Preparation method of anti-noise automobile window sealing strip imitating dragonfly wing characteristics

Abstract

The invention discloses a preparation method of a sealing strip for an anti-noise automobile window imitating dragonfly wing characteristics. The preparation method comprises the following steps: S1, extracting bionic characteristics: acquiring saw-toothed structures at the front edges of dragonfly wings and boss texture structure characteristics of wing surfaces; s2, designing a bionic structure of the sealing strip: designing a micro-sawtooth structure on the upper edge of the sealing strip, and designing a multilateral boss array structure on the inner surface of the sealing strip; s3, laser micromachining is conducted, specifically, a micro-sawtooth structure and a multilateral boss array structure are machined on the upper edge and the inner surface of the sealing strip correspondingly; s4, verifying the noise reduction performance; and S5, friction abnormal sound testing. The design principle is based on cross innovation of a bionics theory and a precision laser processing technology, and noise reduction optimization of the automobile sealing strip is achieved through function deconstruction and engineering reconstruction of dragonfly biological characteristics. The sealing strip has the composite protection function of aerodynamic noise reduction and mechanical vibration damping under the dynamic working condition through double bionic effect and friction coefficient optimization.

Description

Technical Field

[0001] The invention relates to the technical field of sealing strip preparation methods, and in particular to a method for preparing a noise-proof sealing strip for automobile windows that imitates the characteristics of dragonfly wings. Background Art

[0002] As the automotive industry's requirements for NVH (noise, vibration, and harshness) performance continue to rise, noise control technologies for automotive sealing systems face new challenges. Traditional EPDM rubber (EPDM) sealing strips are easily excited by airflow and generate aerodynamic noise during high-speed driving. Friction noise at the interface between the window glass and the seal also significantly impacts vehicle quietness. Current technologies often employ composite material modification or simple geometric optimization approaches, but these approaches present significant limitations in suppressing high-frequency noise and matching structural dynamic characteristics.

[0003] In nature, dragonfly wings, through millions of years of evolution, have developed remarkable fluid dynamics and mechanical vibration control mechanisms. The serrated structure on the leading edge effectively disrupts vortex formation, reducing aerodynamic noise by 10%. The array of hexagonal bosses distributed across the wing surface combines structural reinforcement with vibration damping. Experiments have shown that this microstructure attenuates high-frequency noise between 1000 and 5000 Hz by 37% better than traditional sound-absorbing materials. Inspired by this, biomimetic design offers new approaches for noise reduction in seals. However, conventional processing techniques have made it difficult to precisely fabricate biomimetic microstructures on flexible polymer substrates.

[0004] In recent years, the development of ultrafast laser processing technology has provided breakthrough solutions for the fabrication of micro- and nanostructures. Infrared femtosecond lasers, with their extremely short pulse width and the "cold processing" properties they offer, can achieve micron-level precision in the fabrication of three-dimensional microstructures on rubber surfaces without causing material degradation due to heat-affected zones. Combining biomimetic design with advanced laser micromachining technology has opened up a new dimension in vibration and noise reduction technology for automotive sealing systems, with significant engineering application value. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a noise-proof sealing strip for automobile windows that imitates the characteristics of dragonfly wings, so as to solve the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for preparing a noise-proof automobile window sealing strip that imitates the characteristics of dragonfly wings, which extracts the serrated characteristics of the leading edge of dragonfly wings in nature to reduce aerodynamic noise; at the same time, the hexagonal boss texture structure of the dragonfly wing surface is extracted, and the hexagonal boss microstructure can absorb waves and reduce shock during high-frequency vibrations, and the textured surface can reduce the friction coefficient under low loads. A serrated structure is processed on the upper edge of the rubber automobile sealing strip using a laser femtosecond device, and a hexagonal boss structure is prepared on the inner surface of the rubber window sealing ring using a low-power laser femtosecond, thereby obtaining a low-noise automobile sealing strip with bionic microstructural characteristics. This structural design enables automobile window sealing strips to have the low noise and high structural quality characteristics of dragonfly wings. Finally, a high-noise-proof structural material suitable for automobile window sealing strips is obtained;

