band to pull the tension rod downward, the guide block contacts the top side wall of the guide groove to limit the guide ring and pull the traction rope.

[0019] This invention provides a high-speed tensile testing and mechanical testing method for flexible materials, which is used to implement the aforementioned high-speed tensile testing and mechanical testing device for flexible materials, and includes the following steps:

[0020] Step 100, clamping and positioning: clamp and fix both ends of the film sample using the first film sample pneumatic clamp and the second film sample pneumatic clamp respectively. The first film sample pneumatic clamp is installed on the top of the rigid support frame through a tension sensor, and the second film sample pneumatic clamp is connected to the top of the tension rod.

[0021] Step 200, Pre-tensioning and energy storage: The traction seat is driven downward by the screw rod drive device, so that the traction seat connects to and pulls the rubber band at the bottom of the tension rod to the target length, thus completing the storage of elastic potential energy of the rubber band. During this process, the clamping guide device keeps the tension rod clamped and locked.

[0022] Step 300, High-speed stretching: Control the clamping guide device to release the stretching rod, and use the elastic restoring force of the rubber band to pull the stretching rod and the second film sample pneumatic clamp to move downward at high speed to stretch the film sample at high speed.

[0023] Step 400, Buffer Limit: During the downward movement of the tension rod, the tension rod is decelerated and limited by the buffer mechanism composed of deceleration springs, traction ropes and movable pulleys on both sides of the rigid support frame;

[0024] Step 500, Data Acquisition: Tensile force signals are acquired through a tension sensor, strain signals are acquired through a semiconductor strain gauge on a tension rod, and tensile deformation images of the thin film sample are acquired through a camera to complete the high-speed tensile mechanical test of the flexible material.

[0025] As a preferred embodiment of the present invention, after the film sample is clamped and before high-speed stretching is performed, the initial height of the tension sensor and the first film sample pneumatic clamp is adjusted by a position adjustment device located at the top of the rigid support frame to achieve the centering and pre-tightening of the film sample.

[0026] In a preferred embodiment of the present invention, the deceleration spring is mounted on a fixed seat of a rigid support frame via an adjusting rod. The initial preload and buffer stroke of the deceleration spring are adjusted by adjusting the extension length of the adjusting rod.

[0027] As a preferred embodiment of the present invention, a guide ring is movably sleeved on the tension rod, and a guide block on the inner side of the guide ring slides in cooperation with a guide groove on the tension rod;

[0028] During the high-speed downward movement of the tension rod, the guide block abuts against the top side wall of the guide groove, causing the guide ring to pull the traction rope, thereby achieving smooth deceleration and limiting through the deceleration spring.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention employs a rubber band pre-tensioning and energy storage-instantaneous release driving method. Compared with traditional servo / hydraulic drives, the elastic restoring force can be instantly converted into the high-speed motion of the tension rod, breaking through the traditional tensile speed of thin film samples. It can more accurately simulate the high strain rate stress scenarios of flexible materials under extreme conditions such as impact and collision, filling the gap in the field of high strain rate testing of existing equipment and providing key data support for the impact-resistant design of flexible devices.

[0031] This invention uses first and second pneumatic clamps to hold both ends of the thin film sample. The pneumatic clamping method provides uniform and adjustable clamping force, which avoids slippage or damage when clamping low-modulus flexible materials, and can stably fix high-modulus film materials to ensure effective transmission of tensile force. At the same time, the semiconductor strain gauge on the tension rod works in conjunction with the tension sensor on the top to simultaneously capture strain and force signals during the tensioning process, realizing accurate measurement of mechanical parameters and solving the defect of inaccurate measurement of small force signals of low-modulus materials in existing equipment.

[0032] This invention features a buffer mechanism consisting of a deceleration spring, a traction rope, and a movable pulley on both sides of the screw drive device. When the tension rod moves downward at high speed under the drive of the rubber band, the traction rope transmits the tension to the deceleration spring through the movable pulley. The elastic deformation of the spring generates a buffer braking force, effectively suppressing the impact overload of the tension rod and preventing the sample from breaking and splashing or being damaged by the violent impact at the end of the high-speed tensioning process. At the same time, the clamping and guiding device locks the tension rod during the pre-tensioning stage and guides the movement only along the axial direction after release, preventing the sample from swaying or tilting during the tensioning process and ensuring the straightness of the tensioning path and the stability of the test data.

[0033] The drive structure of this invention only includes a rubber band, a screw drive device, and a traction seat. Compared with a complex hydraulic system, the structure is simpler and easier to maintain. It does not require professional personnel to adjust complex parameters, thus reducing the difficulty of operation. Attached Figure Description

[0034] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the main structure of the high-speed tensile testing device according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the connection structure between the traction seat and the tension rod of the high-speed tensile testing device according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the tension rod structure according to an embodiment of the present invention;

[0038] Figure 4 This is a repeatable tensile stress-strain curve of a low-modulus OCA acrylic optical adhesive material based on a high-speed tensile testing device under different strain rates, according to an embodiment of the present invention.

[0039] Figure 5 This is a repeatable tensile stress-strain curve of a high-modulus CPI polyimide membrane under different strain rates, based on a high-speed tensile testing device according to an embodiment of the present invention.

