A fiber bundle tension and friction coefficient testing device and method with multiple envelope angles

Abstract

The present invention discloses a fiber bundle tension and friction coefficient test device and method with multiple envelope angles, the device comprising a frame module, a traction system, a horizontal motion system and a test unit. The present invention takes the analysis of the envelope angle between the fiber bundle and the guide roller in the automated weaving preparation process of the fiber preform as the entry point, and can model the change of the fiber bundle friction coefficient during the preparation process in multiple directions. The present invention accurately changes the spatial position between the traction action point P, the center point A of the guide roller I, and the center point B of the guide roller II through formula calculation to achieve different envelope angle combinations, making the operation simpler. The arithmetic difference of the hole spacing of each group of adjacent mounting holes on the first mounting plate of the present invention can realize the rapid adjustment of different envelope angle combinations, and reduce the calculation amount of the spatial position of the guide roller I and the guide roller II as much as possible when arranging different envelope angle combination tests. The present invention can realize multiple forms of movement of the fiber bundle on the guide roller I.

Description

Technical Field

[0001] The invention relates to the technical field of high-performance fiber material woven preform detection, and in particular to a fiber bundle tension and friction coefficient testing device and method with multiple enveloping angles. Background Art

[0002] In the preparation of high-performance fiber composites, continuous filament high-performance fiber bundles are usually used to weave the fiber preform to ensure the strength and performance of the fiber reinforcement phase. High-performance fiber bundles have the advantages of high modulus and high strength, while also having brittle properties, such as ceramic fibers, silicon nitride fibers, and a few high-strength glass fibers. In the automated weaving preparation of fiber preforms, high-performance fiber bundles are prone to weaving defects such as fiber breakage or even yarn breakage under the combined effects of multiple coupled mechanical factors such as bending, friction, and stretching. This weaving defect will not only cause severe fuzzing on the appearance of the preform, reduce molding quality, and damage the mechanical properties of high-performance fiber composites, but will also cause the weaving machine to stagnate, affecting the preparation efficiency. Therefore, how to suppress the weaving defects of fiber bundles and improve the molding quality of preforms in the automated weaving preparation of fiber preforms has become a bottleneck problem in the preparation of high-performance fiber-reinforced composites.

[0003] In the existing literature and patent searches, no device or method has been found to simulate the line contact friction between the fiber bundle and the guide roller during the weaving process. There is also a lack of corresponding research on the effect of the change of multiple envelope angles on the friction coefficient of the fiber bundle during the multi-guide roller winding friction process. The fiber bundle friction coefficient multi-mode test device and method (CN 109490190 A) proposed by Zhejiang University of Technology built a friction simulation test bench to simulate the multi-mode friction of fiber bundles during weaving. Since this test bench can only study the friction under point contact between different or the same fiber bundles, it has certain limitations; the fiber bundle friction coefficient test device and method (CN 104849208 B) proposed by Shanghai Xinxian Instrument Co., Ltd. and Donghua University studied the friction between the fiber bundle and the guide roller under different tensions from the perspective of tension. In essence, it is an exploration of the friction and wear performance of the fiber bundle caused by tension. It lacks the exploration of the line contact friction state between the fiber bundle and the guide roller, which has certain limitations; the carbon fiber high-speed machine online unwinding yarn rack unwinding tension test system and method (CN 108483129 A) proposed by Changzhou Xinchuang Intelligent Technology Co., Ltd. starts from the fiber bundle winding and unwinding process, and judges whether the fiber bundle meets the actual use requirements by real-time monitoring of the tension changes during the winding and unwinding process, but does not consider the measurement of the fiber bundle friction coefficient during the winding and unwinding process.

[0004] In summary, a device and method for conducting friction simulation tests on the friction between the fiber bundle and the multi-guide rollers during the automated weaving preparation process of the fiber preform has not yet been proposed, which seriously restricts the development of the preparation process of high-performance fiber-reinforced composite materials. Summary of the invention

[0005] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a device and method for testing the tension and friction coefficient of a fiber bundle with multiple envelope angles.

