Device and method for testing coefficient of sliding friction force under high-speed impact load

Abstract

The invention provides a device and a method for testing a sliding friction coefficient under a high-speed impact load, and relates to the technical field of sliding friction force testing. The device for testing the sliding friction coefficient under the high-speed impact load comprises an impact rod, an incident rod, a transmission rod and a compression-torsion coupling piece, strain sensors are attached to the incident bar and the transmission bar; one end of the pressure-torsion coupling piece is adhered to one end, far away from the impact rod, of the incident rod, a first to-be-tested material block is adhered to the other end of the pressure-torsion coupling piece, a second to-be-tested material block is adhered to the end part of the transmission rod, and the impact rod can impact the incident rod; the pressure-torsion coupling piece comprises two pressure plates and a plurality of inclined supporting rods, and the plurality of inclined supporting rods are arranged between the two pressure plates. And the technical effect of effective characterization capability of the dynamic friction behavior under the impact load is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of sliding friction force testing, and in particular to a device and method for testing a sliding friction force coefficient under high-speed impact load. Background Art

[0002] Friction is a common phenomenon of interfacial interaction, and its theoretical development has evolved from empirical models to contact mechanics models. Although classical theories (such as Coulomb's law) have explained the friction mechanism of rigid bodies, the friction problem of the contact surface between rigid bodies and plastic bodies still lacks a good scientific representation. Existing studies mostly use approximate solutions based on the rigidity assumption. In recent years, although numerical simulation technology (finite element method FEM / finite difference method FDM) has been widely used in contact analysis, it is limited by the complex mechanical behavior of the interface and the uncertainty of the boundary condition definition, which leads to limited calculation accuracy. The distortion of friction parameters will directly affect the credibility of the simulation. Therefore, obtaining the dynamic friction coefficient through experimental means is the key path to solving this problem. Although the current friction test device can simulate the contact characteristics of multiple working conditions, its matching degree with the real state still needs to be optimized. The verification of tribological laws needs to be based on systematic experiments, so it is necessary to develop high-precision friction testing methods.

[0003] In current friction models, friction coefficient values are often derived from conventional static contact test data. However, research has shown that interfacial friction behavior under high-speed impact loads is influenced by multiple factors, including contact surface characteristics (such as roughness), the relative motion rate of the contact surfaces, and transient temperature rise effects, which together influence the friction energy dissipation mechanism. Traditional friction coefficients derived from static friction coefficient parameter libraries (such as recommended values in technical manuals) or quasi-static testing methods are unable to accurately represent the actual friction state during dynamic impact.

[0004] However, existing testing systems generally lack the ability to effectively characterize dynamic friction behavior under impact loads, which has become a bottleneck in research in the field of extreme working conditions friction. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for testing the sliding friction coefficient under high-speed impact loads, so as to alleviate the technical problem that the testing system in the prior art lacks the ability to effectively characterize the dynamic friction behavior under impact loads.

[0006] In a first aspect, an embodiment of the present invention provides a device for testing the coefficient of sliding friction under high-speed impact load, comprising an impact rod, an incident rod, a transmission rod, and a compression-torsion coupling;

[0007] The incident rod and the transmission rod are both provided with strain sensors;

[0008] One end of the compression-torsion coupling is bonded to an end of the incident rod away from the impact rod, the first material block to be tested is bonded to the other end of the compression-torsion coupling, and the second material block to be tested is bonded to the end of the transmission rod, and the impact rod is capable of impacting the incident rod;

[0009] The compression-torsion coupling comprises two pressure plates and a plurality of diagonal bracing rods, wherein the plurality of diagonal bracing rods are arranged between the two pressure plates.

[0010] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the two pressure plates are respectively a first pressure plate and a second pressure plate, and a plurality of diagonal support rods are arranged between the first pressure plate and the second pressure plate.

[0011] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the first pressure plate can be bonded to the first material block to be tested, and the second pressure plate can be bonded to the incident rod.