[0040] The labels in the diagram represent the following:

[0041] 1- Rigid support frame; 2- Tension sensor; 3- First thin film sample pneumatic clamp; 4- Second thin film sample pneumatic clamp; 5- Clamping guide device; 6- Tension rod; 7- Helical rod drive device; 8- Guide block; 9- Rubber band; 10- Traction seat; 11- Deceleration spring; 12- Traction rope; 13- Movable pulley; 14- Thin film sample; 15- Position adjustment device; 16- Fixed seat; 17- Adjusting rod; 18- Guide ring; 19- Guide groove; 20- Helical rod; 21- Drive motor; 22- Semiconductor strain gauge; 23- Guide sleeve; 24- Clamping piece; 25- Guide sleeve. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a high-speed tensile test and mechanical testing device for flexible materials, including a tensile sensor 2, a first thin film sample pneumatic clamp 3, a second thin film sample pneumatic clamp 4, a tensile rod 6 clamped by a clamping guide device 5, and a screw drive device 7, which are arranged from top to bottom on a rigid support frame 1. The first thin film sample pneumatic clamp 3 is connected to the tensile sensor 2, the second thin film sample pneumatic clamp 4 is connected to the top end of the tensile rod 6, and the first thin film sample pneumatic clamp 3 and the second thin film sample pneumatic clamp 4 respectively clamp the two ends of the thin film sample 14.

[0044] The two ends of the thin film sample are clamped by the first and second pneumatic clamps. The pneumatic clamping method can provide uniform and adjustable clamping force, which avoids the slippage or damage problem when clamping low modulus flexible materials (kPa level) and can stably fix high modulus film materials (GPa level) to ensure effective transmission of tensile force. At the same time, the semiconductor strain gauge on the tension rod and the tension sensor on the top can work together to capture the strain and force signals during the tensioning process, realize the accurate measurement of mechanical parameters, and solve the defect of inaccurate measurement of small force signals of low modulus materials in existing equipment.

[0045] A rubber band 9 is connected to the bottom end of the tension rod 6 near the screw drive device 7. The drive method of pre-tensioning and storing energy with rubber band and releasing it instantly is adopted. Compared with the traditional servo / hydraulic drive, the elastic restoring force can be instantly converted into the high-speed motion of the tension rod, so that the tensile speed of the film sample exceeds 20m / s, far exceeding the speed limit of 12m / s of mainstream commercial equipment. It can accurately simulate the high strain rate stress scenario of flexible materials under extreme conditions such as impact and collision, fill the gap of existing equipment in the field of high strain rate testing, and provide key data support for the impact-resistant design of flexible devices.

[0046] A traction seat 10 is provided on the screw drive device 7. The screw drive device 7 is used to drive the traction seat 10 to move up and down along the length direction of the rigid support frame 1. The traction seat 10 is configured to connect the end of the rubber band 9 away from the tension rod 6 when it is driven to move downward by the screw drive device 7, until the rubber band 9 is pulled to the target length.

[0047] A deceleration spring 11 is provided on the rigid support frame 1 on both sides of the screw drive device 7. One end of the deceleration spring 11 is fixed to the rigid support frame 1, and the other end is connected to the traction rope 12. The end of the traction rope 12 away from the deceleration spring 11 passes through the movable pulley 13 and winds around the tension rod 6 radially, and is connected to the side wall of the tension rod 6.

[0048] A buffer mechanism consisting of a deceleration spring, a traction rope, and a movable pulley is installed on both sides of the screw drive device. When the tension rod moves downward at high speed under the drive of the rubber band, the traction rope transmits the tension to the deceleration spring through the movable pulley. The elastic deformation of the spring generates a buffer braking force, which effectively suppresses the impact overload of the tension rod and avoids the sample from breaking and splashing or the mechanism from being damaged due to violent impact at the end of high-speed tensioning. At the same time, the clamping and guiding device locks the tension rod in the pre-tensioning stage and guides the movement only along the axial direction after release, preventing the sample from swinging or tilting during the tensioning process and ensuring the straightness of the tensioning path and the stability of the test data.

[0049] A semiconductor strain gauge is installed on the rod body of the tension rod 6 near the pneumatic clamp 4 of the second thin film sample;

[0050] In this process, after the rubber band 9 is stretched downward to the target length by the traction seat 10, the clamping guide device 5 releases the stretching rod 6. The elastic recovery of the rubber band 9 pulls the stretching rod 6 downward, thereby causing the second film sample pneumatic clamp 4 to stretch the film sample 14, and the camera captures an image of the film sample 14 being stretched.

[0051] In this embodiment, the clamping and guiding device 5 functions to clamp and release the tension rod 6. It can be a pneumatic / electric gripper, such as a Festo DHRS series rotary gripper, a Schunk PRG series radial manipulator, a Stüwe HSD series shrink disc, or an expansion sleeve. Additionally, this embodiment can also guide the tension rod 6 by providing a guide sleeve 25. The tension rod 6 passes axially through the guide sleeve 25, which is fixedly installed. Guide sleeves 25 can be provided at both the upper and lower ends of the clamping and guiding device 5.

