Method and system for testing high-temperature and high-strain-rate tensile mechanical property characterization of ultra-high molecular weight polyethylene fiber monofilament

Abstract

The invention discloses a high-temperature and high-strain-rate tensile mechanical property characterization testing method and system for ultra-high molecular weight polyethylene fiber monofilaments. The system comprises an experimental platform, a loading device, a fiber monofilament fixing clamp, a high and low temperature environment box, a force sensor and a data recording device, the loading device comprises an impact rod, an incident rod, a tensile fixture, a force sensor and an extension rod; the left end of the incident rod is provided with a flange, the incident rod is sleeved with an impact rod close to the left end, the incident rod is provided with strain gauges, and each strain gauge is electrically connected with the data recording device; the fiber monofilament fixing clamp is used for fixing a single fiber, the opposite ends of the incident rod and the extension rod are respectively provided with one stretching clamp, and the two stretching clamps are respectively used for clamping an ultra-high molecular weight polyethylene fiber monofilament. A new testing method and thought are provided for performance research under high-temperature and high-strain-rate coupling, and meanwhile material parameters are provided for establishing related mechanical models.

Description

Technical Field

[0001] This invention relates to the field of dynamic mechanical property testing technology for materials, and in particular to a method and system for characterizing the tensile mechanical properties of ultra-high molecular weight polyethylene fiber monofilament at high temperature and high strain rate. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fibers are widely used in engineering structures such as bulletproof vests, helmets, vehicle armor, and conveyor belts. These structures face high-temperature and high-strain-rate loading environments during service. For example, bulletproof vests experience localized high temperatures and high-speed loading under bullet impact; conveyor belts face extreme high-temperature weather and dynamic loading conditions during operation. As the basic unit of these structures, the mechanical properties of UHMWPE fiber monofilaments under high-temperature and high-strain-rate loading are key parameters for establishing cross-scale models of engineering structures and accurately predicting their service performance. This has significant guiding significance for the design and manufacture of engineering structures such as individual soldier protection, vehicle armor, and conveyor belts. However, UHMWPE fibers have low surface energy and high tensile strength, making them difficult to hold effectively during tensile testing. Therefore, an effective characterization method for obtaining the high-temperature, high-strain-rate tensile mechanical properties of UHMWPE fiber monofilaments is urgently needed. Summary of the Invention

[0003] This invention aims to propose a method and system for characterizing the tensile mechanical properties of ultra-high molecular weight polyethylene (UHMWPE) fiber monofilaments under high temperature and high strain rate. This method addresses the problems of experimental failure caused by slippage of UHMWPE fiber monofilaments during dynamic stretching, premature breakage of fiber monofilaments caused by the movement of the impact rod, and the measurement of minute dynamic forces in existing technologies. It also reveals the failure mechanism of UHMWPE fiber monofilaments under high temperature and high strain rate tensile coupling.

[0004] This invention proposes a high-temperature, high-strain-rate tensile mechanical property characterization and testing system for ultra-high molecular weight polyethylene (UHMWPE) fiber monofilaments, comprising: an experimental platform, a loading device, a fiber monofilament fixing clamp, a high-low temperature environmental chamber, a force sensor, and a data recording device. The loading device includes an impact rod, an incident rod, a tensile clamp, a force sensor, and an extension rod. The incident rod and force sensor are mounted on the experimental platform via a bracket. A flange is provided at the left end of the incident rod, and a pre-tightening device is used to apply a pre-tightening force F against the flange at the left end of the incident rod. An impact rod is fitted onto the incident rod near its left end, and strain gauges are provided on the incident rod. Each strain gauge is electrically connected to the data recording device. The fiber monofilament fixing clamp is used to fix a single fiber. The extension rod connects the tensile clamp and the force sensor. A tensile clamp is provided at each opposite end of the incident rod and the extension rod. The two tensile clamps are used to clamp and stretch the UHMWPE fiber monofilaments. The data recording device displays and saves the strain history and tensile force values ​​of the UHMWPE fiber monofilaments on the strain gauges.

