Fiber monofilament ultrahigh strain rate compression mechanical behavior characterization system

Abstract

The invention relates to a fiber monofilament ultrahigh strain rate compression mechanical behavior characterization system, which comprises: an emission unit, which is used for carrying out emission loading on a fiber monofilament sample so as to carry out a high-precision stable compression test on the fiber monofilament sample; the bearing structure unit is used for bearing the fiber monofilament sample emitted by the emitting unit; the rod group unit is connected with the bearing structure unit and the transmitting unit, and is used for carrying out transverse compression of an over-strain rate on the fiber monofilament sample; and the speed measuring unit is used for measuring the speed of the transmitting process of the transmitting unit. The impedance of a micron-sized fiber monofilament sample is matched, and the strain rate of 104-105 / s can be obtained; meanwhile, the laser Doppler velocimeter is used for replacing a traditional strain gauge to measure the strain of the rod, and the measuring method is non-contact, high in precision, stable and reliable. The ultrahigh strain rate transverse compression mechanical property characterization of the 10-micron-scale high-performance fiber monofilament can be realized, and the nominal stress-strain curve of the fiber during dynamic loading can be accurately measured.

Description

Technical Field

[0001] The invention relates to the technical field of material characterization and mechanical experiment, and in particular to a fiber monofilament ultra-high strain rate compression mechanical behavior characterization system. Background Art

[0002] High-performance fiber materials have high specific strength and specific modulus, and have been widely used in lightweight material design. As a common material for protective equipment, they mainly dissipate the kinetic energy of penetrating objects through delamination, buckling, fiber breakage, and fiber stretching to achieve the purpose of resisting object penetration. In high-speed impact situations, most impacts act in the transverse direction of the fiber. Therefore, experimental characterization of the ultra-high strain rate transverse compression mechanical behavior of fiber monofilaments is the key to modeling and predicting the behavior of yarns, fabrics, and composite laminates with monofilaments as basic units when subjected to important transverse loads such as ballistic impact and composite compression molding. Domestic and foreign experiments on the cross-scale high-speed impact failure behavior of high-performance materials are mainly concentrated on the macroscopic fabric and composite plate scale, the mesoscopic yarn and composite tape scale. In contrast, the testing and characterization of fiber monofilament materials at the microscopic scale is a direct means of multi-axial failure under impact loads. At present, there is a lack of research on the multi-axial failure behavior of high-performance fiber monofilaments in China.

[0003] At present, the most widely used technique for dynamic compression mechanical properties of materials is the Split Hopkinson Pressure Bar (SHPB) technique. SHPB technology is widely used to study the mechanical properties of materials under dynamic loads, especially at high strain rates (10 4 –10 5 / s). The basic principle of this method is to place a short specimen between two compression rods, and to impact load the specimen by means of an accelerated short rod hitting or generating an acceleration pulse. If the compression rod remains in an elastic state, the pulse in the rod will propagate as an elastic wave. By pasting strain gauges on the input rod and the output rod respectively to measure the strain signal (pulse signal) on the rod, the stress and strain curves of the material, as well as the strain rate-time curve of the material are calculated based on the one-dimensional stress wave theory to obtain the dynamic mechanical properties of the material. However, due to the size limitation of the strain gauge, traditional SHPB technology uses steel / aluminum rods with a diameter of more than 3mm, while the diameter of the fiber monofilament is usually 5-30μm, which is quite different from the impedance of the rod, making it difficult to perform dynamic mechanical property tests. Therefore, the diameter of the rod needs to reach the micron level.