[0006] The technical ideas of the present invention are as follows:

[0007] In the automated weaving preparation process of fiber preforms, the contact friction mechanics model of the fiber bundle is different from the classical friction mechanics model, and the friction coefficient of the fiber bundle will change due to different actual working conditions. When the fiber bundle contacts the guide roller and generates friction, the factors that have a greater impact on the friction coefficient are the envelope angle, fiber bundle tension and traction speed. Among them, the envelope angle is the largest influencing factor.

[0008] From a macroscopic perspective, the fiber bundle is in line contact with the guide roller under the traction of the traction device, and the friction force of the line contact is related to the length of the line contact, and the length of the line contact is the arc length corresponding to the envelope angle between the fiber bundle and the guide roller; from a microscopic perspective, the tension of the fiber bundle affects the stretching state of the fiber filaments inside the fiber bundle, and thus affects the actual contact area between the fiber bundle and the guide roller; the friction generated during the contact between the moving fiber bundle and the guide roller is also related to the relative movement speed of the fiber bundle. Therefore, it is particularly important to explore the influence of the envelope angle on the friction coefficient. The present invention takes two guide rollers as the research object and proposes a fiber bundle tension and friction coefficient testing device and method with multiple envelope angles.

[0009] The relationship between the envelope angle between the fiber bundle and the two guide rollers and the friction coefficient can be expressed by the following formula. The influence of different installation positions of guide rollers I and II on the friction coefficient is as follows:

[0010] like Figure 6-8 As shown, the centers of the two guide rollers are A(x A ,y A )、B(x B ,y B ), the radii are r A 、r B The point of action of the traction force is P(x P ,x P ), the connection point of the fiber bundle with the guide roller I is C, the connection point is D, the connection point with the guide roller II is E, the connection point is F, and points A1 and A2 are the horizontally movable positions of the center point A of the guide roller I.

[0011] Assuming the equation of the tangent segment DE is y=kx+b, we can get:

[0012]

[0013] Among them, each factor is expressed as follows:

[0014]

[0015] The envelope angle between the fiber bundle and the guide roller I is θ1, and the envelope angle between the fiber bundle and the guide roller II is θ2. Among them, θ1 consists of two parts, namely the angle θ0 between the connection point D and the horizontal direction, and the angle Δθ between the connection point C and the horizontal direction, and θ0 is equal to θ2.

[0016] θ1=θ0+Δθ (3)

[0017] According to the relationship between the envelope angle θ2 of the fiber bundle and the guide roller II and the slope k, it can be obtained:

[0018]

[0019] From formula (4), we know that the relative position of point A and point B affects the size of θ0 and θ2. Therefore, by controlling the relative position of point A and point B, we can achieve precise control of the size of θ0 and θ2. As for the mathematical expression of Δθ, we can set the angle between PA and the horizontal direction as α, and get the slope of the PA segment line:

[0020]

[0021] Let the angle between the PA and AC segments be β, then:

[0022] Δθ=π-(α+β) (6)

[0023]

[0024] Therefore, the envelope angles θ1 and θ2 between the fiber bundle and the guide rollers Ⅰ and Ⅱ are:

[0025]

[0026] For θ1, there is a critical state so that θ1 = θ2, and the condition to be satisfied is Δθ = 0, that is, α + β = π, which is:

[0027]

[0028] It can be seen from formula (8) that the relative position of point A, point P and point B affects the size of the envelope angle θ1. Therefore, the size of the envelope angle θ1 of the guide roller I can be precisely controlled by controlling the position of point A relative to point P and point B.

