A landslide dynamic friction coefficient testing device

Abstract

The present application discloses a device for testing the coefficient of kinetic friction of a landslide, comprising an L-shaped bracket for supporting the entire testing device, a slide slidably arranged on the L-shaped bracket to maintain a preset tilt angle and serve as a slideway, the slide being a box structure with an upper opening; a sliding frame in contact with the slide and sliding on the slide; and a first timing trigger and a second timing trigger electrically connected to a main control unit arranged along the length direction of the slide, the main control unit being connected to a rechargeable lithium battery and a display screen for displaying the time taken by the sliding frame from the first timing trigger to the second timing trigger. The present application can flexibly replace different materials for multiple tests according to the test needs, the test operation is convenient, and the measurement data is accurate; at the same time, the set slide and sliding frame can adapt to the measurement of the coefficient of kinetic friction between materials of different materials and properties, with strong compatibility and a wide range of applications.

Description

Technical Field

[0001] The present application relates to the technical field of experimental testing devices, in particular to the technical field of dynamic friction coefficient testing between different materials, and specifically to a landslide dynamic friction coefficient testing device. Background Art

[0002] The coefficient of friction refers to the ratio of the friction between two surfaces to the vertical force acting on one of the surfaces. According to the different motion states between the two surfaces in contact, it is divided into static friction coefficient and dynamic friction coefficient. This application mainly studies the dynamic friction coefficient between different materials.

[0003] The friction coefficient is intuitively manifested as anti-slip performance in daily life. Knowing the accurate dynamic friction coefficient between two materials in advance can effectively predict the two materials during operation or working, including running resistance, anti-slip performance or stability and reliability, so as to improve the qualification rate and avoid the problem of unqualified stability caused by insufficient dynamic friction coefficient. Summary of the invention

[0004] In order to better calculate the dynamic friction coefficient between different materials to achieve the resistance to sliding between designated materials and to judge the material stability in advance, the present application provides a landslide dynamic friction coefficient test device for testing the dynamic friction coefficient between two materials to avoid unnecessary rework and waste caused by insufficient stability due to insufficient dynamic friction coefficient after large-scale application of the material. For example, it is necessary to test in advance whether the friction coefficient of the material used on the surface of the entrance and exit of the underground garage meets the anti-skid requirements of the car. If the insufficient friction coefficient leads to poor stability, safety accidents are likely to occur; for another example, it is very important to measure the friction coefficient of other laying materials on the ground, especially those used in humid areas, in advance for anti-skid safety.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is:

[0006] A device for testing the dynamic friction coefficient of a landslide comprises an L-shaped bracket for supporting the entire testing device, a slide frame slidably arranged on the L-shaped bracket to maintain a preset inclination angle and serve as a slideway, wherein the slide frame is a box structure with an upper opening; a sliding frame contacting the slide frame and sliding on the slide frame; and a first timing trigger and a second timing trigger electrically connected to a main control unit arranged along the length direction of the slide frame, wherein the main control unit is connected to a rechargeable lithium battery and a display screen for displaying the time taken for the sliding frame to move from the first timing trigger to the second timing trigger.

[0007] Test method and principle:

[0008] The coefficient of kinetic friction is a coefficient that affects the kinetic friction force between two sliding objects. Its size is determined by the material itself and has nothing to do with the contact area between the objects. The coefficient of kinetic friction is calculated using the following formula:

[0009]

[0010] Among them, μ is the dynamic friction coefficient, which has no unit; f is the friction force, and N is the normal pressure.

[0011] According to Newton's second law of motion: the magnitude of an object's acceleration is proportional to the force, inversely proportional to the mass of the object, and proportional to the inverse of the mass of the object; the direction of acceleration is the same as the direction of the force. The formula is: F = ma (F is the net force on the object, m is the mass of the object, and a is the acceleration of the object's downward slide)

[0012] Acceleration: The ratio of the change in velocity to the time it takes to occur. It is a physical quantity that describes how fast an object's speed changes. It is usually represented by a and its unit is m·s -2 or m / s 2 Acceleration is a vector quantity, and its direction is the direction of the change (amount) of the object's velocity, which is the same as the direction of the resultant external force.

[0013] Displacement formula for uniformly accelerated motion: (x is displacement, v0 is initial velocity, t is movement time, and a is acceleration).

