A kind of friction performance testing device suitable for hemp fiber bundle

Abstract

The application relates to the technical field of textile material testing, and discloses a friction performance testing device suitable for hemp fiber bundles, which comprises a base, a clamping and adjusting mechanism, an air bag testing mechanism, a transverse driving mechanism, a humidity adjusting mechanism and a humidity control mechanism. The application can realize comprehensive testing of the friction performance of hemp fiber bundles under different temperature and humidity conditions through modular design, significantly improves the testing precision and environment simulation capability, and is convenient to assemble, maintain and upgrade, thereby providing reliable data support for the research and application of hemp fibers.

Description

Technical Field

[0001] The invention relates to the technical field of textile material testing, in particular to a friction performance testing device suitable for hemp fiber bundles. Background Art

[0002] Hemp fiber, as an important natural fiber material, has attracted increasing attention in fields such as textiles and composite materials due to its excellent mechanical properties, environmental friendliness, and broad application prospects. However, the friction properties of hemp fiber bundles during processing and use directly affect the fiber's spinnability, wear resistance, and the quality of the final product. Therefore, precise testing and analysis of the friction properties of hemp fiber bundles is of great significance.

[0003] Existing friction performance testing devices typically use rigid contact surfaces or simple flexible contact methods for testing. These methods are unable to fully simulate the complex stress states and environmental conditions of hemp fiber bundles in actual use, resulting in significant deviations between test results and actual conditions. Furthermore, existing technologies lack the ability to precisely control key environmental factors such as temperature and humidity, which significantly affect the friction performance of hemp fiber bundles. In particular, under different temperature and humidity conditions, the surface properties and internal structure of hemp fiber may change, affecting its friction behavior.

[0004] Therefore, there is an urgent need for a hemp fiber bundle friction performance testing device that can simulate a variety of environmental conditions, accurately control test parameters and achieve efficient operation, so as to solve the above technical difficulties and meet practical application needs. Summary of the Invention

[0005] The present invention addresses the shortcomings of existing hemp fiber bundle friction performance testing devices, such as insufficient environmental simulation capabilities, low test accuracy, and limited modularity. By providing a friction performance testing device suitable for hemp fiber bundles, the present invention addresses the shortcomings of existing hemp fiber bundle friction performance testing devices, such as insufficient environmental simulation capabilities, low test accuracy, and limited modularity. Through a modular design, the device incorporates a clamping and adjustment mechanism, an airbag testing mechanism, a traverse drive mechanism, a humidity adjustment mechanism, and a humidity control mechanism, enabling comprehensive testing of the friction performance of hemp fiber bundles under different temperature and humidity conditions.

[0006] The present invention provides a friction performance testing device suitable for hemp fiber bundles, comprising a base, a clamping adjustment mechanism, an airbag testing mechanism, a traverse drive mechanism, a humidity adjustment mechanism, and a humidity control mechanism. Among them:

[0007] The base serves as the basic structure of the entire device. The middle of its top is a concave design with a slope. The right side is sealed by a baffle, and the left side is open to ensure that the liquid generated during the test can be discharged smoothly.

[0008] Furthermore, the clamping and adjusting mechanism is arranged on the left and right sides of the base, and is used to clamp the hemp fiber bundle and adjust its tension. The clamping and adjusting mechanism includes two clamping frames, which are fixed to the left and right sides of the base respectively. A compression strip is slidably arranged inside each clamping frame, and the lower surface of the compression strip is made of soft material to avoid damaging the hemp fiber bundle. A screw rod passes through and is threadedly connected to the top center of the clamping frame. The end of the screw rod rotates relative to the compression strip through a bearing, and a rotating wheel is fixed to the top of the screw rod. Rotating the rotating wheel can drive the screw rod to rotate, thereby adjusting the position of the compression strip to achieve clamping and tension adjustment of the hemp fiber bundle. A pillar is fixed to the bottom of the clamping frame, the end of the left pillar is fixedly connected to the base, and the end of the right pillar is lateral moved and adjusted by a first guide rail and a first slide to accommodate hemp fiber bundles of different lengths. A self-locking hook is fixed near the top of one side of the pillar for hanging the two ends of the hemp fiber bundle.

[0009] In particular, the airbag testing mechanism is arranged on the top of the base, and is used to be sheathed and inflated to contact the hemp fiber bundle for friction performance testing. The airbag testing mechanism includes an annular outer frame, and the inner ring surface of the annular outer frame is detachably connected to an annular airbag. The inner ring surface of the annular airbag is provided with a friction coating, which is used to contact the hemp fiber bundle and generate friction. A micro-cooling pipe is embedded in the annular airbag. The micro-cooling pipe has a depth of 0.5mm to 1mm and a width of 1mm to 2mm. It is made of flexible material and has a layout of a double helix loop or a single helix loop. A refrigerant input pipe is fixed at one end of the micro-cooling pipe, and a heat medium output pipe is fixed at the other end. The refrigerant input pipe and the heat medium output pipe extend to the outside of the annular airbag and are sealed by a sealing structure. The refrigerant input pipe and the heat medium output pipe are respectively connected to the external refrigerant and heat medium supply systems. The temperature of the friction coating is adjusted by inputting media of different temperatures to simulate different test conditions. An inflation interface is passed through and installed at the top of the right side of the annular airbag, and an exhaust valve port is passed through and installed at the bottom, which are used to realize the inflation and exhaust operations of the annular airbag.

