Carbon reinforced resin matrix composite wheel and method of making same

Abstract

The application discloses a carbon reinforced resin matrix composite wheel and a preparation method thereof, and belongs to the technical field of advanced composite material structure design and manufacturing.The preparation method of the carbon reinforced resin matrix composite wheel comprises the following steps: preparing a vertically arranged carbon nanotube / carbon fiber preform with a gradient density distribution; performing integrated hole design on the vertically arranged carbon nanotube / carbon fiber preform; and performing forming treatment on the vertically arranged carbon nanotube / carbon fiber preform after the integrated design treatment.The combination of the gradient VACNT and the bionic special-shaped hole enables the wheel to achieve 50%-150% improvement in key indexes such as interlaminar shear strength, post-impact compression strength and bolt hole extrusion fatigue life compared with a traditional CFRP wheel, and some performances reach or even exceed the level of a traditional aluminum alloy forging, and the weight is greatly reduced.

Description

Technical Field

[0001] This application belongs to the field of advanced composite material structure design and manufacturing technology, and specifically relates to a carbon-reinforced resin-based composite material wheel and its preparation method. Background Technology

[0002] Carbon fiber reinforced resin matrix composites (CFRP), with their excellent specific strength and specific modulus, have become one of the preferred materials for achieving structural lightweighting, and their application in the manufacture of wheels (especially hubs and brake components) is becoming increasingly widespread. However, traditional CFRP wheels face two long-standing technical bottlenecks in practical engineering applications: First, there is the inherent weakness in the interlaminar properties of composite materials. Based on the laminate theory, the interlaminar strength of CFRP structures mainly depends on the relatively weak resin matrix, resulting in interlaminar shear strength and impact delamination resistance being far lower than in-plane properties, making them prone to failure under complex alternating loads.

[0003] Secondly, there are stress concentration and fatigue issues at the connection points. As a typical force-transmitting component, the wheel inevitably has bolt holes. These holes severely disrupt the continuity of the fibers, leading to extremely high local stress concentrations, which become the main source of fatigue crack initiation and propagation, directly limiting the service life and dynamic reliability of the wheel.

[0004] Currently, the industry mainly addresses these issues by increasing local layup, introducing titanium alloy bushings, or employing macroscopic Z-axis reinforcement methods such as stitching / needling. However, these methods often incur significant weight increases or introduce new heterogeneous interface problems, and their effectiveness in suppressing damage initiation at the nano / micro scale is limited.

[0005] In recent years, advanced manufacturing technologies, exemplified by Nawa Technologies of France, have enabled the rapid and low-cost fabrication of large-area, highly ordered, vertically aligned carbon nanotube (VACNT) arrays. This unique VACNT structure, resembling billions of "nano-steel bars" vertically embedded in the substrate, provides a revolutionary tool for fundamentally enhancing the interlaminar properties of composite materials. However, existing technologies largely focus on using VACNT as a simple interlaminar layer, failing to consider the overall stress characteristics of the component and deeply couple and synergistically optimize the reinforcing effect of VACNT with the refined structural design of key components. How to creatively apply the nanoscale reinforcing advantages of VACNT to complex components like engine wheels, which contain pores and multiple stress concentration sources, and develop a complete process system to guide production, is a pressing technical challenge. Summary of the Invention

[0006] The purpose of this invention is to provide a carbon-reinforced resin-based composite material wheel and its preparation method, which solves the technical problems of poor interlayer performance and easy damage to connecting holes in traditional CFRP wheels in the prior art.

[0007] To achieve the above objectives, one embodiment of the present invention provides a method for preparing a carbon-reinforced resin-based composite material wheel, comprising the following steps: Prepare vertically aligned carbon nanotube / carbon fiber preforms with gradient density distribution; Integral pore design on vertically aligned carbon nanotube / carbon fiber preforms; The vertically aligned carbon nanotube / carbon fiber preform after integrated design is molded.

[0008] One preferred embodiment of the present invention involves preparing a vertically aligned carbon nanotube / carbon fiber preform with a gradient density distribution, comprising: Polymer transfer membranes or carbon fiber fabrics are used as growth substrates to grow gradient vertically aligned carbon nanotubes. Carbon fiber bundles are laid out, and a growth substrate with gradient vertically aligned carbon nanotubes is used as an interlayer material, which is simultaneously laid out after each layer of carbon fiber is laid out. After the paving is completed, it is densified and compacted to form a near-net-shape preform.