[0007] The following steps are involved:

[0008] S1. Bionic feature extraction: obtaining the serrated structure of the leading edge of the dragonfly's wings and the convex texture structure features of the wing surface;

[0009] S2. Design of bionic structure of sealing strip: Based on the geometric parameters of the serrated structure and boss texture structure, a micro-serrated structure is designed on the upper edge of the sealing strip, and a polygonal boss array structure is designed on the inner surface;

[0010] S3. Laser micromachining: Using ultrafast laser processing technology, the micro-serration structure and the polygonal boss array structure are respectively machined on the upper edge and inner surface of the sealing strip to obtain a sealing strip with a bionic dragonfly wing surface;

[0011] S4. Noise reduction performance verification: The processed sealing strips are installed on the vehicle windows. Noise signals under high-speed conditions are collected using an acoustic detection device to verify the noise reduction effect.

[0012] S5. Friction noise test: A friction and wear test is performed on the sealing strip of the polygonal boss array structure, and the friction noise suppression effect is evaluated by comparing acoustic signals.

[0013] Preferably, in step S2, the preparation of the micro-serrated structure is a horizontal continuous array structure of solid equilateral trapezoidal units drawn by CAD software, and the lower bases of the solid equilateral trapezoidal units are arranged in parallel, the base length of the solid equilateral trapezoidal units is 5-15 μm, the height is 30-50 μm, the lower base length is 60-80 μm, and the spacing between each solid equilateral trapezoidal unit is 5-15 μm.

[0014] Preferably, in step S2, the polygonal boss array structure is a horizontal and vertical array structure of regular hexagonal units with parallel bottom sides drawn by laser processing software, the spacing between the regular hexagonal units is 20-40 μm, and the side length of the regular hexagonal unit is 70-90 μm.

[0015] Preferably, in step S3, the ultrafast laser processing technology is femtosecond laser processing, which includes hardware and software. The hardware is a femtosecond laser device, and the software is a laser processing software. The operation of the femtosecond laser device can be controlled by the laser processing software. The micro-serrated structure and the polygonal boss array structure are imported into the laser processing software. On the workbench of the femtosecond laser device, the lower bottom edge of the trapezoid is aligned with the upper edge of the sealing strip, and laser femtosecond processing is performed, and finally a micro-serrated structure and a polygonal boss array structure are prepared on the edge of the sealing strip.

[0016] Preferably, in step S3, the process parameters for processing the micro-serrated structure include: power of 20-40 W, processing speed of 1000-2000 mm / s, pulse frequency of 30-40 KHz, pulse width of 300-700 ns, and laser repetition of 3-7 times.

[0017] Preferably, in step S3, the process parameters for processing the polygonal boss array structure are: power of 5-10 W, processing speed of 500-1000 mm / s, pulse frequency of 15-20 KHz, pulse width of 300-700 ns, and laser repetition of 1-3 times.

[0018] Preferably, in step S4, the acoustic detection device includes a handheld acoustic emission sensor, which is arranged on the inner side of the vehicle glass and connected to the noise signal analysis system.

[0019] Preferably, in step S5, the sealing strip containing the surface of the bionic dragonfly wing is fixed on the pin disk of the friction and wear testing machine, the friction pair uses soda-lime glass balls, and the friction and wear test is carried out, and the noise signal is collected by the acoustic emission device.

[0020] Preferably, the load of the friction and wear test is 0.3-0.7N, the wear radius is 1-3mm, the rotation speed is 5-15rpm, and the acoustic emission device sensor is fixed to the load rod 2-4cm above the friction pair using glue.

[0021] Preferably, the sealing strip is made of one of EPDM rubber, silicone rubber or thermoplastic elastomer.

