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CN-121989467-A - Carbon fiber propeller blade and preparation method thereof

CN121989467ACN 121989467 ACN121989467 ACN 121989467ACN-121989467-A

Abstract

The invention relates to the technical field of unmanned aerial vehicle propeller blades, in particular to a carbon fiber propeller blade and a preparation method thereof, wherein the carbon fiber propeller blade comprises a foam sandwich, a carbon fiber skin coated outside the foam sandwich and a pull-out resistant annular piece pre-buried inside a propeller root, the carbon fiber skin comprises three areas with different thicknesses and layering structures along the expanding direction of the blade, namely a propeller root anchoring area, a stress transition area and a pneumatic blade body area, the characteristic ratio of the thickness of the cross section between the thickness of the skin of the propeller root anchoring area and the average thickness of the skin of the pneumatic blade body area is in the range of 5.0-6.0, so that the expanding direction of the blade forms a controllable rigidity gradient.

Inventors

  • LU FAN

Assignees

  • 嘉兴市隆鑫碳纤维制品有限公司

Dates

Publication Date
20260508
Application Date
20251229

Claims (9)

  1. 1. The carbon fiber propeller blade comprises a foam sandwich, a carbon fiber skin coated outside the foam sandwich and a pull-out-resistant annular piece pre-buried inside a propeller root, and is characterized in that the carbon fiber skin comprises a propeller root anchoring area, a stress transition area and three areas with different thicknesses and layering structures in the span direction of the blade; The characteristic ratio of the thickness of the section between the thickness of the skin of the blade root anchoring area and the average thickness of the skin of the aerodynamic blade body area is in the range of 5.0-6.0, so that the blade has controllable rigidity gradient in the spanwise direction.
  2. 2. The carbon fiber propeller blade according to claim 1, wherein the characteristic ratio of the section thickness is K=T1/T3, T1 is the maximum skin thickness of the root anchoring area, the range of the maximum skin thickness is 3.8 mm-4.2 mm, The skin thickness T2 of the stress transition area transits from T1 to T3 in a nonlinear mode along the span direction of the blade, and satisfies T2 which is more than or equal to 1.2mm and less than or equal to 1.6mm, The average skin thickness T3 of the pneumatic blade body region is in a value range of 0.6 mm-0.8 mm, so that the thickness distribution of the three regions forms a continuously-measurable gradual boundary.
  3. 3. A carbon fiber propeller blade according to claim 2, wherein the interface structure of the root anchor zone comprises a metallic phase, a resin phase, and a fibrous phase; the metal phase is a pull-out-resistant annular part, the cross section of the metal phase is of a concentric ring structure, the outer diameter of the metal phase is 12mm, and the inner diameter of the metal phase is 8mm; The resin phase is a compact resin layer surrounding the annular piece and is used for forming interface occlusion with the microstructure on the surface of the annular piece; the fiber phase is a thickened carbon fiber reinforced layer and is used for forming cladding on the metal phase and the resin phase, so that the blade root forms a stable high-strength bearing interface.
  4. 4. A carbon fiber propeller blade according to claim 3, wherein the carbon fiber skin is formed by stacking a plurality of prepreg layers, and different areas adopt different layering angles; The pneumatic blade body area adopts an orthogonal laying mode mainly comprising a 0-degree spanwise direction and a 90-degree chordwise direction, wherein 0-degree layers account for 45% -55% of the total layer number; The anchoring area of the blade root adopts a +/-theta spiral winding layer, so that the +/-theta spiral winding layer accounts for 60% -70%; the stress transition area is paved in a stepwise staggered mode layer by layer, the distance between any adjacent stacking faults is larger than 5mm and is not larger than 12mm, a continuous transition interface is established, a layering sequence is limited to be an odd number of layers, the glue content of each layer of prepreg is controlled within the range of 35% -42% in the paving process, and the thickness deviation is +/-0.02 mm, so that the transition boundary between areas is clear and interlayer bonding is sufficient.