[0004] The Chinese invention patent with publication number CN 117606911 A proposes a Hopkinson micro-rod device for dynamic mechanical property testing of micron-scale materials. It uses optical fiber sensors instead of strain gauges to measure the dynamic strain of input rods and output rods. During the test, the adhesion between the optical fiber and the rod is extremely high, and the sampling rate and range are relatively low. The prior art (Normal and Transverse Displacement Interferometers Applied to Small Diameter Kolsky Bars. Experimental Mechanics (2012) 52: 173–184) uses a lateral displacement interferometer to measure the incident pulse and the reflected pulse on the incident rod, and a normal displacement interferometer to measure the transmitted pulse on the transmission rod. It is worth noting that because the incident rod can only measure the incident pulse and the reflected pulse from the lateral direction, a diffraction grating needs to be installed in the middle of the rod. The grating must be installed on a flat surface, so a plane needs to be processed on the incident rod. At the same time, the processing accuracy of the diffraction grating and its adhesion quality with the incident rod will have a certain impact on the measurement accuracy of the entire experiment. The prior art (Interferometry-based Kolsky bar apparatus. [J]. The Review of scientific instruments, 2011, 82 (7): 073908.) designed a Hopkinson bar apparatus based on the all-fiber interferometry velocimetry method. In this apparatus, the strain gauge is replaced by an interferometer, which is irradiated on the incident bar and the transmission bar to measure the bar velocity. At the same time, the fiber laser measures the radial expansion rate of the specimen at an angle of 90°. Compared with the above two measurement methods that replace the strain gauge, it does not require contact or processing of the bar, but it is difficult to apply to micron-sized bars due to the limitation of the spot size. Based on the existing experimental technology, the main technical difficulties in the lateral compression dynamic mechanical properties test of fiber monofilaments are the following three points: 1. The small size of the bar makes it impossible to install the strain gauge in the traditional Hopkinson bar apparatus, and a new high-precision and high-sampling rate measurement method for the dynamic strain of the bar is required. 2. Due to the small size of the bar, it is difficult to align and focus the spot. 3. The incident bar velocity cannot be measured directly from the end. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a fiber monofilament ultra-high strain rate compression mechanical behavior characterization system, comprising: a launching unit, used to launch and load the fiber monofilament sample, and then perform high-precision and stable compression test on the fiber monofilament sample; a bearing structure unit, used to carry the fiber monofilament sample launched by the launching unit; a rod group unit, connected to the bearing structure unit and the launching unit, and used to perform ultra-strain rate lateral compression on the fiber monofilament sample; a speed measuring unit, used to measure the speed of the launching process of the launching unit.

[0006] In a preferred embodiment, the launching unit includes a launching barrel, a barrel support, a striking rod, a gas tank, an inflation tube and an electromagnetic valve; the striking rod is arranged inside the launching barrel; the launching barrel is mounted on the barrel support, the inflation tube is connected to the gas tank and inflates the gas tank, and when the air pressure of the pressure gauge reaches a set threshold, the electromagnetic valve is triggered so that the striking rod installed in the launching barrel will be instantly accelerated and then ejected.

[0007] In a preferred embodiment, the bearing structure unit includes an alloy base, an incident rod copper sleeve support, a transmission rod copper sleeve support, an incident rod and a transmission rod; the incident rod copper sleeve support and the transmission rod copper sleeve support are both fixed on the alloy base, the incident rod is mounted on the incident rod copper sleeve support, the transmission rod is mounted on the transmission rod copper sleeve support, and the axes of the incident rod and the transmission rod are located on the same straight line; the fiber monofilament sample is arranged between the incident rod and the transmission rod.

[0008] In a preferred embodiment, the impact rod, the incident rod and the transmission rod are all made of maraging steel, the impact rod has a diameter of 1000 μm, the incident rod has a diameter of 1000 μm, and the transmission rod has a diameter of 500 μm.

[0009] In a preferred embodiment, the speed measuring unit includes a normal laser speed meter, an adjustable tripod bracket, a tangential laser speed meter, an objective lens, reflective paint, a data acquisition card and a data processing system; the normal laser speed meter and the tangential laser speed meter synchronize the collected data to the data processing system through the data acquisition card, wherein the tangential laser speed meter is fixed and adjusted by the adjustable tripod bracket, and the normal laser speed meter focuses the light spot on the rod end through the objective lens.

[0010] In a preferred embodiment, the midpoint of the incident rod is coated with a reflective paint for enhancing diffuse reflection.

[0011] In a preferred embodiment, the diameter accuracy of the incident rod and the transmission rod is micron-level, which is used to match the impedance of the fiber monofilament sample of micron level, and then obtain 10 4 –10 5 / s level of strain rate.

[0012] In a preferred embodiment, the normal laser velocimeter and the tangential laser velocimeter both include a velocity measuring component, which includes a laser light source, a fiber beam splitter, a fiber coupler, a fiber circulator, a collimator, a moving end face, a photodetector and an oscilloscope; the laser light source outputs a laser of a fixed wavelength, which is divided into reference light and detection light by the fiber beam splitter, and the splitting ratio is 1:99; the detection light enters the collimator from the port of the fiber circulator and vertically irradiates the moving end face, and then enters the fiber coupler after being reflected back from the surface of the object; the reference light and the detection light interfere with each other after passing through the fiber coupler and then enter the photodetector, and then the voltage amplitude signal is collected by the oscilloscope, and the collected speed is calculated according to a preset algorithm.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Matching the impedance of the fiber monofilament sample at the micron level can obtain 10 4 –10 5 / s level strain rate; at the same time, laser Doppler velocimeter is used to replace the traditional strain gauge to measure the strain of the rod. The measurement method is non-contact, high-precision, stable and reliable. It can achieve ultra-high strain rate transverse compression mechanical properties characterization of 10-micron high-performance fiber monofilaments and accurately measure the nominal stress-strain curve of the fiber under dynamic loading. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the main structure of the fiber monofilament ultra-high strain rate compression mechanical behavior characterization system of the present invention;