[0022] The technical effects and advantages of the present invention are as follows:

[0023] The design principle of the present invention is based on the cross-innovation of bionics theory and precision laser processing technology, and realizes the noise reduction optimization of automobile sealing strips through the functional deconstruction and engineering reconstruction of the biological characteristics of dragonflies. The hexagonal unit body forms a multi-level dissipative structure through fractal geometry design. It not only uses the hexagonal cavity to realize the multi-path interference attenuation of sound waves, but the deformation hysteresis effect of its hexagonal boss structure can also absorb the high-frequency contact vibration energy between the sealing strip and the window glass. In conjunction with low-power femtosecond laser controllable ablation technology, the surface friction coefficient is optimized while maintaining the mechanical properties of the substrate, delaying the wear and failure process of the sealing strip, and avoiding abnormal noise caused by the loss of the sealing strip during long-term use. The dual bionic effects and the superposition of friction coefficient optimization enable the sealing strip to have the composite protection function of aerodynamic noise reduction and mechanical vibration damping under dynamic working conditions, breaking through the limitations of the single sound absorption mode of traditional materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of the laser processing device of the present invention.

[0025] Figure 2 This is a microstructure diagram of the rubber surface treatment of the present invention.

[0026] Figure 3 This is an enlarged view of the microstructure of the rubber surface treatment of the present invention.

[0027] Figure 4 This is a noise signal capture diagram of the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The present invention provides Figure 1-4 The method for preparing a noise-reducing automotive window sealing strip that mimics the characteristics of dragonfly wings is described. The method leverages the serrated pattern of the leading edge of a natural dragonfly wing to reduce aerodynamic noise. The hexagonal platform texture of the dragonfly wing surface is also incorporated. This hexagonal platform microstructure absorbs vibrations and dampens shock during high-frequency vibrations, and the textured surface reduces friction under low loads. A serrated pattern is machined onto the upper edge of the automotive sealing strip using a femtosecond laser. Simultaneously, a low-power femtosecond laser is used to create a hexagonal platform structure on the inner surface of the rubber window seal. This results in a low-noise automotive window sealing strip with biomimetic microstructural features. This structural design imbues the automotive window sealing strip with the low noise and high structural quality characteristics of a dragonfly wing. The result is a highly noise-reducing structural material suitable for automotive window sealing strips.

