Bypass Turbomachine Panel Fastening Without Composite Bosses

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Solution Overview

Problem

The existing methods for fixing panels in turbomachines, particularly those made of composite materials like carbon fibers embedded in resin, face challenges such as increased mass, complex production processes, and lengthy draping times due to the need for bosses and complex heating mold development.

Innovation Solution

The solution involves using sockets and studs to secure panels to the annular wall without bosses, allowing for remote fixing and simplifying the manufacturing process, with the studs being structurally independent and made of thermosetting materials like epoxy resin, ensuring good mechanical strength and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If panels are made of composite material with bosses for fixing, then mass is reduced, but production complexity and draping time increase

Engineering Contradiction:
Improvepanel massVSAvoidproduction process complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The fixing system is segmented into separate components: the panel without bosses, the sleeve inserted into orifices, and the stud forming a spacer. This segmentation allows the panel to be manufactured simply as a composite piece without complex boss structures, while the fixing function is provided by separate sleeve and stud components that are easier to produce and assemble.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The boss structure is extracted from the panel design. Instead of integrating bosses into the composite panel (which complicates manufacturing), the panel is made simple with just orifices, and the fixing function is taken out and implemented by separate sleeve and stud components that can be produced independently and assembled later.

Inventive Principle:
Principle #2Taking out (Extraction)

2Weight of moving object

If panels are made of composite material with bosses, then mass is reduced, but draping time increases

Engineering Contradiction:
Improvepanel massVSAvoiddraping time
Core Design Contradiction:
Weight of moving objectVSLoss of time

Solution Approach 1:

The fixing system is segmented into separate components: the panel without bosses, the sleeve inserted into orifices, and the stud forming a spacer. This segmentation allows the panel to be manufactured simply as a composite piece without complex boss structures, while the fixing function is provided by separate sleeve and stud components that are easier to produce and assemble.

Inventive Principle:
Principle #1Segmentation

3Strength

If bosses are created on panels for fixing, then mechanical connection is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidpanel manufacturing ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The fixing system is segmented into separate components: the panel without bosses, the sleeve inserted into orifices, and the stud forming a spacer. This segmentation allows the panel to be manufactured simply as a composite piece without complex boss structures, while the fixing function is provided by separate sleeve and stud components that are easier to produce and assemble.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sleeve acts as an intermediary component between the panel orifice and the stud. It is inserted into the orifice and provides a interface for the stud to clamp against, enabling mechanical connection without requiring complex boss structures on the panel itself. The sleeve mediates the connection between the panel and the fixing mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If heating mold is developed for composite panel production with bosses, then thermosetting is controlled, but device complexity increases

Engineering Contradiction:
Improvethermosetting control precisionVSAvoidheating mold complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The boss structure is extracted from the panel design. Instead of integrating bosses into the composite panel (which complicates manufacturing), the panel is made simple with just orifices, and the fixing function is taken out and implemented by separate sleeve and stud components that can be produced independently and assembled later.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach reduces the additional mass and production complexity, enabling a standard and simple manufacturing process while maintaining mechanical strength and extending the lifespan of the fixing mechanism.

Implementation Method 1

The clamping force of each fastener is transferred through the first annular portion at the end of each sleeve, around the opening, into the stud, and then to the first annular wall. Thus, when the panel is made of composite material as previously described, the force is evenly distributed annularly around the opening and within the stud, resulting in good mechanical strength and a long service life for the fastener.

Methodology Applied
Scientific EffectClamping force distribution: Mechanical Force

Implementation Method 2

a stud forming a spacer surrounding the sleeve and being clamped radially between the circumference of the orifice and the first annular wall

Methodology Applied
Scientific EffectRadial spacing: Mechanical Force

Data Source

PatentEP3847363B1Bypass turbomachine
Publication Date: 2023.10.25 SAFRAN AIRCRAFT ENGINES SAS
  • EP3847363B1 patent drawingFigure 1~2
  • EP3847363B1 patent drawingFigure 3~5
  • EP3847363B1 patent drawingFigure 6~8

AI summary

The invention relates to an assembly for a turbomachine of longitudinal axis comprising a first annular wall (24), panels (38) being arranged around the longitudinal axis (A) and extending in a manner radially facing said first annular wall (24) so as to form a flow surface for an airflow, each panel (38) being secured to the first annular wall (24) by at least one fastening member (72) that passes through an orifice in the panel (38) and is secured to the first annular wall (24) by means of a socket and a stud forming a spacer.