[0016] Figure 2 It is a simplified structural schematic diagram of the ultra-high strain rate compression mechanical behavior characterization system of a fiber monofilament of the present invention;

[0017] Figure 3 It is a schematic diagram of the planar structure of the ultra-high strain rate compression mechanical behavior characterization system of a fiber monofilament of the present invention;

[0018] Figure 4 It is a schematic diagram of the structure of the speed measurement component in the fiber monofilament ultra-high strain rate compression mechanical behavior characterization system of the present invention.

[0019] Component number description:

[0020] 1. Launch barrel; 2. Barrel support; 3. Incident rod copper sleeve support; 4. Transmission rod copper sleeve support; 5. Alloy base; 6. Impact rod; 7. Incident rod; 8. Transmission rod; 9. Normal laser velocimeter; 10. Adjustable tripod bracket; 11. Tangential laser velocimeter; 12. Solenoid valve; 13. Gas tank; 14. Inflatable tube; 15. Data acquisition card; 16. Data processing system; 17. Objective lens; 18. Reflective paint; 19. Sample; 20. Laser light source; 21. Fiber optic beam splitter; 22 Fiber optic coupler; 23 Fiber optic circulator; 24 Collimator; 25 Moving end face; 26 Photodetector; 27 Oscilloscope. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0022] Please combine Figures 1 to 4 , Figure 1 This is a schematic diagram of the main structure of the fiber monofilament ultra-high strain rate compression mechanical behavior characterization system of the present invention; Figure 2 It is a simplified structural schematic diagram of the ultra-high strain rate compression mechanical behavior characterization system of a fiber monofilament of the present invention; Figure 3 It is a schematic diagram of the planar structure of the ultra-high strain rate compression mechanical behavior characterization system of a fiber monofilament of the present invention; Figure 4 The schematic diagram of the structure of the velocity measuring component in the ultra-high strain rate compression mechanical behavior characterization system of the fiber monofilament of the present invention. The ultra-high strain rate compression mechanical behavior characterization system of the fiber monofilament provided in this embodiment includes: a launching unit, which is used to launch and load the fiber monofilament sample 19, and then perform a high-precision stable compression test on the fiber monofilament sample 19; a bearing structure unit, which is used to carry the fiber monofilament sample 19 launched by the launching unit; a rod group unit, which is connected to the bearing structure unit and the launching unit, and is used to perform super strain rate lateral compression on the fiber monofilament sample; and a velocity measuring unit, which is used to measure the velocity of the launching process of the launching unit.

[0023] The launching unit comprises a launching barrel 1, a barrel support 2, a striking rod 6, a gas tank 13, an air charging pipe 14 and an electromagnetic valve 12; the striking rod 6 is arranged inside the launching barrel 1; the launching barrel 1 is mounted on the barrel support 2, the air charging pipe 14 is connected to the gas tank 13 and inflates the gas tank 13, and when the air pressure of the pressure gauge reaches the set threshold, the electromagnetic valve 12 is triggered so that the striking rod 6 installed in the launching barrel 1 will be instantly accelerated and then ejected. The bearing structure unit includes an alloy base 5, an incident rod copper sleeve support 3, a transmission rod copper sleeve support 4, an incident rod 7 and a transmission rod 8; the incident rod copper sleeve support 3 and the transmission rod copper sleeve support 4 are both fixed on the alloy base 5, the incident rod 7 is mounted on the incident rod copper sleeve support 3, the transmission rod 8 is mounted on the transmission rod copper sleeve support 4, and the axes of the incident rod 7 and the transmission rod 8 are located on the same straight line; the fiber monofilament sample 19 is arranged between the incident rod 7 and the transmission rod 8.