[0030] The method includes the following steps: S1. Bionic feature extraction: obtaining the serrated structure of the leading edge of the dragonfly wing and the convex texture structure features of the wing surface; S2. Bionic structure design of the sealing strip: based on the geometric parameters of the serrated structure and the convex texture structure, a micro-serrated structure is designed on the upper edge of the sealing strip, and a polygonal convex array structure is designed on the inner surface; S3. Laser micromachining: using ultrafast laser processing technology, the micro-serrated structure and the polygonal convex array structure are respectively machined on the upper edge and inner surface of the sealing strip to obtain a sealing strip containing the surface of a bionic dragonfly wing; S4. Noise reduction performance verification: the processed sealing strip is installed on the car window, and the noise signal under high-speed working conditions is collected by an acoustic detection device to verify the noise reduction effect; S5. Friction noise test: a friction and wear test is performed on the sealing strip with the polygonal convex array structure, and the friction noise suppression effect is evaluated by comparing the acoustic signals. The bionic serrated structure significantly suppresses high-frequency noise (2-5kHz) such as whistles by destroying the periodic vortex shedding of the airflow boundary layer. The 40μm sawtooth height design prolongs the airflow separation point, enabling eddy current dissipation earlier and reducing energy accumulation from airflow impacting the edge of the sealing strip. The hexagonal boss array forms a multi-level energy dissipation path through fractal geometry, facilitating the absorption of high-frequency vibration energy between 1000-5000Hz. The boss deformation hysteresis effect reduces the peak vibration acceleration at the interface between the sealing strip and the glass, effectively suppressing any "squeaking" noise. The dual bionic structures work synergistically to reduce the overall noise level inside the vehicle and enhance ride quietness. This invention combines aerodynamic noise reduction with mechanical vibration isolation to achieve a significant improvement in acoustic performance by simulating the aerodynamic structure and vibration characteristics of dragonfly wings to form a dual noise reduction system. The hexagonal fractal texture of the present invention enables graded dissipation of vibration energy, providing wave-absorbing and shock-reducing properties. The laser micro-texturing surface treatment of the present invention significantly optimizes the dynamic friction coefficient between the sealing strip and the glass, extending the wear life of the sealing strip. The present invention utilizes femtosecond precision laser processing technology to process rubber materials, ensuring high precision while avoiding thermal failure of rubber materials caused by traditional machining techniques. Femtosecond precision laser processing technology is an advanced micro-nano processing method based on ultrashort pulse lasers. This technology uses extremely short-duration laser pulses to achieve high-precision microstructure processing on the surface of the material through nonlinear absorption effects. Its core advantage lies in the "cold processing" characteristics. Since the pulse energy deposition time is much shorter than the material's thermal diffusion time, the heat-affected zone in traditional processing can be avoided, and it is particularly suitable for the precision processing of heat-sensitive materials such as rubber. In the present invention, femtosecond laser processing technology is mainly used to prepare microstructures that imitate dragonfly wings on the surface of EPDM sealing strips. Specifically, it includes two key structures: a 40μm high serrated structure on the upper edge of the sealing strip and a hexagonal boss array with a side length of 80μm on the inner surface. The processing uses an infrared femtosecond laser, and by precisely controlling the laser power, scanning speed and pulse parameters, micron-level processing accuracy and excellent surface quality are achieved.Femtosecond laser processing offers significant advantages over traditional machining techniques: First, it produces virtually no thermal damage during machining, improving material performance retention; second, it supports the fabrication of complex three-dimensional microstructures, meeting the requirements of biomimetic design; and third, it boasts high processing efficiency, with a single-piece machining time of less than 5 minutes. These characteristics make it a key technology for the fabrication of high-performance biomimetic sealing strips. Sealing strips processed using this technology have achieved breakthrough improvements in both noise reduction and wear resistance.

[0031] By functionally deconstructing and engineering-reconstructing the biological characteristics of dragonflies, the noise reduction optimization of automotive sealing strips is achieved. The core of this approach lies in the establishment of a biomimetic dual structural synergistic mechanism. First, the serrated aerodynamic stabilization structure of the dragonfly's wing leading edge is extracted, and a femtosecond laser is used to machine a precise biomimetic serration array onto the edge of the EPDM sealing strip. This non-smooth continuous edge disrupts the airflow boundary layer, effectively weakening the periodic vortex shedding generated when high-speed air flows through the window gap. The mechanism of action is that the micron-scale serration structure prolongs the airflow separation point, accelerates the vortex dissipation process, and thus disperses and weakens the vortex, thereby suppressing the source of aerodynamic noise. Second, inspired by the vibration damping properties of hexagonal micro-bosses on the dragonfly's wing surface during high-frequency vibration, a textured interface imitating the dragonfly's wing texture is constructed on the inner surface. The hexagonal unit cells form a multi-level dissipative structure through fractal geometry. Not only does the hexagonal cavity achieve multipath interference attenuation of sound waves, but the deformation hysteresis effect of the hexagonal boss structure also effectively absorbs the high-frequency contact vibration energy between the sealing strip and the window glass. By combining low-power femtosecond laser controllable ablation technology, the surface friction coefficient is optimized while maintaining the mechanical properties of the substrate, slowing the wear and tear of the sealing strip and preventing the noise caused by long-term wear. This dual biomimetic effect combined with friction coefficient optimization enables the sealing strip to provide a combined protective function of aerodynamic noise reduction and mechanical vibration damping under dynamic conditions, breaking through the limitations of traditional materials' single sound absorption mode.

