Exploding Foil Initiator Vibration Resistance via Compartmentalized Housing
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Solution Overview
Problem
Vibration in initiator assemblies can cause output charge fragments to migrate and interfere with the exploding foil initiator, preventing the input charge from being detonated effectively due to increased mass and altered impact dynamics.
Innovation Solution
The initiator assembly includes a housing with a bulkhead separating two cavities, where the exploding foil initiator and input charge are in one cavity, and the output charge, contained in a separate compartment, are isolated from each other to prevent fragments from reaching the flyer, ensuring perpendicular impact and adequate velocity for detonation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the output charge is placed in close proximity to the exploding foil initiator for compact design, then the device complexity is reduced, but vibration causes output charge fragments to migrate onto the flyer, increasing its mass and preventing effective detonation
Solution Approach 1:
The housing is divided into multiple compartments separated by bulkheads, with the output charge isolated in a separate compartment from the exploding foil initiator and input charge. This segmentation prevents fragment migration while maintaining a compact overall design.
Solution Approach 2:
A bulkhead acts as an intermediary barrier between the output charge compartment and the initiator compartment, physically preventing output charge fragments from reaching the flyer while allowing the device to remain compact.
2Length of moving object
If the flyer is accelerated to high velocity over a short distance for effective detonation initiation, then the device dimensions are reduced, but any additional mass from migrated fragments prevents the flyer from reaching threshold velocity
Solution Approach 1:
By segmenting the housing into separate compartments, the invention ensures that the flyer remains free of additional fragment mass, allowing it to be accelerated to the required high velocity over the short barrel length without interference.
Solution Approach 2:
The flyer is designed as a thin, lightweight plastic component that is consumed in the detonation process. Keeping it free of additional mass ensures it can achieve the necessary velocity for initiating detonation of the input charge.
3Reliability
If the output charge is isolated in a separate compartment to prevent fragment migration, then the reliability of detonation is improved, but the device complexity and housing structure are increased
Solution Approach 1:
The housing is segmented into distinct compartments using bulkheads, creating a simple yet effective barrier that isolates the output charge. This segmentation approach improves reliability without requiring complex isolation mechanisms.
Solution Approach 2:
The bulkhead serves multiple functions: it structurally supports the housing, separates the output charge compartment from the initiator compartment, and prevents fragment migration. This multi-functionality reduces the need for additional specialized components.
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 design enhances the reliability of detonation by maintaining the output charge fragments within their compartment, reducing the risk of interference with the exploding foil initiator and ensuring consistent initiation of the input charge, even under significant vibration.
Implementation Method 1
Electrical energy input to an exploding foil initiator causes a thin metal bridge to vaporize, which propels a flyer through a barrel and into contact with the input charge
Implementation Method 2
Energy released from detonation of the input charge in response to operation of the exploding foil initiator penetrates the bulkhead and initiates detonation of the output charge
Data Source
AI summary
An initiator assembly that includes a housing assembly, an exploding foil initiator, an input charge and an output charge. The housing assembly defines a first cavity, a second cavity, and a bulkhead member between the first and second cavities. The exploding foil initiator is received in the housing assembly and includes a bridge, a flyer and a barrel. The flyer overlies the bridge and is disposed between the barrel and the bridge. The barrel defines a barrel aperture. The input charge, which is formed of a secondary explosive, is received in the housing assembly and is disposed in-line with the barrel aperture. The output charge assembly is received in the housing assembly and is formed of a secondary explosive. Energy released from detonation of the input charge in response to operation of the exploding foil initiator penetrates the bulkhead and initiates detonation of the output charge.