Solid Rocket Motor Propellant Grain Aging via Hydraulic Bladder Deformation
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Solution Overview
Problem
Current methods for assessing the lifespan of solid rocket motor propellant grains are destructive, requiring the disassembly of a sacrificial motor to measure mechanical properties, which is inefficient and costly.
Innovation Solution
A non-destructive method involving the application of forces to the propellant grain to measure mechanical properties, such as bulk relaxation modulus, over time, using a bladder to apply pressure and calculate deformations, allowing for the prediction of remaining lifespan without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive disassembly is used to measure mechanical properties of propellant grain, then measurement precision is improved, but productivity is worsened and loss of time increases
Solution Approach 1:
The patent replaces destructive mechanical disassembly with non-destructive acoustic emission monitoring. Sensors detect acoustic signals generated by internal propellant grain changes, allowing mechanical property measurement without physical disassembly. This substitution maintains measurement precision while eliminating the need to sacrifice the motor, thereby improving productivity.
Solution Approach 2:
The patent introduces acoustic emission sensors as intermediaries to indirectly measure propellant grain mechanical properties. Instead of directly accessing and testing the propellant through disassembly, the sensors detect acoustic signals that correlate with mechanical property changes, enabling non-destructive surveillance and improving both productivity and resource utilization.
2Measurement precision
If destructive disassembly is used to assess propellant grain lifespan, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The patent replaces destructive mechanical testing that consumes propellant material with non-destructive acoustic emission monitoring. The acoustic sensors detect internal changes without removing or destroying propellant substance, maintaining measurement precision while eliminating material loss associated with sacrificial testing.
Solution Approach 2:
The propellant grain itself generates the acoustic emission signals that provide the measurement data. The aging and mechanical property changes of the propellant create natural acoustic signatures that can be detected and analyzed, eliminating the need for external destructive testing and preventing loss of substance.
3Productivity
If non-destructive method is used to surveil mechanical properties, then productivity is improved and loss of time is reduced, but measurement precision may be worsened
Solution Approach 1:
The patent uses acoustic emission sensors as intermediaries to detect internal propellant grain changes. These sensors capture acoustic signals that correlate with mechanical property changes, providing indirect but accurate measurements that maintain precision while enabling non-destructive surveillance and improving productivity.
Solution Approach 2:
The acoustic emission monitoring system provides continuous feedback on propellant grain mechanical property changes. By monitoring acoustic signals over time and correlating them with known mechanical property relationships, the system maintains measurement precision while enabling repeated non-destructive assessments that improve productivity and reduce testing time.
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
Enables the non-destructive surveillance of mechanical properties, allowing for accurate prediction of propellant grain lifespan, reducing costs and preserving the integrity of the rocket motor.
Implementation Method 1
A non-destructive method involving the application of forces to the propellant grain to measure mechanical properties, such as bulk relaxation modulus, over time, using a bladder to apply pressure and calculate deformations
Implementation Method 2
A non-destructive method involving the application of forces to the propellant grain to measure mechanical properties, such as bulk relaxation modulus, over time, using a bladder to apply pressure and calculate deformations
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5
AI summary
A method for non-destructively determining a mechanical property of a solid rocket motor propellant grain (110) may comprise applying a force to a surface of the solid rocket motor propellant grain, wherein a deformation is formed on the surface of the solid rocket motor propellant grain in response to the applying, and calculating a value of the mechanical property of the solid rocket motor propellant grain based on the deformation. This process may be performed over time to determine a lifespan of the propellant grain.