[0010] Furthermore, the transverse driving mechanism is arranged below the airbag testing mechanism, and is used to drive the airbag testing mechanism to repeatedly transversely move in the horizontal direction to simulate dynamic friction test conditions. The transverse driving mechanism includes a second guide rail and an auxiliary slide frame, the second guide rail is fixed at the front end of the top of the base, and the auxiliary slide frame is fixed at the rear end of the top of the base. A second slide is slidably connected above the second guide rail, and an auxiliary slider is slidably connected inside the auxiliary slide frame. A U-shaped frame is fixed on the top of the second slide and the auxiliary slider, and connecting inclined plates are fixed on the front and rear sides of the top of the U-shaped frame, and the top of the connecting inclined plates is fixed to the annular outer frame. The transverse driving mechanism drives the second slide and the auxiliary slider to slide along the second guide rail and the auxiliary slide frame, thereby driving the annular outer frame and the annular airbag inside it to repeatedly transversely move in the horizontal direction.

[0011] Specifically, the humidity control mechanism is positioned on the left and right sides of the airbag testing mechanism to simulate the testing environment of hemp fiber bundles under different humidity conditions. The humidity control mechanism comprises two extended annular frames, one on the left and one on the right of the annular outer frame. Each extended annular frame has an annular duct fixed to its inner surface. At least six atomizing nozzles are evenly distributed within the inner surface of the annular duct. The nozzles' tips face the inner surface of the annular airbag, spraying water mist to simulate humidity. The extended annular frames are connected to the annular outer frame via three connecting bars, ensuring their stable position and facilitating disassembly and maintenance.

[0012] Furthermore, the humidity control mechanism is positioned below the transverse drive mechanism and is used to continuously supply water to the humidity adjustment mechanism. The humidity control mechanism includes a water tank and a pump body. The water tank is fixed to the bottom of the U-shaped frame. A refill nozzle is fixed and penetrates one side of the water tank for replenishing liquid. The pump body is fixed to the center of the top of the U-shaped frame. The pump inlet end is connected to the water tank via an inlet pipe. The outlet end is fixed to a tee. The two ends of the tee are connected to the two annular pipes via outlet pipes, respectively. This ensures that the outlet pipe continuously supplies water to the annular pipes, ensuring the normal operation of the atomizing nozzle.

[0013] The present invention also provides a method for preparing a friction coating of a friction performance testing device based on hemp fiber bundles, comprising the following steps:

[0014] Step 1: Substrate pretreatment: The inner surface of the annular airbag is cleaned and activated, and surface organic impurities are removed by plasma bombardment technology. A uniform micro-groove structure is formed on the inner surface by mechanical micro-etching process. The groove depth ranges from 5 to 20 μm and the width ranges from 10 to 50 μm to improve the bonding strength between the subsequent coating and the substrate.

[0015] Step 2: Preparation of coating materials: polyurethane resin is used as the base material, and 5%-15% by mass of nano-alumina particles and 0.5%-2% by mass of silane coupling agent are added. Mix them evenly using high-speed stirring equipment at a stirring speed of 1000-3000 rpm for 10-30 minutes to ensure that the coating material has good fluidity and dispersibility.

[0016] Step 3: Coating: Spin coating is used to evenly coat the prepared coating material on the inner surface of the annular airbag. The spin coating speed is controlled at 500-1500 rpm, the spin coating time is 30-60 seconds, and the coating thickness is controlled at 20-50 μm to ensure the uniformity and consistency of the coating.

[0017] Step four: coating curing, first natural drying at room temperature for 10-30 minutes, then preliminary curing at 60-80℃ for 30-60 minutes, and finally complete curing at 100-120℃ for 1-2 hours, so that the coating material is fully cross-linked and forms a stable structure.

[0018] Step five: surface modification, using laser engraving technology to process a regular array of micropores on the surface of the coating, with a micropore diameter range of 50-200μm, a pore spacing of 100-300μm, and a micropore depth of 10-50μm, to increase the friction coefficient and anti-slippage performance of the coating surface.

[0019] Step six: performance testing, testing the adhesion, hardness, and wear resistance of the completed friction coating, recording the test data and analyzing whether the coating performance meets the design requirements.

[0020] Preferably, the annular airbag substrate in step one is selected from thermoplastic polyurethane elastomers, with a tensile strength of not less than 40MPa and an elongation at break of not less than 300%, to improve the mechanical properties and durability of the substrate.

[0021] Further, in step two, the hardness and wear resistance of the coating are improved by adjusting the addition amount and particle size distribution range of the nano-aluminum oxide particles; when the average particle size of the nano-aluminum oxide particles is D, and D<100nm, the addition amount is set as M1; when D>200nm, the addition amount is set as M2, where M represents the mass fraction of nano-aluminum oxide particles, and D represents the average particle size of nano-aluminum oxide particles.