[0024] The alloy base 5 is fixed under the optical plate to fix the optical plate to the workbench to reduce vibration in the experiment. The copper sleeve support 3 for the incident rod and the copper sleeve support 4 for the transmission rod are placed in the grooves set in the alloy bottom 5. The copper sleeve support 3 for the incident rod and the copper sleeve support 4 for the transmission rod are connected to the rod unit through holes that are precisely machined and matched with the size of the rods.

[0025] The impact rod 6, the incident rod 7 and the transmission rod 8 are all made of maraging steel, the impact rod 6 has a rod diameter of 1000 μm, the incident rod 7 has a diameter of 1000 μm, and the transmission rod 8 has a diameter of 500 μm. The speed measuring unit includes a normal laser speed meter 9, an adjustable tripod bracket 10, a tangential laser speed meter 11, an objective lens 17, a reflective paint 18, a data acquisition card 15 and a data processing system 16; the normal laser speed meter 9 and the tangential laser speed meter 11 synchronize the collected data to the data processing system 16 through the data acquisition card 15, wherein the tangential laser speed meter 11 is fixed and adjusted by the adjustable tripod bracket 10, and the normal laser speed meter 9 focuses the light spot on the rod end through the objective lens 17. The midpoint of the incident rod 7 is coated with a reflective paint 18 for enhancing diffuse reflection. The diameter accuracy of the incident rod 7 and the transmission rod 8 is in the micron level, which is used to match the impedance of the fiber monofilament sample 19 in the micron level, and then obtain 10 4 –10 5 / s level strain rate. The normal laser velocimeter 9 and the tangential laser velocimeter 11 both include a velocity measurement component, which includes a laser light source 20, a fiber beam splitter 21, a fiber coupler 22, a fiber circulator 23, a collimator 24, a moving end face 25, a photodetector 26 and an oscilloscope 27; the laser light source 20 outputs a laser of a fixed wavelength, which is divided into a reference light and a detection light by the fiber beam splitter 21, and the splitting ratio is 1:99. The detection light enters the collimator 24 from the port 23 of the fiber circulator and then vertically irradiates the moving end face 25, and then enters the fiber coupler 22 after being reflected back from the surface of the object; the reference light and the detection light interfere with each other after passing through the fiber coupler 22 and then enter the photodetector 26, and then the voltage amplitude signal is collected by the oscilloscope 27, and the collected speed is calculated according to the preset algorithm.

[0026] In one embodiment, the rods in the impact rod 6, the incident rod 7 and the transmission rod 8 are made of 18Ni300 maraging steel. The impact rod 6 is 30 mm long and 1 mm in diameter. Therefore, the loading time of the entire system is The length of the incident rod 7 is 105 mm, and the diameter is 1 mm. The length of the transmission rod 8 is 84 mm, and the diameter is 500 μm. The diameters of the incident rod and the transmission rod are different, but the total forces on both sides are still equal, that is:

[0027] A1(o I +σ R )=A2σ T (1)

[0028] The speed is equal to the condition:

[0029]

[0030] From the above two equations, we can get the system impedance ratio n, reflection coefficient F, transmission coefficient T velocity relationship ratio:

[0031]

[0032] Further, among them, Figure 3 As shown, the speed measuring unit is used to measure the speed pulse signal of the incident rod 7 and the transmission rod 9. The normal laser speed meter 9 directly measures the end of the transmission rod 8, which is 0.4m away from the end, and the laser wavelength is 632.8nm; the actual speed measured by the tangential laser vibrometer is v m , forming an angle θ with the incident rod 9. During the impact loading process, the incident rod will also expand in the radial direction, and the expansion speed is the lateral speed v L and the Poisson's ratio μ of the rod material, so the actual velocity measured is the component v of the lateral velocity L and the radial velocity component v T sum:

[0033] v n =v L cosθ+v T sinθ=v L cosθ+μv L sinθ,

[0034] The angle selected in this embodiment is 30°, and the speed measured by the above formula is ≈ the lateral speed of the incident rod; the reflective paint 18 is selected in the middle of the incident rod 9, and the incident reflection time interval is This ensures that the two waves do not overlap.

