Pultrusion traction system and method for actively inhibiting stick-slip vibration

Abstract

The invention relates to the field of pultrusion equipment, in particular to a pultrusion traction system and method for actively inhibiting stick-slip vibration, and the pultrusion traction system comprises a chain tension collection module arranged at a stress node of a traction chain of a crawler traction module, and an acoustic energy injection module embedded in a crawler plate assembly of the crawler traction module, the control unit is in communication connection with the chain tension acquisition module and the acoustic energy injection module; the pultrusion traction method comprises the step of increasing the output power of the acoustic energy injection module when a signal which is sent by the chain tension acquisition module and indicates that the tension gradient is in nonlinear sharp increase is received. The clamped profile is used as a stress wave conduction medium, high-frequency mechanical wave energy is reversely conducted to the interface of the profile and the pultrusion die, and the acoustic softening effect is triggered, so that the friction coefficient between the profile and the pultrusion die is actively reduced, and stick-slip vibration can be effectively inhibited.

Description

Technical Field

[0001] This invention relates to the field of pultrusion equipment, and more specifically to a pultrusion traction system that actively suppresses stick-slip vibration.

[0002] This invention also relates to a pultrusion traction method for actively suppressing stick-slip vibration. Background Technology

[0003] Pultrusion is a continuous manufacturing process for composite profiles. In existing technologies, tracked traction modules are typically used, and track plate assemblies are used to perform clamping and pulling actions. Due to material solidification and wall shearing, the profile will generate great frictional resistance at the interface with the mold in the pultrusion die.

[0004] To overcome frictional resistance and prevent slippage between the track plate assembly and the profile, existing technologies typically require a significant increase in the normal clamping pressure of the equipment on the profile. However, due to the limited radial compressive yield strength of composite profiles, excessive normal clamping pressure can easily lead to structural crushing or internal microcrack damage to the profile. Conversely, if the normal clamping pressure is reduced to protect the profile, the traction force cannot overcome the high resistance at the die end, which can easily induce systematic stick-slip vibration, resulting in pull-out instability and seriously affecting the surface quality of the product. Summary of the Invention

[0005] The purpose of this invention is to provide a pultrusion traction system that actively suppresses stick-slip vibration, in order to solve the technical contradiction in existing traction technology that excessively increases the normal clamping force in order to overcome the high static frictional resistance between the profile and the pultrusion die, thereby causing mechanical crushing damage to the profile, or causing stick-slip vibration when the clamping force is insufficient.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A pultrusion traction system, comprising: Track traction module, comprising track plate assembly that contacts profiles and performs clamping and pulling actions; A chain tension acquisition module is arranged at the force-bearing node of the traction chain of the track traction module; An acoustic energy injection module is embedded inside the track plate assembly and configured to generate high-frequency mechanical waves and use the clamped profile as a stress wave transmission medium to transmit vibration energy to the interface between the profile and the pultrusion die. The control unit is communicatively connected to the chain tension acquisition module and the acoustic energy injection module, and is configured to: upon receiving a signal from the chain tension acquisition module indicating a nonlinear surge in the tension gradient, increase the output power of the acoustic energy injection module to reduce the coefficient of friction between the profile and the pultrusion die through an acoustic softening effect.

[0007] Furthermore, the acoustic energy injection module includes: a two-dimensional array resonant cavity processed on the metal skeleton inside the track plate assembly, and multiple piezoelectric ultrasonic transducers coaxially embedded in the resonant cavity.

[0008] Furthermore, the piezoelectric ultrasonic transducer is a shear-type piezoelectric transducer. The output end face of the shear-type piezoelectric transducer generates shear deformation parallel to the drawing direction of the profile, thereby exciting longitudinal waves with a propagation direction parallel to the drawing direction inside the profile, and thus using the solid medium properties of the profile to feed energy back to the pultrusion die.

[0009] Furthermore, it also includes a power supply module, which comprises: The slip ring or wireless power transmitter is mounted on the frame of the track traction module and is positioned along the movement trajectory of the traction chain; And a slip ring brush or wireless power receiver disposed on the track plate assembly and moving synchronously with the track plate assembly.

