Concentric Propellant Structures for Shock Mitigation

Solution Overview

Problem

High impulse energy solid propellants are sensitive to shock and unable to meet fragment impact resistance standards, leading to their exclusion from applications requiring such resistance, while using lower impulse propellants compromises motor performance.

Innovation Solution

A solid rocket motor design incorporating a first solid propellant with higher impulse and a second solid propellant resistant to fragment impact, arranged concentrically, where the second propellant acts as a shock barrier to protect the first propellant, allowing for enhanced performance while meeting impact resistance standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high impulse energy solid propellants are used, then motor performance is improved, but fragment impact resistance deteriorates

Engineering Contradiction:

Improvemotor performanceVSAvoidfragment impact resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The propellant is divided into two distinct segments: an inner core propellant providing high impulse energy and an outer shock-absorbing propellant providing fragment impact resistance. This segmentation allows each segment to perform its specialized function, resolving the contradiction between performance and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite propellant structure combining two different propellant types with complementary properties. The high impulse propellant and shock-absorbing propellant are bonded together to form a composite system that achieves both high performance and fragment impact resistance simultaneously.

Inventive Principle:

Principle #40Composite materials

2Reliability

If lower impulse propellants are used to meet fragment impact resistance, then reliability is improved, but motor performance deteriorates

Engineering Contradiction:

Improvefragment impact resistanceVSAvoidmotor performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The propellant is divided into two distinct segments: an inner core propellant providing high impulse energy and an outer shock-absorbing propellant providing fragment impact resistance. This segmentation allows each segment to perform its specialized function, resolving the contradiction between performance and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite propellant structure combining two different propellant types with complementary properties. The high impulse propellant and shock-absorbing propellant are bonded together to form a composite system that achieves both high performance and fragment impact resistance simultaneously.

Inventive Principle:

Principle #40Composite materials

3Productivity

If high impulse propellants are used without shock protection, then motor performance is improved, but sensitivity to shock increases

Engineering Contradiction:

Improvemotor performanceVSAvoidsensitivity to shock

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The shock-absorbing propellant is positioned around the high impulse propellant core to provide beforehand cushioning against shock and fragment impact. This protective layer absorbs shock waves before they can damage the high impulse propellant, reducing sensitivity to shock while maintaining performance.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention uses a composite propellant structure combining two different propellant types with complementary properties. The high impulse propellant and shock-absorbing propellant are bonded together to form a composite system that achieves both high performance and fragment impact resistance simultaneously.

Inventive Principle:

Principle #40Composite materials

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 configuration enables the use of higher impulse propellants while ensuring fragment impact resistance, achieving improved rocket motor performance by shielding the high impulse propellant from external impacts and maintaining overall motor efficiency.

Implementation Method 1

the second propellant acts as a shock barrier to protect the first propellant

Methodology Applied

Scientific EffectShock absorption: Damping

Implementation Method 2

Ignition of the solid propellant generates high pressure gas, which is expelled through a nozzle to generate thrust

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10731604B2Rocket motor with concentric propellant structures for shock mitigation

Publication Date: 2020.08.04 AEROJET ROCKETDYNE INC

AI summary

A solid rocket motor includes a first solid propellant and a second solid propellant at least partially surrounding the first solid propellant. The second solid propellant is resistant to fragment impact and the first solid propellant has a higher impulse than the second solid propellant.