Pyrotechnic Rupture Device for Aircraft Separation

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Solution Overview

Problem

Existing connection devices for separating aircraft or spacecraft components using pyrotechnic cords face issues with irregular fracture surfaces leading to mechanical collisions and increased vibrations during transverse separation, which compromises the reliability and safety of the separation process.

Innovation Solution

A connection device with asymmetrical double-cutting wings, where the upstream rupture zone is positioned near the junction of the pyrotechnic cord's flat side and rounded end, and the downstream rupture zone is near the top, ensuring pure shearing and bending modes of rupture respectively, minimizing friction and shock wave delays to prevent collisions and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If symmetrical double-cutting wings are used, then vibrations are reduced through shock wave neutralization, but transverse separation causes irregular fracture surfaces leading to mechanical collisions

Engineering Contradiction:
ImprovevibrationsVSAvoidseparation cleanliness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies asymmetry by positioning the upstream rupture zone near the junction of the pyrotechnic cord's flat side and rounded end, while positioning the downstream rupture zone near the top of the rounded end. This asymmetric arrangement ensures that during transverse separation, the fracture surfaces remain clean and flat, preventing mechanical collisions between separating parts while maintaining vibration reduction through controlled shock wave propagation.

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If rupture zones are positioned identically and coplanarly, then shock waves are neutralized effectively, but fracture surfaces become irregular causing parts to catch during lateral separation

Engineering Contradiction:
Improveshock wave propagationVSAvoidfracture surface regularity
Core Design Contradiction:
Object-affected harmful factorsVSShape

Solution Approach 1:

The patent resolves this contradiction by introducing asymmetry in the vertical positioning of rupture zones. The upstream rupture zone is placed at a different height relative to the pyrotechnic cord compared to the downstream rupture zone. This asymmetric configuration ensures that fracture surfaces remain regular and flat during transverse separation, preventing parts from catching while still allowing effective shock wave neutralization through coordinated rupture timing.

Inventive Principle:
Principle #4Asymmetry

3Force

If thrust force brings separated elements together, then elements may collide and cling to each other, but asymmetric rupture zone positioning prevents this collision

Engineering Contradiction:
Improvethrust forceVSAvoidseparation completeness
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent uses asymmetric rupture zone positioning to prevent collision and clinging of separated elements. By placing the upstream rupture zone near the junction of the flat side and rounded end of the pyrotechnic cord, and the downstream rupture zone near the top of the rounded end, the fracture surfaces are configured to remain clear of each other even when thrust force attempts to bring elements together, ensuring complete and reliable separation.

Inventive Principle:
Principle #4Asymmetry

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

The device ensures clean separation with flat fracture surfaces, reduces mechanical collisions, and compensates for shock wave delays to minimize vibrations, maintaining the benefits of symmetrical double-cutting while enabling transverse separation without clinging issues.

Implementation Method 1

the latter suddenly swells and strikes the two wings, which causes the rupture of said wings at the level of their rupture zones

Methodology Applied
Scientific EffectPyrotechnic expansion: Detonation

Implementation Method 2

the shock waves appearing during the impact of the cord, which propagate within the wings and are transmitted to the adjacent elements to induce vibrations therein

Methodology Applied
Scientific EffectShock wave propagation: Shock Wave

Implementation Method 3

when superimposing these waves at the level of the elements bordering the wings, some of the harmonics cancel each other out. The resulting vibration undergone by said elements is therefore significantly attenuated

Methodology Applied
Scientific EffectWave interference: Interference

Data Source

PatentEP2542473B1Connecting device having pyrotechnic rupture
Publication Date: 2015.08.05 AIRBUS DEFENCE & SPACE SAS
  • EP2542473B1 patent drawingFigure 1~2
  • EP2542473B1 patent drawingFigure 3~4

AI summary

According to the invention, said device (1) comprises two substantially parallel flanges (4, 5) which are provided with rupture areas (16, 17), respectively, located in the same element (2) of the elements (2, 3) to be connected. In said device, the rupture areas (16, 17) and the portions (18, 19, 21) of the flanges outside the rupture area are arranged so as to prevent the connected elements (2, 3) from catching after the separation thereof, and to limit the vibrations induced in the element (2) in said rupture areas (16, 17).