[0022] Further, in step three, the spin coating process further includes: optimizing the spin coating speed and time according to the curvature radius of the inner ring surface of the annular airbag and the viscosity characteristics of the coating material; if the curvature radius is R, and R<Rmin, the spin coating speed is appropriately reduced; when R>Rmax, the spin coating time is increased, where Rmin and Rmax represent the set minimum and maximum curvature radius limits.

[0023] Further, in step four, the selection of curing temperature and time further includes: measuring the environmental humidity and the initial water content of the coating material, and recording the corresponding data; analyzing the influence of humidity and water content on the curing effect; adjusting the curing temperature and time based on the measurement data; if the humidity is H, and H>Hmax, the curing time is extended; when H<Hmin, the curing temperature is increased, where H represents the environmental humidity, and Hmin and Hmax represent the set minimum and maximum humidity thresholds, respectively.

[0024] Furthermore, in step five, the laser engraving process further includes: selecting lasers of different powers and frequencies for testing; examining the effects of laser power and frequency on the shape and size of micropores; selecting optimal laser parameters based on the test results; if the laser power is P, the frequency is F, and the goal is to maximize micropore uniformity, then when P*F≥Kmin, ensuring that the process parameters are within the valid range, otherwise the laser power and frequency should be appropriately adjusted.

[0025] Furthermore, in step six, the performance test further includes: using the cross-hatch method to test the adhesion of the coating and record the ratio of the coating peeling area; using a Shore hardness tester to test the hardness of the coating and record the hardness value; using an abrasion tester to test the wear resistance of the coating and record the wear per unit area; if the peeling area ratio is A, the hardness value is B, the wear amount is C, and A>Amax or B<Bmin或C> When Cmax is reached, the coating is judged to be unqualified, where A, B, and C represent the peeling area ratio, hardness value, and wear amount, respectively; Amax, Bmin, and Cmax represent the set maximum peeling area ratio, minimum hardness value, and maximum wear amount limits, respectively.

[0026] The beneficial effects of the present invention are:

[0027] By providing micro cooling pipes and humidity regulating mechanisms, the device can accurately simulate the friction test environment under different temperature and humidity conditions during the test process, significantly improving the accuracy and applicability of the test results.

[0028] The device adopts a modular design, with each functional module independently designed and interoperable, facilitating assembly, maintenance, and upgrades. For example, the clamping adjustment mechanism precisely clamps the hemp fiber bundle by adjusting the position of the compression bar, while the airbag testing mechanism adapts to different test specifications by replacing the annular airbag.

[0029] The micro-cooling channels, made of flexible materials and optimized in layout, maintain a constant temperature of the friction coating during dynamic friction testing while also enabling rapid cooling or heating. Specifically, the refrigerant inlet and heat outlet pipes deliver rapid cooling by feeding low-temperature ethylene glycol-water solutions or compressed liquid CO2, or rapid heating by feeding high-temperature media.

[0030] Both the transverse drive mechanism and the humidity control mechanism utilize automated designs, reducing manual intervention and improving test efficiency and consistency. For example, the transverse drive mechanism drives the second slide and auxiliary slide along the guide rail, driving the annular airbag to repeatedly move horizontally, simulating dynamic friction test conditions. The humidity control mechanism continuously supplies water to the annular pipe via a pump, ensuring the proper operation of the atomizing nozzle, thereby simulating varying humidity environments.

[0031] By performing special pretreatment on the inner surface of the annular airbag, the bonding strength between the coating and the substrate is significantly improved, reducing the risk of coating falling off during testing.

[0032] By optimizing the coating material formula and spin coating process parameters, the uniformity and consistency of the coating are ensured, avoiding the deviation of test results caused by uneven coating.

[0033] By using laser engraving technology to process a micropore array on the coating surface, the friction coefficient and anti-slip performance of the coating are increased, and the applicability and reliability of the test device are improved.

[0034] Through a rigorous performance testing process, friction coatings that meet the design requirements are screened out, providing reliable guarantees for accurate testing of the friction properties of hemp fiber bundles.

[0035] To sum up, the present invention solves the problems of insufficient environmental simulation capability, low testing accuracy and low degree of modularity in the friction performance testing device of hemp fiber bundles in the prior art through the above-mentioned technical scheme, and provides a friction performance testing device suitable for hemp fiber bundles, which has innovative features such as multi-environment simulation function, modular design, efficient temperature control system and high degree of automation. It can be widely used in the field of textile materials and provide reliable data support for the research and development, production and application of hemp fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a three-dimensional structural diagram of the device of the present invention;

[0037] Figure 2 Schematic diagram of the structure of the airbag testing mechanism and the humidity adjustment mechanism in an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of the three-dimensional structure of the clamping adjustment mechanism in an embodiment of the present invention;

[0039] Figure 4 A schematic side view of the structure of the clamping adjustment mechanism in an embodiment of the present invention;

