Composite Turbine Blade Root Manufacturing via 3D Weaving
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Solution Overview
Problem
The production of composite material blades for turbomachines faces challenges such as delicate insert production and positioning during weaving, mechanical resistance issues, and degradation due to oxidation, particularly in bulbous root designs for gas turbines.
Innovation Solution
A manufacturing process involving three-dimensional weaving of central and external fibrous strips to form a bulbous root preform without an insert, allowing for robust attachment via dovetail connection, reducing deformation, and enhancing service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If an insert is added during weaving to create a bulbous root shape, then the blade root can achieve the desired bulbous shape, but the manufacturing process becomes delicate and complex with positioning difficulties
Solution Approach 1:
The blade root is divided into multiple fibrous bands (central band and lateral bands) that are woven separately and then assembled. This segmentation allows each band to be manufactured independently with proper fiber alignment, eliminating the need for complex inserts while achieving the bulbous shape through the arrangement and crossing of bands.
Solution Approach 2:
The invention transitions from a single-plane weaving approach to a three-dimensional assembly of multiple fibrous bands. The lateral bands cross the central band at angles, creating a multi-dimensional structure that forms the bulbous root shape without requiring insert components or complex positioning mechanisms.
2Shape
If traditional weaving methods are used with inserts, then the bulbous shape can be achieved, but the blade attachment degrades due to mechanical stress and oxidation fatigue
Solution Approach 1:
The blade root is constructed as a composite structure using multiple fibrous bands with specific material properties. The central band and lateral bands are made of oxidation-resistant fibers arranged in specific orientations, creating a composite material structure that inherently resists both mechanical stress and oxidation fatigue without requiring protective inserts.
Solution Approach 2:
The invention changes the material parameters by using oxidation-resistant fibers and adjusting the fiber orientation angles (15° to 75°) in the lateral bands. These parameter changes enhance the blade attachment's resistance to mechanical stress and oxidation, improving durability while maintaining the bulbous shape.
3Strength
If forces are not aligned with fiber grain direction, then the blade root may deform under load, but aligning forces requires specific weaving configurations
Solution Approach 1:
Different regions of the blade root have different fiber orientations optimized for their specific load conditions. The central band has fibers aligned with the longitudinal direction, while the lateral bands have fibers oriented at angles (15° to 75°) to handle transverse and shear loads. This local quality optimization ensures forces are aligned with fiber grain direction in each region, maximizing strength without excessive complexity.
4Reliability
If the blade root is made with rigid mounting, then thermal expansion differences cause thermal shear stresses, but flexible mounting creates uncertainty in bearing surface positioning
Solution Approach 1:
The blade root structure is designed with adjustable geometric parameters, particularly the angle of the lateral bands (15° to 75°), which can be optimized to accommodate thermal expansion differences. This parameter adjustment allows the structure to absorb thermal stresses while maintaining bearing surface positioning accuracy, resolving the contradiction between rigid and flexible mounting.
Data Source
Figure 1~3
AI summary
The invention relates to a method for manufacturing a turbine engine blade root made of a composite material including a fibrous reinforcement compregnated by a mould, the method including forming one central fibrous strip (102) and two outer fibrous strips from three sets of layers of threads (C10 to C19) connected to one another by three-dimensional weaving, the central strip passing through the two outer strips with the two outer strips crossing inside the central strip; removing portions of the outer strips which are external to the central strip by cutting; shaping the fibrous blank to obtain a preform having a main portion forming an integral blade root preform with two secondary portions (104a, 106a) forming bearing-surface preforms; and compregnating the preform. The invention also relates to a blade root obtained by such a method.