[0052] By capturing images of a stretched thin-film sample using a camera and combining the force signal from a tensile sensor with the strain signal from a semiconductor strain gauge, a multi-dimensional synchronous acquisition system of mechanical parameters and deformation images was constructed. This system can completely record the dynamic response of flexible materials from elastic deformation and plastic yielding to fracture failure. It solves the problem that traditional equipment can only acquire a single mechanical signal and cannot correlate deformation behavior, providing more comprehensive test data for the analysis of the dynamic mechanical mechanism of materials.

[0053] A position adjustment device 15 is provided at the top of the rigid support frame 1. The position adjustment device 15 is connected to the tension sensor 2 and is used to adjust the initial height position of the tension sensor 2.

[0054] Fixed seats 16 are provided on both sides of the rigid support frame 1 near the top of the screw drive device 7. Adjusting rods 17 are installed on the fixed seats 16. The adjusting rods 17 are installed on the fixed seats 16 along the length of the rigid support frame 1. The bottom end of the deceleration spring 11 away from the traction rope 12 is connected to the end of the adjusting rod 17.

[0055] The adjusting rod 17, the deceleration spring 11, and the traction rope 12 are coaxial and located in the same horizontal and vertical plane as the tension rod 6.

[0056] A guide ring 18 is movably mounted on the rod body of the tension rod 6 near the top of the screw drive device 7. The ends of the two traction ropes 12 are connected to the outer wall of the guide ring 18, and the positions of the two traction ropes 12 connected to the guide ring 18 are symmetrically arranged with the tension rod 6 as the axis of symmetry.

[0057] In this embodiment, to avoid direct connection between the guide ring 18 and the traction rope 12 and the influence of friction between the guide ring 18 and the tension rod 6, this embodiment also provides a guide sleeve 23 through which the tension rod 6 passes. A clamp-shaped member 24 is provided on the guide sleeve 23, which clamps the guide ring 18. At this time, the guide ring 18 has a funnel-shaped structure, and the clamp-shaped member 24 clamps the middle (axial direction) of the guide ring 18.

[0058] Multiple guide grooves 19 are evenly distributed on the circumferential surface of the tension rod 6, and the guide grooves 19 extend along the axial direction of the tension rod 6; guide blocks 8 corresponding to the multiple guide grooves 19 are provided on the inner surface of the guide ring 18, and the guide blocks 8 can move along the guide grooves 19.

[0059] During the process of using the elastic recovery of the rubber band 9 to pull the tension rod 6 downward, the guide block 8 contacts the top side wall of the guide groove 19, limits the guide ring 18, and pulls the traction rope 12.

[0060] This embodiment provides a method for high-speed tensile testing and mechanical testing of flexible materials based on a high-speed tensile testing and mechanical testing device, including the following steps:

[0061] Step 100, clamping and positioning: clamp and fix both ends of the film sample 14 by the first film sample pneumatic clamp 3 and the second film sample pneumatic clamp 4 respectively. The first film sample pneumatic clamp 3 is installed on the top of the rigid support frame 1 through the tension sensor 2, and the second film sample pneumatic clamp 4 is connected to the top of the tension rod 6.

[0062] Step 200, Pre-tensioning and energy storage: The traction seat 10 is driven to move downward by the screw rod drive device 7, so that the traction seat 10 connects to and pulls the rubber band 9 at the bottom of the tension rod 6 to the target length, thus completing the storage of elastic potential energy of the rubber band 9. During this process, the clamping guide device 5 keeps the tension rod 6 clamped and locked.

[0063] Step 300, High-speed stretching: Control the clamping guide device 5 to release the stretching rod 6, and use the elastic restoring force of the rubber band 9 to pull the stretching rod 6 and the second film sample pneumatic clamp 4 to move downward at high speed to stretch the film sample at high speed.

[0064] Step 400, Buffering and Limiting: During the downward movement of the tension rod 6, the tension rod 6 is decelerated and limited by the buffering mechanism composed of the deceleration springs 11, traction ropes 12 and movable pulleys 13 on both sides of the rigid support frame 1.

[0065] Step 500, Data Acquisition: The tensile force signal is acquired through the tensile sensor 2, the strain signal is acquired through the semiconductor strain gauge on the tensile rod 6, and the tensile deformation image of the thin film sample is acquired through the camera to complete the high-speed tensile mechanical test of the flexible material.

[0066] After the film sample is clamped and before high-speed stretching is performed, the initial height of the tension sensor 2 and the first film sample pneumatic clamp 3 is adjusted by the position adjustment device located at the top of the rigid support frame 1 to achieve the centering and pre-tightening of the film sample.

[0067] The deceleration spring 11 is mounted on the fixed seat 16 of the rigid support frame 1 via the adjusting rod 17. The initial preload and buffer stroke of the deceleration spring 11 are adjusted by adjusting the extension length of the adjusting rod 17.

[0068] A guide ring 18 is movably sleeved on the tension rod 6, and the guide block 8 inside the guide ring 18 slides in conjunction with the guide groove 19 on the tension rod 6.

[0069] During the high-speed downward movement of the tension rod 6, the guide block 8 abuts against the top side wall of the guide groove 19, which drives the guide ring 18 to pull the traction rope 12, thereby achieving smooth deceleration and limiting through the deceleration spring 11.