[0009] One preferred embodiment of the present invention uses a polymer transfer film or carbon fiber fabric as a growth substrate, and grows gradient-aligned vertically arranged carbon nanotubes on the growth substrate, comprising: the growth substrate having a catalyst layer with a thickness of 1 nm-5 nm; for regions with interlayer shear stress ≥50 MPa, using an areal density ≥5 × 10⁻⁶. 10 root / cm 2 Vertically aligned carbon nanotube films with heights ranging from 30 μm to 100 μm; for regions where in-plane load-bearing is dominant, areal density ≤ 1 × 10⁻⁶ is used. 10 root / cm 2 Vertically arranged carbon nanotubes or pure resin layers with a height of 10μm-20μm.

[0010] One preferred embodiment of the present invention involves laying carbon fiber bundles and using a growth substrate with gradient vertically arranged carbon nanotubes as an interlayer material. This is done synchronously after each layer of carbon fiber is laid, including: a laying speed of 5m / min-15m / min, a pressure roller pressure of 0.2MPa-0.5MPa, and a heating temperature of 40℃-60℃.

[0011] One preferred embodiment of the present invention involves an integrated pore design on a vertically aligned carbon nanotube / carbon fiber preform, comprising: optimizing the pore shape on the vertically aligned carbon nanotube / carbon fiber preform using a parametric level set method, and inserting vertically aligned carbon nanotube inserts at irregular pore locations.

[0012] In one preferred embodiment of the present invention, the vertically arranged carbon nanotube inserts have an areal density ≥1×10 11 root / cm 2 It consists of vertically arranged carbon nanotube arrays with a length > 50 μm, and the arrangement direction of the vertically arranged carbon nanotubes is radially inclined at 15°-90° relative to the plane of the pore axis.

[0013] One preferred embodiment of the present invention is to perform molding treatment on the vertically arranged carbon nanotube / carbon fiber preform after integrated design treatment, including: placing the vertically arranged carbon nanotube / carbon fiber preform after integrated design treatment into a mold cavity, and performing resin preheating, glue injection, electric field application, curing and demolding treatment.

[0014] In one preferred embodiment of the present invention, the electric field application includes: applying an alternating electric field with a frequency of 10Hz-1kHz and an electric field strength of 100V / mm-500V / mm, for a duration of 5min-30min; the curing process employs a segmented temperature-pressure ramp-up regime: the first stage is 60℃-80℃, 0.1MPa-0.3MPa, held for 20min-40min; the second stage is 90℃-110℃, 0.3MPa-0.5MPa, held for 30min-60min; the third stage is 120℃-140℃, 0.5MPa-0.8MPa, held for 60min-120min; and the fourth stage is 160℃-180℃, 0.5MPa-0.6MPa, held for 120min-240min.

[0015] In one preferred embodiment of the present invention, the method for preparing a carbon-reinforced resin-based composite material wheel further includes: post-processing the wheel after molding, the post-processing including sensor embedding and surface treatment.

[0016] The present invention also discloses a carbon-reinforced resin-based composite material wheel, which is prepared by the above-described preparation method.

[0017] Compared with the prior art, this application has the following advantages: 1. The method for preparing carbon-reinforced resin-based composite material wheels of the present invention uses a three-level synergistic design of "material-structure-process" to precisely guide the nano-reinforcement effect of VACNT to the most needed areas (such as interlayer, hole edge, interface), and combined with non-uniform topology optimization of the connection structure to disperse and reduce stress concentration from the source, and finally obtain a next-generation composite material wheel with ultra-high strength, high damage tolerance and long fatigue life.

[0018] 2. By combining gradient VACNT with biomimetic irregular holes, this invention enables the wheel to achieve a 50%-150% improvement in key indicators such as interlaminar shear strength, post-impact compressive strength, and bolt hole extrusion fatigue life compared to traditional CFRP wheels. Some performance characteristics reach or even exceed those of traditional aluminum alloy forgings, while also achieving significant weight reduction.