[0012] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the strain sensor includes a first strain sensor and a second strain sensor;

[0013] The first strain sensor is disposed on the incident rod, and the second strain sensor is disposed on the transmission rod.

[0014] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the first strain sensor uses a first strain gauge, and the extension direction of the first strain gauge coincides with the direction of the incident rod;

[0015] The number of the first strain gauges is two, and the two first strain gauges are axially symmetrically arranged on the outer wall of the incident rod.

[0016] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the second strain sensor uses a strain gauge rosette, there are two strain gauge rosettes, and the two strain gauge rosettes are axially symmetrically arranged on the outer wall of the transmission rod.

[0017] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the rosette includes a positive 45-degree strain gauge, a 0-degree strain gauge, and a negative 45-degree strain gauge;

[0018] The extending direction of the 0-degree strain gauge coincides with the extending direction of the transmission rod.

[0019] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the number of the diagonal bracing rods is four.

[0020] In combination with the first aspect, an embodiment of the present invention provides a possible implementation of the first aspect, wherein the diagonal bracing rod is made of 316L stainless steel.

[0021] In a second aspect, an embodiment of the present invention provides a method for testing the coefficient of sliding friction under high-speed impact loads, which is used in the device for testing the coefficient of sliding friction under high-speed impact loads, comprising the following steps:

[0022] Glue the first strain gauge to the incident rod and the strain rosette to the transmission rod;

[0023] Adhere one end of the compression-torsion coupling to the end of the incident rod away from the impact rod, adhere the first material block to the other end of the compression-torsion coupling, and adhere the second material block to one end of the transmission rod;

[0024] The impact rod is used to impact the incident rod. The incident rod is forced to drive the compression-torsion coupling to drive the first material block to be tested. The first material block to be tested is forced to impact the second material block to be tested. The second material block to be tested is forced to impact the transmission rod.

[0025] Obtain the electrical signal data of the first strain sensor and the 0-degree strain gauge to obtain the impact velocity V and axial normal pressure N:

[0026] ε i =KU1

[0027] ε r =KU2

[0028] ε t =KU3

[0029] V=c0(ε i -ε r )

[0030] N=SEε t

[0031] Among them, ε i represents the incident strain pulse of the first strain sensor, ε r represents the strain pulse reflected by the first strain sensor, ε t represents the transmitted strain pulse of the 0-degree strain gauge of the second strain sensor, U1 represents the incident wave electrical signal data U1 of the first strain sensor, U2 represents the reflected wave electrical signal data U2 of the first strain sensor, and U3 represents the electrical signal data U of the 0-degree strain gauge of the second strain sensor. 3，K represents the sensitivity coefficient of the first strain sensor and the strain-voltage ratio K of the bridge pressure, V is the impact load velocity V, N is the axial normal pressure N, and E is the elastic modulus of the incident rod and the transmission rod material;

[0032] Obtain the electrical signal data U of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor according to the following formula:

[0033] ε=KU

[0034]

[0035] Wherein, ε represents the strain pulse of the second strain sensor, U represents the electrical signal data U of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor, K represents the sensitivity coefficient of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor and the strain-voltage ratio K of the bridge pressure, τ represents the shear stress, E is the elastic modulus of the material of the incident rod and the transmitted rod, ν is the Poisson's ratio of the material of the incident rod and the transmitted rod, R is the radius of the incident rod and the transmitted rod, J represents the polar moment of inertia of the cross section of the incident rod and the transmitted rod, and T represents the friction torque;

[0036] The impact friction torque T is obtained:

[0037]

[0038] According to the circular contact surface friction torque formula: (where μ is the coefficient of kinetic friction, N is the axial normal pressure, and R is the contact surface radius)

[0039] Get the impact friction coefficient:

[0040]

[0041] Substitute the test data into the final impact friction coefficient.

