Composite Fan Blade Stiff Fiber Insert for Untwisting Control
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Solution Overview
Problem
Fan blades made of composite materials experience significant untwisting due to differential movement of the leading and trailing edges under varying engine speeds, leading to suboptimal aerodynamic performance, particularly during climb and cruise modes.
Innovation Solution
The fan blade design incorporates a fibrous reinforcement structure with varying stiffness along its length, utilizing both first and second strands of carbon fibers, where the second strands are more densely present at the leading edge to reduce untwisting, and a metal shield to manage ingestion resistance, while a third portion with gradually decreasing second strand density transitions between different sections to minimize material discontinuities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal shield is attached to the leading edge to improve ingestion resistance, then the blade's resistance to rapid dynamics ingestion is improved, but the blade's stiffness increases and additional mass is added which increases centrifugal forces near the leading edge
Solution Approach 1:
The patent extracts the ingestion protection function from a traditional metal shield and relocates it to a leading edge insert made of stiff fibers (such as carbon or quartz fibers). This insert is integrated into the composite blade structure during manufacturing, replacing the need for a separate metal shield attachment while maintaining ingestion resistance.
Solution Approach 2:
The patent uses a composite material approach by incorporating an insert of stiff fibers (carbon or quartz) into the leading edge of the blade. This insert is embedded within the composite structure consisting of a polymer matrix and fiber reinforcement, creating a multi-material composite solution that provides both ingestion resistance and optimized mechanical properties.
2Weight of moving object
If the blade is made of composite material to reduce weight, then the blade weight is reduced compared to metal blades, but the blade experiences significant and uneven deformation under centrifugal loading and aerodynamic pressures
Solution Approach 1:
The patent applies local quality by creating regions of different stiffness within the blade structure. A leading edge insert made of particularly stiff fibers (carbon or quartz) is placed in the leading edge region, while the rest of the blade uses standard composite materials. This local reinforcement addresses the deformation issue specifically where it occurs most without unnecessarily increasing weight throughout the entire blade.
Solution Approach 2:
The patent employs composite materials consisting of a polymer matrix and fiber reinforcement (such as carbon, glass, or quartz fibers) to create a lightweight blade structure. The composite material provides both weight reduction and adequate mechanical properties, with the fiber orientation and distribution optimized to resist deformation under operational loads.
3Productivity
If the pitch angle is optimized for top of climb or cruise regime, then the aerodynamic performance is optimized for the desired flow rate, but the pitch angle at other operating points results in suboptimal performance due to blade untwisting
Solution Approach 1:
The patent applies local quality by reinforcing specific regions of the blade (leading edge and extrados wall) with inserts of stiff fibers. This localized stiffening prevents unwanted blade untwisting and deformation while maintaining the optimized pitch angle geometry designed for top of climb or cruise regime performance, thereby preserving aerodynamic efficiency across different operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design balances the stiffness of the blade to reduce untwisting and maintain aerodynamic performance across different engine speeds, ensuring consistent movement and reduced pitch angle differences, thereby enhancing the fan's operational efficiency.
Implementation Method 1
a blade made of a composite material comprising a fiber reinforcement and a matrix in which the fiber reinforcement is embedded, characterized in that the fiber reinforcement (5) comprises an insert of stiff fibers (13) in the leading edge region
Implementation Method 2
In static conditions, each fan blade is subjected to centrifugal loading and aerodynamic pressures
Implementation Method 3
blades made from a composite material comprising a fiber reinforcement densified by a polymer matrix, which are lighter than metal blades with equivalent propulsive characteristics
Implementation Method 4
blades made from a composite material comprising a fiber reinforcement densified by a polymer matrix, which are lighter than metal blades with equivalent propulsive characteristics and which have satisfactory heat resistance
Data Source
Figure 1
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Figure 4
AI summary
The present invention relates to a fan blade (3) having a structure made from a composite material, comprising a fibrous reinforcement (5), which is obtained by three-dimensional weaving of warp strands and weft strands, and a matrix in which the fibrous reinforcement (5) is embedded, wherein - the fibrous reinforcement (5) comprises a first portion (14) forming the trailing edge (9) of the structure made from a composite material and a second portion (15) forming its leading edge (8), and wherein - the warp strands of the fibrous reinforcement (5) comprise first strands (12) having a predetermined stiffness and second strands (13) having a greater stiffness than that of the first strands (12), the first portion (14) comprising all or part of the first strands (12) and being devoid of second strands (13) while the second portion (15) comprises all or part of the second strands (13).