[0019] 3. This invention not only provides local "reinforcement", but also actively guides and redistributes load paths through irregular hole design and directional arrangement of VACNTs, transforming harmful concentrated stress into relatively uniformly distributed load-bearing stress, fundamentally improving the damage tolerance of the structure.

[0020] 4. The gradient VACNT preform preparation and electric field-assisted molding process proposed in this invention is highly compatible with industrial automated placement and liquid molding technology. The process is clear and the parameters are controllable. It solves the engineering application problems of uneven dispersion and difficult orientation control of nanomaterials in macroscopic components, and ensures the stability and repeatability of product performance.

[0021] 5. Thanks to the three-dimensional continuous conductive / thermal network constructed by VACNT, the resulting wheel transcends the single load-bearing function and possesses potential multi-functional characteristics such as in-situ health monitoring, electromagnetic shielding, and anti-icing, thus expanding its application prospects in intelligent equipment.

[0022] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a method for preparing a carbon-reinforced resin-based composite material wheel according to one embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0027] This invention discloses a method for preparing a carbon-reinforced resin-based composite material wheel, such as... Figure 1 As shown, it includes the following steps: Step (1): Prepare vertically aligned carbon nanotube / carbon fiber preforms with a gradient density distribution; specifically, this includes: Step (101): Using a polymer transfer film or carbon fiber fabric as a growth substrate, gradient vertically aligned carbon nanotubes are grown on the growth substrate; specifically, the customized growth of vertically aligned carbon nanotube (VACNT) arrays: using an improved plasma-enhanced chemical vapor deposition (PECVD) process, VACNTs are directly grown on the surface of a flexible polymer transfer film or specially treated carbon fiber fabric; by real-time control of the reactive gas flow rate, plasma power and substrate temperature, VACNT arrays with gradient height (10-100 μm) or gradient density can be prepared in different regions of the same substrate to meet the different requirements of different regions for the degree of interlayer reinforcement; The specific steps are as follows: S1: Substrate pretreatment: Flexible polyimide film (thickness 25-50μm) or plasma-activated carbon fiber fabric is used as the growth substrate; for carbon fiber fabric, oxygen plasma treatment is first performed (power 100W, treatment time 3-5min) to introduce oxygen-containing functional groups on its surface; then an iron / cobalt / nickel catalyst layer is deposited on the growth substrate by impregnation or electron beam evaporation, and the thickness of the catalyst layer is controlled at 1-5nm; S2: PECVD Growth: The growth substrate loaded with the catalyst is placed in a plasma-enhanced chemical vapor deposition reaction chamber, and the vacuum is evacuated to a background pressure ≤1×10⁻⁶. -3 Pa, after heating to the growth temperature, introduce reaction gas and turn on the radio frequency plasma source to grow VACNT; S3: Gradient control: Gradient growth is achieved in different regions of the same substrate by using a movable shield or a zoned independent temperature control electrode; the specific operation is as follows: during the growth process, the shield is gradually moved so that different regions are exposed to plasma for different times, thereby achieving a height gradient; or the substrate temperature is distributed in a gradient by zoned heating to achieve a density gradient. The specific control range of PECVD process parameters is shown in Table 1. Table 1: PECVD Process Parameters

