Aircraft Shock Strut Gas Dissolution Prediction for Accurate Servicing

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Solution Overview

Problem

Existing servicing methods for shock struts assume constant gas solubility, failing to account for dynamic variability, leading to improper servicing and potential overpressurization or underperformance during critical events.

Innovation Solution

A computer-implemented method predicts gas solubility in shock struts using measurable phenomena like temperature, pressure, and stroke position over time, incorporating strut-specific design data to determine the actual servicing state without direct measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If constant gas solubility is assumed in servicing methods, then servicing procedure simplicity is maintained, but servicing accuracy deteriorates leading to improper servicing and potential overpressurization

Engineering Contradiction:
Improveservicing procedure simplicityVSAvoidgas solubility determination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by transitioning from a static assumption of constant gas solubility to a dynamic model where gas solubility varies over time based on operational conditions. The system continuously updates gas solubility predictions using real-time temperature, pressure, and stroke position data, allowing the servicing methodology to adapt to changing operational states rather than relying on fixed assumptions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by using multiple varying parameters (temperature, pressure, stroke position) to determine gas solubility instead of assuming a constant value. The prediction system processes these changing parameters through mathematical models to calculate time-varying gas solubility, enabling more accurate servicing decisions that account for actual operational conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If dynamic gas solubility variability is accounted for, then servicing accuracy is improved, but system complexity increases requiring multiple sensors and computational processing

Engineering Contradiction:
Improvegas solubility determination accuracyVSAvoidservicing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a prediction system that serves multiple functions: it processes temperature data, pressure data, and stroke position data from existing sensors; performs mathematical calculations to determine gas solubility; and provides servicing recommendations. This multi-functional approach consolidates what could be separate complex systems into a unified prediction platform that leverages existing sensor infrastructure.

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

Solution Approach 2:

The patent replaces direct mechanical measurement of gas solubility (which would require complex physical sampling and analysis equipment) with a computational prediction system. By substituting physical measurement mechanisms with mathematical models that process readily available sensor data, the system achieves accurate gas solubility determination without the complexity of direct measurement apparatus.

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

3Device complexity

If traditional servicing methods are used, then equipment simplicity is maintained, but reliability deteriorates due to improper servicing and potential overpressurization during critical events

Engineering Contradiction:
Improveservicing system simplicityVSAvoidshock strut functionality reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring operational parameters (temperature, pressure, stroke position) and using this information to update gas solubility predictions in real-time. The system feeds this predicted gas solubility information back to servicing operations, enabling dynamic adjustment of servicing decisions based on actual shock strut conditions rather than static assumptions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by predicting gas solubility states before servicing operations are performed. The system analyzes historical and real-time operational data to forecast current gas solubility conditions, allowing servicing personnel to make informed decisions about whether servicing is needed and what parameters should be adjusted, rather than relying on routine schedules or post-problem diagnostics.

Inventive Principle:
Principle #10Preliminary action

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

Enables precise automated servicing by accurately determining gas solubility, ensuring proper functionality of shock struts during critical operations.

Implementation Method 1

The gas acts as an energy storage device, such as a spring, so that upon termination of a compressing force the shock strut returns to its original length

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Shock struts also dissipate energy by passing the oil through the orifice so that as the shock absorber is compressed or extended, its rate of motion is limited by the damping action from the interaction of the orifice and the oil

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP4237336B1Gas dissolution prediction system and method for an aircraft shock strut
Publication Date: 2026.03.25 SAFRAN LANDING SYST CANADA INC
  • EP4237336B1 patent drawingFigure 1
  • EP4237336B1 patent drawingFigure 2
  • EP4237336B1 patent drawingFigure 3

AI summary

Techniques and methodologies for servicing a shock strut are provided that account for the variability in gas solubility of the shock strut while in-service. These examples incorporates knowledge of the shock strut's stoke history in order to estimate/predict the amount of gas in solution, its percentage saturation, etc. This may permit a more refined knowledge of the true servicing state of the shock strut.