[0029] Assume that the tension of the fiber bundle in the PC section (between the traction force point P and the guide roller I access point C) is T1, the tension of the fiber bundle in the DE section (between the guide roller I access point D and the guide roller II access point E) is T2, the tension from point F (guide roller II access point) to the weight section is T3, and the friction coefficients between the fiber bundle and the two guide rollers are μ1 and μ2 respectively. Then the following Euler equation can be established:

[0030]

[0031] Eliminating T2, we get:

[0032]

[0033] Simplified to:

[0034] μ1θ1+μ2θ2=ln(T3 / T1) (12)

[0035] Substituting the expressions of the envelope angles θ1 and θ2 about the positions of points P, A, and B into the Euler equation describing the tension of the fiber bundle and its friction coefficient, that is, formula (8) into formula (12), the following formula can be obtained:

[0036]

[0037] From formula (13), we can directly obtain the expression of the friction coefficient μ(μ1,μ2) of the entire system by substituting the spatial positions of points P, A, and B and the magnitude of the tension at both ends of the fiber bundle.

[0038] In order to achieve the above purpose, the technical solution proposed by the present invention according to the above technical ideas is as follows:

[0039] A fiber bundle tension and friction coefficient testing device with multiple envelope angles, comprising a frame module, a traction system, a horizontal motion system and a testing unit;

[0040] The rack module includes a rack, a first mounting plate and a guide roller II; the rack includes a column and a platform, the column is fixedly mounted on one side of the platform; the guide roller II is fixed on the first mounting plate; the first mounting plate is mounted on the platform of the rack; the first mounting plate is a non-equidistant array plane multi-hole plate, and the hole spacing of each group of adjacent holes is:

[0041]

[0042] Among them, S n is the distance between the n+1th point and the nth point; is the horizontal coordinate of the n+1th point, is the horizontal coordinate of the nth point, is the ordinate of the n+1th point, is the ordinate of the nth point; the value range of n is a natural number, and the order from small to large is the order from the upper left to the lower right.

[0043] The traction system includes a servo motor, a first slide module, a second mounting plate and an eye bolt; the first slide module is mounted on a column of a frame; the servo motor is mounted on the first slide module, and the rotating shaft of the servo motor is connected to the lead screw of the first slide module; the slider on the first slide module is connected to the second mounting plate, the second mounting plate is connected to the eye bolt, and the eye bolt is connected to one end of the force measuring device;

[0044] The horizontal motion system includes a stepper motor, a second slide module, a third mounting plate, an electric push rod and a guide roller I; the second slide module is mounted on the platform of the frame; the stepper motor is mounted on the second slide module, and the rotating shaft of the stepper motor is connected to the lead screw of the second slide module; the slider of the second slide module is connected to the third mounting plate, the third mounting plate is connected to the electric push rod, and the electric push rod is connected to the guide roller I;

[0045] The test unit comprises a force measuring device, a sample fiber bundle and a weight. One end of the sample fiber bundle is connected to the force measuring device, and the other end is connected to the weight after passing around the lower side of the guide roller I and the upper side of the guide roller II.

[0046] Furthermore, the servo motor and the stepper motor are controlled by a PLC system, and the data of the force measuring device are fed back to the computer.

[0047] Furthermore, the entire device also includes a lifting platform, which is used to lift heavy objects during testing.

[0048] A method for testing the tension and friction coefficient of a fiber bundle with multiple envelope angles is provided, and the method comprises the following steps:

[0049] A. Fix the entire device on the table top of the workbench, and make the first mounting plate hang over the edge of the table top;

[0050] B. Preset the combination of envelope angles θ1 and θ2 to determine the radius r of guide roller I A and the radius r of guide roller II B Since the eye point P(x P ,y P ) As the first slide module moves in the vertical direction, the upper and lower limit positions of the stroke are defined as points P0 and P1 respectively, and the point P substituted into the formula is fixed as the midpoint of the stroke P0P1 and defined as the coordinate origin (0,0). In addition, since the center point A (x A ,y A) can only move in the horizontal direction, that is, the ordinate remains unchanged, so the vertical distance between point P and point A is set in advance, that is, y is determined A The center point A(x A ,y A ) and the center point B(x B ,y B )’s exact location:

[0051]

[0052] C. Start the servo motor and the stepper motor in sequence, adjust the vertical height of the second mounting plate so that the eye vertex P of the eye bolt is at the position obtained in step B, adjust the horizontal installation position of the guide roller I to the position obtained in step B, and turn off the servo motor and the stepper motor in sequence;

[0053] D. Adjust the installation position of guide roller II on the first installation plate to the position obtained in step B, and fix it on the first installation plate, and record the positions of the eye vertex P of the eye bolt, the center point A of guide roller I, and the center point B of guide roller II;

[0054] E. Take a new sample fiber bundle for testing, fix one end on the weight, and pass the other end around the lower side of guide roller I and the upper side of guide roller II and then connect it to the weight. At the same time, use a lifting platform to hold the bottom of the weight to offset its gravity and make the sample fiber bundle in a relaxed state.

