Turbomachine Blade Leading Edge Shield Fin Detachment
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Solution Overview
Problem
Existing leading edge shields for turbomachine blades are prone to partial detachment during impacts due to deformation peaks that can propagate and cause fin detachment, especially when made of composite materials with fibers oriented perpendicular to the main direction of mechanical resistance.
Innovation Solution
A leading edge shield with an inclined rear edge, specifically an angle of intersection less than 60° between the tangent at the rear edge and the upper edge, is used to prevent detachment, made of metallic materials like titanium alloys or Inconel, which are more resistant to bending forces and impact energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rear edge of the fin is aligned with the main direction of mechanical resistance of the composite blade body, then the fin positioning is simplified, but the fin becomes prone to detachment during impact due to lower mechanical resistance perpendicular to the fiber direction
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the rear edge of the fin with the main direction of mechanical resistance of the composite blade body. This asymmetric positioning ensures that the fin rear edge is not perpendicular to the fiber direction, thereby preventing detachment while maintaining manufacturing feasibility through adjusted bonding surfaces.
Solution Approach 2:
The patent applies local quality by creating a specific localized geometric configuration at the fin-rear edge junction. The rear edge is designed with a specific angle relative to the main direction of mechanical resistance, providing enhanced detachment resistance precisely where needed without affecting the overall blade structure or manufacturing process significantly.
2Weight of moving object
If a thin fin structure is used for the leading edge shield, then the shield weight is reduced, but the fin becomes more susceptible to detachment due to lower structural rigidity
Solution Approach 1:
The patent applies local quality by creating a specific localized geometric configuration at the fin-rear edge junction. The rear edge is designed with a specific angle relative to the main direction of mechanical resistance, providing enhanced detachment resistance precisely where needed without affecting the overall blade structure or manufacturing process significantly.
Solution Approach 2:
The patent applies curvature by designing the rear edge of the fin with a specific angular orientation rather than a straight alignment. This curved or angled configuration helps distribute impact forces more effectively and prevents stress concentration that would lead to detachment, while maintaining the thin profile of the fin.
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
The inclined design of the shield reduces the likelihood of fin detachment by avoiding alignment with the fibers, thus enhancing resistance to impact forces and preventing local detachment along the rear edge, ensuring better protection and stability of the blade.
Implementation Method 1
deformation waves will propagate through this shield, including the fins, until they are entirely dissipated therein
Implementation Method 2
The anisotropic material can thus resist the bending forces of this blade. This anisotropic material may in particular be a composite material reinforced with fibers oriented along at least said main direction of mechanical strength.
Data Source
Figure 1~3
AI summary
The invention relates to a blade which comprises a blade body (30) made of anisotropic material and a leading edge shield (32) made of a material having better resistance to isolated impacts assembled on the blade body and including two fins, each extending over a height from a lower edge (50) to an upper edge (51) and connected to one another via the leading edge (18), at least one fin having a segment (SI) adjacent to the upper edge and extending over at least 6% of the height thereof. An intersection angle (a) between a tangent to the upper edge and to any given point of the rear edge in said segment is less than 75°. An angle (β) of the main direction of mechanical resistance relative to said upper edge is substantially greater than a maximum value of said intersection angle.