[0040] Figure 5 Schematic diagram of the structure of the annular airbag and the annular outer frame in an embodiment of the present invention;

[0041] Figure 6 Schematic diagram of the side structure of the annular airbag in an embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the cross-sectional structure of the annular airbag along the annular surface in an embodiment of the present invention;

[0043] Figure 8 Schematic diagram of the structure of the airbag testing mechanism, humidity adjustment mechanism and humidity control mechanism in an embodiment of the present invention;

[0044] Figure 9 Figure 1 is an exploded view of the air bag testing mechanism, humidity adjusting mechanism and humidity control mechanism according to an embodiment of the present application;

[0045] Figure 10 Figure 2 is another exploded view of the air bag testing mechanism, humidity adjusting mechanism and humidity control mechanism according to an embodiment of the present application;

[0046] Figure 11 Figure 3 is a flow chart of the friction coating preparation method according to an embodiment of the present application;

[0047] Figure 12 Figure 4 is a flow chart of the pretreatment stage of the annular air bag substrate according to an embodiment of the present application;

[0048] Figure 13 Figure 5 is a flow chart of the coating material preparation stage according to an embodiment of the present application;

[0049] Figure 14 Figure 6 is a flow chart of the coating stage according to an embodiment of the present application;

[0050] Figure 15 Figure 7 is a flow chart of the solidification stage according to an embodiment of the present application;

[0051] Figure 16 Figure 8 is a flow chart of the surface modification stage according to an embodiment of the present application;

[0052] Figure 17 Figure 9 is a flow chart of the performance detection stage according to an embodiment of the present application.

[0053] 1, base; 2, baffle; 3, clamping frame; 31, compression strip; 32, bearing; 33, screw; 34, runner; 35, strut; 36, self-locking hook; 37, first guide rail; 371, first sliding seat; 4, annular air bag; 41, annular outer frame; 42, friction coating; 43, micro cooling pipeline; 44, refrigerant input pipe; 45, heat medium output pipe; 46, inflation interface; 47, exhaust valve port; 5, expanded annular frame; 51, annular pipeline; 52, atomizing nozzle; 53, connecting strip; 6, second guide rail; 61, second sliding seat; 62, auxiliary sliding frame; 63, auxiliary sliding block; 64, U-shaped bracket; 65, connecting inclined plate; 7, water storage tank; 71, liquid supplement pipe; 72, pump body; 73, water inlet pipeline; 74, three-way pipe; 75, water outlet pipeline. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] The present invention provides a friction performance testing device suitable for hemp fiber bundles. The technical solution of the present invention is described in detail with reference to the accompanying drawings and specific embodiments. Figure 1 -Attached Figure 10 and the component numbers marked in the figure, and explain the structure, operating principle and operation process of the device in combination with actual application scenarios.

[0056] The core of this invention lies in its modular design, which enables comprehensive testing of the friction properties of hemp fiber bundles under varying temperature and humidity conditions. The testing device comprises a base 1, a clamping and adjustment mechanism, an airbag testing mechanism, a transverse drive mechanism, a humidity adjustment mechanism, and a humidity control mechanism. These modules work together to ensure the accuracy and applicability of the test results.

[0057] The base 1 serves as the basic structure of the entire device. The middle of its top is a concave design with a slope. The right side is sealed by a baffle 2, and the left side is open. This design ensures that the liquid generated during the test can be discharged smoothly from the base 1. The baffle 2 is fixed to the right side of the base 1 to block the liquid and form a closed space. The left and right sides of the base 1 are respectively provided with a first guide rail 37 and a baffle 2. The first guide rail 37 is slidably connected to the first slide 371, and the first slide 371 is connected to the right side support 35 to realize the lateral movement adjustment of the right side support 35. This design allows the device to adapt to hemp fiber bundles of different lengths and improves the test flexibility.

[0058] The clamping and adjusting mechanism is located on the left and right sides of the base 1 and is used to clamp the hemp fiber bundle and adjust its tension. The clamping and adjusting mechanism includes two clamping frames 3, each of which is slidably provided with a compression strip 31. The lower surface of the compression strip 31 is made of soft material to avoid damage to the hemp fiber bundle. A screw 33 passes through the center of the top of the clamping frame 3 and is threadedly connected. The end of the screw 33 rotates relative to the compression strip 31 through a bearing 32, and a rotating wheel 34 is fixed to the top of the screw 33. Rotating the rotating wheel 34 can drive the screw 33 to rotate, thereby adjusting the position of the compression strip 31 to achieve clamping and tension adjustment of the hemp fiber bundle. A pillar 35 is fixed to the bottom of the clamping frame 3. The end of the left pillar 35 is fixedly connected to the base 1, and the end of the right pillar 35 is lateral movable and adjustable through a first guide rail 37 and a first slide 371. A self-locking hook 36 is fixed near the top of one side of the pillar 35 to hang the two ends of the hemp fiber bundle. By adjusting the position of the right support 35, hemp fiber bundles of different lengths can be adapted, while the self-locking hook 36 ensures that the hemp fiber bundle remains stable during the test.