[0035] Among them, Figure 4 As shown, the speed measurement unit specifically includes: a laser light source 20, a fiber beam splitter 21, a fiber coupler 22, a fiber circulator 23, a collimator 24, a moving end face 25, a photodetector 26, and an oscilloscope 27. The laser light source 20 outputs a laser of a fixed wavelength, which is divided into a reference light and a detection light by the fiber beam splitter 21, and the splitting ratio is 1:99. The detection light enters the collimator 24 from the port 23 of the fiber circulator and then vertically irradiates the moving end face 25, is reflected by the surface of the object, and returns to the port 2, and then enters the fiber coupler 22 through the port 3. The reference light and the detection light interfere with each other after passing through the fiber coupler 22. A1 and A2 are the amplitudes of the reference light and the signal light, and f1 and f2 are their frequencies. is the initial phase, and is finally converted into signal light wave E1 and detection light wave E2 by the photodetector:

[0036]

[0037] The two light waves interfere with each other. According to the light interference formula, the light intensity I received by the detector is:

[0038]

[0039] Ignoring the phase information of the light wave signal and the DC component detected by the photodetector 26, the light intensity I is:

[0040]

[0041] u is the speed of the object, λ is the wavelength of the detection light, and the relationship between the speed of the object being measured and the variable of the light beam frequency, i.e., the Doppler frequency shift, is have to:

[0042]

[0043] Wherein, α is the conversion coefficient of the photodetector. The voltage amplitude signal is then collected by an oscilloscope 27, the frequency signal can be recorded, and the change of frequency over time can be studied by time-frequency analysis. The frequency shift curve is extracted, and then the velocity curves of the incident rod and the transmission rod are calculated according to the formula to obtain the strain pulses of the two rods;

[0044] The following takes a fiber monofilament ultra-high strain rate compression mechanical behavior characterization system as an example to explain the actual operation process of the system in detail:

[0045] The launch unit, bearing structure unit, rod group unit and speed measuring unit are installed and connected according to the diagram; the specific position and angle selection, sample clamping and speed measuring unit specific structure are all in accordance with Figures 1 to 4 set up;

[0046] To verify the rationality of the system, without inserting the sample, place the incident rod 7 and the transmission rod 8 close together, put the impact rod 6 into the bottom of the barrel 1, and inflate the gas tank through the inflation tube to reach a certain air pressure; turn on the tangential laser velocimeter 11 and the normal laser velocimeter 9, and adjust the two velocimeters to align with the end of the incident rod 7 and the position of the reflective paint 18 through the adjustable tripod bracket until the light signal is displayed within the appropriate intensity range; turn on the data acquisition system 16 and the oscilloscope 27, complete the preparation work, press the solenoid valve 12 to start loading, and click the tangential laser velocimeter 11 and the normal laser velocimeter 9 to start speed measurement, and obtain the waveforms of the incident wave, reflected wave and transmitted wave of the system without adding the sample, verify the force balance and velocity equality condition, and check whether the reflection coefficient F and the transmission coefficient meet the theoretical values, so as to verify the rationality of the system.

[0047] After verifying the rationality of the system, place the fiber monofilament sample 19 between the incident rod 7 and the transmission rod 8 to ensure that the sample is in contact with the end faces of the two rods; press the electromagnetic valve 12 to start loading, and click the tangential laser velocimeter 11 and the normal laser velocimeter 9 to start speed measurement at the same time, and obtain the waveforms of the incident wave, reflected wave and transmitted wave of the sample added to the system. Perform data processing and analysis on the waveforms to obtain the force-displacement curve of the fiber monofilament under ultra-high strain rate. The compressed fiber monofilament sample can be characterized under a scanning electron microscope to obtain the specific morphology of the compressed fiber.

[0048] The operation implementation steps included in the above embodiment are only for reference. For those skilled in the art, the logical relationship of the installation sequence can be changed according to actual needs.

[0049] Compared with the prior art, the present invention has the following advantages and outstanding effects: 1. The system designs the diameter of the rod to the micrometer scale, realizes the ultra-high strain rate dynamic mechanical property test of the fiber monofilament material, and can obtain a higher strain rate (10 4 –105 / s); Second, different from the traditional method of measuring rod strain with strain gauges, laser Doppler velocimetry (LDV) is used to perform non-contact, high-precision measurement of rods, providing a new method for testing the dynamic mechanical properties of micron-scale materials, and better filling the lack of experimental data on fiber single filaments at the microscopic scale in the high strain rate range, so as to construct a fiber material model covering the entire strain rate and full size range.

[0050] In summary, the present invention introduces a fiber monofilament ultra-high strain rate compression mechanical behavior characterization system, which uses a laser Doppler velocimeter (LDV) to measure the incident pulse and reflected pulse on the incident rod and the transmission pulse on the transmission rod. The overall measurement method is non-contact, accurate in measurement, simple to operate, stable and reliable. Thus, the ultra-high strain rate transverse compression mechanical performance characterization of 10-micron high-performance fiber monofilaments is achieved, and the nominal stress-strain curve of the fiber under dynamic loading is accurately measured. The characterization method can provide fiber-scale dynamic mechanical properties and constitutive model parameters, and provide guidance for the development of cross-scale mechanical models of fabrics and composite materials and the research and development of high-performance fiber materials. In addition to fiber monofilaments, experimental research can also be carried out on a series of micron-level materials such as PDMS films, micro-metamaterials, etc.

