Compacted Fragment Warhead Void Elimination
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Solution Overview
Problem
Pre-formed fragment warheads face challenges in achieving high packing density and fragment velocity due to void spaces between randomly packed fragments, leading to reduced effectiveness and increased manufacturing costs.
Innovation Solution
The technique involves compacting pre-formed metal fragments under high pressure to remove void spaces, using a punch and die press mold to deform and bond the fragments, resulting in a rigid, void-free structure with improved packing density and fragment velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-formed fragments are randomly packaged in a warhead, then manufacturing cost is reduced, but packing density decreases and void spaces create escape channels for explosive gases
Solution Approach 1:
The fragments are pre-formed with adhesive coating applied before packaging, preparing them in advance for both random packing and subsequent bonding. This preliminary adhesive application enables the fragments to bond effectively after random packaging, resolving the contradiction between random packing (low cost) and structural integrity (high density without escape channels).
Solution Approach 2:
The warhead combines metal fragments with an adhesive binder material to create a composite structure. The adhesive fills void spaces between randomly packed fragments and bonds them together, achieving high packing density and eliminating escape channels while maintaining the simplicity of random packaging and low manufacturing cost.
2Ease of manufacture
If pre-formed fragments are randomly packaged in a warhead, then manufacturing cost is reduced, but fragment velocity decreases due to escape channels
Solution Approach 1:
Adhesive coating is applied to fragments before packaging, preparing them to form a bonded structure that will prevent gas escape channels. This preliminary action ensures that the random packaging process maintains both cost-effectiveness and fragment velocity performance.
Solution Approach 2:
The adhesive-bonded composite structure eliminates escape channels between fragments, ensuring high fragment velocity upon detonation while maintaining the cost benefits of random packaging. The composite material fills gaps and creates a unified structure that channels explosive energy efficiently to the fragments.
3Speed
If unitary structure is deeply etched to form fragments, then fragment velocity improves by eliminating escape channels, but manufacturing cost increases
Solution Approach 1:
Instead of etching a unitary structure to create fragments, the warhead uses pre-formed discrete fragments that are simply packaged and bonded. This segmentation approach achieves the same escape-channel elimination effect as etching but through a much simpler, lower-cost manufacturing process.
Solution Approach 2:
The adhesive-bonded composite of randomly packed fragments provides an alternative to etched unitary structures. The composite material fills voids and bonds fragments together, eliminating escape channels without requiring complex etching operations, thus achieving high fragment velocity at low manufacturing cost.
4Strength
If polyurethane matrix is used to hold fragments, then fragments are held together, but void spaces remain and provide escape channels for gases
Solution Approach 1:
The adhesive creates strong bonds between fragments at contact points, providing structural integrity. While the adhesive occupies some void space, the key parameter change is the bonding strength that holds fragments together as a unified structure, preventing gas escape channels while maintaining reasonable packing density.
Solution Approach 2:
The adhesive-bonded fragment composite replaces the polyurethane matrix approach. The adhesive creates a bonded network that provides structural integrity and eliminates continuous escape channels, while allowing higher packing density compared to matrix-embedded fragments.
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 approach enhances fragment velocity by eliminating escape channels for explosive gases, achieving higher packing density and reducing manufacturing costs, resulting in a more effective and cost-efficient fragmenting warhead.
Implementation Method 1
compressing the fragments together in the press mold to form the fragmenting structure as a rigid and substantially void-free structure of compression-deformed, mutually adhering metal fragments
Implementation Method 2
The fragments are made of a ductile metal that deforms under the applied pressure, causing the fragments to better conform to each other and reduce/remove void space
Implementation Method 3
Bonding may be provided by coating the fragments with thin adhesive before compaction
Implementation Method 4
explosive charge of the warhead
Implementation Method 5
the explosive gases transfer their energy to the fragments, launching the fragments at very high velocity
Data Source
AI summary
A method of making a fragmenting structure for an explosive device includes placing a volume of fragments of a deformable metal material into a press mold, the fragments having sufficient surface adhesiveness to adhere to each other upon being compressed together, e.g., by coating the fragments with adhesive. The fragments are compressed together in the press mold to form the fragmenting structure as a rigid and substantially void-free structure of compression-deformed, mutually adhering metal fragments, the fragmenting structure being sized and shaped for subsequent incorporation into the explosive device. An explosive device includes an explosive charge and a fragmenting structure adjacent to the explosive charge, the fragmenting structure being a rigid and substantially void-free structure of compression-deformed, mutually adhering metal fragments. The structure may have been manufactured by the disclosed method.