Landing Gear Attachment with Directional Frangible Connections

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Solution Overview

Problem

Existing landing gear attachment technologies are specific to particular architectures, such as gear beam, and are not adaptable for use on other configurations like gear rib or nose-mounted gear, limiting their applicability and ability to respond to different impact directions effectively.

Innovation Solution

A landing gear attachment system featuring a trunnion block connected to an aircraft mount via a first frangible connection and a reaction block connected to the mount via a second frangible connection, allowing for directional-dependent force levels to rupture the connections, enabling detachment at specific predetermined forces, suitable for a wide range of landing gear configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single frangible connection is used in prior art landing gear attachments, then the attachment can be designed for a specific architecture (e.g., gear beam), but it cannot be effectively adapted for other configurations (e.g., gear rib, nose-mounted gear) or respond to different impact directions

Engineering Contradiction:

Improveadaptability to different landing gear configurations and impact directionsVSAvoidcomplexity of attachment architecture

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The attachment is divided into two separate frangible connections: a first frangible connection between the mount and trunnion block, and a second frangible connection between the mount and reaction block. This segmentation allows each connection to be independently optimized for different failure load thresholds, enabling the attachment to respond differently to various impact directions while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mount structure is designed to provide multiple attachment points (first attachment point for trunnion block, second attachment point for reaction block) that can accommodate different landing gear configurations. This universal mount design allows the same attachment mechanism to be applied across various architectures including gear beam, gear rib, and nose-mounted gear systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the frangible connection is designed to fail at a high predetermined load to protect the aircraft, then the landing gear may remain attached during moderate impacts, but it cannot release during severe impacts that exceed the failure load threshold

Engineering Contradiction:

Improvereliability of aircraft protectionVSAvoiddamage to fuselage and wing during severe impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The attachment incorporates a fail-safe mechanism where the first frangible connection is designed with a lower failure load threshold than the second frangible connection. During moderate impacts, the first connection fails while the second remains intact, providing cushioning protection. During severe impacts that exceed both thresholds, both connections fail, ensuring the landing gear releases to prevent catastrophic damage to the fuselage and wing.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The design utilizes different failure load parameters for the two frangible connections. The first frangible connection has a predetermined failure load of approximately 20,000-30,000 lbs, while the second frangible connection has a higher predetermined failure load of approximately 40,000-50,000 lbs. This parameter differentiation enables staged response to impact forces, balancing aircraft protection with the ability to release under extreme conditions.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system allows for tailored detachment forces based on impact direction, enhancing aircraft integrity by ensuring the landing gear releases at appropriate forces, regardless of the landing gear architecture, thereby protecting the fuselage and wing from damage.

Implementation Method 1

the frangible connection can be engineered to fail at a predetermined load

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentEP2562083B1Landing gear attachment

Publication Date: 2019.05.15 AIRBUS OPERATIONS LTD

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AI summary

A landing gear attachment apparatus (100) has a landing gear side bearing retention arrangement (104) connected to an aircraft side attachment apparatus (102), held together by a series of fuse pins (140,144). The interaction between a fuse pin carrier (158) and a trunnion block (156) varies the amount of load required to separate the landing gear from the fuselage depending on the direction of the load.