[0059] The airbag test mechanism is mounted on top of the base 1 and is used to fit over and inflate the hemp fiber bundle to test its friction properties. The airbag test mechanism comprises an annular outer frame 41 and an annular airbag 4. The annular outer frame 41 is fixed to the top of the base 1, with the annular airbag 4 removably attached to its inner surface. The inner surface of the annular airbag 4 is provided with a friction coating 42, which is designed to contact and generate friction with the hemp fiber bundle. Embedded within the annular airbag 4 is a micro-cooling channel 43. These channels are 0.5mm to 1mm deep and 1mm to 2mm wide, made of flexible material, and arranged in a double or single helix configuration. A refrigerant inlet pipe 44 is fixed to one end of the micro-cooling channel 43, and a heat medium outlet pipe 45 is fixed to the other end. These channels extend to the exterior of the annular airbag 4 and are sealed by a sealing structure. The refrigerant inlet pipe 44 and heat medium outlet pipe 45 are connected to the external refrigerant and heat medium supply systems, respectively. The temperature of the friction coating 42 is adjusted by inputting media of varying temperatures to simulate different test conditions. An inflation port 46 is installed on the right side of the annular airbag 4, relatively near the top, and an exhaust valve 47 is installed on the right side of the annular airbag 4, relatively near the bottom, for inflation and exhaust. The design of the annular airbag 4 enables precise control of the contact pressure and temperature of the hemp fiber bundle during testing, thereby improving test accuracy.

[0060] The transverse driving mechanism is arranged below the airbag testing mechanism and is used to drive the airbag testing mechanism to move horizontally repeatedly to simulate dynamic friction test conditions. The transverse driving mechanism includes a second guide rail 6 and an auxiliary slide frame 62. The second guide rail 6 is fixed to the top front end of the base 1, and the auxiliary slide frame 62 is fixed to the top rear end of the base 1. A second slide 61 is slidably connected above the second guide rail 6, and an auxiliary slider 63 is slidably connected inside the auxiliary slide frame 62. A U-shaped frame 64 is fixed on the top of the second slide 61 and the auxiliary slider 63. Connecting inclined plates 65 are fixed on the front and rear sides of the top of the U-shaped frame 64. The top of the connecting inclined plates 65 is fixed to the annular outer frame 41. The transverse driving mechanism drives the second slide 61 and the auxiliary slider 63 to slide along the second guide rail 6 and the auxiliary slide frame 62, thereby driving the annular outer frame 41 and the annular airbag 4 inside it to move horizontally repeatedly. This design ensures the stability of the dynamic friction test while improving the test efficiency.

[0061] The humidity regulating mechanism is arranged on the left and right sides of the airbag testing mechanism, and is used to simulate the test environment of the hemp fiber bundle under different humidity conditions. The humidity regulating mechanism includes two extended annular frames 5, which are respectively located on the left and right sides of the annular outer frame 41. An annular pipe 51 is fixed to the inner annular surface of each extended annular frame 5, and at least six atomizing nozzles 52 are evenly distributed on the inner annular surface of the annular pipe 51. The ends of the atomizing nozzles 52 face the inner annular surface of the annular airbag 4 and are used to spray water mist to simulate the humidity environment. The extended annular frame 5 is connected to the annular outer frame 41 by three connecting strips 53 to ensure that its position is stable and easy to disassemble and maintain. The design of the humidity regulating mechanism enables the testing device to accurately simulate the friction test environment under different humidity conditions, significantly improving the accuracy and applicability of the test results.

[0062] The humidity control mechanism is arranged below the transverse drive mechanism and is used to continuously supply water to the humidity regulating mechanism. The humidity control mechanism includes a water tank 7 and a pump body 72. The water tank 7 is fixed at the bottom of the U-shaped frame 64. A liquid replenishing pipe 71 is passed through and fixed on one side of the water tank 7 for replenishing liquid. The pump body 72 is fixed at the middle of the top of the U-shaped frame 64. The inlet end of the pump body 72 is connected to the water tank 7 through an inlet pipe 73. A tee pipe 74 is fixed at the outlet end. Both ends of the tee pipe 74 are respectively connected to the two annular pipes 51 through outlet pipes 75, so that the outlet pipe 75 continuously supplies water to the annular pipe 51, ensuring the normal operation of the atomizing nozzle 52. The design of the humidity control mechanism ensures the stable operation of the humidity regulating mechanism, while reducing manual intervention and improving test efficiency and consistency.

[0063] The specific operation steps of the present invention are as follows:

[0064] S1: Hang one end of the hemp fiber bundle to be tested on the left self-locking hook 36, then pass it through the left clamping frame 3, the left annular pipe 51, the annular airbag 4, the right annular pipe 51, and finally pass it through the right clamping frame 3 and hang the end on the right self-locking hook 36;

[0065] S2: Adjust the compression bars 31 in the left and right clamping frames 3. Rotate the wheel 34 to drive the screw 33 to move the compression bars 31 up and down until the hemp fiber bundle is clamped and reaches the required tension.

