Cartridge Case Base Plate Release via Shape Memory Alloy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cartridge cases with temperature-dependent shape memory materials face challenges in reliably releasing the base plate under heating conditions due to the need for a voluminous space for the shape memory material, which can lead to delayed or incomplete release, causing violent reactions in explosive materials.
Innovation Solution
The use of a crushing force mechanism, where the shape memory material exerts a force on either the base plate or the bottom section of the cartridge case, creating a defined opening to relieve overpressure, utilizing v-shaped recesses and support rings to facilitate a controlled release, maintaining the integrity of the base plate and bottom section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voluminous space is provided for the shape memory material to house it in both blocked and unblocked positions, then the shape memory material can be positioned, but the cartridge case volume increases and distinct positioning becomes difficult
Solution Approach 1:
The shape memory material transitions from a static locking mechanism to a dynamic temperature-responsive system. The material automatically changes shape based on temperature conditions, eliminating the need for separate positioning mechanisms for blocked and unblocked states. This dynamic behavior allows reliable base plate release without requiring excessive space for manual positioning.
Solution Approach 2:
The invention utilizes temperature as a controlling parameter to change the shape memory material's configuration. By changing the temperature parameter, the material transitions between locked and unlocked states without requiring physical repositioning or additional space for multiple positioning configurations. This parameter-based control resolves the space-volume contradiction.
2Reliability
If the shape memory material is positioned in a space between the base plate and the bottom section, then the base plate can be locked, but the explosive content expansion under heating may secure the material before critical temperature is reached
Solution Approach 1:
The shape memory material is pre-positioned in a compressed state between the base plate and bottom section, but designed with sufficient thermal response capability to overcome the cushioning effect of explosive expansion. The material's shape memory properties are selected to ensure it maintains its temperature-dependent shape change capability even under the pre-compression caused by explosive expansion, preventing premature securing before the critical temperature is reached.
Solution Approach 2:
The invention uses shape memory material with specific compositional properties that provide both mechanical compliance to accommodate explosive expansion and thermal sensitivity to respond at the critical temperature. This composite functionality within the shape memory material allows it to withstand pre-compression from explosive expansion while maintaining reliable temperature-triggered release.
3Strength
If a shape memory material is used to lock the base plate, then the base plate can be securely held, but under heating the material may not release the base plate reliably causing violent reactions
Solution Approach 1:
The shape memory material exploits phase transition phenomena (martensitic transformation) to achieve both strong locking at lower temperatures and reliable release at critical temperatures. The material exists in different crystalline phases that provide distinct mechanical properties: a martensitic phase for flexible locking and an austenitic phase for forceful release. This phase transition mechanism simultaneously provides the required locking strength and release reliability.
Solution Approach 2:
The invention replaces traditional mechanical locking systems with a thermally-actuated shape memory material system. Instead of using mechanical keys, levers, or springs that may fail to release reliably under heat, the system uses the material's inherent shape memory effect to provide both locking and release functions through temperature control, eliminating the reliability issues of mechanical release mechanisms under thermal stress.
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 solution ensures a reliable and controlled release of the base plate, reducing the violence of reactions in explosive materials when subjected to heat, while minimizing adaptations to existing cartridges.
Implementation Method 1
a base plate locking device comprising a temperature dependent shape memory material
Implementation Method 2
the shape memory material is provided to exert a crushing force on the base plate
Implementation Method 3
there is a risk that the shape memory material is secured between the base plate and the bottom section before a critical temperature for unblocking has been reached
Data Source
AI summary
The present invention relates to a cartridge case (1) intended for explosive materials comprising a releasable base plate (4) provided in a bottom section (3) of the cartridge case (2) and a base plate locking device (25) comprising a temperature dependent shape memory material (13). The principal object of the invention is to obtain a cartridge case (2) that is more reliable in it operation when subjected to heating. According to the invention the shape memory material (13) of the base plate locking device (25) is provided to exert a crushing force on the cartridge case (2) at a temperature increase passing a temperature such that the shape memory material (13) in question struggles to resume a former shape in order to break up the connection between the base plate (4) and the bottom section (3) of the cartridge case (2) and release the base plate (4) from the bottom section (3) of the cartridge case (2). The invention also refers to a round of ammunition (1) comprising a cartridge case (2) as above.