Propeller Blade Lightweight Insert Shear Crack Resistance

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Solution Overview

Problem

Modern propeller blades face issues with foam core cracking under shear forces and stress, which can lead to structural instability and potential failure during aircraft operation.

Innovation Solution

Incorporating a lightweight insert within the foam core of the propeller blade, in operable contact with both the face and camber sides of the structural layer, to distribute and manage shear forces effectively, thereby reducing the likelihood of cracking and stabilizing the blade structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If foam core is used in propeller blade, then weight is reduced and manufacturing is simplified, but structural integrity deteriorates due to cracking under shear forces

Engineering Contradiction:

Improveblade weightVSAvoidresistance to shear force cracking

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by combining foam core with structural layers (fabric and resin) to create a hybrid structure. The foam core provides lightweight construction while the structural layers provide strength and crack resistance, resolving the contradiction between weight reduction and shear force resistance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The blade structure is segmented into distinct functional layers: foam core for weight reduction, structural layers for strength, and leading/trailing edge formations for structural integrity. This segmentation allows each component to optimize its specific function while working together to resolve the contradiction.

Inventive Principle:

Principle #1Segmentation

2Strength

If structural layers are added to foam core, then strength and crack resistance improve, but device complexity increases

Engineering Contradiction:

Improveresistance to shear force crackingVSAvoidblade structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent merges the foam core with structural layers in an integrated manner, where the structural layers are formed directly over the foam core in a single manufacturing process. This merging approach provides strength improvement while minimizing the increase in device complexity through unified construction rather than separate assembly.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If foam core is used without reinforcement, then manufacturing simplicity is maintained, but structural stability deteriorates under applied loads

Engineering Contradiction:

Improveblade manufacturing simplicityVSAvoidblade structural stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The structural layers are formed preliminarily over the foam core during the manufacturing process itself, before the blade undergoes operational loads. This preliminary reinforcement action maintains manufacturing simplicity by incorporating strengthening measures into the standard fabrication process rather than requiring separate reinforcement steps.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9429024B2Propeller blade with lightweight insert

Publication Date: 2016.08.30 HAMILTON SUNDSTRAND CORP

AI summary

A propeller blade includes a foam core and a structural layer that surrounds at least a portion of the foam core and includes a face side and a camber side is disclosed. The propeller blade also includes an insert disposed in the foam core in operable contact with the face side and the camber side of the structural layer.