[0066] S3: Air is inflated into the annular airbag 4 through the inflation port 46, causing it to expand and come into close contact with the hemp fiber bundle. At this point, the micro-cooling channels 43 within the annular airbag 4 begin operating, feeding media of varying temperatures through the refrigerant inlet pipe 44 and the heat medium outlet pipe 45 to adjust the temperature of the friction coating 42 to simulate different test conditions.

[0067] S4: The transverse drive mechanism is activated to drive the second slide 61 and the auxiliary slide 63 to slide along the second guide rail 6 and the auxiliary slide frame 62, thereby driving the annular outer frame 41 and the annular airbag 4 therein to repeatedly transversely move horizontally, simulating dynamic friction test conditions.

[0068] S5: The humidity control mechanism is activated. The pump body 72 draws liquid from the water storage tank 7 through the water inlet pipe 73 and supplies water to the two annular pipes 51 through the tee pipe 74 and the water outlet pipe 75. The atomizing nozzles 52 in the annular pipes 51 spray water mist to simulate different humidity environments.

[0069] S6 During the test, the pressure sensor data in the annular airbag 4 is monitored in real time to record the friction performance of the hemp fiber bundle under different temperature and humidity conditions.

[0070] After the test is completed, the gas in the annular airbag 4 is discharged through the exhaust valve port 47, the hemp fiber bundle is removed and the device is cleaned.

[0071] The present invention solves the problems of insufficient environmental simulation capability, low test accuracy and low modularity of the friction performance testing device for hemp fiber bundles in the prior art through the above-mentioned technical solution, and provides a testing device with multi-environment simulation function, modular design, efficient temperature control system and high degree of automation, which can be widely used in the field of textile materials and provide reliable data support for the research and development, production and application of hemp fibers.

[0072] The present invention also provides a method for preparing a friction coating of a friction performance testing device based on hemp fiber bundles. Figure 11 -Attached Figure 17 Specific embodiments of the present invention are described in detail.

[0073] The present invention first requires preparing an annular airbag substrate. This substrate is a thermoplastic polyurethane elastomer with a tensile strength of at least 40 MPa and an elongation at break of at least 300%. The inner surface of the annular airbag (4) is cleaned and activated using plasma bombardment to remove organic impurities. Subsequently, a mechanical micro-etching process is used to create uniformly distributed microgrooves on the surface. These microgrooves are controlled to have a depth range of 5-20 μm and a width range of 10-50 μm, ensuring the adhesion of the subsequent coating to the substrate and the stability of the coating during use.

[0074] Next, the coating material preparation stage is entered. Polyurethane resin is used as the base material and nano-alumina particles with a mass fraction of 5%-15% and a silane coupling agent with a mass fraction of 0.5%-2% are added. The relationship between the average particle size D of the nano-alumina particles and the addition amount M is adjusted according to actual needs. When D < 100nm, the addition amount is set to M1, and when D > 200nm, the addition amount is set to M2. High-speed stirring equipment is used to mix the above materials. The stirring speed is set in the range of 1000-3000rpm, and the stirring time is controlled between 10-30 minutes to ensure that the coating material has good fluidity and dispersibility. In this step, special attention should be paid to the particle size distribution range of the nano-alumina particles to avoid degradation of coating performance due to particle agglomeration.

[0075] After the coating material is prepared, the coating stage begins. The prepared coating material is evenly coated on the inner surface of the annular airbag 4 using a spin coating process. The spin coating speed is controlled between 500-1500 rpm, the spin coating time is set to 30-60 seconds, and the final coating thickness is controlled within the range of 20-50 μm. For the inner surface of the annular airbag 4 with different curvature radii R, the spin coating parameters need to be optimized according to its curvature characteristics and the viscosity of the coating material. For example, when R<Rmin时适当降低旋涂转速,而当R> When Rmax is reached, the spin coating time is increased to ensure uniformity of the coating on complex curved surfaces. During this process, attention should be paid to the stable operation of the spin coating equipment and the real-time monitoring of the coating thickness.

[0076] After the coating is applied, it enters the curing stage, which is divided into three steps. First, it is naturally dried at room temperature for 10-30 minutes, then it is preliminarily cured at 60-80℃ for 30-60 minutes, and finally it is completely cured at 100-120℃ for 1-2 hours. The influence of ambient humidity H and the initial moisture content of the coating material must be considered during the curing process. If H>Hmax, the curing time is extended. If H <Hmin则提高固化温度以确保涂层充分交联形成稳定的结构。此阶段的关键在于严格控制固化温度和时间,同时对环境条件进行实时监测和调整。

[0077] After curing is completed, the surface modification stage begins, using laser engraving technology to machine a regularly arranged micropore array on the coating surface. The micropore diameter range is controlled between 50-200μm, the pore spacing range is controlled between 100-300μm, and the micropore depth range is controlled between 10-50μm. The selection of laser power P and frequency F needs to be determined based on test results. When P*F≥Kmin, ensure that the process parameters are within the effective range. Otherwise, adjust the laser power and frequency to achieve the best effect. In this step, it is important to pay attention to the operating status of the laser and the dimensional accuracy of the micropore array.

