IM Liner Structure for Controlled Warhead Fragmentation

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Solution Overview

Problem

Existing fragmentation warheads are inefficient and costly to produce, requiring multiple types for different targets, and pose safety risks due to mechanical shock and heat sensitivity.

Innovation Solution

A fragment enhancing insensitive munitions (IM) liner is used, comprising a patterned metal structure embedded in a compressible material, positioned between the outer metal casing and explosive, to control fragment size and shape without compromising safety or stability, using metals like steel or beryllium for faster shock wave propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple types of fragmentation warheads are used for different targets, then the effectiveness against various targets is improved, but the logistics burden and supply complexity increase

Engineering Contradiction:

Improveeffectiveness against various targetsVSAvoidlogistics burden and supply complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a single warhead design with a modular liner system that can produce different fragment patterns. The liner includes multiple sections with different geometries (conical, cylindrical, planar) that can be selectively activated or combined to adapt to different target types, eliminating the need for multiple specialized warhead types while maintaining versatility against personnel, light armor, and hard targets

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If a single warhead is designed for specific application, then the fragmentation efficiency is improved, but the adaptability to different targets deteriorates

Engineering Contradiction:

Improvefragmentation efficiencyVSAvoidadaptability to different targets

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The liner is divided into multiple discrete sections or zones, each with specific geometric characteristics optimized for different fragmentation outcomes. These segmented sections can work independently or in combination, allowing the single warhead to achieve specialized fragmentation efficiency for various target types without requiring multiple dedicated warhead designs

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If grooves or openings are machined or cast in metal casings to induce fragmentation, then the fragment pattern control is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvefragment pattern controlVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of machining complex grooves or openings in metal casings, the patent changes the approach by using a liner with pre-formed geometric features (conical, cylindrical, planar sections) that naturally guide shock wave propagation. This parameter change from post-casing modification to pre-liner configuration maintains precise fragment pattern control while significantly simplifying the manufacturing process and reducing costs

Inventive Principle:

Principle #35Parameter changes

4Reliability

If the explosive charge is made more sensitive to ensure reliable detonation, then the detonation reliability is improved, but the susceptibility to accidental detonation increases

Engineering Contradiction:

Improvedetonation reliabilityVSAvoidsusceptibility to accidental detonation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The IM liner acts as an intermediary between the explosive charge and the metal casing. It transmits and focuses the shock waves from the detonation to ensure reliable casing fragmentation, while simultaneously providing a buffer that reduces the transmission of accidental shocks and thermal effects to the explosive charge, thereby decoupling detonation reliability from susceptibility to accidental detonation

Inventive Principle:

Principle #24Intermediary (Mediator)

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 IM liner enhances fragmentation performance while reducing costs and maintaining safety, allowing a single warhead to be effective against various targets with controlled fragment size and shape, and minimizing accidental detonation risks.

Implementation Method 1

means for propagating shock waves across the inner surface from a selected one of two detonation points with the chamber

Methodology Applied

Scientific EffectShock wave: Shock Wave

Implementation Method 2

The means for directing the shock waves comprise grooves/slots formed in a layer of compressible material (e.g., the insensitive munitions (IM) liner) lining at least a selected portion of the inner surface of the outer casing

Methodology Applied

Scientific EffectShock wave propagation: Shock Wave

Data Source

PatentUS12504261B2Explosive fragmentation structure with a fragment enhancing insensitive munitions (IM) liner

Publication Date: 2025.12.23 RAYTHEON CO

AI summary

An explosive fragmentation structure includes a fragment enhancing insensitive munitions (IM) liner. The IM liner includes a patterned metal structure having openings therethrough embedded in a compressible material to define a desired fragmentation pattern of the outer metal casing upon detonation of the explosive. The IM layer is positioned between and in conformal contact with the outer metal casing's inner surface and the explosive's outer surface.