[0010] Furthermore, the track plate assembly includes an inner track plate and an outer track plate. The inner track plate is fixed to the traction chain, and the outer track plate is detachably connected to the inner track plate. The piezoelectric ultrasonic transducer is integrally formed with the outer track plate.

[0011] Furthermore, the outer track plate and the inner track plate are slidably connected by a dovetail groove, and when the outer track plate slides to a preset position through the dovetail groove, the outer track plate and the inner track plate are locked in position by a spring pin.

[0012] Furthermore, the slip ring brush or the wireless power receiver is disposed on the inner track plate, and the mating surfaces of the inner track plate and the outer track plate are provided with matching power supply interfaces. When the outer track plate is installed on the inner track plate, the piezoelectric ultrasonic transducer is connected to the slip ring brush or the wireless power receiver through the power supply interface.

[0013] Furthermore, the surface of the track plate assembly that contacts the profile is covered with a flexible pad for increasing friction, the flexible pad being made of polyurethane or rubber. The flexible pad has multiple clearance holes corresponding to the positions of the piezoelectric ultrasonic transducer. The front end of the piezoelectric ultrasonic transducer is provided with an acoustic impedance matching layer. The acoustic impedance matching layer passes through the clearance holes and is flush with the surface of the flexible pad, so that the flexible pad and the acoustic impedance matching layer are in contact with the profile at the same time.

[0014] Furthermore, it also includes a rotary encoder disposed on the track spindle of the track traction module, and the control unit is communicatively connected to the rotary encoder; The control unit is configured to: synchronously receive the acceleration signal output by the rotary encoder, which reflects the speed change of the track main axis; when it receives a signal from the chain tension acquisition module indicating that the tension gradient exhibits a nonlinear surge, and the acceleration signal shows a decreasing or stagnant trend, it determines that the system has entered the energy storage state of stick-slip vibration and triggers the operation of increasing the output power of the acoustic energy injection module.

[0015] A pultrusion traction method, applied to a pultrusion traction system, includes the following steps: The track traction module clamps the profile through the track plate assembly and outputs a pulling force. At the same time, the acoustic energy injection module generates a high-frequency mechanical wave with a preset reference power, and uses the clamped profile as a stress wave transmission medium to transmit the vibration energy to the interface between the profile and the pultrusion die. The control unit continuously collects mechanical data of the traction system through the chain tension acquisition module and calculates in real time the tension gradient that shows the change of tension over time. When the control unit receives a signal from the chain tension acquisition module indicating a nonlinear surge in the tension gradient, it issues a power compensation command to increase the output power of the acoustic energy injection module. The acoustic energy injection module with increased power reduces the coefficient of friction between the profile and the pultrusion die through acoustic softening effect.

[0016] The advantages of this invention compared to the prior art are: This invention utilizes an acoustic energy injection module embedded inside the track plate assembly. When the control unit receives a signal indicating a nonlinear surge in the tension gradient, it actively increases its output power. Using the clamped profile itself as a stress wave transmission medium, it reverses the high-frequency mechanical wave energy to the interface between the profile and the pultrusion die, triggering an acoustic softening effect. This actively reduces the coefficient of friction between the profile and the pultrusion die, effectively suppressing stick-slip vibration. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0018] Figure 1This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of a piezoelectric ultrasonic transducer acting on a profile to generate longitudinal waves, according to an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the arrival of longitudinal waves at the interface between the profile and the pultrusion die, according to an embodiment of the present invention. Figure 4 This is a perspective view of the track plate assembly according to an embodiment of the present invention; Figure 5 This is an assembly diagram of the track plate assembly according to an embodiment of the present invention; The labels in the diagram represent the following: 1-Profile; 2-Pultrusion die; 3-Track traction module; 31-Traction chain; 4-Track plate assembly; 41-Inner track plate; 42-Outer track plate; 43-Cover plate; 44-Dovetail groove; 45-Spring pin; 46-Power supply interface; 47-Flexible gasket; 5-Piezoelectric ultrasonic transducer; 6-Slip ring brush. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a pultrusion traction system for actively suppressing stick-slip vibration, including a track traction module 3, a chain tension acquisition module, an acoustic energy injection module, and a control unit.

