Munition Preformed Fragments Controlled Fragmentation

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Solution Overview

Problem

Area weapons with height-of-burst capabilities suffer from uncontrolled fragmentation, leading to collateral damage due to their heavy solid-wall structures, which result in unwanted fragment dispersal beyond the target area.

Innovation Solution

A munition design featuring preformed fragments with a combined mass greater than the casing and shell, filling a continuous volume between them to enhance controlled fragmentation, thereby minimizing collateral damage and improving fragmentation area coverage and pattern density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heavy solid-wall structures (casing and shell) are used in area weapons, then structural strength and containment are improved, but uncontrolled fragmentation increases causing collateral damage

Engineering Contradiction:

Improvestructural strengthVSAvoiduncontrolled fragmentation

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The munition is segmented into distinct functional components: a lightweight casing containing the explosive, a separate shell providing aerodynamic housing, and preformed fragments positioned between them. This segmentation allows each component to be optimized independently - the casing can be thin-walled since it doesn't need to contain pressure, and the fragmentation is controlled by the preformed fragments rather than the casing material

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preformed fragments are prepared in advance with specific mass, shape, and distribution characteristics before being positioned in the munition. This preliminary preparation ensures that when the explosive detonates, the fragments are already optimized for controlled dispersion patterns that maximize target area coverage while minimizing collateral damage, eliminating the need for heavy casing to control fragmentation

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If preformed fragments with mass greater than casing and shell are used, then controlled fragmentation is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improvecontrolled fragment massVSAvoidmunition structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

Different regions of the munition have different material qualities and functions. The preformed fragments in the fragmentation zone have optimized mass and distribution for controlled dispersion, while the casing and shell use lightweight materials appropriate for their containing and aerodynamic functions. This local optimization allows enhanced controlled fragmentation without requiring uniform heavy construction throughout the entire munition

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The design changes the mass parameter distribution within the munition, making the preformed fragments the dominant mass component rather than the casing and shell. This parameter change enables controlled fragmentation to be the primary mechanism while the casing and shell serve secondary containing and aerodynamic functions, reducing overall structural complexity

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If the preformed fragments fill the continuous volume between casing and shell, then fragmentation area coverage is maximized, but assembly difficulty increases

Engineering Contradiction:

Improvefragmentation coverage areaVSAvoidassembly ease

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The preformed fragments are pre-positioned to fill the continuous volume between the casing and shell before final assembly. This preliminary placement ensures maximum fragmentation area coverage is achieved while the fragments are already in their optimal positions, simplifying the final assembly process compared to attempting to position and secure individual fragments during assembly

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 munition achieves a higher ratio of controlled to uncontrolled fragmentation, reducing collateral damage by maximizing the amount of preformed fragments within the target area while maintaining compatibility with existing guidance systems and aerodynamic properties.

Implementation Method 1

an explosive enclosed by the casing

Methodology Applied

Scientific EffectChemical energy to mechanical energy transformation:

Data Source

PatentUS9683822B2Munition with preformed fragments

Publication Date: 2017.06.20 RAYTHEON CO

AI summary

A munition that is adapted to enhance fragmentation effects upon detonation includes preformed fragments between a casing and a shell. The overall mass of the preformed fragments is greater than the overall combined mass of the casing and the shell for enhancing the degree of controlled fragmentation compared to uncontrolled fragmentation. By enhancing the dispersal of controlled fragmentation, the overall fragmentation area coverage and fragmentation pattern density may also be enhanced while limiting travel of the fragmentation beyond the target area for reducing collateral damage. The preformed fragments may fill a continuous volume between the casing and the shell to effectively utilize the munition volume and to maximize the amount of preformed fragments contained within the shell. The preformed fragments may be free flowing pellets that are poured into the volume between the casing and the shell for enhancing distribution of the fragments and for improving assembly of the munition.