Thrust Reverser Cascade Blades with Oriented Composite Fibers

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Solution Overview

Problem

Thrust reverser grids for aircraft turbojet nacelles are fragile, expensive, and have limited mechanical characteristics and aerodynamic performance due to their manufacturing processes, which hinder their effectiveness in providing counterthrust during landing.

Innovation Solution

A thrust reverser grid with blades made entirely of sheets of fibers, where the aerodynamic surfaces are lined with layers of fibers oriented in different directions, and spars and fixing flanges are reinforced with layers of fibers, allowing for high mechanical strength and complex geometries while maintaining good aerodynamic performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thrust reverser grids are manufactured using traditional draping of pre-impregnated fabrics around tools, then the structure can be produced, but the resulting grid is fragile due to delamination and has high manufacturing cost

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses composite materials consisting of a thermoplastic matrix reinforced with continuous or discontinuous fibers (carbon, glass, or aramid). This composite structure provides high mechanical strength and resistance to delamination while maintaining manufacturing feasibility through thermocompression or injection processes, directly resolving the contradiction between structural integrity and manufacturing ease.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If manufacturing processes use materials with short or discontinuous fibers randomly distributed and thermocompressed or injected, then production is simplified, but the mechanical characteristics are very limited and detrimental to aerodynamic performance

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmechanical characteristics
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies different fiber orientations and distributions in different regions of the thrust reverser grid. Fibers are arranged to align with stress trajectories and aerodynamic load directions, providing enhanced mechanical strength in critical areas while maintaining manufacturing simplicity through standardized thermocompression or injection processes. This local optimization resolves the contradiction between manufacturing ease and mechanical strength.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3665380B1Thrust reverser cascade for an aircraft nacelle
Publication Date: 2024.03.13 SAFRAN SA
  • EP3665380B1 patent drawingFigure 1~2
  • EP3665380B1 patent drawingFigure 3~4
  • EP3665380B1 patent drawingFigure 5~6

AI summary

The invention relates to a thrust reverser cascade (1) for an aircraft nacelle, comprising a plurality of blades (2) having a first (6a) and a second surface (6b), the blades (2) being connected to members (3, 4) connected to attachment flanges (5) for attaching the thrust reverser cascade (1) to the nacelle. According to the invention, at least one of the surfaces (6a, 6b) of the blades (2) is covered with at least one layer of fibres (7) each comprising a plurality of fibre pieces which are pre-impregnated with resins, the fibre pieces being superimposed on one another, positioned parallel to the aerodynamic surface of the blade (2) and oriented in different directions.