Mode-Shaped Components for Critical Vibration Suppression

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Solution Overview

Problem

In rotating machinery, such as gas turbine engines, vibrations caused by imbalances and external forces are challenging to control, especially at critical speeds, leading to resonance and potential structural integrity issues, with existing damping systems often being heavy and inefficient.

Innovation Solution

A method involving the design and manufacturing of components based on mode shapes, where the geometry and stiffness distribution are adapted to match non-critical mode shapes, disrupting critical vibrations through Finite Element Modal Analysis and redesigning the component to alter its vibrational response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional damping systems are used to reduce vibrations at critical speeds, then vibration control is improved, but component weight increases

Engineering Contradiction:
Improvevibration controlVSAvoidcomponent weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent changes the geometric parameters of the component by introducing circumferential variations in thickness or cross-sectional area that correspond to the mode shape patterns. This modifies the stiffness distribution and mass distribution of the component, thereby altering its natural frequencies and mode shapes to avoid resonance with critical excitations, achieving vibration control without additional damping components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces asymmetric or non-unymmetric geometric features around the component's circumference, where the thickness or cross-section varies angularly according to the determined mode shape. This breaks the symmetry that would otherwise allow certain mode shapes to be excited, thereby suppressing critical vibrations while maintaining lightweight construction

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If damping systems are designed to handle critical vibrations, then vibration control is improved, but the system complexity increases

Engineering Contradiction:
Improvevibration controlVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the vibration control function from separate damping systems and integrates it directly into the component's geometry itself. By incorporating mode shape-based geometric variations into the component design, the component inherently possesses the vibration control capability, eliminating the need for additional dampers or complex control systems

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the component multi-functional by giving it both its primary structural function and passive vibration control function simultaneously. The geometric variations designed according to mode shapes allow the same component to serve as both a load-bearing structure and a vibration suppression element, reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces vibrations across a broad speed range by disrupting critical mode shapes, potentially extending the lifetime of components and reducing weight, thereby addressing the inefficiencies of traditional damping systems.

Implementation Method 1

Vibrations are specifically pronounced at particular rotational speeds and/or frequencies, known as 'critical' speeds, in view of resonances of the rotating system

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

determining, e.g., by computer simulation, at least one mode shape of the model; redesigning the model based on the determined at least one mode shape

Methodology Applied
Scientific EffectModal analysis:

Data Source

PatentEP3741981B1Mode-shaped components
Publication Date: 2023.03.15 ROLLS ROYCE DEUT LTD & CO KG
  • EP3741981B1 patent drawingFigure 1
  • EP3741981B1 patent drawingFigure 2
  • EP3741981B1 patent drawingFigure 3

AI summary

Embodiments of the invention are shown in the figures, where a method is presented for designing a component (50; 60), comprising designing or receiving (101; 201) a model (M) of the component (50; 60); determining (102; 202) at least one mode shape of at least a portion of the model (M); redesigning (103; 209) the model (M) based on the determined at least one mode shape to obtain a redesigned model (M') of the component (50; 60); and manufacturing (106) the component (50; 60) in accordance with the redesigned model (M').