  5. 5. The carbon fiber propeller blade according to claim 4, wherein the blade is provided with a static negative torsion deviation in the aerodynamic blade body region, so that the spanwise torsion angle of the blade when unloaded is smaller than the designed aerodynamic angle by 0.5-1.0 DEG, wherein the torsion deviation is: ; Wherein, the For the static angle of the blade measured after molding, When the power system runs at 4200rpm plus or minus 200rpm for a target working angle, the blade spanwise warps elastically under the action of centrifugal load and pneumatic bending moment, and the blade tip displacement is 130mm plus or minus 10mm, so that the static negative torsion deviation is compensated and restored to the target pneumatic shape.
  6. 6. The carbon fiber propeller blade according to claim 5, wherein the carbon fiber skins have different resin volume distributions in the thickness direction, wherein the fiber volume fraction of the blade body area is 58% -62%, the stress transition area is 52% -56%, the resin enrichment zone width formed around the metal piece by the blade root anchoring area is 0.8 mm-1.2 mm, and the porosity of the area is less than 1%.
  7. 7. A method of manufacturing a carbon fiber propeller blade according to any one of claims 1 to 6, comprising the steps of: s1, determining a required static pre-deformation value, thickness gradient and layering angle distribution based on a target pneumatic load and centrifugal load, and generating a regional thickness distribution map; s2, performing differential cutting on the foam core material according to the thickness distribution in the step S1 to form a preformed foam sandwich with a non-pneumatic appearance; step S3, sequentially paving prepregs with different thicknesses on the foam sandwich, implanting a pull-out-resistant annular piece in the paddle root anchoring area, and arranging a reinforcing layer around the metal piece; and S4, controlling the temperature rise rates of different areas of the die to realize the internal flow of the resin under the drive of the thickness difference of the areas and obtain an integrated structure after solidification.
  8. 8. The method for manufacturing a carbon fiber propeller blade according to claim 7, wherein the step S4 comprises: S41, applying a rapid heating rate of 3.5-4.5 ℃ per minute to a mold pneumatic blade body region, enabling the temperature of the region to reach 95-105 ℃ within 5min, locking the fiber position by using a rapid gel effect, and inhibiting resin outflow, so that the volume fraction of the solidified fiber in the region reaches 58-62%; S42, maintaining a constant temperature stage of 75-85 ℃ in a paddle root anchoring area for 20-23 min, so that the viscosity of the resin in the area is kept at a low viscosity window of 300-500 mPa.s; meanwhile, a pressure gradient of 0.6-0.8 MPa is established by monitoring the viscosity ratio of the blade body area to the blade root area, and the resin is induced to directionally migrate to the blade root anchoring area and infiltrate the surface microstructure of the drawing-resistant annular piece; S43, uniformly raising the whole die cavity to a curing temperature of 128-132 ℃ and keeping the die cavity for 95-105 min, applying auxiliary vibration with the frequency of 50-80 Hz to raise the interface wettability, and controlling cooling at a rate of 0.5-0.8 ℃ after curing is finished so as to control the internal residual stress below 8 MPa.
  9. 9. The method for manufacturing a carbon fiber propeller blade according to claim 8, wherein the step S3 comprises the following steps: S31, before the pull-out-resistant annular piece is implanted, carrying out micro-sand blasting roughening or chemical etching treatment on the outer surface of the annular piece to enable the surface roughness Ra of the annular piece to reach a limiting value, and then coating a modified epoxy high-toughness transition layer with the thickness of 0.1 mm-0.15 mm on the surface of the annular piece; s32, adopting automatic layering equipment, and according to an angle distribution function: executing a layering path, and arranging + -theta layers around the annular piece in the paddle root anchoring zone; S33, monitoring the thickness deviation and the dislocation distance of the paved layer in real time in the paving process, if the deviation exceeds +/-0.015 mm, adjusting a subsequent paved layer path through a feedback loop, and finely adjusting the torsion angle deviation by 0.6-0.9 degrees according to the pre-deformation value generated in the step S1 so as to ensure that the difference between the static geometric angle of the demoulded blade and the target working angle is controlled within the range of 0.7 +/-0.1 degrees.

