Beaded Bracket for CMC Nacelle Attachment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The disparate thermal expansion properties between ceramic or CMC-based exhaust system components and metallic structures in gas turbine engines pose challenges in attachment design, leading to potential cracking or damage due to differential expansion.

Innovation Solution

A bracket system with radially extending arms and bead structures is used to secure ceramic matrix composite (CMC) components to metallic attachment structures, accommodating thermal expansion differences while minimizing undesirable loads and maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ceramic or CMC components are attached to metallic support structures, then high temperature capability is improved, but differential thermal expansion causes cracking or damage

Engineering Contradiction:

Improvehigh temperature capabilityVSAvoidcracking or damage

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The bracket is designed with flexible portions that can dynamically adjust and flex to accommodate differential thermal expansion between the ceramic nozzle and metallic attachment structure. This dynamic flexibility prevents cracking while maintaining secure attachment at high temperatures.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The bead structures are designed with specific geometric parameters (radius, spacing, cross-section) that enable the bracket to accommodate thermal expansion differences. The flexible portions have controlled stiffness parameters that allow movement within acceptable ranges while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

2Strength

If rigid attachment structures are used to secure CMC components, then structural integrity is improved, but thermal expansion differences create undesirable loads

Engineering Contradiction:

Improvestructural integrityVSAvoidundesirable loads

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The bracket is segmented into rigid portions (for structural strength and attachment) and flexible portions (for accommodating expansion). This segmentation allows the structure to maintain integrity while reducing thermal expansion loads through the flexible sections.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bracket have different mechanical properties - rigid portions provide structural strength while flexible portions provide compliance. The bead structures have specific local geometries that concentrate flexibility where needed while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

3Reliability

If the bracket is made completely flexible to accommodate expansion, then thermal expansion is managed, but attachment strength is reduced

Engineering Contradiction:

Improvethermal expansion managementVSAvoidattachment strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The bracket transitions from a completely rigid structure to a dynamically adaptable structure with flexible portions that can accommodate thermal expansion. This dynamic design maintains attachment strength by allowing controlled movement rather than creating rigid constraints.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The bracket combines rigid and flexible materials or structures in a composite design. The rigid portions provide attachment strength while the flexible portions provide thermal expansion accommodation, creating a composite structure that achieves both objectives simultaneously.

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 bracket system effectively manages thermal expansion differences, preventing damage and ensuring secure attachment of CMC components to metallic structures within the gas turbine engine's exhaust system, even at extreme temperatures.

Implementation Method 1

the disparate thermal expansion properties between the ceramic or CMC-based exhaust system components and the metallic structures to which they are typically attached

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3730772B1Nacelle system comprising an attachment structure with a beaded bracket

Publication Date: 2023.09.06 ROHR INC

Figure 1
Figure 2A~2B
Figure 3A~3C

AI summary

A nacelle system is disclosed. In various embodiments, the nacelle system may include a nacelle component; an attachment structure; and a bracket configured to secure the nacelle component to the attachment structure, the bracket comprising a first arm having a first bead structure disposed between a proximal end and a distal end of the bracket.