[0042] Beneficial effects:

[0043] An embodiment of the present invention provides a device for testing the coefficient of sliding friction under high-speed impact load, comprising an impact rod, an incident rod, a transmission rod and a compression-torsion coupling; strain sensors are attached to both the incident rod and the transmission rod; one end of the compression-torsion coupling is bonded to the end of the incident rod away from the impact rod, a first material block to be tested is bonded to the other end of the compression-torsion coupling, and a second material block to be tested is bonded to the end of the transmission rod, and the impact rod can impact the incident rod; the compression-torsion coupling comprises two pressure plates and multiple diagonal support rods, and the multiple diagonal support rods are arranged between the two pressure plates.

[0044] Specifically, the axial impact load of the incident rod on the transmission rod is converted into a positive pressure and torque with a certain change trend by using a compression-torsion coupling, and the friction torque of the positive pressure and the contact surface of the material to be tested is measured by the Hopkinson rod technology and the strain gauge technology of the strain sensor. At the same time, the contact area between the materials to be tested is known, and the formula (T is the friction torque, μ is the dynamic friction coefficient, N is the normal pressure, and R is the contact surface radius), which can accurately test the friction coefficient of the contact surface of the material to be tested under dynamic impact.

[0045] An embodiment of the present invention provides a method for testing a coefficient of sliding friction under a high-speed impact load, which is used in a device for testing a coefficient of sliding friction under a high-speed impact load. The method comprises the following steps: adhering a first strain gauge to an incident rod and adhering a strain rosette to a transmission rod; adhering one end of a compression-torsion coupling to an end of the incident rod away from the impact rod, adhering a first material block to be tested to the other end of the compression-torsion coupling, and adhering a second material block to be tested to one end of the transmission rod; using the impact rod to impact the incident rod, the incident rod being subjected to force to drive the compression-torsion coupling to drive the first material block to be tested, the first material block to be tested being subjected to force to impact the second material block to be tested, and the second material block to be tested being subjected to force to impact the transmission rod; acquiring electrical signal data from the first strain sensor and the 0-degree strain gauge to obtain an impact velocity V and an axial normal pressure N:

[0046] ε i =KU1

[0047] ε r =KU2

[0048] ε t =KU3

[0049] V=c0(ε i -ε r )

[0050] N=SEε t

[0051] Among them, ε i represents the incident strain pulse of the first strain sensor, ε r represents the strain pulse reflected by the first strain sensor, ε t represents the transmitted strain pulse of the 0-degree strain gauge of the second strain sensor, U1 represents the incident wave electrical signal data U1 of the first strain sensor, U2 represents the reflected wave electrical signal data U2 of the first strain sensor, and U3 represents the electrical signal data U of the 0-degree strain gauge of the second strain sensor. 3， K represents the sensitivity coefficient of the first strain sensor and the strain-voltage ratio K of the bridge pressure, V is the impact load velocity V, N is the axial normal pressure N, and E is the elastic modulus of the incident rod and the transmission rod material;

[0052] Obtain the electrical signal data U of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor according to the following formula:

[0053] ε=KU

[0054]

[0055] Wherein, ε represents the strain pulse of the second strain sensor, U represents the electrical signal data U of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor, K represents the sensitivity coefficient of the positive 45-degree strain gauge and the negative 45-degree strain gauge of the second strain sensor and the strain-voltage ratio K of the bridge pressure, τ represents the shear stress, E is the elastic modulus of the material of the incident rod and the transmitted rod, ν is the Poisson's ratio of the material of the incident rod and the transmitted rod, R is the radius of the incident rod and the transmitted rod, J represents the polar moment of inertia of the cross section of the incident rod and the transmitted rod, and T represents the friction torque;

[0056] The impact friction torque T is obtained:

[0057]

[0058] According to the circular contact surface friction torque formula: (where μ is the coefficient of kinetic friction, N is the axial normal pressure, and R is the contact surface radius)

[0059] Get the impact friction coefficient:

[0060]

[0061] Substitute the test data into the final impact friction coefficient.