Description

Carbon fiber propeller blade and preparation method thereof Technical Field The invention relates to the technical field of unmanned aerial vehicle propeller blades, in particular to a carbon fiber propeller blade and a preparation method thereof. Background The rapid development of Unmanned Aerial Vehicle (UAV) technology has led to the propeller blades as their key power components, playing a vital role in terms of flight performance, energy efficiency and reliability. Early propellers relied primarily on metal or plastic materials, but with the increasing demand for light weight, high strength and low noise, carbon fiber composites became the dominant choice. The material is widely applied to the fields of agricultural plant protection, logistics distribution, military reconnaissance and the like by virtue of the excellent strength-weight ratio, fatigue resistance and pneumatic adaptability. However, at high rotational speeds, 4200rpm and complex loading conditions, carbon fiber propeller blades still face challenges including vibration resonance, root stress concentration, interfacial delamination, and out of control aerodynamic deformation. These problems not only shorten the blade life, but may also cause flight safety hazards. For example, publication number CN111531767B discloses a method for preparing an unmanned aerial vehicle propeller made of an inorganic fullerene carbon fiber composite material, and proposes that the wear resistance, bending resistance and impact resistance of the propeller are improved by adding an inorganic fullerene reinforced carbon fiber matrix. The method relates to material formula optimization, forming and curing processes, and is suitable for light-weight manufacturing of the medium-sized unmanned aerial vehicle propeller. However, the design does not consider nonlinear distribution of the spanwise thickness, so that the rigidity gradient is difficult to regulate and control, a high shear peak value is easy to generate in a stress transition region, meanwhile, the regional resin flow control is lacked, the fiber volume fraction is uneven, the interface porosity is high, and the vibration resonance and delamination risks under high rotating speed are difficult to effectively inhibit. Similarly, the publication number CN102795338B, a method for manufacturing a carbon fiber rotor wing of a microminiature unmanned aerial vehicle, focuses on the molding technology of the carbon fiber rotor wing of the microminiature unmanned aerial vehicle, and uses vacuum-assisted resin transfer molding to realize an integrated structure. This emphasizes material lamination and curing parameter optimization to improve strength-to-weight ratio. The blade root has limited bearing capacity, the drawing load is difficult to reach more than 160kN, the pneumatic appearance design depends on the traditional two-dimensional phyllin theory, the bending-torsion coupling and the frequency isolation are ignored, the vibration frequency of a power system is easy to coincide, in addition, the temperature gradient induction resin migration is not realized in the preparation process, the toughness gradient is weak, and the elastic compensation requirement under complex load cannot be met. For another example, the publication number CN107609243B, a design method of propeller blade, based on the optimal load distribution curve, avoids three-dimensional numerical optimization, directly designs the shape of the small and medium unmanned aerial vehicle propeller, shortens the period to 1-2, while being effective in improving aerodynamic efficiency, does not integrate the characteristics of carbon fiber materials, and is limited to two-dimensional theory, resulting in interface strengthening deficiency, low drawing load, unquantized isolation of frequency design, easy resonance, lack of pre-deformation compensation, uncontrollable deformation. Bulletin number CN109992893A, a propeller aerodynamic profile optimization design method adopts a proxy optimization algorithm to perform aerodynamic optimization on a profile airfoil, and improves hovering efficiency based on an unsteady N-S equation. The method is suitable for multi-rotor unmanned aerial vehicle, but is limited in that the method is not applied to designated carbon fibers, a resin enrichment area is not optimized, the toughness gradient is weak, the calculation depends on multiple N-S solutions, the time consumption is long, the three-phase coupling or vibration isolation is not involved, and the deformation control precision is not sufficient. Disclosure of Invention Therefore, the invention aims to provide the carbon fiber propeller blade and the preparation method thereof, and the vibration suppression, the interface toughness and the aerodynamic efficiency are improved through the nonlinear thickness characteristic ratio, the layering angle change and the regional difference rheological curing process, so that the carbon fiber propeller blade is su