Composite Propeller Blade Inserts for Rigidity and Delamination Resistance
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Solution Overview
Problem
Turbomachine blades made of composite materials face challenges with delamination due to impacts from foreign bodies and require rigidity for variable-pitch stator stages, which complicates their adaptation to different turbomachine types and performance needs.
Innovation Solution
Incorporating radial and axial inserts within the composite material structure of the blade, arranged in intersecting directions to enhance rigidity and allow for pitch modifications, combined with a manufacturing process that embeds these inserts during resin injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the blade uses high-density fibers with high modulus of elasticity to increase rigidity, then the blade can resist vibrations in bending and torsion, but the blade becomes more susceptible to delamination under impact from foreign bodies
Solution Approach 1:
The patent uses a composite fabric structure combining glass fibers and Kevlar® fibers in specific ratios (60-90% glass, 10-40% Kevlar®) to achieve both rigidity and impact resistance. The glass fibers provide stiffness while the Kevlar® fibers absorb impact energy, preventing delamination under foreign object impacts.
Solution Approach 2:
The patent implements different fiber density distributions along the blade height, with higher fiber density (60-90% area coverage) in the lower portion and reduced density (30-70% area coverage) in the upper portion. This local variation optimizes rigidity where needed while reducing weight and improving impact resistance in other regions.
2Reliability
If the fabric plies are arranged without cuts along the blade surface to improve impact resistance, then delamination weakness is reduced, but the blade becomes heavier and more difficult to manufacture
Solution Approach 1:
The patent divides the fabric reinforcement into multiple plies (at least two plies) with different orientations and properties. The first ply has fibers extending in the radial direction while the second ply has fibers extending in the axial direction, allowing each ply to be optimized for specific functions and simplifying the manufacturing process.
Solution Approach 2:
The patent varies the fiber orientation angles between plies, with the first ply having fibers at 0° to 30° relative to the radial direction and the second ply having fibers at 0° to 30° relative to the axial direction. This parameter variation optimizes both mechanical performance and manufacturability.
3Productivity
If the blade uses a wide chord design with large height and leading-to-trailing edge distance, then thrust performance is improved, but the blade becomes more exposed to foreign body impacts and more difficult to manufacture
Solution Approach 1:
The patent employs a composite structure with glass fiber/Kevlar® fiber fabric plies embedded in a thermosetting resin matrix, providing both the structural integrity needed for wide chord designs and enhanced resistance to foreign object impacts through the ductile behavior of Kevlar® fibers.
Solution Approach 2:
The patent applies different fiber density distributions along the blade height, with higher density (60-90% area coverage) in the lower portion and reduced density (30-70% area coverage) in the upper portion, optimizing the balance between structural strength and impact resistance in the wide chord configuration.
Data Source
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AI summary
The present invention relates to a blower vane (1) of a turbomachine, comprising a structure made of composite material which comprises a fibrous reinforcement (11) and a matrix in which the fibrous reinforcement (11) is embedded. The vane (1) comprises a first rigidification insert (20) which extends in a first direction and at least one second insert (21) which is connected to the first in a second direction which is non-collinear with the first direction, the first insert (20) projecting from the vane (1) in order to be connected to a disc of a turbomachine element.