[0055] F. Start the servo motor and lower the lifting platform so that the sample fiber bundle is straightened under the gravity of the weight; after the slider of the first slide module moves upward for a certain distance, turn off the servo motor, remove the sample fiber bundle, number it and save it, and record the value of the force measuring device;

[0056] G. Change the mass of the weight, that is, change the tension on the sample fiber bundle, and jump to step C until all required tension values ​​are completed;

[0057] H. Change the speed of the servo motor, that is, change the magnitude of the traction speed, and jump to step C until all required traction speed values ​​are completed;

[0058] I. Change the access state of the electric push rod, wherein the access state includes locked and non-rotating, rotating with the movement of the fiber bundle, active rotation with adjustable speed and direction, and forward and backward telescopic rotation, and jump to step C until all required access states of the electric push rod are completed;

[0059] J. Change the combination of envelope angles θ1 and θ2, that is, change the relative positions of the eye vertex P of the eye bolt, the center point A of guide roller I and the center point B of guide roller II, and jump to step C until all required envelope angle combinations are completed.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] 1. The present invention takes the analysis of the envelope angle between the fiber bundle and the guide roller in the automated weaving preparation process of the fiber preform as the starting point, studies the influence of different envelope angle combinations on the weaving tension and friction coefficient of the fiber bundle, and provides a feasible method for optimizing the low-damage automated weaving preparation process of the fiber preform; scientific research is conducted on the optimal envelope angle combination for different tensions, different traction speeds and different access states that the fiber bundle is subjected to during the preparation process, and the change of the friction coefficient of the fiber bundle during the preparation process can be modeled and analyzed from all aspects.

[0062] 2. The present invention accurately changes the spatial position between the traction point P, the center point A of the guide roller I, and the center point B of the guide roller II through formula calculation to achieve different envelope angle combinations. In actual operation, point P can be fixed and regarded as the origin of the coordinate system (0,0), and only the spatial position of points A and B is changed, making the operation easier.

[0063] 3. The hole spacing between each group of adjacent mounting holes on the first mounting plate of the present invention Satisfies θ1(x A ,x B ,y B ),θ2(x A ,x B ,y B ), that is, the installation positions of guide rollers I and II can achieve arithmetic changes that satisfy multiple groups of different difference values ​​of envelope angles θ1 and θ2, and can quickly adjust different envelope angle combinations. When arranging different envelope angle combination tests, the calculation amount of the spatial position of guide rollers I and II can be reduced as much as possible.

[0064] 4. The guide roller I of the present invention can change the access state, that is, locked and not rotating, rotating with the movement of the fiber bundle, actively rotating with adjustable speed and direction, and telescopic rotation. The fiber bundle can move in various forms on the guide roller I, simulating various working conditions of the fiber bundle on the guide roller in the preparation of the fiber preform automated weaving process. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic diagram of the device of the present invention.

[0066] Figure 2 It is a schematic diagram of a rack module of the present invention.

[0067] Figure 3 It is a schematic diagram of the traction system of the present invention.

[0068] Figure 4 It is a schematic diagram of a test unit of the present invention.

[0069] Figure 5 It is a schematic diagram of the horizontal motion system of the present invention.

[0070] Figure 6 It is a schematic diagram of a first mounting plate of the present invention.

[0071] Figure 7 It is one of the principle diagrams of the testing method of the present invention.

[0072] Figure 8 This is the second schematic diagram of the testing method of the present invention.