[0005] In a preferred embodiment, the system further includes a pre-tightening device fixed on the experimental platform, which applies a pre-tightening force F against the left flange of the incident rod to prevent the fiber monofilament from breaking during the movement of the impact rod.

[0006] In a preferred embodiment, the fiber monofilament fixing clamp is laser-processed with four navigation holes on its surface for engagement with guide posts. The fiber monofilament is fixed to the central axis of the cardboard template with glue, so that the fiber can be directly clamped by acrylic adhesive sheet in the future.

[0007] In a preferred embodiment, the stretching clamp includes a clamp body, an acrylic sheet, and a clamp cover; the clamp body has two guide posts for fixing the single fiber fixing clamp, and has four through screw holes and a groove for pasting the acrylic sheet on its surface; the clamp cover has a groove on one side for pasting the acrylic sheet, and has four through screw holes on its surface.

[0008] In a preferred embodiment, the data recording device includes a Wheatstone bridge, a strain amplifier, an oscilloscope, and a signal conditioner connected in series; each strain gauge and a temperature compensation gauge resistor are connected in series to form a Wheatstone bridge, which is then electrically connected to the strain amplifier; and a force sensor is electrically connected to the signal conditioner.

[0009] In a preferred embodiment, the incident rod is 1.5m long, the impact rod is 0.5m long, and the extension rod is 0.3m long, used to connect the tension clamp and the force sensor to prevent high temperature damage to the force sensor. The diameter of the incident rod is less than 12mm. The high temperature environment chamber can load the fiber monofilament at 0~350℃.

[0010] This invention also provides a mechanical testing method for a high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene (UHMWPE) fiber monofilaments, including the aforementioned UHMWPE fiber monofilament high-temperature, high-strain-rate tensile mechanical property characterization system. The specific testing steps are as follows: S1: Cut a section of the UHMWPE fiber monofilament for testing and fix it to the fiber monofilament fixing clamp with glue. Clamp the fiber monofilament fixing clamp between the clamp body (with an acrylic film attached) and the clamp cover, tighten four screws, and directly clamp the UHMWPE fiber monofilament. The tensile clamp is respectively installed on the opposite end of the incident rod and the force sensor. A strain gauge is provided on the incident rod. The strain gauge and the temperature compensation plate are connected in series to form a Wheatstone bridge, which is then electrically connected to a strain amplifier. The strain amplifier is connected to an oscilloscope; S2: Use a pre-tightening device to hold the left flange of the incident rod to prevent the UHMWPE fiber monofilament from breaking before the impact rod hits the flange; S3: Preheat the high-temperature environment chamber. When the temperature reaches the required experimental temperature, push the loading device into the high-temperature environment chamber to heat the ultra-high molecular weight polyethylene (UHMWPE) fiber monofilament sample. S4: At the start of the test, use a light air gun to push the impact rod against the flange at the left end of the incident rod, forming an incident wave at the left end of the incident rod. The incident wave is transmitted from the left end to the right end and reflected back to the left end, forming a reflected wave. At this time, the movement of the incident rod causes the left end of the UHMWPE fiber monofilament sample to move to the left. The right end of the UHMWPE fiber monofilament sample pulls the extension rod, which receives the transmitted wave and then also moves to the left. This dynamically tensile loads the UHMWPE fiber monofilament sample. S5: The deformation of the UHMWPE fiber monofilament during the loading process causes the waveform change to be captured by the strain gauge and force sensor. The waveform signal is filtered and amplified by the strain amplifier, and the data recorded by the oscilloscope is transmitted to the computer for processing and analysis.

[0011] In a preferred embodiment, the length of the cut ultra-high molecular weight polyethylene fiber monofilament is 3-4 times the length of the test section; the fiber monofilament fixing clamp is laser-processed with four navigation holes for engaging with guide posts; the fiber monofilament is fixed to the central axis of the cardboard template with glue for subsequent direct clamping of the fiber using acrylic adhesive sheet; the tensile clamp includes a clamp body, an acrylic sheet, and a clamp cover; the clamp body has two guide posts for fixing the sample clamp, grooves for attaching the acrylic sheet, and four through screw holes; the clamp cover has a groove on one side for attaching the acrylic sheet, and four through screw holes; the fiber monofilament fixing clamp is clamped between the clamp body and the clamp cover with the acrylic sheet, and the four screws are tightened to achieve direct clamping of the fiber monofilament.