[0028] Step (102): Lay carbon fiber bundles and use the growth substrate with gradient vertically aligned carbon nanotubes as the interlayer material, simultaneously laying them after each layer of carbon fiber is laid; specifically, using automated fiber placement (AFP) or three-dimensional weaving technology, carbon fiber bundles are laid according to the stress characteristics of substructures such as spokes and rims in the wheel to form a near-net-shape preform; during the laying process, the aforementioned transfer film with gradient VACNTs is simultaneously introduced as the interlayer interface material, so that the roots of the VACNTs are embedded in the uncured resin (if dry fibers are used, they are impregnated during subsequent injection); among which, for areas with interlayer shear stress ≥50MPa, a surface density ≥5×10 is used. 10 root / cm 2 Vertically aligned carbon nanotube films with heights ranging from 30 μm to 100 μm; for regions where in-plane load-bearing is dominant, areal density ≤ 1 × 10⁻⁶ is used. 10 root / cm 2 Vertically arranged carbon nanotubes or pure resin layers with a height of 10μm-20μm; Preferably, an automatic fiber layup (AFP) equipment is used. Based on the principal stress flow line distribution diagram obtained from the finite element analysis of the wheel, T800 / T1100 grade carbon fiber bundles (bundle specifications 12K-24K) are laid in the spoke area along the principal stress direction, with a laying angle deviation ≤ ±2°; the rim area adopts a [±45° / 0° / 90°]s quasi-isotropic layup; and the transfer film with gradient VACNT from step (1) is introduced synchronously as an interlayer interface material, and is laid synchronously after each layer of carbon fiber is laid; wherein the operating parameters are: laying speed is 5-15m / min, pressure roller pressure is 0.2-0.5MPa, and heating temperature is 40-60℃ (to make the surface of the prepreg slightly melted); Step (103): After the paving is completed, it is densified and compacted to form a near-net-shape preform, wherein the densified area is an annular area extending 10mm-15mm outward from the center of the bolt holes; specifically, it includes: Step (1031): After step (102) is completed, add 2-3 layers of high-density VACNT membrane at the planned bolt hole positions, with each layer laid at a 45° angle to form a three-dimensional interlocking network. Step (1032): Perform intermediate pre-compaction every 4-6 layers, with a vacuum degree ≥ -0.095MPa, a pressure holding time of 5-10 minutes, and a temperature of 40-50℃ to remove interlayer air bubbles and initially fix the VACNT position; Step (1033): Near-net-shape cutting. Based on the three-dimensional digital model of the wheel, the preform after being laid up is cut into contours using ultrasonic cutting or laser cutting equipment with a cutting accuracy of ±0.2mm to form a near-net-shape preform and obtain a gradient vertically arranged carbon nanotube / carbon fiber preform. The core innovation of this step lies in abandoning the traditional approach of uniform layup and instead preparing prefabricated units with gradient VACNT distribution and customized fiber orientation based on the principal stress streamline distribution obtained from the finite element analysis of the wheel. VACNT density grading and shear stress threshold definition: (1) Definition of high shear stress zone: According to the design specifications for aerospace composite material structures and the stress analysis results of the wheel bolt hole area, the area with interlaminar shear stress ≥ 50 MPa is defined as the high shear stress zone. This threshold corresponds to the lower limit requirement of interlaminar shear strength of composite materials in ASTM D2344 standard, and is also the typical stress level of the wheel bolt connection area under ultimate load.

[0029] (2) The VACNT density classification is defined as shown in Table 2: Table 2: VACNT Density Classification

[0030] (3) Gradient transition method: Adjacent density areas adopt a gradual transition, and the width of the transition area is controlled within 5-10mm to avoid sudden performance changes; Step (2): Integral pore design on vertically aligned carbon nanotube / carbon fiber preforms; specifically, including: Irregular hole topology optimization: With the dual objectives of reducing the peak value of the maximum equivalent stress at the hole edge and improving the uniformity of stress distribution, the parametric level set method is used for topology optimization. The optimized hole shape is not a standard circle, but is composed of a series of smoothly transitioning curve segments. Its contour simulates the hole morphology in biological load-bearing structures such as bones, which can guide concentrated stress more evenly to the surrounding reinforced area. “Root-like” VACNT local reinforcement: In step (1) when preparing the gradient vertically arranged carbon nanotube / carbon fiber preform, a special VACNT insert is pre-implanted at the location planned as the bolt hole. The VACNT insert is positioned and implanted by a soluble mold. The insert is composed of a high-density, long (>50μm) VACNT array. The arrangement direction of the VACNT is not completely vertical, but is radial or tilted at a specific angle according to the stress field direction around the hole, resembling the root system of a plant. During the subsequent resin impregnation and curing process, the insert can form an extremely strong three-dimensional interlocking reinforcement zone with the surrounding composite material, effectively inhibiting the delamination at the hole edge and the propagation of cracks along the interlayer. Among them, the density range of VACNT plug-in: the root-type VACNT local reinforcement adopts an ultra-high density VACNT array, and the areal density range is defined as: ≥1×10 11 root / cm 2 (That is, 100 billion per square centimeter); Preferred range: 1×10 11 -5×10 11 root / cm 2 ; At this density, the spacing between VACNTs is approximately 10-20 nm, forming a nearly continuous "forest" of carbon nanotubes, which can produce a significant nanoscale mechanical interlocking effect. VACNT arrangement direction and specific angle range: According to the finite element analysis results of the stress field at the edge of the perforated laminate, the maximum interlaminar shear stress occurs at a position of 66°-74° with respect to the loading direction, and the maximum interlaminar normal stress occurs at a position of 90° with respect to the loading direction. Accordingly, the tilt angle range of the VACNT plug is defined in Table 3 of this invention; Table 3: Tilting Angle Range of VACNT Plug-in

