Thermoplastic Composite Propulsion Case Layering for Efficient Manufacturing

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Solution Overview

Problem

Existing propulsion system cases and methods for forming them lack improvements in efficiency and ease of manufacturing, particularly in integrating composite materials for aircraft propulsion systems.

Innovation Solution

A method involving a liner made of elastomeric material, bonded with a thermoplastic film layer using an adhesive, followed by depositing a thermoplastic composite material to form an outer shell, utilizing automated fiber placement for composite propulsion system cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional propulsion system cases are manufactured using conventional methods, then manufacturing processes are well-established, but manufacturing efficiency and ease of manufacturing are limited

Engineering Contradiction:
Improveease of manufacturingVSAvoidmanufacturing efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The propulsion system case is divided into multiple layers including an inner liner, adhesive layer, thermoplastic film layer, and outer shell layer. Each layer can be manufactured and prepared separately, then assembled together, improving both ease of manufacture and manufacturing efficiency by allowing parallel processing of different components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner liner and thermoplastic film layer are prepared and bonded together before the outer shell is formed. This preliminary preparation of internal layers allows the outer shell to be deposited efficiently using automated fiber placement, thereby improving manufacturing efficiency while maintaining ease of manufacture through staged production

Inventive Principle:
Principle #10Preliminary action

2Strength

If composite materials are integrated into propulsion system cases, then structural performance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvestructural performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent utilizes the thermoplastic nature of materials, changing their physical state through temperature control during manufacturing. The thermoplastic film layer and composite material are heated to become pliable during deposition, then cool and solidify to form strong bonds, achieving high structural performance without proportionally increasing manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The propulsion system case employs multiple composite material layers including the thermoplastic film layer and fiber-reinforced outer shell. These composite materials provide enhanced structural performance while the automated fiber placement process manages manufacturing complexity through automation

Inventive Principle:
Principle #40Composite materials

3Productivity

If automated fiber placement is used to deposit composite material, then manufacturing efficiency is improved, but process complexity increases

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The thermoplastic film layer serves as an intermediary between the inner liner and the outer composite shell. It provides a stable substrate that facilitates the automated fiber placement process, allowing efficient deposition of composite materials while the film layer itself simplifies the overall process by providing a uniform bonding surface

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical assembly methods with automated fiber placement technology. This substitution uses computer-controlled deposition of composite materials, improving manufacturing efficiency through automation while the standardized process reduces long-term operational complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Facilitates the efficient and secure assembly of composite propulsion system cases by allowing in-situ formation of the outer shell on a prepared liner, improving manufacturing efficiency and integration of composite materials.

Implementation Method 1

bonding a thermoplastic film layer to the liner using an adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

depositing a thermoplastic composite material onto the thermoplastic film layer to form an outer shell

Methodology Applied
Scientific EffectDeposition: Deposition (physical)

Data Source

PatentEP4428358B1Composite propulsion system case and method for forming same
Publication Date: 2025.10.29 ROHR INC
  • EP4428358B1 patent drawingFigure 1
  • EP4428358B1 patent drawingFigure 2
  • EP4428358B1 patent drawingFigure 3

AI summary

A method for forming a composite propulsion system case includes providing a liner, bonding a thermoplastic film layer to the liner using an adhesive, and, subsequent to bonding the thermoplastic film layer to the liner, depositing a thermoplastic composite material onto the thermoplastic film layer to form an outer shell of the composite propulsion system case. The outer shell extends circumferentially about an axial centerline of the composite propulsion system case. The outer shell forms an outer radial surface of the composite propulsion system case.