[0012] In a preferred embodiment, the oscilloscope records the voltage signal history of the incident rod and force sensor of the sample. The force sensor is calibrated to 23.7 mV / N for both voltage and force. The diameter of the fiber filaments was obtained by scanning the fiber bundle using a SEM (scanning electron microscope) before the experiment. The stress history Fi of each fiber under load is obtained by converting the calibration value, and the stress history of each fiber is calculated using the following formula: Acquire the incident wave signal on the incident rod. and reflected wave signal Based on the one-dimensional wave propagation theory, the strain and strain rate history of each fiber are calculated: , In the formula: —Strain generated by the fiber% —The strain rate s⁻¹ in each group of experiments; —The speed of wave propagation on the incident rod (m / s); —Effective test length of the sample (m).

[0013] The method and system for characterizing the high-temperature, high-strain-rate tensile mechanical properties of ultra-high molecular weight polyethylene fiber monofilament of the present invention have the following advantages: An improved Hopkinson bar test method was used to obtain the tensile properties of ultra-high molecular weight polyethylene (UHMWPE) monofilaments under high temperature and high strain rate coupling. Observation of the broken monofilaments revealed that the clamped end of the UHMWPE monofilament did not slip or come off. The tensile clamp can effectively hold the UHMWPE monofilament, ensuring uniform stress on the measured section. The failure of the UHMWPE monofilament occurred in the measured section, not in the clamped area. This provides a new testing method and approach for performance research under high temperature and high strain rate coupling, and also provides material parameters for establishing mechanical models of UHMWPE monofilaments to fabrics and composite structures. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 The diagram shows a schematic of the high-temperature, high-strain-rate tensile mechanical property characterization and testing system for ultra-high molecular weight polyethylene fiber monofilaments in this invention.

[0015] Figure 2 The diagram shown is a structural schematic of the fiber monofilament fixing clamp of the present invention.

[0016] Figure 3The diagram shown is a structural schematic of the fiber monofilament fixing clamp of the present invention.

[0017] Figure 4 The diagram shows the original test data recorded by the incident rod and force sensor in this invention.

[0018] Figure 5 The diagram shows the stress-strain curves of UHMWPE fiber monofilaments at high strain rates and different temperatures in this invention.

[0019] In the figure: 1. Pre-tightening device, 2. Flange, 3. Impact rod, 4. Incident rod, 5. Strain gauge, 6. High temperature environment chamber, 7. Force sensor, 8. Fiber monofilament fixing clamp, 9. Tension clamp, 91. Clamp body, 92. Clamp cover, 93. Acrylic film. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] like Figures 1 to 5 As shown, this invention provides a high-temperature, high-strain-rate tensile mechanical property characterization and testing system for ultra-high molecular weight polyethylene fiber monofilaments, comprising: an experimental platform, a loading device, a fiber monofilament fixing clamp 8, a high-low temperature environment chamber 6, a force sensor 7, and a data recording device; the loading device includes an impact rod 3, an incident rod 4, a tensile clamp 9, a force sensor 7, and an extension rod; the incident rod 4 and the force sensor 7 are both mounted on the experimental platform via brackets; the left end of the incident rod 4 is provided with a flange 2; the pre-tightening device 1 is used to apply a pre-tightening force F against the flange 2 at the left end of the incident rod 4; and an impact rod is sleeved on the incident rod 4 near its left end. 3. The incident rod 4 is provided with strain gauges 5, and each strain gauge 5 is electrically connected to the data recording device; the fiber monofilament fixing clamp 8 is used to fix a single fiber, the extension rod is used to connect the tension clamp 9 and the force sensor 7, and each of the incident rod 4 and the extension rod is provided with a tension clamp 9 at one end. The two tension clamps 9 are used to clamp the ultra-high molecular weight polyethylene fiber monofilament and stretch the ultra-high molecular weight polyethylene fiber monofilament. The data recording device includes an oscilloscope for displaying and saving the strain history and the tensile force value of the ultra-high molecular weight polyethylene fiber monofilament on the strain gauge 5.

