Munition Blast Attenuators and Composite Case Design

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Solution Overview

Problem

Existing tandem warhead munitions face challenges in protecting the aft explosive charge from the blast shock of the forward charge, which can cause premature damage and reduce the effectiveness of the secondary penetration and damage upon delayed detonation.

Innovation Solution

Incorporating a blast cone and multiple blast attenuators, including a third attenuator in an internal cavity, formed from materials like polyurethane foam and composite materials, to deflect and dissipate the blast shock, and a composite case that disintegrates to minimize interference with the blast, ensuring the aft charge can penetrate effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a blast cone and blast attenuators are added to protect the aft explosive charge, then the reliability of the munition is improved, but the device complexity increases

Engineering Contradiction:
Improveprotection of aft explosive chargeVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blast protection system is divided into multiple separate components: a blast cone positioned between the charges and multiple blast attenuators placed in different locations (including internal cavities). This segmentation allows each component to perform its protective function independently while maintaining overall system reliability without requiring a single complex protective structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blast attenuators are positioned within available spaces and cavities within the munition structure, nesting the protection elements within the existing geometry. This allows the protective components to be integrated into the overall design without significantly increasing external dimensions or overall structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If multiple blast attenuators and a blast cone are incorporated to deflect blast shock, then the protection of the aft charge is improved, but the weight of the munition increases

Engineering Contradiction:
Improveblast shock protectionVSAvoidmunition weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The blast attenuators are constructed from porous or cellular materials that provide effective blast shock absorption and deflection through their internal structure. These materials achieve high protective performance relative to their weight by utilizing the energy-absorbing characteristics of porous structures, thereby protecting the aft charge while minimizing weight increase.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The blast cone and attenuators utilize composite material constructions that combine different materials to achieve optimal strength-to-weight ratios. This allows the protective components to effectively deflect and dissipate blast shock waves while maintaining minimal added weight compared to solid homogeneous structures.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the composite case is designed to disintegrate to minimize blast interference, then the effectiveness of the aft charge penetration is improved, but the strength of the case is reduced

Engineering Contradiction:
Improvepenetration effectivenessVSAvoidcase strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The composite case is pre-designed with specific structural characteristics and material properties that cause it to disintegrate or break apart upon exposure to the blast shock from the forward charge. This preliminary design ensures that when the forward charge detonates, the case automatically fragments in a controlled manner to minimize interference with the aft charge's penetration function, while still providing sufficient strength to contain the charges during transport and handling.

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

The solution effectively protects the aft explosive charge from premature damage, allowing it to penetrate and cause further damage upon delayed detonation, enhancing the overall performance and reliability of the munition by weakening and deflecting the blast shock.

Implementation Method 1

the blast cone and multiple blast attenuators, including a third attenuator in an internal cavity, formed from materials like polyurethane foam and composite materials, to deflect and dissipate the blast shock

Methodology Applied
Scientific EffectShock wave dissipation: Shock Wave

Implementation Method 2

formed from materials like polyurethane foam and composite materials, to deflect and dissipate the blast shock

Methodology Applied
Scientific EffectCellular material energy absorption: Foam

Implementation Method 3

a composite case that disintegrates to minimize interference with the blast, ensuring the aft charge can penetrate effectively

Methodology Applied
Scientific EffectComposite material fragmentation: Composite Materials

Data Source

PatentEP3120106B1Lightweight munition
Publication Date: 2020.10.21 AEROJET ROCKETDYNE INC
  • EP3120106B1 patent drawingFigure 1A~1B
  • EP3120106B1 patent drawingFigure 2

AI summary

A munition includes a composite case, a blast cone housed by the composite case, a grenade aft of the blast cone and housed by the composite case, a first attenuator forward of the blast cone, and a second attenuator aft of the blast cone and forward of the grenade.