[0070] The core drive structure of the device involved in this embodiment only includes a rubber band, a screw drive device, and a traction seat. Compared with a complex hydraulic system, the structure is simpler and easier to maintain. It does not require professional personnel to debug complex parameters, thus reducing the difficulty of operation. At the same time, the core components (rigid support frame, pneumatic clamp, and screw drive device) are all conventional mechanical parts, and the manufacturing cost is significantly lower than that of imported hydraulic high-speed stretching equipment. This is conducive to the popularization and application of the device by scientific research institutions and small and medium-sized enterprises, and promotes the large-scale development of dynamic mechanics research on flexible materials.

[0071] The specific embodiments of this implementation method are as follows:

[0072] Design process of high-speed tensile testing equipment

[0073] 1.1. Support system assembly (steps S1-S2)

[0074] S1: Select a level, rigid surface, clear away any debris, and place the support base (steel) stably on the surface, ensuring that the bottom of the base is completely in contact with the ground without any shaking, thus providing a stable foundation for the device.

[0075] S2: Align the rigid support frame 1 (hollow stainless steel) vertically with the preset bolt holes of the support base, and use high-strength bolts to fasten the frame to the base; after assembly, use a level to check the verticality of the frame to ensure that the deviation does not exceed 0.5°; at the same time, clean the internal channels of the frame to remove impurities, so as to facilitate the subsequent wiring and ensure that the internal wiring is neat and orderly.

[0076] 1.2. Drive system assembly (steps S3-S10)

[0077] S3: At the preset installation position at the bottom of the rigid support frame 1, fix the drive motor 21 of the screw drive device 7 (located at the bottom of the rigid support frame 1) with bolts, ensuring that the motor output shaft faces upward and is precisely aligned with the transmission interface of the traction seat 10 (located above the drive motor of the screw drive device 7); after fixing, shake the motor by hand to check whether it is stable and has no looseness, and avoid displacement when the motor is running.

[0078] S4: Install the end fixing device of the screw rod 20 at the skeleton slide rail above the traction seat 10, connect the traction seat 10 to the transmission component of the drive motor 21, test the operation of the drive motor 21 by powering on, and observe whether the traction seat 10 can move smoothly along the screw rod 20 with the motor to verify that the transmission function is normal (screw rod drive device 7).

[0079] S5: Connect the lower end of the screw rod 20 to the drive motor of the screw rod drive device 7. During the connection process, use a level to assist in calibration to ensure that the screw rod 20 is perpendicular to the ground and has no deviation when rotating. Then, fix the fixing devices at both ends of the screw rod 20 to the preset height position of the rigid support frame 1 with bolts to ensure that the screw rod lifting device is installed firmly.

[0080] S6: Select the corresponding number of rubber bands 9 according to the common material modulus testing requirements (e.g., 3-5 for low modulus rubber materials and 8-10 for high modulus film materials); connect one end of the rubber band 9 to the fixed hook set on the traction seat 10, and connect the other end to the lower end of the tension rod 6. Check whether the connection point is firm and whether the rubber band 9 is twisted to ensure that there is no loss in power transmission.

[0081] S7: Fix the start control button in the preset mounting hole on the back of the rigid support frame 1; thread the wire through the internal channel of the frame and connect the start control button to the control module of the drive motor 21 of the screw drive device 7 and the electromagnetic switch of the clamping guide device 5 respectively; after the connection is completed, press the button to test the function: confirm that the motor can be started and stopped when pressed, and the clamping guide device 5 can be triggered to clamp and release the tension rod 6, verifying that the control logic of the start control button is normal.

[0082] S8: Set the guide rail installation position on the surface of the middle part of the rigid support frame 1, and fix the clamping guide device 5 (with protruding slot); use a level to adjust the verticality of the guide rail to ensure that it matches the size of the tension rod 6 (with recessed slot); put the tension rod 6 into the guide rail so that the recessed slot of the tension rod 6 fits into the protruding slot of the clamping guide device 5, test the slot fixing effect, and then trigger the release function to check whether the slot release is smooth, and ensure that the fixing and release functions are reliable.

[0083] S9: Check the connection status between the 5-anti-fatigue rubber band drive acceleration system and the tension rod 6; manually push the tension rod 6 along the guide rail and observe the elastic recovery of the rubber band 9 to ensure there is no jamming and verify the flexibility of the rubber band 9 drive.

[0084] S10: After completing the installation of all components of the drive system, power on and perform an overall test: Press the start control button to start the drive motor of the screw drive device 7, and observe whether the screw 20 rises smoothly along the slide rail, causing the rubber band 9 to stretch; at the same time, observe the fixed state of the tension rod 6 to ensure that the tension rod 6 does not swing during the stretching process and that the entire drive system operates stably.

[0085] 1.3. Assembly of the deceleration system (steps S11-14)

[0086] S11: On the rigid support frame 1, determine the preset installation position that is on the same horizontal plane as the center point of the helical rod 20, and install it on the rigid support frame 1 with bolts (located above the 7-motor drive traction device); use a level to check the verticality of the device to ensure that there is no tilt, so as to provide a horizontal reference for the subsequent spring installation.

[0087] S12: Install the fixed base 16 on the side of the rigid support frame 1 (located in the middle of the tension rod 6), and connect the lower end hook of the deceleration spring 11 (selecting a high elastic coefficient spring) to the fixed base 16.