[0073] In the figure: 1. rack module, 2. traction system, 3. test unit, 4. horizontal motion system, 11. rack, 12. first mounting plate, 13. guide roller II, 21. servo motor, 22. first slide module, 23. second mounting plate, 24. eye bolt, 31. force measuring device, 32. sample fiber bundle, 33. weight, 41. stepper motor, 42. second slide module, 43. third mounting plate, 44. guide roller I, 45. electric push rod. DETAILED DESCRIPTION

[0074] The present invention will be further described below in conjunction with the technical scheme and the accompanying drawings. Figure 1-8 As shown, a fiber bundle tension and friction coefficient testing device with multiple envelope angles includes a rack module 1, a traction system 2, a horizontal motion system 4 and a testing unit 3;

[0075] The rack module 1 includes a rack 11, a first mounting plate 12 and a guide roller II 13; the rack 11 includes a column and a platform, the column is fixedly mounted on one side of the platform; the guide roller II 13 is fixed on the first mounting plate 12; the first mounting plate 12 is mounted on the platform of the rack 11; the first mounting plate 12 is a non-equidistant array plane multi-hole plate, and the hole spacing of each group of adjacent holes is:

[0076]

[0077] Among them, S n is the distance between the n+1th point and the nth point; is the horizontal coordinate of the n+1th point, is the horizontal coordinate of the nth point, is the ordinate of the n+1th point, is the ordinate of the nth point; the value range of n is a natural number, and the order from small to large is the order from the upper left to the lower right.

[0078] The traction system 2 includes a servo motor 21, a first slide module 22, a second mounting plate 23 and an eyebolt 24; the first slide module 22 is mounted on the column of the frame 11; the servo motor 21 is mounted on the first slide module 22, and the rotating shaft of the servo motor 21 is connected to the lead screw of the first slide module 22; the slider on the first slide module 22 is connected to the second mounting plate 23, the second mounting plate 23 is connected to the eyebolt 24, and the eyebolt 24 is connected to one end of the force measuring device 31;

[0079] The horizontal motion system 4 includes a stepper motor 41, a second slide module 42, a third mounting plate 43, an electric push rod 45 and a guide roller I 44; the second slide module 42 is mounted on the platform of the frame 11; the stepper motor 41 is mounted on the second slide module 42, and the rotating shaft of the stepper motor 41 is connected to the lead screw of the second slide module 42; the slider of the second slide module 42 is connected to the third mounting plate 43, the third mounting plate 43 is connected to the electric push rod 45, and the electric push rod 45 is connected to the guide roller I 44;

[0080] The testing unit 3 includes a force measuring device 31, a sample fiber bundle 32 and a weight 33. One end of the sample fiber bundle 32 is connected to the force measuring device 31, and the other end is connected to the weight 33 after passing around the lower side of the guide roller I44 and the upper side of the guide roller II13.

[0081] Furthermore, the servo motor 21 and the stepper motor 41 are controlled by a PLC system, and the data of the force measuring device 31 are fed back to the computer.

[0082] Furthermore, the entire device also includes a lifting platform, which is used to lift the heavy object 33 during testing.

[0083] A method for testing the tension and friction coefficient of a fiber bundle with multiple envelope angles is provided, and the method comprises the following steps:

[0084] A. Fix the entire device on the table of a workbench, and make the first mounting plate 12 overhang the edge of the table;

[0085] B. Preset the combination of envelope angles θ1 and θ2 to determine the radius r of guide roller I44 A and the radius r of the guide roller Ⅱ13 B Since the eye point P (x P ,y P ) As the first slide module 22 moves in the vertical direction, the upper and lower limit positions of the stroke can be defined as points P0 and P1, respectively. The point P substituted into the formula can be fixed as the midpoint of the stroke P0P1 and defined as the coordinate origin (0,0). In addition, since the center point A (x A ,yA ) can only move in the horizontal direction, that is, the ordinate remains unchanged, so the vertical distance between point P and point A can be set in advance, that is, the y A The center point A(x A ,y B ) and the center point B (x B ,y B )’s exact location:

[0086]

