Wound Composite Roots for Compact Variable-Pitch Propeller Blades
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Solution Overview
Problem
Existing turboprop engine blades and propeller airfoils made of metallic materials are heavy, and those made of composite materials face challenges in manufacturing compact roots with axisymmetric shapes and resisting mechanical loads, especially when incorporating variable-pitch systems.
Innovation Solution
A method for manufacturing composite material blades using three-dimensional weaving to create a fiber reinforcement with a non-interlinking root part, wound around an insertion element, ensuring a compact and mechanically resilient root shape suitable for variable-pitch systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic material is used for blade or airfoil, then mechanical resistance is improved, but mass increases
Solution Approach 1:
The patent employs composite materials consisting of fiber reinforcement (such as carbon or glass fibers) embedded in a matrix material to manufacture propeller airfoils. This composite structure provides high mechanical resistance while maintaining low mass, directly resolving the contradiction between strength and weight. The fibers carry the primary mechanical loads while the matrix binds them together and distributes stresses.
2Adaptability or versatility
If compact root shape is implemented, then adaptability to variable-pitch systems is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent incorporates reinforcement elements (such as fibers or stiffening structures) into the root region during the initial manufacturing process, before the blade is assembled into the variable-pitch system. This preliminary reinforcement ensures that the compact root shape can withstand the mechanical loads and stresses it will encounter during operation, while maintaining the manufacturing feasibility of the overall structure.
3Strength
If 3D weaving is used for fiber reinforcement, then mechanical resistance is improved, but manufacturing compact axisymmetric root becomes more difficult
Solution Approach 1:
The patent divides the blade structure into distinct regions: the aerodynamic profile portion and the root portion. The 3D woven fiber reinforcement is primarily applied to the aerodynamic profile where it provides excellent mechanical resistance, while the root portion uses a different manufacturing approach or reinforcement strategy that is better suited for achieving compact axisymmetric shapes. This segmentation allows each region to be optimized for its specific functional requirements.
4Reliability
If root is incorporated into rotor disc with metallic shells, then structural integration is improved, but additional circumferential compression load is generated
Solution Approach 1:
The patent applies different material properties and structural characteristics to different parts of the blade. Specifically, the root region is designed with local quality enhancements such as increased fiber density, specialized reinforcement patterns, or modified geometry to better withstand the circumferential compression loads generated during operation. This localized optimization allows the blade to maintain good structural integration with the rotor disc while managing the additional stresses.
Data Source
AI summary
A turboprop engine blade or propeller airfoil made of composite material includes a fiber reinforcement densified by a matrix, the blade or propeller airfoil including along a longitudinal direction a root and an aerodynamic profile. The fiber reinforcement includes a fiber preform having a three-dimensional weave with a root preform part located in the root and an aerodynamic profile part located in the aerodynamic profile, the root preform and aerodynamic profile parts being connected to one another by three-dimensional weaving. The root preform part includes two woven skins wound around an insertion element.