[0088] S13: Take the traction rope 12 (based on the principle of a bicycle flexible brake cable), and connect the upper end of the traction rope 12 to the lower end of the deceleration spring 11. The traction rope 12 needs to pass through two movable pulley devices. Adjust the position of the traction rope 12 to ensure that it is tightly wound on the movable pulley 13 without the risk of slippage, and test the smoothness of the traction rope 12 when it is pulled.

[0089] S14: Adjust the height of the movable pulley 13 to simulate the state of the tension rod 6 stretched to its maximum stroke, and check whether the recessed groove at the lower end of the rod can accurately engage with the protruding groove of the movable pulley 12; test the tension of the traction rope 12 to ensure that after the tension rod 6 is engaged, the deceleration spring 11 can generate an effective pulling force on the tension rod 6 through the traction rope 12 to achieve the rapid deceleration function. Before the tension test, the deceleration spring 11 should be naturally suspended without tension or compression; check the appearance of the deceleration spring 11 to check for defects such as rust and breakage, and ensure that the deceleration spring 11 is in good working order. During the tension test, the tension rod 6 moves downward, and the guide block 8 set on the inner wall of the guide ring 18 cooperates with the guide groove 19 (the guide block 8 is engaged and embedded in the guide groove 19, and moves along the guide groove 19).

[0090] 1.4. Measurement System Assembly (Steps S15-S21)

[0091] S15: Fix the grating displacement sensor with bolts on the preset bracket on the side of the rigid support frame 1; connect the detection end of the tension sensor 2 to the side of the tension rod 6 through a special connecting cable (passing through the inside of the frame), ensuring that the connection is firm and there is no looseness; connect the sensor to the data acquisition system, adjust the sampling frequency to 1MHz, check the displacement data in the data acquisition software, and ensure that the data acquisition is normal and there are no abnormal fluctuations.

[0092] S16: Wipe the pre-set bonding area of ​​the tension rod 6 (located in the middle of the tension rod 6, avoiding the connection point) with alcohol. After the alcohol evaporates, attach the semiconductor strain gauge 22 to the area with a special adhesive. During the bonding process, gently press the semiconductor strain gauge 22 with a tool to ensure that it is tightly attached to the surface of the tension rod 6 without air bubbles. After the adhesive has cured, connect the semiconductor strain gauge 22 to the multi-channel dynamic strain gauge through a wire, adjust the sampling frequency of the strain gauge to 1MHz, and perform zero-point calibration to ensure that the initial state of the strain test is accurate.

[0093] S17: At the upper part of the middle of the rigid support frame 1, install the second film sample pneumatic clamp 4 at the upper end of the tension rod 6: fix the second film sample pneumatic clamp 4 on the preset bracket, adjust the clamp opening to face upward and be in the vertical direction; connect the high-pressure air pipe and air pump of the clamp, adjust the air pressure, control the clamping and loosening of the second film sample pneumatic clamp 4, check whether the clamping action is flexible and whether there is any air leakage, and ensure that the sample can be clamped stably.

[0094] S18: Connect the lower end of the tensile sensor 2 (select the range according to the test requirements, such as 1kg range for low modulus materials and 50kg range for high modulus materials) to the first thin film sample pneumatic clamp 3 (not shown in the figure), and connect the upper end of the tensile sensor 2 to the position adjustment device 15; slowly adjust the height of the tensile sensor 2 to align the upper and lower clamps, test the clamp spacing adjustment function, and ensure that the gauge length can be set according to the requirements.

[0095] S19: Connect the tensile sensor 2 to the data acquisition system via wires, adjust the sensor sampling frequency to 1MHz, and perform range calibration (using standard weights for loading and testing) to ensure accurate tensile data acquisition; at the same time, connect the multi-channel dynamic strain gauge connected to the semiconductor strain gauge 22 to the data acquisition system, check the strain data transmission status in the software, and ensure stable and lossless data transmission.

[0096] S20: Place the 21-high-speed camera system directly in front of the pre-set test area of ​​the thin film sample (50~100cm away from the sample, without obstruction); adjust the camera height and angle so that the gauge length area of ​​the sample is completely in the center of the camera's field of view and occupies more than 70% of the field of view; connect the camera to the data acquisition computer, adjust the camera's sampling frequency (100kHz), resolution and recording time and other parameters, and play back to check the image clarity. If it is blurry, readjust the focus to ensure that the speckle on the sample surface can be clearly captured.

[0097] S21: Organize all wires of the drive system, deceleration system and measurement system, and thread the wires into the rigid support frame 1 to avoid exposed and tangled wires; power on and test all systems: start the drive motor and check the slot release function; trigger the tension sensor 2 to collect data and check the displacement, tension and strain data; turn on the high-speed camera and confirm that the image acquisition is normal; ensure that all components of the entire device work together and operate smoothly.

[0098] S22: Manually fix the tension rod 6 in the clamping guide device 5, press the start control button to control the drive motor 21 of the screw drive device 7, stretch the rubber band 9 to a medium length, trigger the release of the slot; observe whether the tension rod 6 moves vertically downward, whether the guide ring 18 after stretching is engaged with the guide groove 19 on the tension rod 6, and whether the deceleration spring 11 decelerates normally; at the same time, check whether each sensor collects data synchronously to verify the overall reliability of the device operation.