[0078] Finally, enter the performance testing stage, use the cross-hatch method to test the coating adhesion and record the peeling area ratio A, use the Shore hardness tester to test the coating hardness and record the hardness value B, use the abrasion tester to test the coating wear resistance and record the wear per unit area C. If A>Amax or B<Bmin或C> If the coating fails the test, the coating will be deemed unqualified if the test is below Cmax. Amax, Bmin, and Cmax are the maximum peeling area ratio, minimum hardness value, and maximum wear limit, respectively. During this stage, strict adherence to testing standards is essential, and all data must be recorded for subsequent analysis.

[0079] The various steps involved in implementing the present invention are closely coordinated. For example, the pretreatment of the inner surface of the annular airbag 4 directly affects the coating's ability to bond to the substrate, while the formulation and application of the coating material determine the coating's uniformity and consistency. Temperature and time control during the curing stage further influence the coating's ultimate performance, while microporous array processing during the surface modification stage improves the coating's coefficient of friction and anti-slip properties. Feedback from the performance testing stage can be used to optimize process parameters in previous steps, thereby achieving closed-loop control of the entire preparation process.

[0080] The present invention, through the synergistic effect of the aforementioned steps, addresses the existing problems of insufficient adhesion, poor uniformity, and low wear resistance of the friction coating on the inner surface of the annular airbag 4. The microscopic grooves on the inner surface of the annular airbag 4 significantly enhance the bonding strength between the coating and the substrate. The optimized formulation of the coating material and the spin coating process ensure coating uniformity. The micropore array formed by laser engraving technology increases the coating's coefficient of friction and anti-slip performance. A rigorous performance testing process selects friction coatings that meet design requirements. These combined steps enable the present invention to reliably guarantee accurate testing of the friction properties of hemp fiber bundles.

[0081] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A friction performance testing device for hemp fiber bundles, characterized in that: include: A base (1) for fixing the structure of the entire test device; A clamping and adjusting mechanism is provided on both sides of the base (1) for clamping the hemp fiber bundle and adjusting its tension; the clamping and adjusting mechanism comprises clamping frames (3) respectively provided on the left and right sides of the base (1), a pressing strip (31) is slidably provided inside the two clamping frames (3), and the lower surface of the pressing strip (31) is made of soft material, a screw rod (33) is passed through the top center of the two clamping frames (3) and is threadedly connected, and the ends of the two screw rods (33) are respectively rotated relative to the two pressing strips (31) through bearings (32), and a rotating wheel (34) is fixed to the top of the two screw rods (33); An airbag testing mechanism is arranged on the top of the base (1) and is used for sheathing and inflating the hemp fiber bundle and performing a friction performance test on the hemp fiber bundle; the airbag testing mechanism includes an annular outer frame (41) arranged on the top of the base (1); the inner ring surface of the annular outer frame (41) is detachably connected to an annular airbag (4); a pressure sensor is installed inside the annular airbag (4); the inner ring surface of the annular airbag (4) is provided with a friction coating (42); the inner ring surface of the annular airbag (4) is provided with a friction coating (42); A micro cooling channel (43) is embedded in the inner ring wall, the depth of the micro cooling channel (43) is 0.5-1 mm, the width is 1-2 mm, and the micro cooling channel (43) is made of flexible material. The layout of the micro cooling channel (43) is a double spiral loop or a single spiral loop. A refrigerant input pipe (44) is fixed at one end of the micro cooling channel (43), and a heat medium output pipe (45) is fixed at the other end. The refrigerant input pipe (44) and the heat medium output pipe (45) both extend to the outside of the annular airbag (4); A transverse driving mechanism, which is arranged below the airbag testing mechanism and is used to drive the airbag testing mechanism to repeatedly transversely move in a horizontal direction; A humidity regulating mechanism is provided on the left and right sides of the airbag testing mechanism and is used to simulate the testing environment of the hemp fiber bundle under different humidity conditions; the humidity regulating mechanism comprises two expansion annular frames (5), and the expansion annular frames (5) are provided on the left and right sides of the annular outer frame (41); an annular pipe (51) is fixed to the inner annular surface of the two expansion annular frames (5); at least six evenly distributed atomizing nozzles (52) are passed through and fixed to the inner annular surface of the two annular pipes (51), and the ends of the atomizing nozzles (52) are both directed toward the inner annular surface of the annular airbag (4); and the two expansion annular frames (5) are connected to the annular outer frame (41) through three connecting strips (53); The humidity control mechanism is arranged below the transverse driving mechanism and is used for continuously supplying water to the humidity regulating mechanism.

2. A friction performance testing device for hemp fiber bundles according to claim 1, characterized in that: The bottoms of the two clamping frames (3) are fixed with pillars (35), and one side of the two pillars (35) is fixed with a self-locking hook (36) near the top. The end of the pillar (35) on the left is fixedly connected to the base (1), and the end of the pillar (35) on the right can be moved and adjusted laterally through a first guide rail (37) and a first slide (371). The left end of the first guide rail (37) is fixedly connected to the right side of the base (1) through a baffle (2).