[0014] Since the displacement x and time t can be measured, the acceleration a can be calculated by the above formula, and the default initial velocity v0 is 0 during the test. Since the mass m of the object can be obtained by weighing, the resultant force F on the object can be known, and the value of the dynamic friction coefficient μ can be known according to F=mgsinθ-μmgcosθ, where θ is the angle between the slide and the horizontal plane. The above-mentioned object in this application is a sliding frame equipped with the material to be tested.

[0015] When conducting the test, first install the two materials to be tested according to the shapes of the sliding frame and the slide respectively. The fixed test materials need to be pre-cut to achieve installation. For the solidifying materials, they can be directly filled into the sliding frame and the slide. The filling process is carried out according to the filling process in actual use to eliminate the numerical errors between the test and the actual use.

[0016] After the above operations are completed, check whether the surface roughness and flatness of the material to be tested filled in the sliding frame meet the requirements, check whether the surface roughness and flatness of the material to be tested filled in the slide meet the requirements, and whether the surface of the material to be tested in the sliding frame and the surface of the material filled in the slide can be in good contact. When everything is ready, start the following tests:

[0017] The inclination of the slide is adjusted so that the slide frame can slide freely on the slide, the opening surface of the slide frame is placed upside down on the slide, and the edge of the slide frame is placed flush with the first timing trigger. The slide frame is naturally released to trigger the first timing trigger so that the main control unit starts timing. The slide frame continues to slide along the slide until it reaches the second timing trigger. The main control unit records the time t of the slide frame from the first timing trigger to the second timing trigger, and the dynamic friction coefficient μ between the two materials to be tested is finally obtained through the above calculation formula.

[0018] In order to better adjust the inclination angle of the slide, preferably, the L-shaped bracket is composed of a fixedly connected vertically arranged column frame and a horizontally arranged slide rail, one end of the slide slides or locks along the column frame through a locking mechanism, and the other end of the slide is provided with a roller, the position of the roller corresponds to the slide rail and is installed in a slide groove provided on the slide rail.

[0019] In order to facilitate fixing the slide at any required inclination angle, preferably, the locking mechanism adopts a symmetrical structure, including two coaxially mounted sleeves fixedly connected to the end faces of the slide, a push rod is installed in either sleeve, and a rubber ball is fixedly connected to one end of the push rod close to the column frame; a locking groove is also fixedly connected between the two sleeves, and a locking block for pushing the push rod to move axially is slidably installed in the lock groove.

[0020] In order to maintain good contact between the rubber ball and the column frame so that the two always maintain friction, which is beneficial to the linear adjustment of the slide and prevents the slide from falling abnormally in the unlocked state, preferably, a first spring is sleeved on the push rod. In order to prevent the locking block from being over-embedded and not easy to loosen, a second spring for resetting the locking block and limiting the over-embedded locking block is also provided between the locking block and the slide.

[0021] For movable solidified materials and loose materials, in order to better securely mount the materials in the carriage, preferably, a plurality of ribs are evenly spaced on the two inner side walls of the carriage along the length direction, and a gap for mounting a partition is reserved between two adjacent ribs. Different numbers of partitions can be set to block the loose materials according to the looseness and fluidity of the materials to be tested.

[0022] In order to better improve the fixing effect of the slide, preferably, a slot for accommodating the rubber ball is provided on the column frame.

[0023] Preferably, the first timing trigger comprises a first probe and a first receiver arranged on both sides of the slide relative to each other, and the second timing trigger comprises a second probe and a second receiver arranged on both sides of the slide relative to each other. The locking block has an inclined surface arranged relative to each other for contacting and abutting against the end surface of the push rod, and the inclination angle of the inclined surface is 10-15°. The L-shaped bracket is also fixedly connected to a table for placing an electronic weighing device.

[0024] Beneficial effects:

[0025] The present application can flexibly replace different materials for multiple tests according to the test needs, the test operation is convenient, and the measurement data is accurate; at the same time, the set slide and sliding frame can adapt to the measurement of the dynamic friction coefficient between materials of different materials and properties, with strong compatibility and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 It is a three-dimensional structural axonometric diagram of the present invention;

[0028] Figure 2 yes Figure 1 Another visual stereoscopic structure diagram of ;

[0029] Figure 3 yes Figure 2 A magnified view of the structure of the middle A area;

[0030] Figure 4 yes Figure 2 Schematic diagram of the structure in which the middle carriage is filled with test materials;

[0031] Figure 5 yes Figure 4 A magnified view of the structure of the middle B region;

[0032] Figure 6 It is the three-dimensional structural assembly drawing of the locking mechanism;

[0033] Figure 7 yes Figure 6 Another visual structure diagram of ;

[0034] Figure 8 It is a schematic diagram of the sliding friction test performed in this application.