[0022] Preferably, the system further includes a pre-tightening device 1, which is fixed on the experimental platform and is used to apply a pre-tightening force F against the left end flange 2 of the incident rod 4 to prevent the fiber monofilament from breaking when the impact rod moves. Further, the fiber monofilament fixing clamp 8 is laser-processed with four navigation holes on its surface for engagement with guide posts. The fiber monofilament is fixed to the central axis of the cardboard template with glue, for subsequent direct clamping of the fiber using acrylic adhesive sheets. Further, the stretching clamp 9 includes a clamp body 91, an acrylic sheet 93, and a clamp cover 92; the clamp body 91 has two guide posts for fixing the single fiber fixing clamp, and its surface has four through screw holes and a groove for attaching the acrylic sheet 93; the clamp cover 92 has a groove on one side for attaching the acrylic sheet 93, and its surface has four through screw holes. Furthermore, the data recording device includes a Wheatstone bridge, a strain amplifier, an oscilloscope, and a signal conditioner connected in series. Each strain gauge 5 is connected in series with a temperature compensation resistor to form a Wheatstone bridge, which is then electrically connected to the strain amplifier. A force sensor is electrically connected to the signal conditioner. The incident rod 4 has a length of 1.5m, the impact rod 3 has a length of 0.5m, and the extension rod has a length of 0.3m. It is used to connect the tension clamp and the force sensor 7 to prevent high temperature damage to the force sensor 7. The diameter of the incident rod 4 is less than 12mm. The high-temperature environment chamber 6 can load the fiber monofilament at 0~350℃.

[0023] This invention also provides a mechanical testing method for a high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene (UHMWPE) fiber monofilaments, including the aforementioned high-temperature, high-strain-rate tensile mechanical property characterization system for UHMWPE fiber monofilaments. The specific testing steps are as follows: S1: Cut a section of the UHMWPE fiber monofilament for testing and fix it to the fiber monofilament fixing clamp 8 with glue. Clamp the fiber monofilament fixing clamp 8 between the clamp body 91 (with acrylic film 93 attached) and the clamp cover 92, tighten the four screws, and directly clamp the UHMWPE fiber monofilament. The tensile clamp is respectively installed on the opposite end of the incident rod 4 and the force sensor 7. A strain gauge 5 is provided on the incident rod 4. The strain gauge 5 and the temperature compensation plate resistor are connected in series to form a Wheatstone bridge, which is then electrically connected to the strain amplifier. The strain amplifier is connected to an oscilloscope; S2: Use a pre-tightening device 1 to hold the left flange 2 of the incident rod 4 to prevent the UHMWPE fiber monofilament from breaking before the impact rod 3 hits the flange 2. S3: Preheat the high-temperature environment chamber 6. When the temperature reaches the required experimental temperature, push the loading device into the high-temperature environment chamber 6 to heat the ultra-high molecular weight polyethylene fiber monofilament sample. S4: At the start of the test, use a light air gun to push the impact rod 3 to strike the flange 2 at the left end of the incident rod 4. An incident wave is formed at the left end of the incident rod 4. The incident wave is transmitted from the left end of the incident rod 4 to the right end and reflected back to the left end at the right end to form a reflected wave. At this time, the movement of the incident rod 4 causes the left end of the ultra-high molecular weight polyethylene fiber monofilament sample to move to the left. The right end of the ultra-high molecular weight polyethylene fiber monofilament sample pulls the extension rod. The extension rod receives the transmitted wave and then also moves to the left, thereby dynamically tensile loading the ultra-high molecular weight polyethylene fiber monofilament sample. S5: The deformation of the ultra-high molecular weight polyethylene fiber monofilament generated during the loading process causes the waveform change to be captured by the strain gauge 5 and the force sensor 7. The waveform signal is filtered and amplified by the strain amplifier. The data recorded by the oscilloscope is transmitted to the computer for processing and analysis. Furthermore, the length of the tested ultra-high molecular weight polyethylene fiber monofilament is 3-4 times the length of the test section; the fiber monofilament fixing clamp 8 is laser-processed with four navigation holes on its surface for engagement with guide posts; the fiber monofilament is fixed to the central axis of the cardboard template with glue for subsequent direct clamping of the fiber using acrylic adhesive sheet; the tensile clamp includes a clamp body 91, an acrylic sheet 93, and a clamp cover 92; the clamp body 91 has two guide posts for fixing the sample clamp, grooves on its surface for attaching the acrylic sheet 93, and four through screw holes on its surface; the clamp cover 92 has a groove on one side for attaching the acrylic sheet 93, and four through screw holes on its surface; the fiber monofilament fixing clamp 8 is clamped between the clamp body 91 and the clamp cover 92 with the acrylic sheet 93 attached, and the four screws are tightened to achieve direct clamping of the fiber monofilament. Furthermore, the oscilloscope records the history of voltage signals on the incident rod and force sensor of the sample.The force sensor was calibrated to 23.7 mV / N for both voltage and force signals. The diameter of the fiber filaments was obtained by scanning the fiber bundle with a SEM (Scanning Electron Microscope) before the experiment. The stress history Fi of each fiber under load is obtained by converting the calibration value, and the stress history of each fiber is calculated using the following formula: Acquire the incident wave signal on the incident rod. and reflected wave signal Based on the one-dimensional wave propagation theory, the strain and strain rate history of each fiber are calculated: , In the formula: —Strain generated by the fiber% —The strain rate s⁻¹ in each group of experiments; —The speed of wave propagation on the incident rod (m / s); —Effective test length of the sample (m).