[0087] C. Start the servo motor 21 and the stepper motor 41 in sequence, adjust the vertical height of the second mounting plate 23 so that the eye vertex P of the eye bolt 24 is at the position obtained in step B, adjust the horizontal mounting position of the guide roller I 44 to the position obtained in step B, and turn off the servo motor 21 and the stepper motor 41 in sequence;

[0088] D. Adjust the installation position of the guide roller II 13 on the first installation plate 12 to the position obtained in step B, and fix it on the first installation plate 12, and record the positions of the eye vertex P of the eye bolt 24, the center point A of the guide roller I 44, and the center point B of the guide roller II 13;

[0089] E. Take a new test sample fiber bundle 32, fix one end of it on the weight 33, and connect the other end to the weight 33 after passing the lower side of the guide roller I 44 and the upper side of the guide roller II 13. At the same time, use a lifting platform to support the bottom of the weight 33 to offset its gravity and make the sample fiber bundle 32 in a relaxed state;

[0090] F. Start the servo motor 21 and lower the lifting platform so that the sample fiber bundle 32 is straightened under the gravity of the weight 33; after the slider of the first slide module 22 moves upward for a certain distance, turn off the servo motor 21, take out the sample fiber bundle 32, store it by number, and record the value of the force measuring device 31;

[0091] G. Change the mass of the weight 33, that is, change the tension on the sample fiber bundle 32, and jump to step C until all required tension values ​​are achieved;

[0092] H. Change the speed of the servo motor 21, that is, change the magnitude of the traction speed, and jump to step C until all required traction speed values ​​are completed;

[0093] I. Change the access state of the electric push rod 45, wherein the access state includes locked and non-rotating, rotating with the movement of the fiber bundle, active rotation with adjustable speed and direction, and forward and backward telescopic rotation, and jump to step C until all required access states of the electric push rod 45 are completed;

[0094] J. Change the combination of envelope angles θ1 and θ2, that is, change the relative positions of the eye vertex P of the eye bolt 24, the center point A of the guide roller Ⅰ44 and the center point B of the guide roller Ⅱ13, and jump to step C until all required envelope angle combinations are completed.

[0095] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Any modification made according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, equivalent creation, improvement, etc., should be included in the protection scope of this creation.

Claims

1. A fiber bundle tension and friction coefficient testing device with multiple envelope angles, characterized in that: It comprises a rack module (1), a traction system (2), a horizontal motion system (4) and a test unit (3); The frame module (1) comprises a frame (11), a first mounting plate (12) and a guide roller II (13); the frame (11) comprises a column and a platform, the column being fixedly mounted on one side of the platform; the guide roller II (13) is fixed on the first mounting plate (12); the first mounting plate (12) is mounted on the platform of the frame (11); the first mounting plate (12) is a non-equidistant array plane multi-hole plate, and the hole spacing of each group of adjacent holes is: Among them, S n is the distance between the n+1th point and the nth point; is the horizontal coordinate of the n+1th point, is the horizontal coordinate of the nth point, is the ordinate of the n+1th point, is the ordinate of the nth point; the value range of n is a natural number, and the order from small to large is the order of the points from the upper left to the lower right; The traction system (2) comprises a servo motor (21), a first slide module (22), a second mounting plate (23) and a lifting eye bolt (24); the first slide module (22) is mounted on a column of a frame (11); the servo motor (21) is mounted on the first slide module (22), and the rotating shaft of the servo motor (21) is connected to the lead screw of the first slide module (22); the slider on the first slide module (22) is connected to the second mounting plate (23), the second mounting plate (23) is connected to the lifting eye bolt (24), and the lifting eye bolt (24) is connected to one end of a force measuring device (31); The horizontal motion system (4) comprises a stepper motor (41), a second slide module (42), a third mounting plate (43), an electric push rod (45) and a guide roller I (44); the second slide module (42) is mounted on a platform of the frame (11); the stepper motor (41) is mounted on the second slide module (42), and the rotating shaft of the stepper motor (41) is connected to the lead screw of the second slide module (42); the slider of the second slide module (42) is connected to the third mounting plate (43), the third mounting plate (43) is connected to the electric push rod (45), and the electric push rod (45) is connected to the guide roller I (44); The test unit (3) comprises a force measuring device (31), a sample fiber bundle (32) and a weight (33); one end of the sample fiber bundle (32) is connected to the force measuring device (31), and the other end is connected to the weight (33) after passing around the lower side of the guide roller I (44) and the upper side of the guide roller II (13).