[0099] 2. High-speed tensile testing method for thin film materials

[0100] 2.1. Sample preparation (steps S23-S26)

[0101] S23: Determine the size of the dumbbell-shaped sample according to the test standard; select a steel standard cutter of the corresponding size, check whether the cutter blade is sharp, and whether there are any nicks or curls. If there are any defects, replace the cutter to ensure the cutting quality.

[0102] S24: Take the flexible film material to be tested, retaining the surface release film; lay the material flat on a flat acrylic cutting table, and use tape to fix the edges of the material to prevent the material from moving during cutting and to ensure accurate cutting position.

[0103] S25: Hold the cutting knife, align the blade with the preset cutting line on the material, and apply uniform vertical pressure to press and cut; keep the cutting knife stable during the cutting process to avoid blade deviation; after cutting, remove the sample, tear off the release film, and check whether the sample edges are neat and free of burrs or cracks. If there are defects, discard the sample to ensure that the sample quality is qualified.

[0104] S26: Repeat steps S24-S25 to prepare 3-5 parallel samples; place the qualified samples in a dry and clean sample box, seal and store them to avoid moisture, contamination or deformation, and ensure that the samples are in the same condition before testing.

[0105] 2.2. Parameter Measurement (S27-29)

[0106] S27: Take a sample from the sample box and lay it flat on the measuring table. Use a micrometer (accuracy 0.001mm) to measure the thickness of the gauge length area of ​​the sample. Select three measuring points (left, middle, and right) within the gauge length area. Measure each measuring point three times and record all data. Calculate the average value of the three measuring points as the actual thickness of the sample to ensure accurate thickness measurement.

[0107] S28: Use a vernier caliper (accuracy 0.02mm) to measure the gauge length and gauge width of the specimen: the gauge length is measured as the distance between the clamping lines at both ends of the specimen, and the gauge width is measured as the width of the middle position of the gauge length area; each parameter is measured 3 times, the average value is taken, and recorded in the experimental record table to provide accurate parameters for subsequent calculations.

[0108] S29: Calculate the cross-sectional area of ​​the specimen (cross-sectional area = gauge length width × thickness) based on the measured gauge length width and thickness, and record the calculation results in the experimental table as the key basis for stress calculation.

[0109] 2.3. Sample installation and equipment preheating (S30-35)

[0110] S30: Turn on the main power of the high-speed tensile testing device, and start the data acquisition system, drive system, measurement system and high-speed camera system (camera) in sequence; preheat the equipment for 15-20 minutes to ensure that all components work stably and avoid test data deviation due to insufficient preheating.

[0111] S31: According to the gauge length of the sample to be tested, slowly adjust the height of the first film sample pneumatic clamp 3 by turning the knob of the position adjustment device 15 so that the clamping port of the first film sample pneumatic clamp 3 is aligned with the upper end of the sample; put the upper end of the calibrated film sample 14 into the first film sample pneumatic clamp 3 and control the first film sample pneumatic clamp 3 to clamp; after clamping, gently hold the sample by hand and observe whether the sample is vertical and not tilted, to ensure that the force is uniform when the sample is stretched.

[0112] S32: Take a test sample and place it flat and vertically into the clamping area of ​​the second thin film sample pneumatic clamp 4; adjust the sample position so that the gauge length area of ​​the sample is centered and without offset; turn on the air pump and adjust the air pressure to 0.4~0.6MPa to control the second thin film sample pneumatic clamp 4 to clamp the sample; after clamping, gently pull the sample to confirm that there is no slippage and ensure that the sample is firmly installed.

[0113] S33: Use a black marker pen (for film materials) and direct spraying (for adhesive materials) to evenly distribute speckles in the gauge length area of ​​the sample, controlling the speckle diameter to be 50~100μm and the density to be 1~2 speckles per square millimeter; after spraying, let stand for 2~5 minutes until the speckles are completely dry; check whether the speckles are uniform and whether there is any agglomeration or peeling. If they do not meet the requirements, re-spray to ensure the DIC test results.

[0114] S34: Adjust the focal length and field of view of the high-speed camera system: Observe through the camera viewfinder to ensure that the gauge length area of ​​the sample is clearly visible; start the camera preview function, record a 10-second test video, and play it back to check the image clarity. If it is blurry, readjust the focal length until the image is clear to ensure accurate capture of the speed and strain field in the future.

[0115] S35: Check the connection status of the grating displacement sensor, semiconductor strain gauge 22, and tension sensor 2. View the real-time data of each sensor in the data acquisition software. Confirm that the displacement data is stable at 0, the strain data is stable at 0, and the tension data is stable at 0, with no abnormal fluctuations, to ensure that the sensors are working properly.

[0116] 2.4. Parameter settings and tensile testing (steps S36-41)

[0117] S36: Based on the sample modulus range, confirm that a tension sensor 2 with the appropriate range has been installed; if the range of tension sensor 2 is not suitable, turn off the power to the equipment, remove the old sensor, and install a sensor with the appropriate range; after reconnecting the wires, perform range calibration to ensure that the sensor matches the sample.

[0118] S37: Based on the strain rate required for the experiment, calculate the target tensile speed using the formula "tensile speed = strain rate × gauge length" to clarify the target parameters.

