Segmented Ammunition Envelope for Shock Protection

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Solution Overview

Problem

Current shrapnel-generating ammunition lacks protection against mechanical shocks, such as fragment impacts, while high-performance explosives with detonation speeds greater than or equal to 8000 meters per second are sensitive to shocks, making them vulnerable and unable to meet NATO standards like STANAG 4439, which require resistance to both thermal and mechanical attacks.

Innovation Solution

A protective envelope with an internal wall featuring non-contiguous cells distributed angularly and longitudinally around the ammunition body, providing mechanical resistance without interfering with the operation of the ammunition, manufactured using additive manufacturing technology to minimize interference with the explosive's functioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional protection structures are added to protect against mechanical shocks, then resistance to fragment impacts improves, but the projection speed of fragments is slowed down and operational characteristics are disturbed

Engineering Contradiction:

Improveresistance to mechanical shocksVSAvoidprojection speed of fragments

Core Design Contradiction:

StrengthVSSpeed

Solution Approach 1:

The envelope is segmented into multiple non-contiguous cells distributed angularly and longitudinally around the ammunition body. This segmentation allows the structure to provide mechanical protection through distributed support points while maintaining gaps that prevent interference with fragment projection, thus resolving the contradiction between strength and speed

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cells are positioned at specific locations around the ammunition body rather than forming a continuous enclosure. This local quality approach provides protection only where structurally necessary while leaving other areas open for optimal fragment ejection, balancing mechanical resistance with operational performance

Inventive Principle:

Principle #3Local quality

2Power

If high-performance explosives with detonation speed greater than or equal to 8000 meters per second are used, then effectiveness against hardened targets improves, but sensitivity to shock increases making ammunition vulnerable

Engineering Contradiction:

Improvedetonation speedVSAvoidvulnerability to shock

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The envelope with its cellular structure is installed beforehand to cushion and absorb mechanical shocks before they can reach the explosive charge. This prior protection allows the use of high-performance explosives with high detonation speeds while mitigating their increased shock sensitivity, thereby maintaining both power and reliability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If additional protections are added to protect the ammunition body, then resistance to mechanical attacks improves, but the projection of fragments is slowed down

Engineering Contradiction:

Improveprotection against mechanical attacksVSAvoidfragment projection efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The protective envelope is divided into discrete non-contiguous cells rather than forming a solid barrier. This segmentation provides mechanical protection at specific points while maintaining overall openness, allowing fragments to be projected efficiently without being significantly slowed by the protective structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The envelope provides partial protection through its cellular structure rather than complete enclosure. This partial action approach delivers sufficient mechanical protection while minimizing interference with fragment projection, achieving the optimal balance between protection and productivity

Inventive Principle:

Principle #16Partial or excessive 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

The envelope enhances the ammunition's resistance to mechanical shocks by deforming to absorb impact energy without disturbing the generation of splinters, ensuring compliance with NATO standards and maintaining the desired detonation performance.

Implementation Method 1

The envelope enhances the ammunition's resistance to mechanical shocks by deforming to absorb impact energy

Methodology Applied

Scientific EffectDeformation: Deformation

Implementation Method 2

high-performance explosives with a detonation speed greater than or equal to 8000 meters per second

Methodology Applied

Scientific EffectDetonation: Detonation

Data Source

PatentEP3633313B1Enclosure for ammunition and ammunition including such an enclosure

Publication Date: 2021.06.09 NEXTER MUNITIONS SA

Figure 1a~1b
Figure 2a~3b
Figure 4

AI summary

The invention relates to a casing (4) intended to be placed around a fragmentation-generating body (2) of a munition (1). This casing is characterized in that it comprises an inner wall (9) having a geometry such that it can be positioned in conformity with the shape of the body (2) to which it is intended to be attached. This inner wall (9) carries cells (11) having a closed profile attached to the wall (9) at one end. The cells (11) are not contiguous and are therefore separated from each other around their perimeter by a non-zero distance (d). The invention also relates to an explosive munition comprising such a casing.