3. A friction performance testing device for hemp fiber bundles according to claim 1, characterized in that: An inflation interface (46) is passed through and installed at the right side of the annular airbag (4), which is relatively close to the top. An exhaust valve port (47) is passed through and installed at the right side of the annular airbag (4), which is relatively close to the bottom.

4. A friction performance testing device for hemp fiber bundles according to claim 1, characterized in that: The transverse driving mechanism includes a second guide rail (6) and an auxiliary slide frame (62), wherein the second guide rail (6) is fixed at the front end of the top of the base (1), and the auxiliary slide frame (62) is fixed at the rear end of the top of the base (1); the second guide rail (6) is slidably connected to the top of a second slide seat (61), and the auxiliary slide frame (62) is slidably connected to the inside of the auxiliary slide frame (63); a U-shaped frame (64) is fixed on the top of the second slide seat (61) and the auxiliary slide frame (62); connecting inclined plates (65) are fixed on both the front and rear sides of the top of the U-shaped frame (64), and the top ends of the connecting inclined plates (65) are fixed to the annular outer frame (41).

5. The friction performance testing device for hemp fiber bundles according to claim 1, characterized in that: The humidity control mechanism comprises a water storage tank (7) fixed at the bottom of a U-shaped frame (64) and a pump body (72) fixed at the middle of the top of the U-shaped frame (64). A liquid infusion pipe port (71) is passed through and fixed on one side of the water storage tank (7). The inlet end of the pump body (72) is connected to the water storage tank (7) through a water inlet pipe (73). A three-way pipe (74) is fixed to the outlet end of the pump body (72), and both ends of the three-way pipe (74) are connected to the two annular pipes (51) through water outlet pipes (75).

6. The friction performance testing device for hemp fiber bundles according to claim 1, characterized in that: The method for preparing the friction coating (42) comprises the following steps: Step 1: pre-treatment of the substrate, cleaning and activating the inner surface of the annular airbag (4), removing organic impurities on the surface by plasma bombardment technology, and forming uniformly distributed micro-grooves on the inner surface by mechanical micro-etching technology, wherein the depth of the micro-grooves ranges from 5 to 20 μm and the width ranges from 10 to 50 μm; Step 2: Prepare the coating material by using polyurethane resin as the base material, adding 5%-15% by mass of nano-alumina particles and 0.5%-2% by mass of a silane coupling agent, and mixing them evenly using a high-speed stirring device at a stirring speed of 1000-3000 rpm for 10-30 minutes; Step 3: coating, using a spin coating process to evenly coat the prepared coating material on the inner surface of the annular airbag (4), with the spin coating speed controlled at 500-1500 rpm, the spin coating time at 30-60 seconds, and the coating thickness controlled at 20-50 μm; Step 4: Coating curing: first dry naturally at room temperature for 10-30 minutes, then preliminarily cure at 60-80℃ for 30-60 minutes, and finally fully cure at 100-120℃ for 1-2 hours; Step 5: Surface modification: laser engraving technology is used to process a regularly arranged micropore array on the coating surface. The micropore diameter ranges from 50-200μm, the pore spacing is 100-300μm, and the micropore depth is 10-50μm. Step 6: Performance testing: Conduct adhesion testing, hardness testing, and wear resistance testing on the prepared friction coating.

7. A friction performance testing device for hemp fiber bundles according to claim 6, characterized in that: The base material of the annular airbag (4) in step 1 is a thermoplastic polyurethane elastomer with a tensile strength of not less than 40 MPa and an elongation at break of not less than 300%; In the step 2, the average particle size of the nano-alumina particles is D. When D is less than 100 nm, the addition amount is set to M1. When D is greater than 200 nm, the addition amount is set to M2, where M represents the mass fraction of the nano-alumina particles. In the step 3, the spin coating parameters are optimized according to the curvature radius R of the inner annular surface of the annular airbag (4), the spin coating speed is reduced when R is less than Rmin, and the spin coating time is increased when R is greater than Rmax, wherein Rmin and Rmax represent the set minimum and maximum curvature radius limits, respectively; In the fourth step, the curing parameters are adjusted according to the ambient humidity H. When H is greater than Hmax, the curing time is extended, and when H is less than Hmin, the curing temperature is increased, where H represents the ambient humidity, and Hmin and Hmax represent the set minimum and maximum humidity thresholds, respectively. In step 5, the laser power is P and the frequency is F. When P multiplied by F is greater than or equal to Kmin, the process parameters are ensured to be within the valid range, where Kmin represents the set minimum process parameter threshold; In step six, the coating adhesion is tested using the cross-hatch method and the peeling area ratio A is recorded, the coating hardness is tested using a Shore hardness tester and the hardness value B is recorded, and the coating wear resistance is tested using an abrasion tester and the wear per unit area C is recorded. If A is greater than Amax or B is less than Bmin or C is greater than Cmax, the coating is judged to be unqualified, where Amax, Bmin and Cmax represent the set maximum peeling area ratio, minimum hardness value and maximum wear limit, respectively.

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