[0062] The method for testing the coefficient of sliding friction under high-speed impact load has the above advantages compared with the existing technology, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] Figure 1 A schematic diagram of the structure of a device for testing the coefficient of sliding friction under high-speed impact loads provided by an embodiment of the present invention (the guide sleeve is not shown);

[0065] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0066] Figure 3 Schematic diagram of a compression-torsion coupling in a device for testing the coefficient of sliding friction under high-speed impact loads provided by an embodiment of the present invention.

[0067] icon:

[0068] 10-first material block to be tested; 20-second material block to be tested;

[0069] 100-impact rod;

[0070] 200-incident rod;

[0071] 300-transmission rod;

[0072] 400-compression-torsion coupling; 410-diagonal brace; 421-first pressure plate; 422-second pressure plate;

[0073] 510 - first strain sensor; 520 - second strain sensor; 521 - positive 45-degree strain gauge; 522 - 0-degree strain gauge; 523 - negative 45-degree strain gauge. DETAILED DESCRIPTION

[0074] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0075] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0077] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0078] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0079] See also Figure 1 、 Figure 2 and Figure 3 As shown, this embodiment provides a device for testing the coefficient of sliding friction under high-speed impact load, including an impact rod 100, an incident rod 200, a transmission rod 300 and a compression-torsion coupling 400; strain sensors are attached to the incident rod 200 and the transmission rod 300; the compression-torsion coupling 400 is bonded to one end of the incident rod 200 away from the impact rod 100, the first material block to be tested 10 is bonded to the other end of the compression-torsion coupling 400, and the second material block to be tested 20 is bonded to the end of the transmission rod 300; the impact rod 100 can impact the incident rod 200, and the compression-torsion coupling 400 includes two pressure plates and multiple diagonal support rods 410, and the multiple diagonal support rods 410 are arranged between the two pressure plates.

[0080] Specifically, the compression-torsion coupling 400 is used to convert the axial impact load of the incident rod 200 on the transmission rod 300 into a positive pressure and torque with a certain change trend, and the friction torque between the positive pressure and the contact surface of the material to be tested is measured by the Hopkinson rod technology and the strain gauge technology of the strain sensor. At the same time, the contact area between the materials to be tested is known, and the formula (T is the friction torque, μ is the dynamic friction coefficient, N is the normal pressure, and R is the contact surface radius), which can accurately test the friction coefficient of the contact surface of the material to be tested under dynamic impact.

[0081] The incident rod 200 and the transmission rod 300 are made of the same material and have the same radius. In addition, the impact rod 100, the incident rod 200, the transmission rod 300 and the compression-torsion coupling 400 form a Hopkinson rod system.

[0082] It should be noted that the device for testing the coefficient of sliding friction under high-speed impact load provided in this embodiment can measure material blocks to be tested that are made of the same material, and can also measure material blocks to be tested that are made of different materials.

[0083] Among them, the impact rod 100, the incident rod 200, the transmission rod 300 and the compression-torsion coupling 400 will be installed in the guide sleeve during the actual testing process. The impact rod 100 is applied with a set initial velocity by an external device, and then the impact rod 100 hits the incident rod 200. The incident rod 200 carries the compression-torsion coupling 400 and the first test material block 10 to hit the transmission rod 300 attached with the second test material block 20. The compression-torsion coupling 400 can act as a stress converter, converting the normal stress applied by the first test material block 10 to the second test material block 20 into a shear stress and a normal stress, that is, converting the force along the rod axis transmitted by the impact rod 100 to the incident rod 200 into a torsional force and a normal pressure.

[0084] The two pressure plates of the compression-torsion coupling 400 are a first pressure plate 421 and a second pressure plate 422, respectively. A plurality of diagonal bracing rods 410 are disposed between the first and second pressure plates 421, 422. Four diagonal bracing rods 410 are disposed at the same angle between the first and second pressure plates 421, 422. Furthermore, those skilled in the art can adjust the number of diagonal bracing rods 410 based on actual needs, and this will not be further described here.

