Temperature-Sensitive Decoupling Joint for Rocket Motor Pressure Relief
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Solution Overview
Problem
Existing designs for rocket motors fail to fully comply with insensitive munitions standards, particularly in reducing the risk of accidental initiation due to excessive temperatures, and do not effectively balance safety and cost-effective production.
Innovation Solution
A decoupling assembly is introduced, featuring a rocket motor tube with a temperature-sensitive joint that softens at predetermined temperatures, allowing the insert to detach from the motor tube, thereby relieving pressure in a controlled manner, which can be used in various vessels and devices to prevent accidental ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rocket motor is designed with traditional rigid joints to ensure structural integrity and operational reliability, then the structural strength is improved, but the safety under excessive temperature conditions deteriorates because pressure cannot be relieved
Solution Approach 1:
The joint material's physical state is changed based on temperature conditions. At normal temperatures, the joint material maintains a rigid state providing structural integrity. At excessive temperatures, the joint material transitions to a softened state allowing decoupling and pressure relief. This parameter change resolves the contradiction by making the joint's mechanical properties temperature-dependent.
Solution Approach 2:
The joint transitions from a static rigid connection to a dynamic decouplable connection when temperature conditions change. The system moves from a fixed structural state to a movable decoupled state, allowing the joint to adapt its degree of freedom based on thermal conditions while maintaining structural integrity during normal operation.
2Reliability
If a temperature-sensitive joint material is used to enable pressure relief at excessive temperatures, then safety is improved, but the manufacturing complexity increases
Solution Approach 1:
The pressure relief function is extracted as a separate decoupling action from the primary structural joint. The joint structure includes a dedicated decoupling mechanism with clearance that activates only under excessive temperature conditions, separating the normal structural function from the emergency pressure relief function and simplifying the overall design.
Solution Approach 2:
The joint material is designed as a sacrificial element that permanently deforms or fails under excessive temperature conditions to achieve pressure relief. This disposable approach to the joint material simplifies the design by eliminating complex sensors, actuators, or reversible mechanisms, relying instead on the material's inherent thermal response characteristics.
3Object-affected harmful factors
If the joint is designed to allow decoupling at elevated temperatures, then pressure relief capability is improved, but the structural strength under normal conditions deteriorates
Solution Approach 1:
The joint structure incorporates localized features such as reduced-section regions, clearance gaps, or specific geometric configurations in critical areas that enable temperature-dependent decoupling, while other portions of the joint maintain full structural strength for normal operation. This local differentiation allows the joint to exhibit different mechanical properties in different regions based on operational conditions.
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 decoupling assembly effectively reduces the risk of explosion when subjected to excessive temperatures, ensuring compliance with insensitive munitions standards and maintaining operational performance, as demonstrated by successful tests such as the hydroburst and slow cook-off tests.
Implementation Method 1
comprises a material that softens when exposed to predetermined temperatures
Data Source
AI summary
A vessel, such as a rocket motor tube, comprised of an insert, and a joint that allows the insert to decouple from the vessel to relieve pressure when subjected to excessive temperatures and/or a predetermined temperature or temperature range.