[0031] The VACNT plug-in preparation and implantation method includes the following steps: (1) Growth of materials with a height ≥ 50 μm and a density ≥ 1 × 10⁻⁶ on an independent substrate using PECVD process. 11 root / cm 2 VACNT array; (2) The VACNT array is processed into a ring insert that matches the shape of the irregular hole by laser cutting. The outer diameter of the VACNT insert is equal to the maximum profile of the irregular hole + 5-8mm (width of the reinforcement area), and the inner diameter of the VACNT insert is equal to the nominal diameter of the bolt. (3) Using water-soluble polyvinyl alcohol (PVA) 3D printing mold, the VACNT plug is positioned at the planned position of the bolt hole of the preform. When implanting, ensure that the free end of the VACNT faces the center of the hole and the tilt angle is consistent with the direction of the preset stress field. (4) During the subsequent VARTM injection process, the PVA mold dissolves in the injected resin, and the VACNT plug-in remains in place, forming a three-dimensional interlocking reinforcement zone. Step (3): The vertically arranged carbon nanotube / carbon fiber preform after integrated design processing is shaped. Among them, the mold and runner intelligent design: the molding mold is designed according to the geometric characteristics of the wheel, and the glue injection runner layout follows the principle of "from the inside out, from the core to the periphery" to ensure that the resin can first fully wet the VACNT dense area and key parts such as the irregular hole reinforcement plug-in, and avoid these areas from lacking glue due to the end of the resin flow. Multi-physics field synergistic curing: In the vacuum-assisted resin transfer molding (VARTM) process, an alternating electric field is introduced as an auxiliary process. In the pre-gel stage, a moderate DC or low-frequency AC electric field is applied to the electrodes embedded in the mold. Due to the excellent conductivity of VACNT, a slight dielectric force or Joule heating effect is generated under the action of the electric field, which helps to further align VACNT and improve its interfacial bonding with the resin. The curing regime adopts segmented temperature and pressure coupling control. The initial low pressure and low temperature allow the resin to flow and wet fully, while the subsequent pressure and temperature increase ensure complete curing and compaction of the structure. Specifically, including: Step (301) Mold preparation: A constant temperature controlled steel mold is used, and the inner wall of the mold cavity is coated with a high temperature release agent; the mold is designed with upper and lower molds and a side core pulling mechanism to form the complex spoke and rim structure of the machine wheel; Step (302) Precast body installation: The precast body prepared in step (2) with the irregular hole implantation completed is accurately placed into the mold cavity. After the mold is closed, the bolts are tightened evenly in diagonal order using a torque wrench, with a tightening torque of 50-80 N·m. Step (303) Vacuum establishment: Turn on the vacuum pump and evacuate the mold cavity. The vacuum degree should be ≤-0.098MPa (absolute pressure about 2.7kPa). Hold the pressure for 10-15 minutes and check the sealing. The leakage rate should be ≤5Pa / min. Step (304) Resin preheating: Preheat the low viscosity epoxy resin system (such as V601, RTM6, etc.) to 60-80℃ to reduce its viscosity to ≤300mPa·s, which is conducive to flow and wetting; Step (305) Injection: Under vacuum drive, preheated resin is injected into the mold cavity through multiple injection ports. The injection pressure is controlled within the range of 0.1-0.3MPa, the injection temperature is 60-80℃, and the injection flow rate is 50-200ml / min. The injection process continues until continuous resin flow is observed in the return tank without any bubbles. Step (306) Electric field application: After the glue is injected and before the gelation begins, the ionic viscosity of the resin is monitored online by the dielectric sensor embedded in the mold. When the ionic viscosity reaches 1.2 to 1.5 times the initial value, it is determined to be the gelation start point, triggering the electric field to stop, and the ring electrode integrated with the mold is turned on to apply an alternating electric field. Step (307) Curing: Curing is carried out according to the preset segmented temperature-pressure increase regime; Step (308) Demolding: After curing is complete and the machine wheel blank is cooled naturally to ≤60℃, open the mold and remove the blank; The AC electric field parameter range in step (306) is defined as follows: Based on the mature technology of AC dielectric monitoring through the insulating layer in the VARTM process, and the dielectric orientation mechanism of VACNT under the action of an electric field, the AC electric field parameter range defined in this invention is shown in Table 4: Table 4: AC electric field parameters

