Flex Beam With Structurally Tunable Cores

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Solution Overview

Problem

Existing aircraft flex beam designs are limited in the degree and extent of vertical deflection they can achieve while maintaining adequate chordwise and spanwise stiffness, leading to increased drag and maintenance requirements.

Innovation Solution

The implementation of structurally tunable cores in flex beams, which include composite laminates and resilient core members that can be configured to achieve high vertical deflection while maintaining necessary stiffness, reducing drag and maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If known flex beam implementations are used, then chordwise and spanwise stiffness can be maintained, but the degree and extent of vertical deflection is limited

Engineering Contradiction:
Improvevertical deflection capabilityVSAvoidoperational range
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The flex beam is divided into multiple discrete elements (first flex beam element, second flex beam element, third flex beam element) that can independently deflect vertically. Each element contains torsion elements that allow rotational movement, enabling the segments to move relative to one another while maintaining overall structural integrity and stiffness in the chordwise and spanwise directions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flex beam incorporates dynamic capabilities through torsion elements with twist angles that can be optimized for different operating conditions. The structure transitions from a static rigid beam to a dynamic system where the torsion elements can rotate to accommodate varying vertical deflection requirements, allowing the beam to adapt its stiffness characteristics based on operational needs.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If vertical deflection is increased, then operational range improves, but chordwise and spanwise stiffness may be compromised

Engineering Contradiction:
Improvevertical deflection rangeVSAvoidchordwise and spanwise stiffness
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

Different portions of the flex beam are designed with different properties: the torsion elements are configured to provide vertical deflection flexibility, while the flex beam elements themselves maintain adequate chordwise and spanwise stiffness. This local differentiation allows the structure to have soft vertical compliance while retaining horizontal rigidity where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The flex beam employs composite construction combining multiple materials with different properties: elastomeric materials for the torsion elements that provide vertical flexibility, and fiber-reinforced polymer materials for the flex beam elements that maintain chordwise and spanwise stiffness. This composite approach allows simultaneous optimization of vertical deflection and horizontal stiffness.

Inventive Principle:
Principle #40Composite materials

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 structurally tunable cores enable a higher degree of vertical deflection in aircraft flex beams, reducing drag and maintenance requirements by allowing for customizable and optimized operational capabilities.

Implementation Method 1

at least one of the resilient core members comprises an elastomeric material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

said at least one flex beam element comprising at least one twisted area in which said at least one flex beam element is twisted in said associated longitudinal direction

Methodology Applied
Scientific EffectTorsion: Torsion Spring

Implementation Method 3

each one of these separation layers is preferably adapted to allow relative movement between adjacent ones of the FRP layers, wherein at least one and preferably each one of the separation layers comprises shear soft material

Methodology Applied
Scientific EffectShear deformation: Shear Stress

Data Source

PatentEP3712064B1Flex beam comprising structurally tunable cores
Publication Date: 2022.06.22 THE BOEING CO
  • EP3712064B1 patent drawingFigure 1
  • EP3712064B1 patent drawingFigure 2~3
  • EP3712064B1 patent drawingFigure 4

AI summary

Structurally tunable cores are described that can be implemented, for example, in aircraft components. An example flex beam for coupling a rotor blade to a rotor hub includes a first composite laminate, a second composite laminate, a third composite laminate, first resilient core members and second resilient core members. The first composite laminate forms a first skin of the flex beam. The second composite laminate is located opposite the first composite laminate and forms a second skin of the flex beam. The third composite laminate is located between the first composite laminate and the second composite laminate. The first resilient core members extend between the first composite laminate and the third composite laminate. The second resilient core members extend between the second composite laminate and the third composite laminate.