[0021] The track traction module 3 includes a track plate assembly 4 that contacts the profile 1 and performs clamping and pulling actions; a chain tension acquisition module is arranged at the force-bearing node of the traction chain 31 of the track traction module 3; an acoustic energy injection module is embedded inside the track plate assembly 4 and is configured to generate high-frequency mechanical waves and use the clamped profile 1 as a stress wave transmission medium to transmit vibration energy to the interface of the front pultrusion die 2.

[0022] The control unit communicates with the chain tension acquisition module and the acoustic energy injection module. The control unit includes a processor and a memory storing a computer program. When the computer program is executed by the processor, the control unit performs the following operations: when it receives a signal from the chain tension acquisition module indicating that the tension gradient is showing a nonlinear surge, it increases the output power of the acoustic energy injection module to reduce the coefficient of friction between the profile 1 and the pultrusion die 2 through the acoustic softening effect.

[0023] Specifically, the acoustic energy injection module includes a two-dimensional array resonant cavity processed on the metal skeleton inside the track plate assembly 4, and multiple piezoelectric ultrasonic transducers 5 coaxially embedded in the resonant cavity. The piezoelectric ultrasonic transducers 5 are shear-type piezoelectric transducers. The output end face of the shear-type piezoelectric transducer generates shear deformation parallel to the pulling direction of the profile 1. The shear deformation is coupled to the surface of the profile 1 by the interfacial static friction force formed by the normal pressure applied by the track plate assembly 4, thereby exciting longitudinal waves inside the profile 1 with a propagation direction parallel to the pulling direction and pointing in the opposite direction, so as to use the solid medium characteristics of the profile 1 to feed the energy back to the pultrusion die 2.

[0024] Its working principle is as follows: the shear-type piezoelectric transducer utilizes the inverse piezoelectric effect of the piezoelectric material. When it receives a high-frequency alternating electric field, its crystal undergoes relative displacement parallel to the interface, rather than thickness expansion and contraction perpendicular to the interface.

[0025] Under the high-pressure clamping environment applied by the track plate assembly 4 to the side wall of the profile 1, the parallel shear deformation at the front end of the transducer is strongly captured by the macroscopic static friction force of the interface, directly forcing the particles on the surface of the profile 1 to undergo high-frequency micro-amplitude displacement along the drawing direction, thereby successfully exciting high-frequency longitudinal mechanical waves with amplitudes above 20kHz and in the micrometer range inside the profile 1; since the cured composite material profile 1 has a high axial elastic modulus, it becomes an excellent stress wave transmission medium, and the high-frequency longitudinal wave can be transmitted in the reverse direction and with low attenuation to the demolding interface of the pultrusion die 2 along the drawing direction; when the vibration reaches the interface, the micro-protrusions undergo microsecond-level contact and separation cycles under the action of high-frequency micro-inertial force, thereby triggering an acoustic softening effect, reducing the static friction force between the profile 1 and the pultrusion die 2 to a level close to the dynamic friction coefficient.

[0026] To ensure a continuous energy supply during operation, the pultrusion traction system also includes a power supply module; the power supply module includes a slip ring or wireless power transmitter set on the frame of the track traction module 3, and a slip ring brush 6 or wireless power receiver set on the track plate assembly 4.

[0027] In terms of structural design, the track plate assembly 4 includes an inner track plate 41 and an outer track plate 42. The inner track plate 41 is fixed to the traction chain 31, and the outer track plate 42 is detachably connected to the inner track plate 41. The piezoelectric ultrasonic transducer 5 is integrally formed with the outer track plate 42.

[0028] Specifically, the outer track plate 42 and the inner track plate 41 are slidably connected by a dovetail groove 44, and when the outer track plate 42 slides to a preset position, the two are locked in position by a spring pin 45.

[0029] Correspondingly, the slip ring brush 6 or the wireless power receiver is set on the inner track plate 41, and the mating surfaces of the inner track plate 41 and the outer track plate 42 are provided with matching power supply interfaces 46; when the outer track plate 42 is installed on the inner track plate 41, the piezoelectric ultrasonic transducer 5 can be electrically connected to the slip ring brush 6 or the wireless power receiver through the power supply interface 46.

