Eutectic Separation Bolt for Fragment-Free On-Command Release
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Solution Overview
Problem
Conventional explosive fasteners pose risks due to premature thermal and electrical initiation, and the resulting fragments can damage nearby sensitive components, necessitating extensive shielding.
Innovation Solution
An axially separable fastener system using a structural metal bolt with a liquid metal eutectic, where an internal plug drives an auger into a frangible ampoule containing the eutectic upon command, causing intergranular decohesion and mechanical separation without explosive pressure or fragmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an explosive charge is used to sever the bolt, then the bolt can be suddenly and destructively severed on command, but extensive shielding is required to protect nearby sensitive components from damage caused by the resulting fragments
Solution Approach 1:
The invention extracts the harmful explosive charge from the fastener system and replaces it with a benign liquid metal eutectic substance contained in a frangible ampoule. The eutectic substance is injected into the bolt shank to cause decohesion without generating explosive fragments, thereby eliminating the need for extensive shielding while maintaining the ability to sever the bolt on command
Solution Approach 2:
The invention changes the physical and chemical parameters of the separation mechanism from high-energy explosive decomposition to low-energy liquid metal eutectic decohesion. The eutectic substance alters the material properties of the bolt metal at the molecular level, causing brittle failure without the high-temperature, high-pressure conditions that generate dangerous fragments
2Speed
If an explosive charge is used to sever the bolt, then the bolt can be suddenly severed, but the explosive charge poses risks of premature thermal and electrical initiation
Solution Approach 1:
The invention replaces the sensitive explosive charge with a disposable frangible ampoule containing liquid metal eutectic. The ampoule is designed to be broken on command by an actuator, releasing the eutectic substance that causes rapid decohesion. This disposable approach eliminates the need for complex safety systems required for explosive charges while maintaining reliable on-command separation
Solution Approach 2:
The invention substitutes the thermal and electrical initiation mechanisms of explosive charges with a purely mechanical actuation system. An actuator mechanically breaks the frangible ampoule, which then releases the eutectic substance to cause decohesion. This mechanical substitution eliminates the risk of premature thermal or electrical initiation while preserving the ability to sever the bolt suddenly on command
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 system effectively severs the fastener without blast pressure or secondary fragmentation, reducing the risk of damage to nearby components and eliminating the hazards associated with explosive charges.
Implementation Method 1
causing intergranular decohesion and mechanical separation without explosive pressure or fragmentation
Data Source
AI summary
An axially separable fastener for securing a structure is provided to detach upon command of an electric signal. The fastener includes a metal bolt, an external nut, a frangible ampoule containing a liquid metal eutectic and an internal plug. The bolt has a metal shank with proximal and distal ends. The shank includes a first head at the proximal end, and a first helical external thread and an axial bore with a first helical internal thread at the distal end. The fastener secures a structure in compression between the first head and the external nut. The external nut screws onto the first external thread. The ampoule contains a liquid metal eutectic. The ampoule is insertable into the bore. The internal plug includes a second head, an actuator mechanism, and an auger opposite thereto. The internal plug has a second helical external thread between the second head and the auger for screwing into the bore along the first internal thread. Upon receipt of the signal, the internal plug axially drives the auger towards the proximal end into the ampoule to release the eutectic, thereby fracturing the bolt.