[0035] In the figure: 0-sliding frame; 1-L-shaped bracket; 2-slide rail; 3-slide; 4-locking slot; 5-main control unit; 6-table; 7-display screen; 8-first probe; 9-first receiver; 10-second probe; 11-second receiver; 12-roller; 13-partition; 14-rib; 15-gap; 16-slot; 17-sleeve; 18-rubber ball; 19-push rod; 20-first spring; 21-second spring; 22-locking block; 23-inclined surface. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of this application, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the application is usually placed when in use. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, if the terms "first", "second", etc. appear in the description of this application, they are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0040] In addition, if the terms "horizontal" or "vertical" appear in the description of this application, it does not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0041] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Embodiment 1:

[0043] In conjunction with the instruction manual Figure 1-Figure 4 and Figure 8 The device for testing the dynamic friction coefficient of a landslide shown in the figure comprises an L-shaped bracket 1 for supporting the entire testing device, a slide 3 slidably arranged on the L-shaped bracket 1 to maintain a preset inclination angle and serve as a slideway, wherein the slide 3 is a box structure with an upper opening; further comprising a sliding frame 0 in contact with the slide 3 and sliding on the slide 3; and a first timing trigger and a second timing trigger electrically connected to a main control unit 5 arranged along the length direction of the slide 3, wherein the main control unit 5 is connected to a rechargeable lithium battery and a display screen 7 for displaying the time taken for the sliding frame 0 to go from the first timing trigger to the second timing trigger.

[0044] Test method and principle:

[0045] The coefficient of kinetic friction is a coefficient that affects the kinetic friction force between two sliding objects. Its size is determined by the material itself and has nothing to do with the contact area between the objects. The coefficient of kinetic friction is calculated using the following formula:

[0046]

[0047] Among them, μ is the dynamic friction coefficient, which has no unit; f is the friction force, and N is the normal pressure.

[0048] According to Newton's second law of motion: the magnitude of an object's acceleration is proportional to the force, inversely proportional to the mass of the object, and proportional to the inverse of the mass of the object; the direction of acceleration is the same as the direction of the force. The formula is: F = ma (F is the net force on the object, m is the mass of the object, and a is the acceleration of the object's downward slide)

[0049] Acceleration: The ratio of the change in velocity to the time it takes to occur. It is a physical quantity that describes how fast an object's speed changes. It is usually represented by a and its unit is m·s -2 or m / s 2 Acceleration is a vector quantity, and its direction is the direction of the change (amount) of the object's velocity, which is the same as the direction of the resultant external force.

[0050] Displacement formula for uniformly accelerated motion: (x is displacement, v0 is initial velocity, t is movement time, and a is acceleration).

[0051] Since the displacement x and time t can be measured, the acceleration a can be calculated by the above formula, and the default initial velocity v0 is 0 during the test. Since the mass m of the object can be obtained by weighing, the resultant force F on the object can be known, and the value of the dynamic friction coefficient μ can be known according to F=mgsinθ-μmgcosθ, where θ is the angle between the slide 3 and the horizontal plane. The above-mentioned object in this application is a sliding frame 0 containing the material to be tested.

[0052] When conducting the test, first install the two materials to be tested according to the shapes of the sliding frame 0 and the slide 3 respectively. The fixed test materials need to be pre-cut to achieve installation. For the solidifying materials, they can be directly filled into the sliding frame 0 and the slide 3. The filling process is carried out according to the filling process during actual use to eliminate the numerical errors between the test and the actual use.

