Variable-Density Composite Blade Leading Edge
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Solution Overview
Problem
Aeronautical gas turbine engine blades with metal leading edges made of composite materials face deformation under high-speed foreign body impacts, leading to increased stiffness and mass, which exacerbates centrifugal forces at critical areas like the stilt.
Innovation Solution
A manufacturing process for composite material blades with a metal leading edge featuring variable density zones, where the highest density material is used in the most impact-sensitive areas and lower density materials in less exposed areas, achieved through additive manufacturing and strategic bonding, reducing overall mass and static stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the leading edge is increased to increase stiffness, then the impact resistance is improved, but the overall mass of the leading edge is significantly increased
Solution Approach 1:
The leading edge is designed with non-uniform thickness distribution, where the thickness varies along the longitudinal direction. The thickness is greatest at the lower end (near the stilt) and decreases toward the upper end (near the blade tip). This local variation in geometry provides the necessary stiffness in the most critical area while minimizing mass in less critical areas, thereby resolving the contradiction between strength and weight.
Solution Approach 2:
The leading edge is divided into multiple zones with different thickness characteristics. The lower portion (first zone) has greater thickness for maximum stiffness requirements, while the upper portion (second zone) has reduced thickness. This segmentation allows each zone to be optimized independently for its specific functional requirements, achieving overall stiffness with minimal mass.
2Strength
If a denser material is used to increase the stiffness of the leading edge, then the impact resistance is improved, but the overall mass of the leading edge is significantly increased
Solution Approach 1:
The material density is varied locally along the longitudinal direction of the leading edge. The lower end portion uses a first material with higher density to provide maximum stiffness where impact forces are greatest, while the upper end portion uses a second material with lower density. This local material optimization achieves the required stiffness without the penalty of uniformly increasing mass throughout the entire leading edge.
Solution Approach 2:
The leading edge is constructed as a composite structure combining two different metallic materials with different density characteristics. The first material (higher density) is positioned in the lower zone where maximum mechanical strength is required, while the second material (lower density) is positioned in the upper zone. This composite approach allows the leading edge to achieve the necessary stiffness properties while minimizing overall mass through strategic material selection and placement.
Data Source
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AI summary
Disclosed are a method for manufacturing a blade made of composite material with an attached metal leading edge for a gas turbine aeronautical engine as well as the corresponding blade, wherein the leading edge (200) comprises a first portion (210) which is made of a first metal material and extends from the lower end (206) of the leading edge and as far as an intermediate position (207) located between the lower end (206) and the upper end (208) of the leading edge, and a second portion (220) which is made of a second metal material and extends from the intermediate portion (207) and as far as the upper end (208) of said leading edge, the second metal material having a density greater than the density of the first metal material.