Aircraft Frame Assembly Load Distribution via Supporting Element

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Solution Overview

Problem

Current methods for attaching a vertical tail plane (VTP) to an aircraft fuselage concentrate high out-of-plane forces and stress concentrations in a small area, leading to thick and heavy structural components, and do not efficiently distribute thermal loads.

Innovation Solution

A frame assembly with a supporting element that redirects VTP loads to both sides of the fuselage, transforming out-of-plane forces into shear forces and increasing the moment arm, allowing for lighter frames and reduced skin thickness, using bi-clamped supporting elements that can be made of carbon fiber reinforced plastic (CFRP) to alleviate thermal loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If shear joints or tension joints are used to attach the VTP to the fuselage, then the VTP loads can be transferred to the fuselage, but high out of plane forces and stress concentrations occur in a small area of the upper zone of skin and frames, leading to very thick and heavy structural components

Engineering Contradiction:
Improveload transfer capabilityVSAvoidweight of structural components
Core Design Contradiction:
ForceVSWeight of stationary object

Solution Approach 1:

The invention divides the load transfer function into multiple segments: the VTP attaches to multiple fittings distributed along the fuselage, each fitting transfers loads to the skin and frames. This segmentation distributes the concentrated forces into multiple smaller force paths, reducing stress concentrations and allowing lighter structural components while maintaining load transfer capability.

Inventive Principle:
Principle #1Segmentation

2Force

If shear joints are used to attach the VTP, then the loads are transferred as pure moment without other substantive loads, but high out of plane forces and stress concentrations still occur in the upper zone of skin and frames

Engineering Contradiction:
Improvemoment transfer efficiencyVSAvoidout of plane forces and stress concentrations
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The invention transitions from a single-point moment transfer to a distributed multi-dimensional load path. Multiple fittings are positioned at different locations along the fuselage, creating a three-dimensional load distribution system. This transforms the concentrated moment into distributed forces across multiple dimensions (length, height, and depth of the fuselage structure), eliminating harmful stress concentrations.

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

3Force

If the VTP is attached to the upper part of the tail cone structure, then the loads are directly transferred to the closest area, but this concentrates loads in a small area requiring very thick and heavy frames made of machined or forged metal

Engineering Contradiction:
Improvedirect load transferVSAvoidmanufacturing complexity and weight
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The invention applies local quality by positioning fittings at specific locations where the fuselage structure naturally provides load-bearing capacity. Instead of concentrating loads at the upper tail cone, fittings are distributed to areas with optimal structural properties, allowing the use of lighter, easier-to-manufacture components while maintaining direct and efficient load transfer paths.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3653490B1Frame assembly for a rear section of an aircraft and rear section of an aircraft comprising said frame assembly
Publication Date: 2024.01.03 AIRBUS OPERATIONS SL
  • EP3653490B1 patent drawingFigure 1a~1c
  • EP3653490B1 patent drawingFigure 2a~2b
  • EP3653490B1 patent drawingFigure 3a~3c

AI summary

Frame assembly for a rear section of an aircraft, comprising at least one frame (2) having a plane of symmetry (4), wherein the frame assembly also comprises at least one supporting element (3) having two ends (3'), wherein each one of the ends (3') is attached to said at least one frame (2) at different sides of the plane of symmetry (4). It permits a more effective transfer of loads coming from the vertical tail plane of the aircraft to the fuselage.