[0053] After the above operations are completed, check whether the surface roughness and flatness of the material to be tested filled in the sliding frame 0 meet the requirements, check whether the surface roughness and flatness of the material to be tested filled in the sliding frame 3 meet the requirements, and whether the surface of the material to be tested in the sliding frame 0 and the surface of the material filled in the sliding frame 3 can be in good contact. After everything is ready, start the following test:

[0054] Adjust the inclination of the slide 3 so that the sliding frame 0 can slide freely on the slide 3, place the opening surface of the sliding frame 0 upside down on the slide 3, and place the edge of the sliding frame 0 flush with the first timing trigger, naturally release the sliding frame 0 to trigger the first timing trigger so that the main control unit 5 starts timing, and the sliding frame 0 continues to slide along the slide 3 until it reaches the second timing trigger. The main control unit 5 records the time t of the sliding frame 0 from the first timing trigger to the second timing trigger, and finally obtains the dynamic friction coefficient μ between the two materials to be tested through the above calculation formula. The main control unit 5 described in this embodiment is implemented by a low-voltage timing chip of model DS1672. Of course, the timing chip and timing circuit are one of the most common units in the prior art, and can have a wide range of choices. But the most important thing is to consider cost and compatibility factors. For example, a more fully functional STC89C52 chip is used in conjunction with an infrared timing trigger to achieve accurate timing. This principle part is a mature prior art, and this embodiment only integrates the mature principle into a device to facilitate accurate timing of the sliding frame 0.

[0055] Embodiment 2:

[0056] On the basis of Example 1, in order to further improve the convenience of operation and the test compatibility for different test materials, further combined with the appendix of the specification Figure 1-Figure 8 As shown, the following structure is optimized as follows:

[0057] The L-shaped bracket 1 is composed of a fixedly connected vertically arranged column frame and a horizontally arranged slide rail 2. One end of the slide 3 slides or locks along the column frame through a locking mechanism. The other end of the slide 3 is provided with a roller 12. The position of the roller 12 corresponds to the slide rail 2 and is installed in a slide groove provided on the slide rail 2.

[0058] In order to facilitate fixing the slide 3 at any desired tilt angle, in this embodiment, the locking mechanism adopts a symmetrical structure, including two coaxially mounted sleeves 17 fixedly connected to the end surface of the slide 3, a push rod 19 is installed in any sleeve 17, and a rubber ball 18 is fixedly connected to one end of the push rod 19 close to the column frame; a locking groove 4 is also fixedly connected between the two sleeves 17, and a locking block 22 for pushing the push rod 19 to move axially is slidably installed in the locking groove 4. Figure 6 As shown, when the locking block 22 is pulled out, the push rods 19 on both sides are in a free state, and the rubber ball 18 can slide freely in the column frame of the L-shaped bracket 1 under the action of external force. When the inclination angle of the slide 3 is in a preset state, the locking block 22 is pressed into the lock groove 4, so that the locking block 22 applies axial thrust to the push rods 19 on both sides, and the rubber ball 18 is squeezed with the column frame, thereby maintaining the state of the slide 3 through the increased static friction. In the above manner, the slide 3 can be fixed at any position within the limit of the sliding range of the column frame, and any angle adjustment within the adjustable range can be achieved.

[0059] In order to maintain good contact between the rubber ball 18 and the column frame so that the two always maintain friction, which is beneficial to the linear adjustment of the slide 3 and prevents the slide 3 from falling abnormally in the unlocked state, preferably, a first spring 20 is sleeved on the push rod 19. In order to prevent the locking block 22 from being embedded in a transitional manner and making it difficult to loosen, a second spring 21 is also provided between the locking block 22 and the slide 3 for resetting the locking block 22 and limiting the locking block 22 from being embedded in a transitional manner.

[0060] For movable solidified materials and loose materials, in order to better securely install the materials in the slide 3, multiple ribs 14 are evenly spaced on the two inner side walls of the slide 3 along the length direction, and a gap 15 for installing the partition 13 is reserved between two adjacent ribs 14. The loose material can be blocked by setting different numbers of partitions 13 according to the looseness and fluidity of the material to be tested. For example, when it is necessary to measure the internal friction coefficient of soil or a mixture of soil and gravel, in order to ensure that the relative friction object acting as a stationary part in the slide 3 needs to maintain the relative fixity of the soil, multiple partitions 13 arranged horizontally in the slide 3 can be used to form an effective internal barrier for the soil to maintain the relative fixity of the loose materials including the soil. The purpose of this arrangement is to effectively measure the friction coefficient of slippage or displacement between objects of uncertain shapes. This point cannot be experimentally measured in the prior art, and its function is mainly used for the prediction of geological landslides. Knowing the dynamic friction coefficient inside the soil can effectively calculate the landslide risk. If a landslide occurs, the sliding distance and affected range can be predicted in advance, prevented in advance, and evacuated in advance to ensure the safety of life and property as much as possible.

