Device and method for measuring friction coefficient of fiber composite material

Abstract

The invention discloses a device and a method for measuring the friction coefficient of a fiber composite material. The device comprises a vibration table, a connecting disc, an accelerometer, the fiber composite material, a pulley tension sensor and a load block, a connecting disc is fixedly installed on the vibration table, the center of the connecting disc is connected with one end of a fiber composite, the other end of the fiber composite penetrates through a pulley tension sensor and then is fixedly connected to the center of a load block, and friction force is generated on the pulley tension sensor through movement traction of the vibration table. An accelerometer is fixedly installed on the load block and used for measuring the motion acceleration of the load block and calculating the friction coefficient. The mass of the connecting disc is larger than or equal to that of the load block, so that the vibration table is in a compressed state, and the pre-tightening force of the fiber composite material is adjusted through different weight ratios of the connecting disc and the load block; and the fiber composite material is kept vertical after sequentially passing through the three groups of pulley tension sensors. The friction coefficient measuring precision can be effectively improved, the measuring efficiency is improved, and the measuring application range is widened.

Description

Technical Field

[0001] The invention belongs to the field of material experiment and testing, and in particular relates to a fiber composite friction coefficient measuring device and method. Background Art

[0002] The friction coefficient of fiber is a physical quantity that describes the friction behavior between fiber and another material. The friction coefficient can be divided into static friction coefficient and dynamic friction coefficient. The friction coefficient is affected by factors such as the material, roughness, temperature, humidity, sliding speed and contact pressure of the contact surface, which directly affects the size and properties of fiber friction. At present, the fiber friction coefficient is usually measured by a friction coefficient tester using the capstan method, but there are the following problems: first, the friction coefficient tester uses a torsion balance or force sensor to measure the friction value, and the dynamic response and accuracy of the force measurement are low; second, the friction coefficient tester cannot provide sufficient preload, the force range is small, and the applicable fiber material range is limited; third, the friction coefficient tester mostly uses transmission mechanisms such as gears and screws, which will reduce the accuracy of friction measurement. Summary of the invention

[0003] The purpose of the present invention is to provide a fiber composite friction coefficient measurement device and method, which can effectively improve the friction coefficient measurement accuracy, enhance the measurement efficiency, and increase the applicable scope of the measurement.

[0004] In order to achieve the above-mentioned object, one aspect of the present invention provides a fiber composite friction coefficient measuring device, comprising a vibration table (1), a connection plate (2), an accelerometer (3), a fiber composite (4), a pulley tension sensor (5) and a load block (6);

[0005] A connecting plate (2) is fixedly mounted on the vibration table (1), the center of the connecting plate (2) is connected to one end of a fiber composite material (4), and the other end of the fiber composite material (4) is connected to the center of a load block (6) after being passed through a pulley tension sensor (5), so that the fiber composite material (4) can be pulled by the vibration table (1) to generate friction force on the pulley tension sensor (5);

[0006] An accelerometer (3) is fixedly mounted on the load block (6) and is capable of measuring the motion acceleration of the load block (6) for calculating the friction coefficient;

[0007] The mass of the connection disk (2) is greater than or equal to the mass of the load block (6), so that the vibration table (1) is in a compressed state, and the preload force of the fiber composite material (4) can be adjusted by using different weight ratios of the connection disk (2) and the load block (6);

[0008] There are three groups of pulley tension sensors (5), and the three groups of pulley tension sensors (5) are arranged in an inverted isosceles triangle. The fiber composite material (4) is sequentially passed through the three groups of pulley tension sensors (5) and then kept vertical, so as to increase the friction between the fiber composite material (4) and the pulley.

[0009] Preferably, the pulley tension sensor (5) comprises a pulley and a tension sensor, and the tension sensors of the three groups of pulley tension sensors (5) have the same specifications and the pulley diameters are equal.

[0010] Preferably, the fiber composite material (4) is a flexible non-metallic material, including carbon fiber, glass fiber and synthetic fiber.

