Exploding Foil Initiator Bridge Geometry for Uniform Current Density
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Solution Overview
Problem
Existing exploding foil initiators (EFI) suffer from nonuniform current density and heating, leading to inefficient and nonuniform bursting of the metallic foil, which affects the uniform acceleration and detonation of high explosives.
Innovation Solution
Modifying the shape and dimensions of the conductors, particularly the bridge and bottom-side return path, to achieve uniform current density, with thicker regions except under the flyer to prevent vaporization and melting, and using electromagnetic modeling tools to optimize these designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional conductor shapes and dimensions are used in EFI, then the design is simple and easy to manufacture, but the current density becomes nonuniform leading to inefficient bursting
Solution Approach 1:
The conductor geometry is modified with varying thickness throughout its structure. Thinner regions are positioned where higher current density is needed to promote uniform heating and bursting, while thicker regions provide structural support and control current distribution. This local variation in conductor properties resolves the contradiction by achieving uniform current density through strategic geometric modification rather than uniform design.
Solution Approach 2:
The conductor's physical parameters, specifically its thickness and cross-sectional area, are deliberately changed at different locations along its path. By adjusting these geometric parameters, the current density distribution is controlled to achieve uniformity across the EFI element, transforming the simple conventional design into an optimized configuration that balances manufacturing feasibility with performance requirements.
2Strength
If conductor thickness is increased to prevent vaporization, then structural integrity is improved, but current density uniformity deteriorates
Solution Approach 1:
The conductor is designed with spatially varying thickness to simultaneously satisfy structural and electrical requirements. Thicker sections provide the necessary structural integrity and resistance to vaporization in regions where high mechanical strength is needed, while thinner sections are strategically placed where uniform current density is critical for efficient bursting. This local differentiation resolves the contradiction between strength and current density uniformity.
3Use of energy by moving object
If conventional EFI design is used, then energy consumption is high due to nonuniform bursting, but modifying conductor shape increases design complexity
Solution Approach 1:
The conductor's geometric parameters are optimized to achieve uniform current density distribution, which directly improves energy utilization efficiency. By carefully controlling the thickness and cross-sectional variations along the conductor path, the design minimizes energy waste from nonuniform bursting while maintaining manufacturability. The parameter changes are designed to be practical and implementable, balancing energy efficiency improvements with reasonable design complexity.
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 results in improved current density uniformity, increased efficiency, and reduced energy consumption in EFI systems, enabling more reliable and cost-effective high explosive initiation systems.
Implementation Method 1
a fireset produces a current pulse having a peak of applied current, wherein the bridge shape and bridge dimensions are chosen such that an optimized burst of said bridge occurs at the peak of the applied current
Implementation Method 2
electromagnetic effects may act to make current density in EFI's nonuniform
Data Source
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AI summary
Exploding foil initiator apparatus, system, and method that improve the current density in the bridge region by modifying the shape and dimensions of the bridge and related components. The exploding foil initiator reduces burn-back by making areas of the bridge thicker except directly under the flyer. The exploding foil initiator boards are built so the flyer is not connected to the rest of the top cover-lay. This avoids losing energy due to the flyer having to tear away from the solid cover-lay.