Shock-Hardened Initiator Bridge Substrate for Explosive Charge Integrity

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Solution Overview

Problem

Conventional initiator assemblies fail to reliably initiate explosive payloads due to shock loading and rapid deceleration, which cause stress and fracture of the explosive charge during impact and penetration, leading to incomplete detonation.

Innovation Solution

The initiator assembly features a robust bridge substrate with a continuous planar mounting surface that provides uniform support to the explosive charge, minimizing stress risers and ensuring surface-to-surface contact across the charge's surface area, combined with an isolation sleeve for lateral support, to maintain the charge's integrity during dynamic events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional initiator assemblies are used, then the structure is simple, but the explosive charge fractures during shock loading and rapid deceleration

Engineering Contradiction:

Improveinitiation reliabilityVSAvoidinitiator structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The explosive charge is pre-formed with a flat face geometry designed to mate with the planar mounting surface of the bridge substrate. This preliminary configuration ensures uniform stress distribution during subsequent shock loading and rapid deceleration, preventing fracture while maintaining initiation reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The bridge substrate provides a localized planar mounting surface with specific dimensional tolerances that create uniform contact across the explosive charge face. This localized precision geometry concentrates support where needed most during dynamic loading, preventing stress risers without requiring complex overall structure

Inventive Principle:

Principle #3Local quality

2Strength

If the explosive charge is supported during impact and penetration, then fracture is prevented, but stress is transmitted to the charge

Engineering Contradiction:

Improvecharge integrityVSAvoidstress on explosive charge

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The planar mounting surface creates homogeneous stress distribution across the entire contact area between the bridge substrate and explosive charge. This uniform stress field prevents localized stress concentrations that would cause fracture, while the distributed nature of the stress reduces peak pressure values on the charge

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS9879951B2Shock hardened initiator and initiator assembly

Publication Date: 2018.01.30 RAYTHEON CO

AI summary

An initiator assembly includes an initiator housing having an initiator cavity and a housing orifice edge. A bridge substrate is positioned within the initiator cavity, the bridge substrate includes a substrate base including a uniform first planar surface and first and second bridge contacts flush with the uniform first planar surface. The first and second bridge contacts form a continuous planar mounting surface. An explosive charge and a flyer plate are within the initiator cavity, the flyer plate interposed between the explosive charge and the bridge substrate. A plunger head is telescopically received in the initiator cavity and includes an anchoring cylinder face having a face perimeter and extends between first and second face ends. The housing orifice edge is anchored to the anchoring cylinder face at a position between the first and second face ends and extends around the face perimeter.