[0011] Another aspect of the present invention provides a method for measuring the friction coefficient of a fiber composite material, wherein the friction coefficient of the fiber composite material is measured using the above-mentioned device for measuring the friction coefficient of the fiber composite material, comprising:

[0012] Step S1: reset the pulley tension sensor (5) to zero, connect one end of the fiber composite material (4) to the connection plate (2), pass the other end through three sets of pulley tension sensors (5) in sequence and keep it vertical, and connect the other end to the load block (6);

[0013] Step S2: Start and adjust the vibration frequency of the vibration table (1) to move the fiber composite (4). When the pulley of the pulley tension sensor (5) rotates with the fiber composite (4), the force value data T of the three groups of tension sensors (5) are measured. A 、T B 、T C , the accelerometer (3) measures the acceleration value a;

[0014] Step S3: Turn off the vibration table (1) and calculate the static friction coefficient:

[0015]

[0016] Wherein, θ is the wrap angle of the fiber composite material around the pulley tension sensor, which is π;

[0017] Step S4: lift the load block (6) so that the pulley tension sensor (5) is no longer subjected to force, reset the tension sensor (5) to zero, and put down the load block (6);

[0018] Step S5: Start and increase the vibration frequency of the vibration table (1) to move the fiber composite material (4). When the pulley of the pulley tension sensor (5) does not rotate with the fiber composite material (4), the force value data T of the three groups of tension sensors (5) are measured. A ′、T B ′、T C ′, the accelerometer (3) measures the acceleration value a′;

[0019] Step S6: Turn off the vibration table (1) and calculate the dynamic friction coefficient:

[0020]

[0021] The fiber composite friction coefficient measurement device and method according to the above aspects of the present invention can effectively improve the friction coefficient measurement accuracy, enhance the measurement efficiency, and increase the applicable scope of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0023] Figure 1 It is a schematic structural diagram of a fiber composite friction coefficient measuring device according to an embodiment of the present invention;

[0024] Figure 2 The figure is a flow chart of a method for measuring friction coefficient of a fiber composite material according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] One embodiment of the present invention provides a fiber composite friction coefficient measuring device, such as Figure 1 As shown, the fiber composite friction coefficient measuring device according to the embodiment of the present invention comprises a vibration table 1, a connection plate 2, an accelerometer 3, a fiber composite 4, a pulley tension sensor 5, and a load block 6.

[0027] A connecting plate 2 is fixedly installed on the vibration table 1, and the center of the connecting plate 2 is connected to one end A of the fiber composite material 4. The other end B of the fiber composite material 4 is connected to the center of the load block 6 after being passed through the pulley tension sensor 5. The fiber composite material 4 is pulled by the movement of the vibration table 1 to generate friction force on the pulley tension sensor 5.

[0028] The mass m1 of the connection plate 2 is greater than or equal to the mass m2 of the load block 6 , so that the vibration table 1 is in a compressed state, and the preload force of the fiber composite material 4 is adjusted by different weight ratios of the connection plate 2 and the load block 6 .

[0029] The accelerometer 3 is fixedly mounted on the load block 6, and the accelerometer 3 measures the motion acceleration of the load block 6 for calculating the friction coefficient.

[0030] The pulley tension sensor 5 includes a pulley and a tension sensor. The pulley material can be replaced. By replacing the pulley material, the friction coefficient between different materials and fibers can be calculated. The pulley material can be nylon, metal, rubber, etc.

[0031] The pulley tension sensor 5 has three groups of sensors of the same specification, which are arranged in an inverted isosceles triangle. The fiber composite material 4 passes through the three groups of pulley tension sensors 5 in sequence and ensures verticality to increase the friction between the fiber and the pulley.