[0051] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A fiber monofilament ultra-high strain rate compression mechanical behavior characterization system, characterized in that: include: A launching unit, used for launching and loading the fiber monofilament sample (19), thereby performing a high-precision and stable compression test on the fiber monofilament sample (19); A bearing structure unit, used for bearing the fiber monofilament sample (19) launched by the launching unit; A rod group unit is connected to the load-bearing structure unit and the emission unit and is used for performing lateral compression of the fiber monofilament sample at an ultra-strain rate; The speed measuring unit is used to measure the speed of the emission process of the emission unit.

2. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 1, characterized in that: The launching unit comprises a launching barrel (1), a barrel support (2), a striking rod (6), a gas tank (13), an air charging pipe (14) and an electromagnetic valve (12); the striking rod (6) is arranged inside the launching barrel (1); the launching barrel (1) is mounted on the barrel support (2), the air charging pipe (14) is connected to the gas tank (13) and inflates the gas tank (13); when the air pressure of the pressure gauge reaches a set threshold value, the electromagnetic valve (12) is triggered, so that the striking rod (6) installed in the launching barrel (1) is instantly accelerated and then fired.

3. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 2, characterized in that: The bearing structure unit comprises an alloy base (5), an incident rod copper sleeve support (3), a transmission rod copper sleeve support (4), an incident rod (7) and a transmission rod (8); The incident rod copper sleeve support (3) and the transmission rod copper sleeve support (4) are both fixed on the alloy base (5); the incident rod (7) is mounted on the incident rod copper sleeve support 3; the transmission rod (8) is mounted on the transmission rod copper sleeve support (4); the axes of the incident rod (7) and the transmission rod (8) are located on the same straight line; and the fiber monofilament sample (19) is arranged between the incident rod (7) and the transmission rod (8).

4. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 3, characterized in that: The impact rod (6), the incident rod (7) and the transmission rod (8) are all made of maraging steel; the impact rod (6) has a rod diameter of 1000 μm, the incident rod (7) has a diameter of 1000 μm, and the transmission rod (8) has a diameter of 500 μm.

5. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 4, characterized in that: The speed measuring unit comprises a normal laser speed meter (9), an adjustable tripod bracket (10), a tangential laser speed meter (11), an objective lens (17), a reflective paint (18), a data acquisition card (15) and a data processing system (16); The normal laser velocimeter (9) and the tangential laser velocimeter (11) synchronize the collected data to the data processing system (16) through the data acquisition card (15), wherein the tangential laser velocimeter (11) is fixed and adjusted through the adjustable tripod bracket (10), and the normal laser velocimeter (9) focuses a light spot on the rod end through the objective lens (17).

6. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 5, characterized in that: The midpoint of the incident rod (7) is coated with a reflective paint (18) for enhancing diffuse reflection.

7. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 6, characterized in that: The diameter accuracy of the incident rod (7) and the transmission rod (8) is in the micron level, which is used to match the impedance of the fiber monofilament sample (19) in the micron level, thereby obtaining 10 4 –10 5 / s level of strain rate.

8. The fiber monofilament ultra-high strain rate compression mechanical behavior characterization system according to claim 7, characterized in that: The normal laser velocimeter (9) and the tangential laser velocimeter (11) both comprise a velocity measurement component, which comprises a laser light source (20), an optical fiber beam splitter (21), an optical fiber coupler (22), an optical fiber circulator (23), a collimator (24), a moving end face (25), a photodetector (26) and an oscilloscope (27); the laser light source (20) outputs a laser beam with a fixed wavelength, which is divided into a reference light and a detection light by the optical fiber beam splitter (21), and the splitting ratio is 1:99; the detection light enters the collimator (24) from the port of the optical fiber circulator (23), and then vertically irradiates the moving end face (25), and then enters the optical fiber coupler (22) after being reflected from the surface of the object; the reference light and the detection light interfere with each other after passing through the optical fiber coupler (22), and then enter the photodetector (26); after that, the voltage amplitude signal is collected by the oscilloscope (27), and the collected speed is calculated according to a preset algorithm.

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