Aircraft Fatigue Management via Load Signal Extraction

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Solution Overview

Problem

Current fatigue management systems for aircraft rely on conservative assumptions for fatigue damage accumulation, leading to unnecessary component replacements and increased costs, as they lack precise methods to determine individual component life based on actual usage patterns.

Innovation Solution

A fatigue management system that utilizes high-frequency load signal data from load classification flights, processed with heuristic models and statistical methods to accurately calculate fatigue damage, bypassing the need for full signal reconstruction and accounting for aircraft weight and position, thereby optimizing fatigue damage assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If load sensors are installed on all structural elements to accurately measure component loads, then measurement precision is improved, but device complexity and cost increase substantially

Engineering Contradiction:
Improvecomponent load measurement accuracyVSAvoidsensor installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the physical load measurement system through finite element models and simulation data. Instead of installing physical sensors on every component, the system uses computational models that replicate the behavior of instrumented structures, allowing accurate load estimation without physical intrusion.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical sensor-based measurement system with an analytical approach using finite element analysis and operational data. The mechanical measurement chain (sensors, wiring, signal conditioning) is substituted with computational mechanics that calculate loads from operational parameters and structural models.

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

2Reliability

If a conservative Standard Mission Profile is assumed for all aircraft, then reliability is improved through safety margins, but productivity decreases due to unnecessary component replacements

Engineering Contradiction:
Improvecomponent failure preventionVSAvoidaircraft availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent transitions from static, one-size-fits-all replacement schedules to dynamic, condition-based maintenance planning. The system continuously updates component life predictions based on actual operational data, allowing maintenance timing to adapt to real usage patterns rather than following fixed conservative intervals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the fundamental parameter from fixed replacement intervals to variable component life predictions. By incorporating actual operational parameters (flight hours, mission types, environmental conditions) into the assessment model, the system adjusts maintenance schedules based on real component degradation rates rather than conservative assumptions.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If full high-frequency load signal reconstruction is performed to calculate fatigue damage, then measurement precision is improved, but loss of time increases due to extensive data processing

Engineering Contradiction:
Improvefatigue damage calculation accuracyVSAvoiddata processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential information needed for fatigue damage calculation from the full load signal. Instead of reconstructing and processing complete high-frequency load time histories, the system identifies and uses only the critical load parameters (peak loads, cycle counts, stress ranges) that directly contribute to fatigue damage accumulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by calculating fatigue damage using a simplified subset of the full load signal information. Rather than performing complete signal reconstruction and analysis, the method uses strategically selected load parameters that provide sufficient accuracy for fatigue assessment while dramatically reducing computational effort.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2725337B1Fatigue management system and method of operating such a fatigue management system
Publication Date: 2018.04.11 AIRBUS HELICOPTERS DEUT GMBH
  • EP2725337B1 patent drawingFigure 1~2
  • EP2725337B1 patent drawingFigure 3~4
  • EP2725337B1 patent drawingFigure 5

AI summary

The invention relates to a fatigue management system for determining the individual life of components of at least one aircraft, particularly the individual life of at least one helicopter and/or components of said at least one helicopter. The invention relates as well to a method of operating said fatigue management system.