Segmented Rocket Motor Grain Assembly Without Field Joints
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Solution Overview
Problem
Solid rocket motors with field joints between propellant grain segments introduce structural inconsistencies and weight penalties, which can negatively impact performance.
Innovation Solution
A rocket motor design that stacks propellant grains within a case, using a resin to maintain their position and create gaps between grain segments, eliminating the need for field joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If field joints are used to join propellant grain segments, then the grain can be assembled in multiple segments, but the structural integrity deteriorates and weight increases
Solution Approach 1:
The propellant grain is divided into multiple segments that can be manufactured separately and then joined together using field joints. This allows for easier manufacturing of large grains by assembling smaller, more manageable segments, while the field joints provide the necessary mechanical connection to maintain structural integrity during operation.
2Ease of manufacture
If field joints are used to join propellant grain segments, then the grain can be assembled in multiple segments, but the weight increases
Solution Approach 1:
The propellant grain is divided into multiple segments that can be manufactured separately and then joined together using field joints. This allows for easier manufacturing of large grains by assembling smaller, more manageable segments, while the field joints provide the necessary mechanical connection to maintain structural integrity during operation.
3Volume of stationary object
If propellant grains are stacked without gaps, then the space utilization is maximized, but the burning characteristics become inconsistent
Solution Approach 1:
Gaps are intentionally left between stacked propellant grains during assembly, before the resin is injected. This preliminary positioning allows the resin to be distributed uniformly throughout the case, ensuring consistent burning characteristics while maintaining efficient space utilization once the resin cures and locks the grains in place.
Data Source
AI summary
A rocket motor comprises at least two propellant grains/grain segments; a case comprising the propellant grains/grain segments, stacked within the case; and a resin for substantially maintaining the grains/grain segments in position within the case. In another aspect, a rocket motor comprises at least two propellant grains/grain segments, each having an aft-end face and a fore-end face. At least two of the propellant grains/grain segments comprise a sleeve having propellant cast therein. The motor further comprises a case comprising the propellant grains/grain segments, stacked within the case, wherein the sleeve of one propellant grain/grain segment is coupled to the sleeve of an adjacent propellant grain/grain segment such that the fore-end face of one grain/grain segment is spaced from the aft-end face of an other grain/grain segment creating a gap therebetween. Methods for making the rocket motors are described.