3D-Woven Composite Blade Root for Low-Bulk High-Strength Hubs

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Solution Overview

Problem

Propeller blades or vanes for turboprop engines face challenges in achieving reduced bulk and enhanced mechanical resistance, particularly at the root, due to the need for axisymmetric shapes and exposure to various mechanical loadings including centrifugal forces and bending vibrations, which are difficult to manufacture from composite materials and require additional pre-stressing for circumferential compression resistance.

Innovation Solution

A method for manufacturing propeller blades or vanes using a fibrous reinforcement densified by a matrix, involving three-dimensional weaving with specific non-interlinking patterns to create a fibrous blank that includes a root part with internal weft yarn crossings, ensuring high circumferential stiffness at the root and smooth transitions to transverse stiffness in the airfoil part, using materials like silicon carbide fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If propeller blades or vanes are made of composite material to reduce mass, then weight is reduced, but mechanical resistance particularly at the root is insufficient

Engineering Contradiction:

Improveweight of propeller bladeVSAvoidmechanical resistance at root

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent uses composite materials consisting of fibrous reinforcement (silicon carbide fibers, carbon fibers, or glass fibers) densified by a matrix (ceramic, carbon, or organic polymer). This provides both weight reduction and enhanced mechanical properties. The composite structure allows tailoring of mechanical characteristics to meet both weight and strength requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by creating different fibrous reinforcement architectures in different parts of the blade. The root part has a specific weaving pattern with weft yarns crossing on either side of a non-interlinking to provide high circumferential stiffness, while the airfoil part has a different structure optimized for its specific loading conditions. This localized optimization allows each part to have the exact mechanical properties needed.

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If the root is made compact with reduced bulk to integrate low on the disk, then volume is reduced, but manufacturing difficulty increases

Engineering Contradiction:

Improvebulk of rootVSAvoidmanufacturing difficulty of root

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent segments the fibrous reinforcement into distinct functional zones: a root part with specific weaving characteristics and an airfoil part with different weaving characteristics. The root part includes a non-interlinking that creates an internal housing, and weft yarns are arranged to cross on either side of this non-interlinking in a changing sub-area. This segmentation allows each zone to be optimized independently for its specific function while maintaining manufacturability through a systematic weaving approach.

Inventive Principle:

Principle #1Segmentation

3Volume of moving object

If axisymmetric shape is used to reduce root bulk, then volume is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvebulk of rootVSAvoidmanufacturing complexity of root

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent moves from conventional two-dimensional fabric laying to three-dimensional weaving to create the root structure. The 3D weaving process inherently creates axisymmetric or substantially axisymmetric shapes by weaving yarns in multiple directions and layers. The non-interlinking and the arrangement of weft yarns crossing on either side of it are created through the 3D weaving process, which integrates shape formation and structural reinforcement in a single manufacturing step, reducing overall manufacturing complexity despite the sophisticated geometry.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Strength

If pre-stressing is applied to counter bending vibration loading, then resistance to circumferential compression is improved, but additional mechanical loading is generated

Engineering Contradiction:

Improveresistance to circumferential compressionVSAvoidadditional mechanical loading

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The patent incorporates pre-stressing into the root design during the manufacturing process. The fibrous reinforcement architecture, particularly the 3D weaving pattern with weft yarns crossing on either side of the non-interlinking, is designed to naturally provide circumferential stiffness and resist pre-stressing forces. This preliminary structural design allows the root to withstand circumferential compression from pre-stressing without requiring additional reinforcement that would increase overall loading.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12559224B2Blade or vane with a root made by crossing weft yarns

Publication Date: 2026.02.24 SAFRAN SA

AI summary

A method for manufacturing a propeller blade or vane made of composite material, includes making a single-piece fibrous blank by three-dimensional weaving between warp yarns and weft yarns, including an airfoil part and a root part including a non-interlinking, the root part including at least one changing sub-area in which the number of weft yarns crossing on either side of the non-interlinking increases gradually from the airfoil part to the free end of the root part, shaping the fibrous blank to obtain a fibrous preform, densifying the preform by a matrix to obtain a propeller blade or vane made of composite material.