[0024] Taking a test method that allows axial stretching of ultra-high molecular weight polyethylene fiber monofilaments under high temperature and high strain rate coupling to determine the tensile properties of the material under high temperature and high strain rate as an example, the test includes the following steps: Step 1: Determine the specified length of the UHMWPE (ultra-high molecular weight polyethylene) fiber monofilament and prepare the specimen for the dynamic tensile test. Determine the specified length of the UHMWPE fiber monofilament according to the test requirements. Cut a section of the UHMWPE fiber monofilament for testing and fix it to the fiber monofilament fixing clamp with glue. Clamp the fiber monofilament fixing clamp between the clamp body (attached with acrylic sheet 93) and the clamp cover, and tighten the four screws to directly hold the UHMWPE fiber monofilament. A schematic diagram of the clamp is shown below. Figure 3 As shown.

[0025] Step Two: Conduct dynamic tensile tests and obtain data recorded by the oscilloscope at different strain rates. The Hopkinson rod used in this experiment has a diameter of 12mm, is made of 7A04 aluminum alloy, has a length of 1.5m for the incident rod, a length of 0.5m for the extension rod, and a length of 0.5m for the impact rod. A high-temperature environmental chamber was used. The overall experimental setup is as follows: Figure 1 As shown, before the test begins, a pre-tightening device is used to hold the flange in place to prevent the fiber monofilaments from breaking during the movement of the impact rod. At the start of the test, a light air gun is used to push the impact rod against the flange at the left end of the incident rod, creating an incident wave tensile stress wave at the left end of the incident rod. The incident wave is transmitted from the left end to the right end of the incident rod, and then reflected back to the left end, forming a reflected wave. Simultaneously, the incident rod moves, causing the left end of the sample to move to the left. The right end of the sample is fixed to the extension rod, which receives the transmitted wave and then also moves to the left, thereby applying a dynamic tensile load to the sample.

[0026] A semiconductor strain gauge is attached to the incident rod. The deformation generated during loading is captured by the strain gauge. The waveform signal is filtered and amplified by a strain amplifier. The test settings for the incident rod channel amplification are ×10, bridge voltage is 2V, and low-pass filter is 100kHz. The signal is transmitted to an oscilloscope, which records the incident wave signal to obtain the voltage-time curve of the incident rod. An extension rod is connected to a force sensor to record the transmitted wave signal. This signal is also transmitted to an oscilloscope, which records the transmitted wave signal to obtain the voltage-time curve of the transmitted wave. Figure 4 As shown.