[0032] In the fiber composite friction coefficient measuring device of the embodiment of the present invention, when the movement speed of the vibration table 1 causes the fiber composite 4 to drive the pulley of the pulley tension sensor 5 to rotate, the output values ​​of the three groups of pulley tension sensors 5 are T A 、T B 、T C , the load block 6 moves up and down, and the acceleration value a is obtained, and the static friction coefficient μ s Solve and satisfy the following relationship:

[0033]

[0034] Wherein, θ is the wrap angle of the fiber composite material 4 around the pulley tension sensor 5, which is π.

[0035] When the movement speed of the vibration table 1 causes the fiber composite material 4 to slip on the pulley tension sensor 5 and the pulley of the pulley tension sensor 5 does not rotate, the output values ​​of the three groups of pulley tension sensors 5 are T A ′、T B ′、T C ′, the load block 6 moves up and down, and the acceleration value a′ is obtained, and the dynamic friction coefficient μ d Solve and satisfy the following relationship:

[0036]

[0037] The embodiment of the present invention further provides a method for measuring the friction coefficient of a fiber composite material, wherein the friction coefficient of a fiber composite material is measured by using the device for measuring the friction coefficient of a fiber composite material according to the above embodiment. Figure 2 As shown, the method comprises the following steps:

[0038] Step S1: connect all devices, reset the pulley tension sensor 5 to zero, connect one end A of the fiber composite 4 to the connection plate 2, and sequentially string the other end B through three sets of pulley tension sensors 5, and ensure that the fiber composite 4 is vertical after stringing, and connect the B end to the load block 6.

[0039] Step S2: Start and adjust the vibration frequency of the vibration table 1 to make the fiber composite material 4 move. When it can be clearly observed that the pulley of the pulley tension sensor 5 rotates with the fiber composite material 4, the force value data T of the three groups of tension sensors 5 are measured. A 、T B 、T C , the accelerometer 3 measures the acceleration value a.

[0040] Step S3: Turn off the vibration table 1 and calculate the static friction coefficient according to formula (1).

[0041] Step S4: lift the load block 6 so that the pulley tension sensor 5 is no longer under stress, reset the tension sensor 5 to zero, and put down the load block 6.

[0042] Step S5: Start and increase the vibration frequency of the vibration table 1 to move the fiber composite material 4. Observe that the pulley of the pulley tension sensor 5 does not rotate with the fiber composite material 4. Measure and obtain the force value data T of the three groups of tension sensors 5. A ′、T B ′、T C ′, the accelerometer 3 measures the acceleration value a′.

[0043] Step S6: Turn off the vibration table 1 and calculate the dynamic friction coefficient according to formula (2).

[0044] In summary, according to the fiber composite friction coefficient measurement device and method of the embodiment of the present invention, the fiber composite is pulled to move on three sets of pulley tension sensors at fixed positions by a vibration table, and the friction coefficient is calculated by obtaining measurement results such as acceleration and tension. By adjusting the movement speed of the fiber composite, the static friction coefficient and the dynamic friction coefficient can be calculated separately on the same device, and the system error can be reduced by the measurement results of the three sets of tension sensors, thereby effectively improving the measurement accuracy, thereby being able to solve the following problems of the existing friction coefficient measuring instrument and measurement method: (1) A torsion balance or a force sensor is often used to measure the friction force value, and the dynamic response and accuracy of the sensor itself are low, resulting in inaccurate measurement of the friction coefficient; (2) The measurement range of the friction coefficient measuring instrument is small, most of which are in the order of cN, and cannot provide more preload for the fiber. Only a few fiber materials can be used for friction coefficient measurement, and the types of fiber materials are limited; (3) Transmission mechanisms such as gears and screws are often used, and mechanical transmission will affect the measurement of friction force, resulting in a decrease in the accuracy of friction coefficient measurement.