[0032] The specific implementation of the electric field application is as follows: ring-shaped copper electrodes are embedded in the upper and lower molds respectively, and the surface of the electrodes is coated with a high-temperature resistant insulating layer (polyimide film, 25μm thick); when the electric field is applied, VACNT rotates along the direction of the electric field due to its high aspect ratio and polarizability, achieving further vertical alignment; The specific range of values ​​for the segmented curing regime in step (307) is based on the mature curing process of medium-temperature curing epoxy resin system. Combined with the temperature field control requirements of thick cross-section composite materials, the segmented curing regime defined in this invention is shown in Table 5. Table 5: Segmented Solidification System

[0033] Preferred curing regime: 80℃ / 0.2MPa / 30min→100℃ / 0.4MPa / 45min→135℃ / 0.6MPa / 90min→180℃ / 0.5MPa / 120min→Oven cooling to below 60℃ for demolding; Pressure application method: Compressed gas is used to apply back pressure to the resin in the mold cavity, or a hydraulic press is used to apply mold closing pressure to the mold; Online monitoring of the molding process: Flexible thin-film fiber optic sensors or dielectric sensors are embedded in key locations of the mold (injection port, flow end, periphery of irregular holes, and spoke-rim corner) to monitor the resin flow front, degree of curing, and internal strain development in real time, providing a basis for dynamic adjustment of process parameters and realizing visualization and precise control of the molding process. Among them, the monitoring parameters are: Resin flow front: Employs a fiber optic grating (FBG) sensor array with a spatial resolution ≤5mm; Curing degree: Dielectric sensor, measurement frequency 100Hz-10kHz, real-time output of logarithmic curve of ionic viscosity; Internal strain: Fiber optic strain sensor, accuracy ±2με; Temperature: Thermocouple array, accuracy ±0.5℃; Feedback control logic: When the sensor detects that the flow front has reached the designated position, the corresponding dispensing port is closed in sequence; when the ionic viscosity inflection point (gel initiation) is detected, the next stage of the heating program is automatically started.

[0034] The preparation method of carbon-reinforced resin-based composite wheel also includes: post-processing the wheel after molding, including sensor embedding and surface treatment; specifically, performing necessary finishing on the wheel after molding; utilizing the intrinsic conductive network imparted to the composite material by VACNT, a printed or embedded sensor network can be integrated inside the wheel for real-time monitoring of wheel strain, temperature and damage, achieving structural health management (SHM); in addition, a high thermal conductivity and wear-resistant coating based on VACNT can be constructed in the rim friction area through surface treatment, further improving its performance as a mating component of the braking system.

[0035] The present invention also discloses a carbon-reinforced resin-based composite material wheel, which is prepared by the above-described preparation method.

[0036] This invention uses a three-level collaborative design of "materials-structure-process" to precisely guide the nano-reinforcement effect of VACNT to the most needed areas (such as interlayer, hole edge, and interface), and combines it with non-uniform topology optimization of the connection structure to disperse and reduce stress concentration from the source, ultimately obtaining a next-generation composite wheel with ultra-high strength, high damage tolerance and long fatigue life.

[0037] Example 1 Preparation of high-load wheel hubs for aerial drones Objective: To develop a carbon fiber composite main wheel hub suitable for medium-sized fixed-wing UAVs, requiring high impact toughness and ultra-long fatigue life.

[0038] Implementation details: Gradient preform fabrication: A three-dimensional woven wheel hub preform of T800 grade carbon fiber was used. In the high-shear region connecting the spokes and the central bushing of the hub, a surface density of 20 μg / cm³ was introduced. 2 (5×10) 10 root / cm 2 A high-density VACNT transfer film with a VACNT height of 30 μm was used; in the rim area, a surface density of 5 μg / cm³ was used. 2 A low-density membrane with a height of 15 μm. The fiber layup adopts a hybrid layup design of 0° / ±45° / 90°s based on the load simulation results.