[0061] In order to better improve the fixing effect of the slide 3 , preferably, a slot 16 for accommodating the rubber ball 18 is provided on the column frame.

[0062] In the embodiment of the present invention, the first timing trigger comprises a first probe 8 and a first receiver 9 arranged on both sides of the slide 3, and the second timing trigger comprises a second probe 10 and a second receiver 11 arranged on both sides of the slide 3. The locking block 22 has an inclined surface 23 arranged relatively to contact and abut against the end face of the push rod 19, and the inclination angle of the inclined surface 23 is 10-15°. If the inclination angle of the inclined surface 23 is too small, it has a better fixed locking effect, but its disadvantage is that it will significantly increase the travel distance of the locking block 22. If the angle of the inclined surface 23 is too large, although the travel distance of the locking block 22 can be shortened, the stability is reduced due to the large inclination angle, and the locking block 22 is prone to natural loosening. In order to solve this problem and further increase the stability of the locking block 22, in the present embodiment, a soft material that increases friction is bonded to the contact surface of the locking block 22 or the lock groove 4 to prevent the locking block 22 from naturally coming out and loosening in the locked state. The L-shaped bracket 2 is also fixedly connected to a table 6 for placing an electronic weighing device. In order to facilitate multiple tests to calculate the precise average value of the friction coefficient as accurately as possible, it is necessary to repeatedly change the sliding object, that is, the mass of the sliding frame 0, and to weigh it repeatedly, which can be achieved by quickly weighing it using an electronic weighing device placed on the table 6.

[0063] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A landslide dynamic friction coefficient testing device, characterized in that: It comprises an L-shaped bracket (1) for supporting the entire test device, and a slide frame (3) slidably arranged on the L-shaped bracket (1) to maintain a preset tilt angle and serve as a slideway, wherein the slide frame (3) is a box structure with an upper opening; It also includes a sliding frame (0) in contact with the sliding frame (3) and sliding on the sliding frame (3); and a first timing trigger and a second timing trigger arranged along the length direction of the sliding frame (3) and electrically connected to a main control unit (5), wherein the main control unit (5) is connected to a rechargeable lithium battery and a display screen (7) for displaying the time taken for the sliding frame (0) to move from the first timing trigger to the second timing trigger; The L-shaped bracket (1) is composed of a vertically arranged column frame and a horizontally arranged slide rail (2) which are fixedly connected. One end of the slide frame (3) slides or is locked along the column frame through a locking mechanism. The other end of the slide frame (3) is provided with a roller (12). The position of the roller (12) corresponds to the slide rail (2) and is installed in a slide groove provided on the slide rail (2). The L-shaped bracket (1) is also fixedly connected to a table top (6) for placing an electronic weighing device.

2. A landslide dynamic friction coefficient testing device according to claim 1, characterized in that: The locking mechanism adopts a symmetrical structure, comprising two coaxially mounted sleeves (17) fixedly connected to the end surface of the slide (3), a push rod (19) being installed in any sleeve (17), and a rubber ball (18) being fixedly connected to one end of the push rod (19) close to the column frame; a locking groove (4) is also fixedly connected between the two sleeves (17), and a locking block (22) for pushing the push rod (19) to move axially is slidably installed in the locking groove (4).

3. A landslide dynamic friction coefficient testing device according to claim 2, characterized in that: The push rod (19) is sleeved with a first spring (20).

4. A landslide dynamic friction coefficient testing device according to any one of claims 1 to 3, characterized in that: A plurality of ribs (14) are evenly spaced on two inner side walls of the slide (3) along the length direction, and a gap (15) for installing a partition (13) is reserved between two adjacent ribs (14).

5. A landslide dynamic friction coefficient testing device according to claim 2, characterized in that: The column frame is provided with a slot (16) for accommodating the rubber ball (18).

6. A landslide dynamic friction coefficient testing device according to claim 1, characterized in that: The first timing trigger comprises a first probe (8) and a first receiver (9) arranged on two sides of the slide (3) in a relative manner, and the second timing trigger comprises a second probe (10) and a second receiver (11) arranged on two sides of the slide (3) in a relative manner.

7. A landslide dynamic friction coefficient testing device according to claim 2, characterized in that: The locking block (22) has an inclined surface (23) arranged opposite to the end surface of the push rod (19) and used for contacting and abutting against the end surface of the push rod (19); the inclined surface (23) has an inclination angle of 10-15°.

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