Universal EPDM Rocket Motor Insulation Composition

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Solution Overview

Problem

Conventional rocket motor insulations require multiple materials for different sections, increasing manufacturing complexity and cost due to the need for varying mechanical, thermal, and ablative properties, while also being prone to erosion and failure from high-temperature and high-pressure conditions.

Innovation Solution

A universal precursor composition comprising ethylene propylene diene monomer (EPDM), zinc oxide, silica, polymerized 1,2-dihydro-2,2,4-trimethylquinoline, solid chlorinated paraffin, stearic acid, a five carbon petroleum hydrocarbon, and a peroxide, which can be cured to form a single insulation that provides improved mechanical, thermal, and ablative properties across different regions of the rocket motor, reducing the need for multiple insulation types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different insulations are used on different sections of the rocket motor case, then the desired mechanical, thermal, and ablative properties are achieved, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improvemechanical, thermal, and ablative propertiesVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by developing a single insulation composition that can be used across all sections of the rocket motor case, replacing the conventional approach of using multiple specialized insulations. This universal composition provides the necessary mechanical, thermal, and ablative properties throughout the entire motor, thereby reducing manufacturing complexity while maintaining required performance characteristics.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of multiple different insulations into a single composite material. By combining various components (EPDM rubber, silica, zinc oxide, and other additives) into one unified insulation composition, the patent eliminates the need to apply separate insulation layers for different sections, thus simplifying the manufacturing process while achieving the desired protective properties.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If conventional silica-filled EPDM-based insulations are used, then good insulative properties are achieved, but fibers are required which increase manufacturing complexity

Engineering Contradiction:
Improveinsulative propertiesVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes porous materials by incorporating silica as a filler component in the insulation composition. The silica provides the necessary insulative properties and structural integrity without requiring the addition of separate fibrous materials. This approach maintains good insulative performance while eliminating the manufacturing complexity associated with incorporating and processing fibers.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent employs composite materials by creating a homogeneous mixture of EPDM rubber, silica, zinc oxide, and various additives that work together to provide the required insulative properties. This composite formulation eliminates the need for fibrous reinforcements, simplifying the manufacturing process while maintaining or improving upon the insulative performance of conventional silica-filled EPDM insulations.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If a single universal insulation is used across all sections, then manufacturing cost and complexity are reduced, but the ability to provide optimized properties for specific sections is lost

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsection-specific property optimization
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by formulating a universal insulation composition with adjustable components and ratios that can be tailored to provide optimized properties for different motor sections. By modifying the composition parameters (such as the ratios of EPDM, silica, zinc oxide, and additives), the same basic formulation can deliver section-specific performance characteristics while maintaining the simplicity of a single-material application process.

Inventive Principle:
Principle #35Parameter changes

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 universal insulation offers comparable or improved mechanical and ablative properties to conventional silica-filled EPDM-based insulations without using fibers, thereby simplifying manufacturing and reducing costs while effectively protecting against extreme conditions.

Implementation Method 1

a peroxide

Methodology Applied
Scientific EffectPeroxide decomposition and free radical crosslinking:

Implementation Method 2

polymerized 1,2-dihydro-2,2,4-trimethylquinoline

Methodology Applied
Scientific EffectAntioxidant action:

Data Source

PatentEP3375817A1Precursor compositions for an insulation, insulated rocket motors, and related methods
Publication Date: 2018.09.19 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3375817A1 patent drawingFigure 1~2
  • EP3375817A1 patent drawingFigure 3~4
  • EP3375817A1 patent drawingFigure 5

AI summary

A precursor composition comprising, before curing, an ethylene propylene diene monomer (EPDM), a filler, polymerized 1,2-dihydro-2,2,4-trimethylquinoline, a solid chlorinated paraffin, stearic acid, a five carbon petroleum hydrocarbon, trimethylolpropane a co-agent, and a peroxide. A rocket motor including a reaction product of the precursor composition and a method of insulating a rocket motor.