Rocket Nozzle Plate Leaf-Spring Damping for Vibration Control

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Solution Overview

Problem

Space launchers face challenges in minimizing mass while controlling dynamic couplings and displacement amplitudes, particularly due to the radial plate around the nozzle, which experiences significant displacements and stress from thermal expansion, making traditional support methods like connecting rods unsuitable.

Innovation Solution

The implementation of a space launcher with a universal joint fixing the engine to the launcher body and a plate around the nozzle equipped with damping elements, such as leaf springs, to attenuate vibrations and reduce displacement amplitudes without increasing mass or stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If connecting rods are added to support the plate, then the plate's structural stability is improved, but the mass increases and thermal expansion stresses become excessive

Engineering Contradiction:
Improveplate structural stabilityVSAvoidmass
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent changes the physical parameters of the plate by adding damping elements that modify its vibrational characteristics. The damping elements alter the plate's natural frequencies and reduce displacement amplitudes, achieving stability enhancement without adding rigid supports. This parameter change approach allows the plate to maintain structural integrity while avoiding the mass penalty of connecting rods.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If connecting rods are added to support the plate, then the plate's structural stability is improved, but thermal expansion stresses become excessive

Engineering Contradiction:
Improveplate structural stabilityVSAvoidthermal expansion stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The damping elements modify the plate's dynamic response parameters, reducing displacement amplitudes and thereby lowering the stresses induced by thermal expansion. By changing the vibrational characteristics rather than adding rigid constraints, the system accommodates thermal expansion without generating excessive stresses.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the plate has a free external contour to accommodate engine movements, then the engine's range of motion is maintained, but the plate experiences significant displacement amplitudes

Engineering Contradiction:
Improveengine range of motionVSAvoidplate displacement amplitude
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies dynamic damping elements to the plate that actively counteract vibrational movements. These elements provide frequency-dependent damping that reduces displacement amplitudes across different operating conditions while allowing the plate to maintain its free contour and accommodate engine movements. The dynamic nature of the damping allows adaptability without sacrificing stability.

Inventive Principle:
Principle #15Dynamics

4Stability of the object's composition

If damping elements are added to the plate, then displacement amplitudes are reduced, but the device complexity increases

Engineering Contradiction:
Improvedisplacement amplitudeVSAvoiddamping system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The damping system is segmented into multiple independent damping elements distributed across the plate surface. Each damping element operates independently, allowing the system to achieve complex damping characteristics through simple, modular components. This segmentation reduces overall system complexity while effectively reducing displacement amplitudes.

Inventive Principle:
Principle #1Segmentation

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 damping elements effectively reduce displacement amplitudes and stress, achieving non-linear damping that minimizes eigenmode maintenance and reduces the range of motion, thereby addressing the mass and stress concerns while maintaining mechanical strength.

Implementation Method 1

a plurality of damping elements positioned on the internal face of the plate, each damping element comprising a spring blade parallel to the internal face of the plate

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

each damping element comprising a spring blade parallel to the internal face of the plate

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 3

each damping element comprising a spring blade parallel to the internal face of the plate

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3973172B1Non linear damping system comprising leaf springs for a rocket engine
Publication Date: 2023.08.09 ARIANEGRP SAS
  • EP3973172B1 patent drawingFigure 1~2
  • EP3973172B1 patent drawingFigure 3~7

AI summary

Space launcher comprising a launcher body (1), an engine (2), a combustion chamber (4), a nozzle (5) having a main axis (Z-Z), the nozzle (5) being provided with a plate (6) extending radially, the plate (6) having an inner face and an outer face positioned respectively in the internal volume and in the external environment, characterized in that it additionally comprises a plurality of damping elements (7) positioned on the inner face of the plate (6), each damping element (7) comprising a leaf spring (71) parallel to the inner face of the plate (6).