Viscoelastic Stacked Layer Aircraft Engine Attachment

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Solution Overview

Problem

Existing aircraft engine attachment systems lack sufficient flexibility to absorb vibrations and thermal movements, leading to increased stiffness and stress on the aircraft structure, while also being complex and costly.

Innovation Solution

A lightweight attachment system using a stacked layer with viscoelastic properties, composed of composite materials, featuring multiple fasteners and sheets that can be adjusted for stiffness, allowing for flexible movement and reduced stress, and eliminating the need for spherical bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional rigid attachment systems are used to connect aircraft engine to aircraft structure, then structural strength and force transfer are improved, but flexibility to absorb vibrations and thermal movements deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The attachment system is divided into multiple discrete components: rigid connecting elements for force transfer, viscoelastic dampers for vibration absorption, and clearance provisions for thermal movement. This segmentation allows each component to specialize in one function, achieving both strength and flexibility simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment system combines materials with different properties: rigid metallic components for structural strength, viscoelastic polymer materials for vibration damping, and clearance gaps for thermal expansion accommodation. This composite approach resolves the contradiction between rigidity and flexibility.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If spherical bearings are added to provide flexibility and absorb vibrations, then adaptability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
ImproveflexibilityVSAvoidcomplexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts the vibration absorption function from complex spherical bearing assemblies and implements it through simpler viscoelastic damper elements integrated directly into the attachment structure. This maintains flexibility while reducing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using mechanical spherical bearings with complex geometry, the invention changes the approach by using viscoelastic material properties (creep, hysteresis) to provide the same flexibility and vibration absorption function with simpler components.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple fasteners and stacked layers are used to create adjustable stiffness, then adaptability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveadjustable stiffnessVSAvoidmanufacturing ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The attachment system provides dynamically adjustable stiffness through the viscoelastic dampers whose effective stiffness varies with vibration frequency and amplitude. The stacked layer configuration with selective fastening allows static adjustment during assembly, combining dynamic and static adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention merges the fastening function with the stiffness adjustment function by using the same fasteners to both secure the stacked layers and control the effective stiffness of the attachment system, reducing the number of separate components and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

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 attachment system effectively absorbs vibrations and thermal movements, reduces stiffness, and simplifies installation by providing a flexible and adjustable solution that minimizes constraint forces and stress on the aircraft structure, while being cost-effective and easy to manufacture.

Implementation Method 1

The stacked layer comprises at least two sheets that are arranged parallel to a longitudinal axis of the attachment and at least three holes through the stacked layer that each extend in direction of a perpendicular axis that is perpendicular to the longitudinal axis. The stacked layer further comprises a suspension portion that is located between the first connecting portion and the second connecting portion and that is viscoelastic deformable in a direction that is parallel to the perpendicular axis.

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3663206B1An attachment for suspending an aircraft engine
Publication Date: 2023.09.06 AIRBUS HELICOPTERS DEUT GMBH
  • EP3663206B1 patent drawingFigure 1
  • EP3663206B1 patent drawingFigure 2
  • EP3663206B1 patent drawingFigure 3A~3B

AI summary

An attachment 107 for attaching an aircraft engine 106 with a first receiving element 108 to an aircraft structure 105 with a second receiving element 109 may include at least three fasteners 114 and a stacked layer 110. Stacked layer 110 may include at least two sheets 111, at least three holes 113 through the stacked layer 110, a first connecting portion 115 that includes a first hole 113 of the at least three holes 113, a second connecting portion 116 that includes second and third holes 113 of the at least three holes 113, and a suspension portion 117 that is located between the first connecting portion 115 and the second connecting portion 116.