[0030] Furthermore, a cover plate 43 is provided on the side of the track outer plate 42 that contacts the profile 1. The cover plate 43 is used to protect the piezoelectric ultrasonic transducer 5 inside the track outer plate 42. The surface of the cover plate 43 is covered with a flexible pad 47 to increase friction. The flexible pad 47 is made of polyurethane or rubber. Multiple clearance holes corresponding to the positions of the piezoelectric ultrasonic transducer 5 are provided on the cover plate 43 and the flexible pad 47.

[0031] The front end of the piezoelectric ultrasonic transducer 5 is provided with an acoustic impedance matching layer. The acoustic impedance matching layer passes through the clearance hole and is flush with the inner surface of the flexible pad 47, so that the flexible pad 47 and the acoustic impedance matching layer are in contact with the profile 1 at the same time. The acoustic impedance matching layer is made of epoxy resin or polyurethane.

[0032] When the acoustic softening effect occurs, although the static friction between the acoustic impedance matching layer and the profile 1 decreases significantly, the flexible pad 47 can undergo adaptive viscoelastic deformation, converting local micro-vibrations into heat energy, thereby maintaining a high-friction tight fit with the profile 1 and effectively preventing slippage between the track plate assembly 4 and the profile 1.

[0033] Furthermore, the system also includes a rotary encoder mounted on the track spindle of the track traction module 3, and the control unit is communicatively connected to the rotary encoder. When the computer program stored in the control unit is executed by the processor, the control unit performs the following operations: when it receives a signal from the chain tension acquisition module indicating a nonlinear surge in the tension gradient, it simultaneously receives the acceleration signal from the rotary encoder reflecting the speed change of the track spindle axis for cross-verification; when the tension gradient surges nonlinearly and the acceleration of the track spindle shows an abnormal decrease or stagnation trend, it determines that the system has entered a stick-slip vibration energy storage state, thereby triggering the operation of increasing the output power of the acoustic energy injection module to avoid misjudgment under normal acceleration conditions.

[0034] In addition to the aforementioned hardware system, this invention also provides a pultrusion traction method, which is applied to a pultrusion traction system and specifically includes the following steps: The track traction module 3 clamps the profile 1 through the track plate assembly 4 and outputs a pulling force. At the same time, the acoustic energy injection module generates a high-frequency mechanical wave with a preset reference power, and uses the clamped profile 1 as a stress wave transmission medium to transmit the vibration energy to the interface of the front pultrusion die 2. The processor of the control unit continuously collects mechanical data of the traction system through the chain tension acquisition module and calculates the tension gradient in real time, which shows the change of tension over time. When the control unit receives a signal from the chain tension acquisition module and the rotary encoder indicating that the tension gradient is showing a non-linear surge, it sends a power compensation command to increase the output power of the acoustic energy injection module. The acoustic energy injection module with increased power reduces the coefficient of friction between profile 1 and pultrusion die 2 through acoustic softening effect.

[0035] Regarding the protection logic for process safety, when the computer program is executed by the processor, it also causes the control unit to periodically read the data from the chain tension acquisition module. When the tension gradient or absolute acceleration vector is detected to continuously exceed the preset safety threshold, the mechanical amplitude of the acoustic energy injection module is increased to 10 to 15 micrometers within a 10-millisecond time window. After the mechanical amplitude is increased, if the chain tension acquisition module detects that the pull tension continues to rise and reaches the preset mechanical yield limit, the main power of the track traction module 3 is cut off and a hardware alarm is triggered.

[0036] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A pultrusion traction system for actively suppressing stick-slip vibration, characterized in that, include: Track traction module (3) includes track plate assembly (4) that contacts profile (1) and performs clamping and pulling action. The chain tension acquisition module is arranged at the force-bearing node of the traction chain (31) of the track traction module (3); An acoustic energy injection module is embedded inside the track plate assembly (4) and configured to generate high-frequency mechanical waves and use the clamped profile (1) as a stress wave transmission medium to transmit vibration energy to the interface between the profile (1) and the pultrusion die (2). The control unit is communicatively connected to the chain tension acquisition module and the acoustic energy injection module, and is configured to: when receiving a signal from the chain tension acquisition module indicating that the tension gradient exhibits a nonlinear surge, increase the output power of the acoustic energy injection module to reduce the coefficient of friction between the profile (1) and the pultrusion die (2) through the acoustic softening effect.