[0032] Wherein, in step S2, the preparation of the micro-sawtooth structure is a horizontal continuous array structure of solid equilateral trapezoidal units drawn by CAD software, and the lower bases of the solid equilateral trapezoidal units are arranged in parallel, the base length of the solid equilateral trapezoidal units is 5-15μm, the height is 30-50μm, the lower base length is 60-80μm, and the spacing between each solid equilateral trapezoidal unit is 5-15μm. The trapezoidal structure with a lower base length of 60-80μm enhances mechanical strength and improves the ability to resist deformation caused by airflow impact, ensuring that the sawtooth maintains a stable shape at high speed. The array density of 5-15μm spacing makes the airflow disturbance frequency match the sensitive frequency band of the human ear (1-4kHz), and the subjective perception of noise loudness is reduced. Parametric CAD modeling is used, which is more efficient than traditional etching processes. The noise reduction efficiency is best when the spacing is 10μm, and the processing cost per unit area is reduced. The trapezoidal structure with a bottom length of 60-80μm enhances mechanical strength and improves the ability to resist deformation caused by airflow impact by 30%, ensuring that the saw teeth maintain a stable shape at high speeds.

[0033] Among them, in step S2, the polygonal boss array structure is a horizontal and vertical array structure of regular hexagonal units with parallel bottom edges drawn by laser processing software. The spacing between the regular hexagonal units is 20-40μm, and the side length of the regular hexagonal unit is 70-90μm. The hexagonal cavity reflects the sound wave path, generating multipath interference, which attenuates the noise energy in the 1000-5000Hz frequency band. The 30μm spacing design avoids resonant coupling between adjacent bosses and reduces the vibration transmission rate. The amplitude of the friction abnormal sound is reduced.

[0034] Among them, in step S3, the ultrafast laser processing technology is femtosecond laser processing, which includes hardware and software. The hardware is the femtosecond laser equipment, and the software is the laser processing software. The operation of the femtosecond laser equipment can be controlled by the laser processing software. The micro-serrated structure and the polygonal boss array structure are imported into the laser processing software. On the workbench of the femtosecond laser equipment, the lower bottom edge of the trapezoid is aligned with the upper edge of the sealing strip, and laser femtosecond processing is performed, and finally the micro-serrated structure and the polygonal boss array structure are prepared on the edge of the sealing strip.

[0035] Among them, in step S3, the process parameters for processing the micro-serrated structure include: power of 20-40W, processing speed of 1000-2000mm / s, pulse frequency of 30-40KHz, pulse width of 300-700ns, and laser repetition of 3-7 times.

[0036] Among them, in step S3, the process parameters for processing the polygonal boss array structure are: power of 5-10W, processing speed of 500-1000mm / s, pulse frequency of 15-20KHz, pulse width of 300-700ns, and laser repetition of 1-3 times.

[0037] Wherein, in step S4, the acoustic detection device includes a handheld acoustic emission sensor, which is arranged on the inner side of the vehicle glass and connected to the noise signal analysis system.

[0038] In step S5, the sealing strip containing the surface of the bionic dragonfly wing is fixed on the pin disk of the friction and wear testing machine, and the friction pair uses soda-lime glass balls to perform a friction and wear test, and the noise signal is collected by the acoustic emission device.

[0039] Specifically, the load of the friction and wear test is 0.3-0.7N, the wear radius is 1-3mm, the rotation speed is 5-15rpm, and the acoustic emission device sensor is fixed to the load rod 2-4cm above the friction pair using glue. After the glue is cured, the vibration strength is improved to reduce the sensor displacement during the test and further reduce the signal acquisition distortion rate.

[0040] The sealing strip is made of EPDM, silicone rubber, or a thermoplastic elastomer. EPDM's performance advantages include reducing the compression set of biomimetic structures and being suitable for temperatures between -40°C and 120°C. Silicone rubber's temperature resistance also includes maintaining elasticity at temperatures as low as -50°C and increasing its friction coefficient by only 10% at 200°C, making it suitable for sealing high-temperature battery compartments in electric vehicles. Thermoplastic elastomers are also environmentally friendly, offering high recyclability, low production costs, and a short processing cycle.