2. According to the multi-envelope angle fiber bundle tension and friction coefficient testing device of claim 1, it is characterized by: The servo motor (21) and the stepper motor (41) are controlled by a PLC system, and the data of the force measuring device (31) are fed back to the computer.

3. According to the multi-envelope angle fiber bundle tension and friction coefficient testing device of claim 1, it is characterized by: The entire device also includes a lifting platform, which is used to lift heavy objects (33) during testing.

4. A method for testing the tension and friction coefficient of a fiber bundle with multiple enveloping angles, using a device for testing the tension and friction coefficient of a fiber bundle with multiple enveloping angles as described in claim 1, comprising the following steps: A. Fix the entire device on the table top of a workbench, and make the first mounting plate (12) overhang the edge of the table top; B. Preset the combination of envelope angles θ1 and θ2 to determine the radius r of guide roller I (44) A and the radius r of guide roller II (13) B , since the eye point P(x P ,y P ) As the first slide module (22) moves in the vertical direction, the upper and lower limit positions of the stroke are defined as points P0 and P1 respectively, and the point P substituted into the formula is fixed as the midpoint of the stroke P0P1 and defined as the coordinate origin (0,0). In addition, since the center point A (x A ,y A ) can only move in the horizontal direction, that is, the ordinate remains unchanged, so the vertical distance between point P and point A is set in advance, that is, the y A The center point A(x A ,y A ) and the center point B(x B ,y B )’s exact location: C. Start the servo motor (21) and the stepper motor (41) in sequence, adjust the vertical height of the second mounting plate (23) so that the eye vertex P of the eye bolt (24) is at the position obtained in step B, adjust the horizontal mounting position of the guide roller I (44) to the position obtained in step B, and turn off the servo motor (21) and the stepper motor (41) in sequence; D. Adjust the installation position of the guide roller II (13) on the first installation plate (12) to the position obtained in step B, and fix it on the first installation plate (12), and record the positions of the eye vertex P of the eye bolt (24), the center point A of the guide roller I (44), and the center point B of the guide roller II (13); E. Take a new test sample fiber bundle (32), fix one end of it on the weight (33), and pass the other end around the lower side of the guide roller I (44) and the upper side of the guide roller II (13) and then connect it to the weight (33). At the same time, use a lifting platform to support the bottom of the weight (33) to offset its gravity, so that the sample fiber bundle (32) is in a relaxed state; F. Start the servo motor (21) and lower the lifting platform so that the sample fiber bundle (32) is straightened under the gravity of the weight (33); after the slider of the first slide module (22) moves upward for a certain distance, turn off the servo motor (21), remove the sample fiber bundle (32), number it and save it, and record the value of the force measuring device (31); G. Changing the mass of the weight (33), that is, changing the tension on the sample fiber bundle (32), and jumping to step C until all required tension values ​​are achieved; H. Change the speed of the servo motor (21), that is, change the magnitude of the traction speed, and jump to step C until all required traction speed values ​​are completed; I. Change the access state of the electric push rod (45), wherein the access state includes locked and non-rotating, rotating with the movement of the fiber bundle, active rotation with adjustable speed and direction, and forward and backward telescopic rotation, and jump to step C until all required access states of the electric push rod (45) are completed; J. Change the combination of envelope angles θ1 and θ2, that is, change the relative positions of the eye vertex P of the eye bolt (24), the center point A of the guide roller I (44) and the center point B of the guide roller II (13), and jump to step C until all required envelope angle combinations are completed; Substitute the spatial positions of point P, point A, and point B and the magnitude of the tension at both ends of the fiber bundle into the following formula: That is, the expression of the friction coefficient μ(μ1,μ2) of the entire system is obtained.

Images