Gas Turbine Engine Case Electron Beam Welding

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Solution Overview

Problem

Existing gas turbine engine case manufacturing methods are inefficient and lack innovative solutions for creating durable, lightweight structures that balance stiffness and weight reduction, particularly in the context of near net shape fabrication and assembly.

Innovation Solution

The method involves forming a unitary annular gas turbine engine case through electron beam welding of forged annular case sections and near net shape rings, which are machined to precise faying surfaces and welded circumferentially to create a strong, lightweight structure with optional scalloped rings for reduced weight and enhanced stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional manufacturing methods are used for gas turbine engine cases, then manufacturing simplicity is maintained, but manufacturing efficiency and structural performance are insufficient

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidmanufacturing process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The engine case is divided into multiple annular case sections that are formed separately and then assembled together through electron beam welding. This segmentation allows for more efficient manufacturing of individual sections while maintaining the overall structural integrity of the engine case, resolving the contradiction between manufacturing efficiency and process complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple annular case sections and reinforcement rings are combined through electron beam welding to form a unified structure. This merging process integrates multiple components into a single engine case, improving manufacturing efficiency while maintaining structural strength, thus addressing the contradiction between productivity and device complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If the engine case structure is made more robust to improve structural integrity, then strength is improved, but weight increases

Engineering Contradiction:

Improvestructural integrityVSAvoidengine case weight

Core Design Contradiction:

StrengthVSWeight of stationary object

Solution Approach 1:

Reinforcement rings are strategically positioned at specific locations on the engine case where additional strength is most needed. This localized reinforcement approach provides enhanced structural integrity in critical areas without unnecessarily increasing the weight of the entire engine case, resolving the contradiction between strength and weight.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The engine case utilizes composite construction combining annular case sections with reinforcement rings of appropriate materials. This composite approach allows for optimization of strength-to-weight ratio by selecting materials and configurations that provide maximum structural integrity with minimum weight, addressing the contradiction between strength and weight.

Inventive Principle:

Principle #40Composite materials

3Stability of the object's composition

If annular case sections are welded together to form a unitary structure, then structural integrity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveunitary structure integrityVSAvoidassembly process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Electron beam welding is used to join the annular case sections together, replacing traditional mechanical joining methods. This substitution provides a more precise and reliable welding process that creates strong joints between sections while managing assembly complexity through controlled, automated welding operations, thus resolving the contradiction between structural integrity and manufacturing 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

This approach results in a robust, efficient gas turbine engine case that balances structural integrity with weight reduction, improving manufacturing efficiency and performance by utilizing near net shape fabrication techniques and electron beam welding for precise assembly.

Implementation Method 1

electron beam welding the first near net shape ring to the first annular case section at the faying surface

Methodology Applied

Scientific EffectElectron beam welding: Electron Beam

Data Source

PatentEP2472070B1Methods of manufacturing a gas turbine engine case and corresponding case

Publication Date: 2018.05.23 ROLLS ROYCE CORP

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AI summary

One embodiment of the present invention is a unique gas turbine engine case (60). Another embodiment is a method of manufacturing a near net shape unitary annular engine case (60) formed from electron beam welded parts (92,94,96,98,100,102,104).