[0085] It should also be pointed out that by adjusting the compression-torsion coupling 400, such as adjusting the rod diameter and inclination angle of the diagonal support rod 410 and the number of diagonal support rods 410, it is possible to obtain a positive pressure and torque with a certain trend and measurable magnitude under a certain impact velocity, and under the same conditions (the impact load and the number of diagonal support rods 410, the inclination angle, the rod diameter, etc. are the same), the torsional speed of the end face of the compression-torsion material is the same. Therefore, it is possible to measure the friction coefficient between two materials to be tested (which can also be the same material) under a given impact velocity and a specified positive pressure under dynamic impact.

[0086] The material of the diagonal brace 410 can be 316L stainless steel, TC4 titanium alloy or AlSi 0Mg. Those skilled in the art can adjust the size and material of the compression-torsion coupling 400 according to the actual test plan, which will not be described in detail here.

[0087] The first pressure plate 421 can be bonded to the first material block 10 to be tested, and the second pressure plate 422 can be bonded to the incident rod 200 .

[0088] The strain sensor includes a first strain sensor 510 and a second strain sensor 520 ; the first strain sensor 510 is disposed on the incident rod 200 , and the second strain sensor 520 is disposed on the transmissive rod 300 .

[0089] The first strain sensor 510 uses a first strain gauge, the extension direction of which coincides with the direction of the incident rod 200 ; there are two first strain gauges, which are axially symmetrically arranged on the outer wall of the incident rod 200 .

[0090] The second strain sensor 520 is a strain rosette. There are two strain rosettes, which are axially symmetrically arranged on the outer wall of the transmission rod 300 .

[0091] The strain rosette includes a positive 45-degree strain gauge 521 , a 0-degree strain gauge 522 and a negative 45-degree strain gauge 523 ; the extending direction of the 0-degree strain gauge 522 coincides with the extending direction of the transmission rod 300 .

[0092] This embodiment provides a method for testing the coefficient of sliding friction under high-speed impact loads, which is used in a device for testing the coefficient of sliding friction under high-speed impact loads. The method comprises the following steps: adhering a first strain gauge to an incident rod 200 and a strain gauge rosette to a transmission rod 300; adhering one end of a compression-torsion coupling 400 to an end of the incident rod 200 away from the impact rod 100, adhering a first test material block 10 to the other end of the compression-torsion coupling 400, and adhering a second test material block 20 to an end of the transmission rod 300; using the impact rod 100 to impact the incident rod 200, whereby the incident rod 200 is driven by the compression-torsion coupling 400 to drive the first test material block 10 to impact the second test material block 20, and the second test material block 20 is then forced to impact the transmission rod 300; and acquiring electrical signal data from the first strain sensor 510 and the 0-degree strain gauge 522 to obtain the impact velocity V and the axial normal pressure N:

[0093] ε i =KU1

[0094] ε r =KU2

[0095] ε t =KU3

[0096] V=c0(ε i -ε r )

[0097] N=SEε t

[0098] Among them, ε i represents the incident strain pulse on the first strain sensor 510, ε r represents the strain pulse reflected by the first strain sensor 510, ε trepresents the transmitted strain pulse of the 0-degree strain gauge 522 of the second strain sensor 520, U1 represents the incident wave electrical signal data U1 of the first strain sensor 510, U2 represents the reflected wave electrical signal data U2 of the first strain sensor 510, and U3 represents the electrical signal data U of the 0-degree strain gauge 522 of the second strain sensor 520. 3， K represents the sensitivity coefficient of the first strain sensor 510 and the strain-voltage ratio K of the bridge pressure, V is the impact load velocity V, N is the axial normal pressure N, and E is the elastic modulus of the material of the incident rod 200 and the transmission rod 300;