[0041] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a noise-proof sealing strip for automobile windows that imitates the characteristics of dragonfly wings, characterized in that: The following steps are involved: S1. Bionic feature extraction: obtaining the serrated structure of the leading edge of the dragonfly's wings and the convex texture structure features of the wing surface; S2. Design of bionic structure of sealing strip: Based on the geometric parameters of the serrated structure and boss texture structure, a micro-serrated structure is designed on the upper edge of the sealing strip, and a polygonal boss array structure is designed on the inner surface; S3. Laser micromachining: Using ultrafast laser processing technology, the micro-serration structure and the polygonal boss array structure are respectively machined on the upper edge and inner surface of the sealing strip to obtain a sealing strip with a bionic dragonfly wing surface; S4. Noise reduction performance verification: The processed sealing strips are installed on the vehicle windows. Noise signals under high-speed conditions are collected using an acoustic detection device to verify the noise reduction effect. S5. Friction noise test: A friction and wear test is performed on the sealing strip of the polygonal boss array structure, and the friction noise suppression effect is evaluated by comparing acoustic signals.

2. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S2, the preparation of the micro-serrated structure is a horizontal continuous array structure of solid equilateral trapezoidal units drawn by CAD software, and the lower bases of the solid equilateral trapezoidal units are arranged in parallel, the base length of the solid equilateral trapezoidal units is 5-15 μm, the height is 30-50 μm, the lower base length is 60-80 μm, and the spacing between each solid equilateral trapezoidal unit is 5-15 μm.

3. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S2, the polygonal boss array structure is a horizontal and vertical array structure of regular hexagonal units with parallel bottom sides drawn by laser processing software, the spacing between the regular hexagonal units is 20-40 μm, and the side length of the regular hexagonal unit is 70-90 μm.

4. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S3, the ultrafast laser processing technology is femtosecond laser processing, which includes hardware and software. The hardware is the femtosecond laser equipment, and the software is the laser processing software. The operation of the femtosecond laser equipment can be controlled by the laser processing software. The micro-serrated structure and the polygonal boss array structure are imported into the laser processing software. On the workbench of the femtosecond laser equipment, the lower bottom edge of the trapezoid is aligned with the upper edge of the sealing strip, and laser femtosecond processing is performed. Finally, the micro-serrated structure and the polygonal boss array structure are prepared on the edge of the sealing strip.

5. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S3, the process parameters for processing the micro-serrated structure include: power of 20-40 W, processing speed of 1000-2000 mm / s, pulse frequency of 30-40 KHz, pulse width of 300-700 ns, and laser repetition of 3-7 times.

6. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S3, the process parameters for processing the polygonal boss array structure are: power of 5-10 W, processing speed of 500-1000 mm / s, pulse frequency of 15-20 KHz, pulse width of 300-700 ns, and laser repetition of 1-3 times.

7. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S4, the acoustic detection device includes a handheld acoustic emission sensor, which is arranged on the inner side of the vehicle glass and connected to the noise signal analysis system.

8. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: In step S5, the sealing strip containing the surface of the bionic dragonfly wing is fixed on the pin disk of the friction and wear testing machine, and the friction pair uses soda-lime glass balls to perform a friction and wear test, and the noise signal is collected by the acoustic emission device.

9. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 8, characterized in that: The load of the friction and wear test is 0.3-0.7N, the wear radius is 1-3mm, the rotation speed is 5-15rpm, and the acoustic emission device sensor is fixed on the load rod 2-4cm above the friction pair using glue.

10. The method for preparing a noise-proof sealing strip for automobile windows imitating the characteristics of dragonfly wings according to claim 1, characterized in that: The sealing strip is made of one of EPDM rubber, silicone rubber or thermoplastic elastomer.

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