[0119] S38: Start the drive motor 21. The drive motor 21 drives the traction seat 10 to move downward along the slide rail through the screw rod 20, stretching the rubber band 9. When the rubber band 9 reaches the target length, stop to prevent the rubber band 9 from rebounding and lock the stretching speed.

[0120] S39: Check the engagement state of the guide groove 19 of the tension rod 6 and the guide block 8; observe the deceleration spring 11 to confirm that it is in the pre-tension state and the traction rope 12 is taut to ensure that the deceleration function can be triggered normally.

[0121] S40: Set the data storage path in the data acquisition software and start acquisition; at the same time, press the start control button to release the tension rod 6; the rubber band 9 drives the tension rod 6 to move vertically downward, and then drives the film sample 14 to be stretched at high speed through the first film sample pneumatic clamp 3 and the second film sample pneumatic clamp 4; during the stretching process, observe the real-time image of the high-speed camera system to ensure that the sample is stretched normally.

[0122] S41: After the specimen breaks, the tension rod 6 continues to move downward. The guide groove 19 on the tension rod 6 engages with the guide block 8 protruding from the inner surface of the guide ring 18 (the protruding guide block 8 is embedded in the guide groove 19). The deceleration spring 11 is activated, and the tension rod 6 gradually decelerates until it stops. Click the "Stop Acquisition" button in the data acquisition software to save the displacement, tension, strain data and image sequence of this experiment. Repeat steps S31-S41 to perform tensile tests on the remaining 2-4 parallel specimens, ensuring that the test conditions for each specimen are consistent (such as tensile speed and clamp pressure) to ensure data repeatability.

[0123] 2.5. Data Processing and Result Analysis (S42-46)

[0124] S42: Export all experimental data of parallel specimens from the data acquisition system, including displacement-time data, tensile-time data, strain-time data, and image sequences captured by high-speed cameras, organize the data files, and ensure data integrity.

[0125] S43: Process the displacement-time data: Calculate the stretching speed-time curve using numerical differentiation methods such as the finite difference method; compare the actual stretching speed with the target speed, and if the deviation exceeds -5%, analyze the reasons (such as insufficient stretching length of the rubber band or slippage of the clamp) and evaluate the validity of the data.

[0126] S44: Synchronous processing of tensile-time and displacement-time data: Based on the cross-sectional area of ​​the specimen, the stress is calculated using the formula: Stress = Tensile Force / Cross-sectional Area; based on the gauge length, the strain is calculated using the formula: Strain = Displacement / Gauge Length; based on the stress and strain data, stress-strain curves are plotted to visually present the mechanical properties of the material.

[0127] S45: Open the DIC digital image correlation technology software and import the image sequence captured by the high-speed camera; set the analysis area to the gauge length area of ​​the specimen, select an appropriate speckle matching algorithm, and perform strain field calculation; obtain the strain field distribution-time curve, analyze the strain concentration location and evolution law during the tensile process of the specimen, and gain a deeper understanding of the material deformation characteristics.

[0128] S46: Compare the stress-strain curve obtained from strain gauge 17 with the curve calculated from tensile and displacement data; if the difference in elastic modulus between the two curves is less than 5%, the data is valid; if the difference is large, check the strain gauge bonding quality or sensor calibration, and retest if necessary; perform statistical analysis on the stress-strain curves of 3-5 parallel specimens, calculate the average and standard deviation of elastic modulus (slope of the linear segment of the curve), fracture strength (maximum stress), and elongation at break (strain at break × 100%), and evaluate the repeatability of the material's mechanical properties; organize the experimental data and analysis results to form an experimental report, including specimen information, experimental parameters, experimental curves, mechanical property parameters, and conclusions; after the experiment, turn off the equipment power, remove the specimen fragments from the fixture, and clean the fixture and measurement area; perform routine maintenance on the equipment, check the elastic performance of rubber band 9 and deceleration spring 11, and replace them promptly if aging or damage is found to ensure normal use of the equipment next time, as in section 4 and... Figure 5 As shown.

[0129] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A high-speed tensile testing apparatus for flexible materials, characterized in that, The device includes a tension sensor (2) mounted on a rigid support frame (1) from top to bottom, a first thin film sample pneumatic clamp (3), a second thin film sample pneumatic clamp (4), a tension rod (6) clamped by a clamping guide device (5), and a screw drive device (7). The first thin film sample pneumatic clamp (3) is connected to the tension sensor (2), and the second thin film sample pneumatic clamp (4) is connected to the top end of the tension rod (6). The first thin film sample pneumatic clamp (3) and the second thin film sample pneumatic clamp (4) respectively clamp the two ends of the thin film sample (14). A rubber band (9) is connected to the bottom end of the tension rod (6) near the screw drive device (7). A traction seat (10) is provided on the screw drive device (7). The screw drive device (7) is used to drive the traction seat (10) to move up and down along the length direction of the rigid support frame (1). The traction seat (10) is configured to connect the end of the rubber band (9) away from the tension rod (6) when it is driven to move downward by the screw drive device (7) until the rubber band (9) is pulled to the target length. On both sides of the rigid support frame (1) of the screw drive device (7), there are deceleration springs (11). One end of the deceleration spring (11) is fixed to the rigid support frame (1), and the other end is connected to the traction rope (12). The end of the traction rope (12) away from the deceleration spring (11) is wound around the tension rod (6) radially through the movable pulley (13) and connected to the side wall of the tension rod (6). A semiconductor strain gauge (22) is provided on the rod body of the tension rod (6) near the second thin film sample pneumatic clamp (4); In this process, after the rubber band (9) is stretched downward to the target length by the traction seat (10), the clamping guide device (5) releases the stretching rod (6), and the elastic recovery of the rubber band (9) pulls the stretching rod (6) downward, thereby causing the second film sample pneumatic clamp (4) to stretch the film sample (14), and the camera captures an image of the film sample (14) being stretched.

