Composite Fan Blade Delamination Control
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Solution Overview
Problem
Composite fan blades in gas turbine engines face delamination issues during impact events, which are currently addressed by reinforcement methods like z-pinning, but these increase the cost and weight of the blades.
Innovation Solution
A composite fan blade design incorporating a deflector region with a high strain energy release rate and a delamination region with minimal reinforcement, allowing delamination to occur in a controlled manner that minimizes performance impact, with the deflector region deflecting delamination away from critical areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If z-pins are used to reinforce the fan blade, then delamination resistance is improved, but cost and weight increase
Solution Approach 1:
The patent applies local quality by creating distinct regions with different properties: a deflector region with high strain energy release rate (≥4000 J/m²) that resists delamination, and a delamination region with lower strain energy release rate where delamination is permitted. This localized differentiation allows reinforcement only where necessary, reducing overall weight while maintaining delamination resistance in critical areas.
Solution Approach 2:
The fan blade is segmented into functionally distinct regions: a deflector region that actively prevents delamination through high strain energy release rate characteristics, and a delamination region where delamination is controlled to occur. This segmentation allows the blade to manage delamination locally rather than requiring uniform reinforcement across the entire structure.
2Strength
If z-pins are used to reinforce the fan blade, then delamination resistance is improved, but manufacturing cost increases
Solution Approach 1:
By concentrating reinforcement characteristics only in the deflector region rather than uniformly across the entire blade, the patent reduces material costs and manufacturing complexity. The deflector region's high strain energy release rate properties are localized to where delamination resistance is most critical, eliminating the need for expensive full-blade z-pin reinforcement.
Solution Approach 2:
The patent accepts that delamination will occur in the designated delamination region, treating this as a controlled, acceptable failure mode. This approach eliminates the need for expensive permanent reinforcement in areas where delamination is permitted, reducing manufacturing costs while maintaining overall blade integrity through the deflector region.
3Weight of moving object
If delamination is permitted in the delamination region, then weight is reduced, but component performance may be impacted
Solution Approach 1:
The patent ensures that the deflector region maintains sufficient structural integrity to preserve critical functions even when delamination occurs in the delamination region. The high strain energy release rate of the deflector region (≥4000 J/m²) provides a safety margin that maintains blade performance and reliability while allowing weight reduction through the delamination region.
Solution Approach 2:
The patent converts the potential harm of delamination into a beneficial weight reduction strategy by designating specific delamination regions where delamination is permitted. This controlled approach transforms what would normally be a failure mode into a deliberate weight-saving feature, while the deflector region ensures performance is maintained.
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 maintains the natural frequency of the blade post-delamination, reduces weight by allowing delamination in non-critical areas, and achieves a strain energy release rate suitable for effective delamination management, while minimizing the need for extensive reinforcement.
Implementation Method 1
The average strain energy release rate of the deflector region is equal to or greater than 4000 J/m2
Data Source
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AI summary
A composite component having a body formed from a plurality of fibre reinforced non-metallic layers. The body comprises a delamination region configured so as to permit delamination; and a deflector region configured so as to resist delamination. In the event of delamination, delamination is deflected to and continues to propagate in the delamination region.