2. The pultrusion traction system according to claim 1, characterized in that, The acoustic energy injection module includes: a two-dimensional array resonant cavity processed on the metal skeleton inside the track plate assembly (4), and multiple piezoelectric ultrasonic transducers (5) coaxially embedded in the resonant cavity.

3. The pultrusion traction system according to claim 2, characterized in that, The piezoelectric ultrasonic transducer (5) is a shear-type piezoelectric transducer. The output end face of the shear-type piezoelectric transducer generates shear deformation parallel to the drawing direction of the profile (1) to generate longitudinal waves with a propagation direction parallel to the drawing direction inside the profile (1), thereby utilizing the solid medium characteristics of the profile (1) to feed energy back to the pultrusion die (2).

4. The pultrusion traction system according to claim 2, characterized in that, It also includes a power supply module, which comprises: A collector ring or wireless power transmitter is mounted on the frame of the track traction module (3) and arranged along the movement trajectory of the traction chain (31); And a slip ring brush (6) or a wireless power receiver that is disposed on the track plate assembly (4) and moves synchronously with the track plate assembly (4).

5. The pultrusion traction system according to claim 4, characterized in that, The track plate assembly (4) includes an inner track plate (41) and an outer track plate (42). The inner track plate (41) is fixed to the traction chain (31). The outer track plate (42) is detachably connected to the inner track plate (41). The piezoelectric ultrasonic transducer (5) is integrally formed with the outer track plate (42).

6. The pultrusion traction system according to claim 5, characterized in that, The outer track plate (42) and the inner track plate (41) are slidably connected by a dovetail groove (44), and when the outer track plate (42) slides to a preset position through the dovetail groove (44), the outer track plate (42) and the inner track plate (41) are locked in position by a spring pin (45).

7. The pultrusion traction system according to claim 5, characterized in that, The slip ring brush (6) or the wireless power receiver is disposed on the inner track plate (41). The inner track plate (41) and the outer track plate (42) are provided with matching power supply interfaces (46). When the outer track plate (42) is installed on the inner track plate (41), the piezoelectric ultrasonic transducer (5) is connected to the slip ring brush (6) or the wireless power receiver through the power supply interface (46).

8. The pultrusion traction system according to claim 2, characterized in that, The surface of the track plate assembly (4) that contacts the profile (1) is covered with a flexible pad (47) for increasing friction, the flexible pad (47) being made of polyurethane or rubber. The flexible pad (47) has a plurality of clearance holes corresponding to the position of the piezoelectric ultrasonic transducer (5). The front end of the piezoelectric ultrasonic transducer (5) is provided with an acoustic impedance matching layer. The acoustic impedance matching layer passes through the clearance holes and is flush with the surface of the flexible pad (47) so that the flexible pad (47) and the acoustic impedance matching layer simultaneously contact the profile (1).

9. The pultrusion traction system according to claim 1, characterized in that, It also includes a rotary encoder disposed on the track spindle of the track traction module (3), and the control unit is communicatively connected to the rotary encoder; The control unit is configured to: synchronously receive the acceleration signal output by the rotary encoder, which reflects the speed change of the track main axis; when it receives a signal from the chain tension acquisition module indicating that the tension gradient exhibits a nonlinear surge, and the acceleration signal shows a decreasing or stagnant trend, it determines that the system has entered the energy storage state of stick-slip vibration and triggers the operation of increasing the output power of the acoustic energy injection module.

10. A pultrusion traction method, applied to a pultrusion traction system as described in any one of claims 1 to 9, characterized in that, Includes the following steps: The track traction module (3) clamps the profile (1) through the track plate assembly (4) and outputs a pulling force. At the same time, the acoustic energy injection module generates a high-frequency mechanical wave with a preset reference power, and uses the clamped profile (1) as a stress wave transmission medium to transmit the vibration energy to the interface between the profile (1) and the pultrusion die (2). The control unit continuously collects mechanical data of the traction system through the chain tension acquisition module and calculates in real time the tension gradient that shows the change of tension over time. When the control unit receives a signal from the chain tension acquisition module indicating a nonlinear surge in the tension gradient, it issues a power compensation command to increase the output power of the acoustic energy injection module. The acoustic energy injection module with increased power reduces the coefficient of friction between the profile (1) and the pultrusion die (2) through acoustic softening effect.

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