[0045] Therefore, compared with the prior art, the fiber composite friction coefficient measuring device and method according to the embodiment of the present invention have the following advantages:

[0046] (1) The present invention uses three sets of tension sensors to increase the friction of the fiber on the one hand, and improve the redundancy of the measurement data on the other hand. The data reliability is higher than that measured by a traditional single sensor, and the measurement accuracy of the friction coefficient is improved;

[0047] (2) The present invention adopts electromagnetic linear drive and bearing rotation, which effectively reduces the influence of friction force measurement compared with the transmission mechanism such as gears and screws of the existing friction coefficient tester;

[0048] (3) The present invention can effectively calculate the static friction coefficient and the dynamic friction coefficient of the fiber by simply adjusting the fiber movement acceleration, thereby effectively improving the measurement efficiency;

[0049] (4) The present invention adjusts the initial preload force of the fiber by matching load blocks of different masses at both ends of the fiber, effectively expanding the measuring range of the device;

[0050] (5) The pulley on the tension sensor of the present invention is replaceable. By replacing different pulley materials, the applicable range of the measurement of the friction coefficient between the fiber and different materials is effectively increased.

[0051] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fiber composite friction coefficient measuring device, characterized in that: It comprises a vibration table (1), a connection plate (2), an accelerometer (3), a fiber composite material (4), a pulley tension sensor (5) and a load block (6); A connecting plate (2) is fixedly mounted on the vibration table (1), the center of the connecting plate (2) is connected to one end of a fiber composite material (4), and the other end of the fiber composite material (4) is connected to the center of a load block (6) after being passed through a pulley tension sensor (5), so that the fiber composite material (4) can be pulled by the vibration table (1) to generate friction force on the pulley tension sensor (5); An accelerometer (3) is fixedly mounted on the load block (6) and is capable of measuring the motion acceleration of the load block (6) for calculating the friction coefficient; The mass of the connection disk (2) is greater than or equal to the mass of the load block (6), so that the vibration table (1) is in a compressed state, and the preload force of the fiber composite material (4) can be adjusted by using different weight ratios of the connection disk (2) and the load block (6); There are three groups of pulley tension sensors (5), and the three groups of pulley tension sensors (5) are arranged in an inverted isosceles triangle. The fiber composite material (4) is sequentially passed through the three groups of pulley tension sensors (5) and then kept vertical, so as to increase the friction between the fiber composite material (4) and the pulley.

2. The fiber composite friction coefficient measuring device according to claim 1, characterized in that: The pulley tension sensor (5) comprises a pulley and a tension sensor. The tension sensors of the three groups of pulley tension sensors (5) have the same specifications and the pulley diameters are equal.

3. The fiber composite friction coefficient measuring device according to claim 1 or 2, characterized in that: The fiber composite material (4) is a flexible non-metal material, including carbon fiber, glass fiber and synthetic fiber.

4. A method for measuring the friction coefficient of a fiber composite, characterized in that: Measuring the friction coefficient of a fiber composite material using the fiber composite material friction coefficient measuring device according to any one of claims 1 to 3 comprises: Step S1: reset the pulley tension sensor (5) to zero, connect one end of the fiber composite material (4) to the connection plate (2), pass the other end through three sets of pulley tension sensors (5) in sequence and keep it vertical, and connect the other end to the load block (6); Step S2: Start and adjust the vibration frequency of the vibration table (1) to move the fiber composite (4). When the pulley of the pulley tension sensor (5) rotates with the fiber composite (4), the force value data T of the three groups of tension sensors (5) are measured. A 、T B 、T C , the accelerometer (3) measures the acceleration value a; Step S3: Turn off the vibration table (1) and calculate the static friction coefficient: Wherein, θ is the wrap angle of the fiber composite material around the pulley tension sensor, which is π; Step S4: lift the load block (6) so that the pulley tension sensor (5) is no longer subjected to force, reset the tension sensor (5) to zero, and put down the load block (6); Step S5: Start and increase the vibration frequency of the vibration table (1) to move the fiber composite material (4). When the pulley of the pulley tension sensor (5) does not rotate with the fiber composite material (4), the force value data T of the three groups of tension sensors (5) are measured. A ′、T B ′、T C ′, the accelerometer (3) measures the acceleration value a′; Step S6: Turn off the vibration table (1) and calculate the dynamic friction coefficient:

Images