[0027] Step 3: Process the data recorded by the oscilloscope to obtain the tensile properties of UHMWPE ultra-high molecular weight polyethylene fiber monofilaments under different strain rates.

[0028] The oscilloscope records the voltage signal history of the incident rod and force sensor of the sample. The force sensor's calibration value for voltage and force is 23.7 mV / N. The diameter Di of the fiber filaments was obtained by scanning the fiber bundle using a SEM (Scanning Electron Microscope) before the experiment. The force history Fi of each fiber under load was obtained by converting the calibration value, and the stress history of each fiber was calculated using the following formula.

[0029] Specifically, Example 1: The dynamic tensile properties of 10 mm long UHMWPE (ultra-high molecular weight polyethylene) fiber monofilaments were tested at a strain rate of 500 s⁻¹ and at temperatures of 25°C, 50°C, 75°C, and 100°C. Step 1: The specified length of the UHMWPE fiber monofilaments was determined to be 10 mm, and several specimens were prepared for the dynamic tensile test. Step 2: The specimens were installed, and a pre-tightening device was used to hold the flange in place to ensure the experiment proceeded normally. Step 3: Preheat the high-temperature environment chamber. When the temperature reaches the required experimental temperature, push the loading device into the high-temperature environment chamber to heat the ultra-high molecular weight polyethylene fiber monofilament sample. Step 4: Conduct a dynamic tensile test to obtain a 500 s⁻¹ strain rate and data recorded by the oscilloscope at different temperatures. Insert the air pump into the cylinder inflation port, open the pressure gauge, and observe the pressure reading. Connect the loading trigger device to the solenoid valve; the trigger device should be in the closed state. Place the incident rod in the initial position and push the bullet into the bottom of the barrel. Connect the bridge circuit connecting the incident rod strain gauge to the strain amplifier, and set the required gain, bridge voltage, and low-pass on the strain amplifier. Connect the oscilloscope to the strain amplifier using a BNC connector data cable. Connect the force sensor to the signal conditioner, and connect the signal conditioner to the oscilloscope using a BNC connector data cable. Set the required parameters for each channel, such as time, voltage, and trigger conditions, on the oscilloscope. Connect the storage device to the oscilloscope's USB interface for data storage. Step 5: Process the data recorded by the oscilloscope to obtain the tensile properties of a 10 mm long UHMWPE ultra-high molecular weight polyethylene fiber monofilament at a strain rate of 500 s⁻¹ and different temperatures. In the experiment, the tensile force on the sample during loading was directly obtained through a force sensor, and the strain history of the incident rod was measured by a strain gauge attached to the incident rod. The strain and strain rate history of the ultra-high molecular weight polyethylene fiber monofilament sample were then calculated. Figure 4 The original experimental data are displayed, where the red line represents the voltage signal corresponding to the tensile force of the sample recorded by the force sensor, and the black line represents the voltage signal corresponding to the strain history on incident rod 4. The obtained experimental results are plotted, showing the stress-strain curves of 10 mm UHMWPE ultra-high molecular weight polyethylene fiber monofilaments at a strain rate of 500 s⁻¹ and different temperatures. The tensile property test curves are as follows. Figure 5 As shown. Figure 5 The stress-strain curves of UHMWPE (ultra-high molecular weight polyethylene) fiber monofilament samples at a strain rate of 500 s⁻¹ and different temperatures show that the fully straightened UHMWPE fiber monofilament directly bears the force, indicating that direct clamping is effective and the fiber does not slip. It can also be seen that the curves are relatively linear at 25℃ and 50℃, but as the temperature increases further, the curves show some non-linear segments, which may be due to fiber softening caused by high temperatures. Furthermore, it can be seen that when the temperature increases to 75℃ and 100℃, the fiber tensile strength decreases and the failure strain increases.