[0039] Integrated hole design: A four-leaf clover-shaped irregular hole is optimized for wheel axle mounting holes. "Root-like" VACNT reinforcement inserts are pre-installed around the hole, with the VACNTs radiating outwards at a 15° angle. The inserts are positioned during the pre-forming stage using a soluble mold.

[0040] Intelligent molding: A custom-designed steel mold is used, and a pair of ring electrodes are integrated into the VARTM system to apply an AC electric field with a frequency of 1kHz and a field strength of 200 V / mm. The injected resin is a high-temperature resistant, high-toughness epoxy system (brand: Hexcel HexFlow®RTM6). The curing cycle is as follows: injection is completed at 120°C with low viscosity for 40 minutes; then cured at 180°C for 2 hours under 1 bar pressure.

[0041] Post-processing: After demolding, a flexible strain sensor array is attached to the inner wall of the wheel hub and connected to the built-in data interface.

[0042] Comparative Example 1 (Traditional Process): Using the same T800 carbon fiber and RTM6 resin, with ordinary nylon nanofiber toughening film used between layers, and the wheel axle hole is a standard circular hole, the conventional VARTM process (without electric field assistance) is used for curing.

[0043] The performance indicators of the turbine wheels prepared in Example 1 and Comparative Example 1 are compared as shown in Table 6.

[0044] Table 6: Performance indicators of the wheels obtained in Example 1 and Comparative Example 1

[0045] As can be seen from Table 6, the high-load wheel hub of the aviation UAV prepared in Example 1 of the present invention has better interlaminar shear strength, tensile fatigue life of wheel axle hole, residual compressive strength after drop hammer impact (10J) and radial limit load capacity than Comparative Example 1.

[0046] Example 2 Manufacturing of integrated wheels (including brake disc mating surfaces) for high-performance racing cars Objective: To manufacture integrated racing wheel hubs that meet extreme dynamic operating conditions and require integrated brake cooling functions.

[0047] Implementation details: Precast innovation: A hybrid weave of T1100 grade carbon fiber and basalt fiber is used to balance strength and heat resistance. At the bolt connection surfaces of the wheel spokes and brake discs, a double-layer high thermal conductivity VACNT membrane interlayer is innovatively used, with micron-sized diamond particles incorporated between the membranes to construct an axially efficient heat conduction pathway.

[0048] Unconventional bore design in conjunction with thermal management: Brake disc bolt holes are optimized into a near-elliptical shape with pressure relief grooves. The VACNT reinforcement insert around the bore also serves as a heat diffuser.

[0049] Enhanced molding process: High-pressure resin transfer molding (HP-RTM) is employed with an injection pressure of up to 20 bar to rapidly fill the dense preform with a fiber content of up to 60%. During the curing stage, pulsed pressure (frequency 0.1 Hz, amplitude ±3 bar) is applied to promote resin penetration into the VACNT clusters.

[0050] Functional integration: Utilizing the conductivity of VACNT on the inner side of the wheel rim, a copper circuit is selectively deposited by laser activation to form an embedded wheel speed sensor coil and temperature sensing unit.

[0051] Comparative Example 2 (Metal Matrix Composite): SiC particle-reinforced aluminum alloy wheel hub prepared by powder metallurgy.

[0052] The performance indicators of the turbine wheels prepared in Example 2 and Comparative Example 2 are compared as shown in Table 7.

[0053] Table 7: Performance indicators of the wheels obtained in Example 2 and Comparative Example 2

[0054] As can be seen from Table 7, the high-performance integrated racing wheel hub prepared in Example 2 of this invention has better room temperature shear strength of brake disc mating surface, high temperature shear strength of brake disc mating surface at 300℃, and track simulation full-cycle vibration attenuation rate than Comparative Example 2. Furthermore, the radial thermal deformation of the wheel hub under braking conditions in Example 2 is much smaller than that in Comparative Example 2.