2. The high-speed tensile testing and mechanical testing device for flexible materials according to claim 1, characterized in that, A position adjustment device (15) is provided at the top of the rigid support frame (1). The position adjustment device (15) is connected to the tension sensor (2). The position adjustment device (15) is used to adjust the initial height position of the tension sensor (2).

3. The high-speed tensile testing and mechanical testing device for flexible materials according to claim 1, characterized in that, Fixed seats (16) are provided on both sides of the rigid support frame (1) near the top of the screw drive device (7). An adjusting rod (17) is installed on the fixed seat (16). The adjusting rod (17) is installed on the fixed seat (16) along the length direction of the rigid support frame (1). The bottom end of the deceleration spring (11) away from the traction rope (12) is connected to the end of the adjusting rod (17). The adjusting rod (17), the deceleration spring (11), and the traction rope (12) are coaxial and located in the same horizontal and vertical plane as the tension rod (6).

4. The high-speed tensile testing and mechanical testing device for flexible materials according to claim 1, characterized in that, A guide ring (18) is movably fitted on the rod body of the tension rod (6) near the top of the screw drive device (7). The ends of the two traction ropes (12) are connected to the outer wall of the guide ring (18), and the positions of the two traction ropes (12) connected to the guide ring (18) are symmetrically arranged with the tension rod (6) as the axis of symmetry. Multiple guide grooves (19) are evenly distributed on the circumferential surface of the tension rod (6), and the guide grooves (19) extend along the axial direction of the tension rod (6); guide blocks (8) corresponding to the multiple guide grooves (19) are provided on the inner surface of the guide ring (18), and the guide blocks (8) can move along the guide grooves (19). During the process of using the elastic recovery of the rubber band (9) to pull the tension rod (6) downward, the guide block (8) contacts the top side wall of the guide groove (19) to limit the guide ring (18) and pull the traction rope (12).

5. A method for high-speed tensile testing and mechanical testing of flexible materials, used to implement the apparatus for high-speed tensile testing and mechanical testing of flexible materials as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 100, clamping and positioning: clamp and fix the two ends of the film sample (14) by the first film sample pneumatic clamp (3) and the second film sample pneumatic clamp (4) respectively. The first film sample pneumatic clamp (3) is installed on the top of the rigid support frame (1) through the tension sensor (2), and the second film sample pneumatic clamp (4) is connected to the top of the tension rod (6). Step 200, Pre-tensioning and energy storage: Drive the traction seat (10) downward by the screw rod drive device (7) so that the traction seat (10) connects to and pulls the rubber band (9) at the bottom of the tension rod (6) to the target length, thus completing the storage of elastic potential energy of the rubber band (9). During this process, the clamping guide device (5) keeps the tension rod (6) clamped and locked. Step 300, High-speed stretching: Control the clamping guide device (5) to release the stretching rod (6), and use the elastic restoring force of the rubber band (9) to pull the stretching rod (6) and the second film sample pneumatic clamp (4) to move downward at high speed to stretch the film sample at high speed. Step 400, buffer limit: During the downward movement of the tension rod (6), the tension rod (6) is decelerated and limited by the buffer mechanism composed of the deceleration spring (11), traction rope (12) and movable pulley (13) on both sides of the rigid support frame (1); Step 500, Data Acquisition: The tensile force signal is acquired by the tensile sensor (2), the strain signal is acquired by the semiconductor strain gauge on the tension rod (6), and the tensile deformation image of the thin film sample is acquired by the camera to complete the high-speed tensile mechanical test of the flexible material.

6. The method for high-speed tensile testing and mechanical testing of flexible materials according to claim 5, characterized in that, After the film sample is clamped and before high-speed stretching is performed, the initial height of the tension sensor (2) and the first film sample pneumatic clamp (3) is adjusted by the position adjustment device located at the top of the rigid support frame (1) to achieve the centering and pre-tightening of the film sample.

7. The method for high-speed tensile testing and mechanical testing of flexible materials according to claim 5, characterized in that, The deceleration spring (11) is mounted on the fixed seat (16) of the rigid support frame (1) via the adjusting rod (17). By adjusting the extension length of the adjusting rod (17), the initial preload and buffer stroke of the deceleration spring (11) are adjusted.

8. The method for high-speed tensile testing and mechanical testing of flexible materials according to claim 5, characterized in that, A guide ring (18) is movably sleeved on the tension rod (6), and the guide block (8) inside the guide ring (18) slides in conjunction with the guide groove (19) on the tension rod (6). During the high-speed downward movement of the tension rod (6), the guide block (8) abuts against the top side wall of the guide groove (19), driving the guide ring (18) to pull the traction rope (12), thereby achieving smooth deceleration and limiting through the deceleration spring (11).

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