Pinned Fuselage-to-Wing Connection for Load Distribution

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Solution Overview

Problem

Existing aircraft designs face challenges in efficiently managing aerodynamic forces at the wing-to-body connection, leading to undesirable fuselage loads and weight increases due to heavy structural support requirements, which elevate fuel consumption and operating costs.

Innovation Solution

A pinned fuselage-to-wing connection system featuring forward, aft, and intermediate pin joints with specific configurations to allow axial load transfer without rotational deflections, utilizing lug, clevis, and pin arrangements, along with a flexible shear plate to distribute loads and reduce structural weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a rigid wing-to-body connection is used to transfer all wing bending deflections to the fuselage, then load transfer is complete, but fuselage components rotate and bend causing increased weight and fuel consumption

Engineering Contradiction:
Improveload transferVSAvoidaircraft weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The connection is divided into multiple pin joints (forward, intermediate, and aft) rather than a single rigid connection. Each pin joint is spaced at specific intervals along the wing span, segmenting the load transfer path and allowing localized flexibility while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection transitions from a rigid fixed-parameter state to a compliant state by introducing pin joints with specific spacing parameters. The distance between pin joints is carefully controlled to allow wing bending deflections without transferring excessive loads to the fuselage, changing the mechanical behavior from rigid to semi-flexible.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If a compliant wing-to-body connection is used to allow independent wing bending, then fuselage loads are reduced, but heavy wing and fuselage structure is required to support concentrated loads at discrete connection locations

Engineering Contradiction:
Improvefuselage loadVSAvoidstructural strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

Multiple pin joints are distributed along the wing span to segment the concentrated loads into smaller, more distributed forces. This segmentation prevents excessive load concentration at any single connection point while still allowing the wing to bend independently of the fuselage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution adds the spatial dimension of pin joint distribution along the wing span. By spacing pin joints at specific intervals in the spanwise direction, the system distributes loads across multiple locations rather than concentrating them at a single point, reducing the structural strength requirements at each individual connection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Weight of moving object

If multiple pin joints are used to distribute loads, then structural weight is reduced, but the connection complexity increases with multiple lugs, clevises, and pins

Engineering Contradiction:
Improvestructural weightVSAvoidconnection complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

Each pin joint assembly (lug, clevis, and pin) is designed as a standardized multi-functional unit that can be repeated at multiple locations along the wing span. This universal design allows the same basic components to serve multiple functions: structural connection, load transfer, and controlled flexibility, reducing the need for custom-designed complex mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The pin joint assembly is copied and repeated at multiple locations (forward, intermediate, and aft positions) rather than designing a completely unique complex mechanism for each connection point. This replication of standardized components simplifies manufacturing and assembly while achieving the desired load distribution and weight reduction.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3118104B1Pinned fuselage-to-wing connection
Publication Date: 2019.06.26 THE BOEING CO
  • EP3118104B1 patent drawingFigure 1
  • EP3118104B1 patent drawingFigure 2
  • EP3118104B1 patent drawingFigure 3

AI summary

An aircraft comprises a fuselage (110), a wing assembly (130), and a pinned fuselage-to-wing connection (150) including a forward pin joint (210), an aft pin joint (230), and intermediate pin joints (220) between the forward and aft pin joints. The intermediate pin joints have pins aligned in an axial direction and are configured to slide along the axial direction without transferring axial loads from the wing assembly to the fuselage. At least one of the forward and aft pin joints is constrained to prevent translation along the axial direction.