Double Inner Coating for Warhead Explosive Decoupling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for producing large-caliber warheads with plastic-bonded explosive charges face challenges such as time-consuming liner introduction, incomplete lining, contamination, and cracking due to temperature fluctuations, as well as inefficiencies in decoupling the explosive from the warhead casing.

Innovation Solution

A double inner coating system is applied to the warhead casing, where the first coating with low adhesion is used as a binding layer and the second coating, matching the explosive's plastic binder, ensures decoupling by polymerizing with the explosive charge, preventing separation and ensuring complete filling without defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prefabricated plastic liner is introduced through the mouth hole, then decoupling of explosive from warhead casing is achieved, but the process becomes extremely time consuming and the liner cannot be fully positioned

Engineering Contradiction:
Improvedecoupling of explosiveVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical insertion system (prefabricated liner through mouth hole) with a chemical deposition system (spray application of coating materials). The liner is built in situ by spraying successive layers of coating materials that polymerize to form the decoupling structure, eliminating the need for mechanical insertion through the constrained mouth hole.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies preliminary action by first coating the inner wall with a binding layer before applying the decoupling layer. This sequence ensures proper adhesion and positioning from the start, preventing the positioning problems that occur when trying to insert a complete liner through the mouth hole.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the liner is folded during insertion, then the liner can be introduced into the warhead casing, but creases and distortions occur that prevent complete lining

Engineering Contradiction:
Improveliner insertionVSAvoidlining completeness
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent eliminates mechanical folding and manipulation of the liner by replacing the insertion process with in-situ spray deposition. The coating materials are sprayed directly onto the inner wall and polymerize to form a continuous, crease-free liner that completely lines the warhead casing interior.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the mouth hole diameter is small, then the head fuse can be screwed in, but the introduction and positioning of liner and explosive charge becomes extremely time consuming

Engineering Contradiction:
Improvehead fuse installationVSAvoidcharge introduction time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent replaces mechanical insertion operations with spray deposition. Both the binding layer and decoupling layer are applied by spraying through the existing mouth hole, and the explosive charge is introduced as a sprayable composition that polymerizes in place. This eliminates the time-consuming manual manipulation required when working through a small mouth hole.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If the liner material is not sufficiently elastic, then the liner can be produced with fewer materials, but the liner cannot be properly introduced and positioned

Engineering Contradiction:
Improveliner productionVSAvoidliner insertion
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent replaces mechanical insertion of a pre-formed liner with chemical deposition of the liner material. The coating materials are sprayed onto the inner wall and polymerize to form the liner in place, eliminating the need for elastic properties that would be required to force a rigid liner through the mouth hole and into position.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This method simplifies the production process, prevents contamination and cracking, ensures complete filling, and maintains decoupling under temperature fluctuations, enhancing the reliability and accuracy of the warhead assembly.

Implementation Method 1

The first coating which adjoins the inner wall of the warhead casing and serves as a binding layer has a low level of adhesion

Methodology Applied
Scientific EffectAdhesion control: Adhesive

Implementation Method 2

The second coating, which adjoins the first coating on the explosive charge side, is selected in such a way that it has the same (at least essentially the same) chemical composition as the plastic binder of the explosive charge

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

The leveling layer lies exactly against the inner wall of the warhead casing, so that surface defects such as dents / bumps, etc., which could be between the leveling layer and the inner wall of the warhead casing, are leveled out

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3114426B1Method for producing a large-caliber warhead, and warhead produced according to said method
Publication Date: 2018.05.02 RHEINMETALL WAFFE MUNITION GMBH
  • EP3114426B1 patent drawingFigure 1

AI summary

The invention relates to a method for producing a large-caliber warhead (1) with a warhead casing (2) which surrounds an explosive charge (6) made of a plastic-bonded explosive. A compensation layer (8) made of an elastic material is arranged between the explosive charge (6) and the inner wall (7) of the warhead casing (2). In order to allow the compensation layer (8) to lie on the inner wall (7) of the warhead casing (2) in an exact manner, a double inner coating is provided as the compensation layer (8) between the explosive charge (6) and the inner wall (7) of the warhead casing (2). The first coating (9), which rests against the inner wall (7) of the warhead casing (2), is used as a binding coating with a low adhesive capability. The subsequent second coating (10) has the same chemical composition as the plastic binder of the explosive charge (6). A low adhesive bond, which is intentionally broken upon the temperature-dependent volumetric expansion/shrinkage of the explosive, is produced between a first (adhesion-reduced) anticorrosive paint and a second "binder coating".