[0030] Therefore, the high-temperature, high-strain-rate tensile mechanical property characterization test method and system for ultra-high molecular weight polyethylene (UHMWPE) fiber monofilaments provided by this invention improves upon the traditional Hopkinson bar test method, obtaining the tensile properties of UHMWPE fiber monofilaments under high-temperature, high-strain-rate coupling. Observation of the broken fiber monofilaments revealed that the sample at the clamping end of the UHMWPE fiber monofilament did not slip or come off. The tensile clamp can effectively hold the UHMWPE fiber monofilament, ensuring uniform stress on the measured section. The failure of the UHMWPE fiber monofilament occurs in the measured section, not in the clamping area. This provides a new test method and approach for performance research under high-temperature, high-strain-rate coupling, and also provides material parameters for establishing mechanical models of UHMWPE fiber monofilaments into fabrics and composite structures.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-temperature, high-strain-rate tensile mechanical property characterization and testing system for ultra-high molecular weight polyethylene fiber monofilaments, characterized in that: include: Experimental platform, loading device, fiber monofilament fixing clamp (8), high and low temperature environment chamber (6), force sensor (7) and data recording device; The loading device includes an impact rod (3), an incident rod (4), a tension clamp (9), a force sensor (7), and an extension rod; the incident rod (4) and the force sensor (7) are both mounted on the experimental platform via brackets. The incident rod (4) has a flange (2) at its left end. The pre-tightening device (1) is used to apply a pre-tightening force F against the flange (2) at the left end of the incident rod (4). The incident rod (4) has an impact rod (3) near its left end. The incident rod (4) has a strain gauge (5). Each strain gauge (5) is electrically connected to the data recording device. The fiber monofilament fixing clamp (8) is used to fix a single fiber. The extension rod is used to connect the tension clamp (9) and the force sensor (7). The incident rod (4) and the extension rod are each provided with a tension clamp (9) at opposite ends. The two tension clamps (9) are used to clamp the ultra-high molecular weight polyethylene fiber monofilament and stretch the ultra-high molecular weight polyethylene fiber monofilament. The data recording device is used to display and save the strain history and the tensile force value of the ultra-high molecular weight polyethylene fiber monofilament on the strain gauge (5).

2. The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 1, characterized in that: The system also includes a pre-tightening device (1), which is fixed on the experimental platform and is used to apply a pre-tightening force F against the left flange (2) of the incident rod (4) to prevent the fiber monofilament from breaking when the impact rod moves.

3. The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 2, characterized in that: The fiber monofilament fixing clamp (5) is laser-processed with four navigation holes on the surface for use with guide posts. The fiber monofilament is fixed to the central axis of the cardboard template with glue for subsequent use of acrylic adhesive sheets to directly clamp the fiber.

4. The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 3, characterized in that: The stretching clamp (9) includes a clamp body (91), an acrylic sheet (93), and a clamp cover (92); the clamp body (91) has two guide posts for fixing the single fiber clamp, and has four through screw holes and a groove for pasting the acrylic sheet (93) on its surface; the clamp cover (92) has a groove on one side for pasting the acrylic sheet (93), and has four through screw holes on its surface.

5. The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 4, characterized in that: The data recording device includes a Wheatstone bridge, a strain amplifier, an oscilloscope, and a signal conditioner connected in series. Each strain gauge (5) is connected in series with a temperature compensation plate resistor to form a Wheatstone bridge, which is then electrically connected to the strain amplifier. The signal conditioner is electrically connected to a force sensor.

6. The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 5, characterized in that: The lengths of the incident rod (4) are 1.5m, the impact rod 3 is 0.5m, and the extension rod is 0.3m. It is used to connect the tension clamp and the force sensor (7) to prevent high temperature damage to the force sensor (7). The diameter of the incident rod (4) is less than 12mm. The high temperature environment chamber (6) can load the fiber monofilament at 0~350℃.

