Self-Fracturing Shape Memory Alloy Latch for Ordnance Venting
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Solution Overview
Problem
Existing safety mechanisms fail to effectively prevent over-pressurization and detonation of ordnance in high-temperature environments, as they either lead to detonation or do not adequately vent to relieve pressure during 'slow cook-off' or 'fast cook-off' events.
Innovation Solution
A passive safety mechanism utilizing a self-fracturing shape memory material is integrated into containers and latches, which fractures at elevated temperatures to vent the container, preventing over-pressurization by separating the lid from the main body and allowing pressure relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional safety mechanisms are used in high-temperature environments, then the container structure remains intact, but over-pressurization and detonation cannot be prevented
Solution Approach 1:
The patent utilizes the temperature-dependent mechanical properties of shape memory alloys, specifically transitioning from the martensite phase (low temperature, ductile) to austenite phase (high temperature, brittle). This parameter change in material phase allows the latch to maintain strength at operating temperatures while automatically fracturing at predetermined failure temperatures to prevent detonation
Solution Approach 2:
The shape memory alloy latch is pre-configured with a specific microstructure and phase transformation characteristics during manufacturing. The material is trained to undergo martensite-to-austenite transformation at a predetermined temperature threshold, so that when exposed to elevated temperatures, it automatically transitions and fractures to release pressure before detonation can occur
2Reliability
If the container is designed to maintain structural integrity, then it cannot vent pressure during cook-off events, but if it is designed to vent, then structural integrity is compromised
Solution Approach 1:
The patent separates the container structure into two functional components: a robust main body for structural integrity and a specialized latch mechanism for pressure relief. The latch is made from shape memory alloy with specific phase transformation properties, while the container body maintains conventional structural design, allowing each component to optimize its function independently
3Reliability
If active safety systems with sensors and actuators are implemented, then detonation can be detected and prevented, but device complexity and failure points increase
Solution Approach 1:
The shape memory alloy latch is a passive, self-actuating device that automatically responds to temperature changes through its inherent phase transformation properties. It requires no external power source, sensors, control systems, or actuators. The material itself serves as both the sensor (detecting temperature) and the actuator (fracturing to release pressure), eliminating complex electronic systems while maintaining reliable detonation prevention
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 self-fracturing shape memory material effectively vents containers to prevent over-pressurization and potential detonation, ensuring safer storage and transportation of ordnance by triggering a passive safety mechanism at specific temperature thresholds.
Implementation Method 1
a self-fracturing shape memory material integrated into containers and latches, which fractures at elevated temperatures
Implementation Method 2
The first substrate end fractures from the second substrate end at or above the specified temperature range
Data Source
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AI summary
A system includes a structure having a first structural element and a second structural element. The system also includes a latch configured to releasably secure the first structural element to the second structural element. The latch includes first and second portions. The latch also includes a ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged: The ball lock is also configured to allow the first and second portions of the latch to separate when the ball lock is disengaged. The latch further includes a shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock. The shape memory material member could include an elongated structure that is configured to decrease in length when exposed to the elevated temperature. The elongated structure could have at least one notch.