Cellular Structure End Cap for Ammunition Rounds

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional ammunition end caps are heavy due to their dense materials, which increases the overall mass of the cartridge case without providing significant reduction in weight, compromising the structural integrity and functionality.

Innovation Solution

A lightweight cellular structure end cap with a porous three-dimensional structure, featuring a surface skin for a gas-tight seal, made from materials like low-density metals, polymers, or ceramics, which reduces mass while maintaining functionality by allowing energetic output to flow through a fire hole and preventing gas leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If conventional dense materials are used for end cap, then structural integrity and strength are maintained, but mass increases

Engineering Contradiction:

Improveend cap massVSAvoidend cap strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The end cap employs a porous three-dimensional spatial structure with controlled void volumes (30-70% porosity) that significantly reduces mass while maintaining structural integrity. The porous framework provides sufficient strength to contain propellant and withstand firing pressures, eliminating the need for solid dense materials.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The end cap integrates multiple materials including metal matrix composites, ceramic particles, and polymer binders to achieve optimal strength-to-weight ratio. This composite approach allows the porous structure to maintain mechanical properties despite reduced material density.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If porous structure is used to reduce mass, then end cap mass decreases, but gas tightness may be compromised

Engineering Contradiction:

Improveend cap massVSAvoidgas tightness

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The porous structure features localized density variations with higher material concentration at critical regions such as the periphery and gas containment zones. This local quality enhancement ensures gas tightness in areas where it is most needed while maintaining porosity in non-critical regions for weight reduction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

A thin film or skin layer is applied to the porous structure's outer surface to provide a gas-tight barrier. This thin protective layer prevents gas leakage through the porous framework while adding minimal mass, effectively resolving the contradiction between porosity and gas tightness.

Inventive Principle:

Principle #30Flexible shells and thin films

3Weight of moving object

If porous structure is used to reduce mass, then end cap mass decreases, but shock resistance may be compromised

Engineering Contradiction:

Improveend cap massVSAvoidshock resistance

Core Design Contradiction:

Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The porous structure inherently provides shock absorption through its void spaces that can compress and deform under impact, dissipating energy before it reaches critical components. This beforehand cushioning effect protects the propellant and primer from shock damage while maintaining low mass.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The incorporation of ceramic particles and metal matrix composites enhances the porous structure's shock resistance by providing hard, impact-resistant phases within the lightweight framework, enabling the end cap to withstand firing shocks and handling impacts.

Inventive Principle:

Principle #40Composite materials

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 cellular structure end cap achieves a significant reduction in mass without compromising the functionality, providing a gas-tight seal and enhanced shock resistance, making it suitable for use in ammunition rounds.

Implementation Method 1

wherein in said porous 3D spatial structure comprises a surface skin; wherein said surface skin provides a gas tight seal

Methodology Applied

Scientific EffectGas tight seal:

Implementation Method 2

The surface skin must at least be located around the cap chamber, such that all of the gases that evolve from the primer cap do not leak out of the end cap and only flow through the firehole to the cartridge case and propellant located therein

Methodology Applied

Scientific EffectFlow through fire hole:

Implementation Method 3

The cellular end cap may further comprise a binder matrix, which may be added to aid the deposition, or formation of the cellular structure, the binder matrix may be selected from ceramics, polymers, further metals. The binder matrix may act as a porogen, such that it may be removed from the final structure, to furnish the void structure within the cellular end cap

Methodology Applied

Scientific EffectPorogen:

Data Source

PatentEP4086566A1Lightweight end cap

Publication Date: 2022.11.09 BAE SYSTEMS PLC

Figure 1
Figure 2~3
Figure 4a

AI summary

The invention relates to a method of improved ammunition production, more specifically to a cellular structure end cap, suitable for an ammunition round, said end cap comprising a porous 3D spatial structure in the shape of said end cap, wherein in said porous 3D spatial structure comprises a surface skin.