[0055] In summary, the above embodiments fully demonstrate that the preparation method provided by this invention, through the deep synergy of material gradient design (VACNT), structural biomimetic optimization (irregular hole), and multi-field coupling process (electric field / pressure field), can systematically solve the inherent weaknesses of composite material wheels. The prepared wheels not only achieve a leap in static strength and fatigue life, but also exhibit comprehensive advantages in lightweighting, high temperature resistance, impact resistance, and functional integration that are unmatched by traditional metal wheels or conventional CFRP wheels. This preparation method has a clear route, well-defined parameters, and possesses high repeatability and potential for large-scale production.

[0056] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a carbon-reinforced resin-based composite material wheel, characterized in that, Includes the following steps: Prepare vertically aligned carbon nanotube / carbon fiber preforms with gradient density distribution; Integral pore design on vertically aligned carbon nanotube / carbon fiber preforms; The vertically aligned carbon nanotube / carbon fiber preform after integrated design is molded.

2. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 1, characterized in that: The preparation of the vertically aligned carbon nanotube / carbon fiber preform with a gradient density distribution includes: Polymer transfer membranes or carbon fiber fabrics are used as growth substrates to grow gradient vertically aligned carbon nanotubes. Carbon fiber bundles are laid out, and a growth substrate with gradient vertically aligned carbon nanotubes is used as an interlayer material, which is simultaneously laid out after each layer of carbon fiber is laid out. After the paving is completed, it is densified and compacted to form a near-net-shape preform.

3. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 2, characterized in that: The process involves using a polymer transfer film or carbon fiber fabric as a growth substrate to grow gradient-aligned vertically arranged carbon nanotubes. This includes: the growth substrate having a catalyst layer with a thickness of 1 nm-5 nm; and for regions with interlayer shear stress ≥50 MPa, using a surface density ≥5 × 10⁻⁶. 10 root / cm 2 Vertically aligned carbon nanotube films with heights ranging from 30 μm to 100 μm; for regions where in-plane load-bearing is dominant, areal density ≤ 1 × 10⁻⁶ is used. 10 root / cm 2 Vertically arranged carbon nanotubes or pure resin layers with a height of 10μm-20μm.

4. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 2, characterized in that: Carbon fiber bundles are laid out, and a growth substrate with gradient vertically arranged carbon nanotubes is used as an interlayer material. The substrate is laid out synchronously after each layer of carbon fiber is laid out, including: a laying speed of 5m / min-15m / min, a pressure roller pressure of 0.2MPa-0.5MPa, and a heating temperature of 40℃-60℃.

5. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 1, characterized in that: The integrated pore design on the vertically arranged carbon nanotube / carbon fiber preform includes: optimizing the pore shape on the vertically arranged carbon nanotube / carbon fiber preform using a parametric level set method, and inserting vertically arranged carbon nanotube inserts at the irregular pore locations.

6. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 5, characterized in that: The vertically arranged carbon nanotube inserts have an areal density ≥1×10 11 root / cm 2 It consists of vertically arranged carbon nanotube arrays with a length > 50 μm, and the arrangement direction of the vertically arranged carbon nanotubes is radially inclined at 15°-90° relative to the plane of the pore axis.

7. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 1, characterized in that: The molding process for the vertically aligned carbon nanotube / carbon fiber preform after integrated design processing includes: placing the vertically aligned carbon nanotube / carbon fiber preform after integrated design processing into a mold cavity, and then performing resin preheating, glue injection, electric field application, curing, and demolding processes.

8. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 7, characterized in that, The electric field application includes: applying an alternating electric field with a frequency of 10Hz-1kHz, an electric field strength of 100V / mm-500V / mm, and an application time of 5min-30min; the curing adopts a segmented temperature-pressure increase regime: the first stage is 60℃-80℃, 0.1MPa-0.3MPa, held for 20min-40min; the second stage is 90℃-110℃, 0.3MPa-0.5MPa, held for 30min-60min; the third stage is 120℃-140℃, 0.5MPa-0.8MPa, held for 60min-120min; and the fourth stage is 160℃-180℃, 0.5MPa-0.6MPa, held for 120min-240min.

9. The method for preparing a carbon-reinforced resin-based composite material wheel as described in claim 1, characterized in that, The method for preparing the carbon-reinforced resin-based composite wheel further includes: post-processing the wheel after molding, the post-processing including sensor embedding and surface treatment.

10. A carbon-reinforced resin-based composite material wheel, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.

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