7. A mechanical testing method for a high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments, characterized in that: The high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments as described in any one of claims 1-6 includes the following specific testing steps: S1: Cut a section of ultra-high molecular weight polyethylene fiber monofilament and fix it to the fiber monofilament fixing clamp (8) with glue. Clamp the fiber monofilament fixing clamp (8) between the clamp body (91) with acrylic film (93) and the clamp cover (92) and tighten the four screws to directly clamp the ultra-high molecular weight polyethylene fiber monofilament. The tensile clamps are respectively installed on the opposite end of the incident rod (4) and the force sensor (7). A strain gauge (5) is provided on the incident rod (4). The strain gauge (5) and the temperature compensation plate resistor are connected in series to form a Wheatstone bridge and then electrically connected to the strain amplifier. The strain amplifier is connected to the oscilloscope. S2: Use the pre-tightening device (1) to hold the left flange (2) of the incident rod (4) to prevent the fiber ultra-high molecular weight polyethylene fiber monofilament from breaking before the impact rod (3) hits the flange (2); S3: Preheat the high temperature environment chamber (6). When the temperature reaches the temperature required for the experiment, push the loading device into the high temperature environment chamber (6) to heat the fiber ultra-high molecular weight polyethylene fiber monofilament sample. S4: At the start of the test, a light air cannon is used to push the impact rod (3) to strike the flange (2) at the left end of the incident rod (4), forming an incident wave at the left end of the incident rod (4). The incident wave is transmitted from the left end of the incident rod (4) to the right end, and is reflected back to the left end at the right end to form a reflected wave. At this time, the movement of the incident rod (4) causes the left end of the ultra-high molecular weight polyethylene fiber monofilament sample to move to the left. The right end of the ultra-high molecular weight polyethylene fiber monofilament sample pulls the extension rod, and the extension rod receives the transmitted wave and then moves to the left as well. Thus, the ultra-high molecular weight polyethylene fiber monofilament sample is subjected to dynamic tensile loading. S5: The deformation of the ultra-high molecular weight polyethylene fiber monofilament generated during the loading process causes the waveform change to be captured by the strain gauge (5) and force sensor (7). The waveform signal is filtered and amplified by the strain amplifier, and the data recorded by the oscilloscope is transmitted to the computer for processing and analysis.

8. The mechanical testing method for a high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 7, characterized in that: The length of the cut ultra-high molecular weight polyethylene fiber monofilament is 3-4 times the length of the test section; the fiber monofilament fixing clamp (8) is laser-processed with four navigation holes on the surface for cooperation with the guide posts. The fiber monofilament is fixed with glue to the central axis of the cardboard template for subsequent direct clamping of the fiber using acrylic adhesive film; the tensile clamp includes a clamp body (91), an acrylic film (93), and a clamp cover (92); the clamp body (91) has two guide posts for fixing the sample clamp, and grooves on the surface for pasting the acrylic film (93), and four through screw holes on the surface; the clamp cover (92) has a groove on one side for pasting the acrylic film (93), and four through screw holes on the surface; the fiber monofilament fixing clamp (8) is clamped between the clamp body (91) and the clamp cover (92) with the acrylic film (93) attached, and the four screws are tightened to achieve direct clamping of the fiber monofilament.

9. The mechanical testing method for a high-temperature, high-strain-rate tensile mechanical property characterization system for ultra-high molecular weight polyethylene fiber monofilaments according to claim 8, characterized in that: The oscilloscope records the voltage signal history of the incident rod and force sensor on the sample. The force sensor's calibration value for both voltage and force is 23.7 mV / N. The diameter of the fiber filaments was obtained by scanning the fiber bundle using a SEM (scanning electron microscope) before the experiment. The stress history Fi of each fiber under load is obtained by converting the calibration value, and the stress history of each fiber is calculated using the following formula: , Acquire the incident wave signal on the incident rod and reflected wave signal Based on the one-dimensional wave propagation theory, the strain and strain rate history of each fiber are calculated: ， ， In the formula: —Strain generated by the fiber% —The strain rate s⁻¹ in each group of experiments; —The speed of wave propagation on the incident rod (m / s); —Effective test length of the sample (m).

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