Engine Component Stress Zones for Guided Crack Propagation

Solution Overview

Problem

Engine components, particularly in gas turbine engines, face challenges in predicting and controlling crack propagation under complex dynamic loads, leading to potential uncontrolled failure and efficiency losses due to existing methods that increase material costs and weight.

Innovation Solution

The introduction of a spatially delimited modification zone with internal tensile stresses guides crack propagation away from critical loading zones, preventing uncontrolled crack growth without varying material thicknesses, using techniques like shot peening or deep cold rolling to introduce stresses that influence crack direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different material or layer thicknesses are provided on a rotor blade to define a defined crack edge, then crack propagation is controlled to prevent uncontrolled failure, but material costs and weight increase

Engineering Contradiction:

Improvecrack propagation controlVSAvoidrotor blade weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The invention changes the stress state parameter by introducing internal tensile stresses in a modification zone, rather than changing material thickness. This creates a preferential path for crack propagation through stress field manipulation, achieving crack control without adding material weight.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical approach of varying material thickness with a stress field approach using internal tensile stresses. This substitution achieves the same crack propagation control function without the physical mass increase associated with thicker materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If different material or layer thicknesses are provided on a rotor blade to define a defined crack edge, then crack propagation is controlled to prevent uncontrolled failure, but material costs increase

Engineering Contradiction:

Improvecrack propagation controlVSAvoidmaterial quantity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention changes the stress state parameter by introducing internal tensile stresses in a modification zone, rather than changing material thickness. This creates a preferential path for crack propagation through stress field manipulation, achieving crack control without adding material weight.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical approach of varying material thickness with a stress field approach using internal tensile stresses. This substitution achieves the same crack propagation control function without the physical mass increase associated with thicker materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If material thickness is varied to control crack propagation, then crack direction is influenced, but efficiency losses occur due to flow losses and turbulence

Engineering Contradiction:

Improvecrack propagation controlVSAvoidengine efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention applies local quality by creating a modification zone with specific internal tensile stress characteristics in a localized area. This localized stress modification influences crack propagation without requiring global changes to material thickness that would affect overall engine performance and efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the stress state parameter by introducing internal tensile stresses in a modification zone, rather than changing material thickness. This creates a preferential path for crack propagation through stress field manipulation, achieving crack control without adding material weight.

Inventive Principle:

Principle #35Parameter changes

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 effectively controls crack propagation, reducing the risk of critical failures and maintaining engine efficiency by guiding cracks into less critical zones, thus avoiding material and weight increases.

Implementation Method 1

at least one spatially delimited modification zone with introduced internal tensile stress is formed, via which zone a crack propagating in the engine component is guided

Methodology Applied

Scientific EffectStress field manipulation:

Implementation Method 2

using techniques like shot peening or deep cold rolling to introduce stresses that influence crack direction

Methodology Applied

Scientific EffectShot peening: Shot Peening

Implementation Method 3

using techniques like shot peening or deep cold rolling to introduce stresses that influence crack direction

Methodology Applied

Scientific EffectCold forming: Cold-forming

Data Source

PatentUS11939885B2Engine component with modification area for influencing crack propagation and method of manufacturing

Publication Date: 2024.03.26 ROLLS ROYCE DEUT LTD & CO KG

AI summary

The proposed solution relates, in particular, to an engine component havingat least one first loading zone, which is designed for dynamic loads arising at the engine component when the engine component is correctly built into an engine and when the engine is operating, anda second loading zone, which is provided spaced at a distance from the first loading zone on the engine component and likewise is designed for dynamic loads arising at the engine component when the engine component is correctly built into an engine and when the engine is operating.The proposal is, in particular, that at least one spatially delimited modification zone with introduced internal tensile stress is formed on the engine component, via which zone a crack propagating in the engine component is guided to the and/or within the second loading zone.