Resonant Acoustic Mixing for Homogeneous Explosive Casting
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Solution Overview
Problem
Conventional casting techniques for polymer-bonded explosives often result in non-homogeneous crosslinking and air bubbles, leading to reduced explosive performance and increased sensitivity to shock, impact, and heat, which can cause inadvertent initiation.
Innovation Solution
A process involving microencapsulated cross-linking reagents with resonant acoustic stimulus is used to control the curing reaction, ensuring a homogeneous crosslinked polymer bonded explosive composition by rupturing microcapsules at specific frequencies, allowing uniform mixing and delayed curing to prevent defects and hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional casting techniques are used with immediate polymerisation during filling, then the casting process can be completed quickly, but air bubbles are trapped and crosslinking becomes non-homogeneous
Solution Approach 1:
The crosslinking reagent is pre-encapsulated in microcapsules and uniformly distributed in the composition before filling. This preliminary preparation allows the composition to be filled quickly without immediate polymerisation, then cured uniformly afterward without trapping air bubbles or creating non-homogeneous crosslinking.
Solution Approach 2:
The crosslinking reagent is segmented into microcapsules that can be uniformly distributed throughout the composition. This segmentation allows controlled release and uniform crosslinking throughout the entire volume, preventing localized non-homogeneous crosslinking while maintaining fast casting speeds.
2Productivity
If polymerisation commences during the fill stage, then the process is efficient, but air bubbles introduced during mixing are retained in the solidified composition
Solution Approach 1:
The microcapsules are prepared and distributed in advance before filling, allowing the composition to be filled efficiently without initiating polymerisation. The actual crosslinking action is delayed until after filling is complete, ensuring air bubbles are eliminated before solidification begins.
3Ease of manufacture
If high processing temperatures are used for melt-casting high melting point explosives, then the explosives can be cast, but the hazard increases
Solution Approach 1:
The invention changes the processing parameters by using room temperature mixing and delayed curing instead of high temperature melt-casting. The crosslinking reagent remains inactive in microcapsules during mixing and filling, allowing safe handling of high melting point explosives, then activates at lower temperatures after filling to complete the curing process.
4Manufacturing precision
If the composition solidifies before all munitions are filled, then the filling process stops, but this prevents proper filling of all munitions
Solution Approach 1:
The microcapsules are prepared and distributed in advance, creating a stable precursor composition that does not polymerize during mixing and filling. This preliminary preparation allows continuous filling of multiple munitions without the composition solidifying, maintaining both complete filling and high productivity.
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 method enhances the stability and reduces sensitivity of the explosive composition to friction, impact, and heat, improving the quality and safety of the final product by ensuring a uniform polymeric matrix and reducing the risk of accidental initiation.
Implementation Method 1
applying a resonant acoustic stimulus to the admixture, wherein resonant acoustic stimulus system operates in the frequency range of less than 200 Hz causing the microcapsule to rupture and release said cross linking reagent
Implementation Method 2
Resonant acoustic mixing (RAM) of an explosive composition
Data Source
Figure 1~2a
Figure 2b~3
AI summary
The invention relates to a cast explosive composition, particularly to a pre-cure castable explosive composition comprising an explosive material, a polymerisable binder, a microencapsulated cross linking reagent, said microencapsulated cross linking reagent, comprising a cross linking agent encapsulated in a microcapsule. Providing a process for formulating a homogenous crosslinked polymer bonded explosive composition comprising the steps of: i) forming an admixture of pre-cure castable explosive composition, said composition comprising an explosive material, a polymerisable binder, a microencapsulated cross linking reagent, said microencapsulated cross linking reagent, comprising a cross linking reagent encapsulated in a microcapsule; wherein the microcapsule, comprises at least one shell wall polymer, wherein the microcapsule's shell wall polymer comprises at least one resonant acoustic stimulus labile linkage, ii) applying resonant acoustic stimulus to the admixture, causing the microcapsule to rupture and release said cross linking reagent, to cause the cure process to start.