[0099] The electrical signal data U of the positive 45-degree strain gauge 521 and the negative 45-degree strain gauge 523 of the second strain sensor 520 is obtained according to the following formula:

[0100] ε=KU

[0101]

[0102] Wherein, ε represents the strain pulse of the second strain sensor 520, U represents the electrical signal data U of the positive 45-degree strain gauge 521 and the negative 45-degree strain gauge 523 of the second strain sensor 520, K represents the sensitivity coefficient of the positive 45-degree strain gauge 521 and the negative 45-degree strain gauge 523 of the second strain sensor 520 and the strain-voltage ratio K of the bridge pressure, τ represents shear stress, E is the elastic modulus of the material of the incident rod 200 and the transmission rod 300, ν is the Poisson's ratio of the material of the incident rod 200 and the transmission rod 300, R is the radius of the incident rod 200 and the transmission rod 300, J represents the polar moment of inertia of the cross section of the incident rod 200 and the transmission rod 300, and T represents the friction torque;

[0103] The impact friction torque T is obtained:

[0104]

[0105] According to the circular contact surface friction torque formula: (where μ is the coefficient of kinetic friction, N is the axial normal pressure, and R is the contact surface radius);

[0106] Get the impact friction coefficient:

[0107]

[0108] Substitute the test data into the final impact friction coefficient.

[0109] Specifically, during the specific operation of the method for testing the coefficient of sliding friction under high-speed impact loads provided in this embodiment, a 45-degree strain rosette is attached to the transmission rod 300. The dimensions of the impact rod 100 and the compression-torsion coupling 400 are selected according to the desired research situation. The compression-torsion coupling 400, the first test material block 10, the second test material block 20, the incident rod 200, and the transmission rod 300 are tightly glued together, with no glue between the two test material blocks. The compression-torsion coupling 400 is glued to the end of the incident rod 200 away from the impact rod 100, the first test material block 10 is glued to the other end of the compression-torsion coupling 400, and the second test material block 20 is glued to the end of the transmission rod 300. The impact process is then recorded using a high-speed camera for subsequent data analysis and reliability verification. After the adhesive reaches working strength, the impact rod 100 is installed and the launch pressure is set. The impact rod 100 is then launched. The data from multiple strain sensors is recorded using an oscilloscope. The electrical signals recorded by the oscilloscope are processed to calculate the friction coefficient under impact.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for testing the coefficient of sliding friction under high-speed impact load, characterized in that: include: An impact rod (100), an incident rod (200), a transmission rod (300) and a compression-torsion coupling (400); The incident rod (200) and the transmission rod (300) are both provided with strain sensors; One end of the compression-torsion coupling (400) is bonded to an end of the incident rod (200) away from the impact rod (100), the first material block (10) to be tested is bonded to the other end of the compression-torsion coupling (400), the second material block (20) to be tested is bonded to the end of the transmission rod (300), and the impact rod (100) is capable of impacting the incident rod (200); The compression-torsion coupling (400) comprises two pressure plates and a plurality of diagonal bracing rods (410), wherein the plurality of diagonal bracing rods (410) are arranged between the two pressure plates.

2. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 1, characterized in that: The two pressure plates are respectively a first pressure plate (421) and a second pressure plate (422), and a plurality of diagonal support rods (410) are arranged between the first pressure plate (421) and the second pressure plate (422).

3. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 2, characterized in that: The first pressure plate (421) can be bonded to the first material block (10) to be tested, and the second pressure plate (422) can be bonded to the incident rod (200).

4. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 1, characterized in that: The strain sensor comprises a first strain sensor (510) and a second strain sensor (520); The first strain sensor (510) is arranged on the incident rod (200), and the second strain sensor (520) is arranged on the transmission rod (300).

5. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 4, characterized in that: The first strain sensor (510) uses a first strain gauge, and the extension direction of the first strain gauge coincides with the direction of the incident rod (200); The number of the first strain gauges is two, and the two first strain gauges are arranged axially symmetrically on the outer wall of the incident rod (200).

6. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 4, characterized in that: The second strain sensor (520) uses a strain rosette, and the number of the strain rosettes is two. The two strain rosettes are axially symmetrically arranged on the outer wall of the transmission rod (300).

7. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 6, characterized in that: The strain rosette includes a positive 45-degree strain gauge (521), a 0-degree strain gauge (522), and a negative 45-degree strain gauge (523); The extension direction of the 0-degree strain gauge (522) coincides with the extension direction of the transmission rod (300).

8. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 1, characterized in that: The number of the diagonal bracing rods (410) is four.

9. The device for testing the coefficient of sliding friction under high-speed impact load according to claim 1, characterized in that: The diagonal support rod (410) is made of 316L stainless steel.

10. A method for testing the coefficient of sliding friction under high-speed impact load, characterized in that: The device for testing the coefficient of sliding friction under high-speed impact load according to any one of claims 1 to 9 comprises the following steps: Pasting the first strain gauge on the incident rod (200) and pasting the strain rosette on the transmission rod (300); One end of the compression-torsion coupling (400) is bonded to an end of the incident rod (200) away from the impact rod (100), the first material block to be tested (10) is bonded to the other end of the compression-torsion coupling (400), and the second material block to be tested (20) is bonded to one end of the transmission rod (300); The impact rod (100) is used to impact the incident rod (200), the incident rod (200) is forced to drive the compression-torsion coupling (400) to drive the first material block to be tested (10), the first material block to be tested (10) is forced to impact the second material block to be tested (20), and the second material block to be tested (20) is forced to impact the transmission rod (300); The electrical signal data of the first strain sensor (510) and the 0-degree strain gauge (522) are obtained to obtain the impact velocity V and the axial normal pressure N: e i =KU1 e r =KU2 e t =KU3 V=c0(ε i -e r ) <h2 style=";text-align:left;direction:ltr">N=SEε<h2 style=";text-align:left;direction:ltr"> t Among them, ε i represents the incident strain pulse of the first strain sensor (510), ε r represents the reflected strain pulse of the first strain sensor (510), ε t represents the transmitted strain pulse of the 0-degree strain gauge (522) of the second strain sensor (520), U1 represents the incident wave electrical signal data U1 of the first strain sensor (510), U2 represents the reflected wave electrical signal data U2 of the first strain sensor (510), U3 represents the electrical signal data U3 of the 0-degree strain gauge (522) of the second strain sensor (520), K represents the sensitivity coefficient of the first strain sensor (510) and the strain-voltage ratio K of the bridge pressure, V is the impact load velocity V, N is the axial normal pressure N, and E is the elastic modulus of the material of the incident rod (200) and the transmission rod (300); The electrical signal data U of the positive 45-degree strain gauge (521) and the negative 45-degree strain gauge (523) of the second strain sensor (520) is obtained according to the following formula: ε=KU Wherein, ε represents the strain pulse of the second strain sensor (520), U represents the electrical signal data U of the positive 45-degree strain gauge (521) and the negative 45-degree strain gauge (523) of the second strain sensor (520), K represents the sensitivity coefficient of the positive 45-degree strain gauge (521) and the negative 45-degree strain gauge (523) of the second strain sensor (520) and the strain-voltage ratio K of the bridge pressure, τ represents shear stress, E is the elastic modulus of the material of the incident rod (200) and the transmission rod (300), ν is the Poisson's ratio of the material of the incident rod (200) and the transmission rod (300), R is the radius of the incident rod (200) and the transmission rod (300), J represents the polar moment of inertia of the cross section of the incident rod (200) and the transmission rod (300), and T represents the friction torque; The impact friction torque T is obtained: According to the circular contact surface friction torque formula: (where μ is the coefficient of kinetic friction, N is the axial normal pressure, and R is the contact surface radius) Get the impact friction coefficient: Substitute the test data into the final impact friction coefficient.

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