Blast Mitigation Composite with Tuned Viscoelastic Damping

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Solution Overview

Problem

Existing designs for blast and impact protection, such as helmets and vehicle armor, are inadequate in efficiently dissipating the energy from impact loads, as they either rely solely on highly dissipative materials that are not effective or use elastic impedance mismatch without addressing the impulse aspect, leading to incomplete protection against both force and impulse damage.

Innovation Solution

The MITIGATIUM ™< design employs a multi-layered composite system with elastic and viscoelastic layers, where the elastic layers modulate the frequency of stress waves to match the dissipative properties of the viscoelastic layers, optimizing energy dissipation and reducing both pressure and impulse transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If highly dissipative materials are used for blast and impact protection, then energy dissipation is improved, but the materials are not effective in efficiently dissipating energy from impact loads

Engineering Contradiction:
Improveenergy dissipationVSAvoideffectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The protective system is segmented into multiple functional layers: an elastic impedance layer for frequency modulation and a viscoelastic layer for energy dissipation. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction by combining materials that individually have limitations but together achieve effective energy dissipation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining elastic and viscoelastic materials. The elastic layer modulates stress wave frequency while the viscoelastic layer dissipates energy, creating a composite system that overcomes the limitations of using highly dissipative materials alone and achieves both effectiveness and efficiency in energy dissipation.

Inventive Principle:
Principle #40Composite materials

2Force

If elastic impedance mismatch is used for protection, then force transmission is reduced, but impulse transmission is not adequately addressed

Engineering Contradiction:
Improveforce transmissionVSAvoidimpulse transmission
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The elastic layer acts as an intermediary between the impact source and the viscoelastic layer. It modulates the frequency content of stress waves to match the dissipative properties of the viscoelastic material, enabling optimal energy dissipation. This intermediary function resolves the contradiction by preparing the stress waves for effective dissipation while reducing both force and impulse transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the frequency parameter of stress waves through the elastic layer to match the dissipative characteristics of the viscoelastic layer. This parameter transformation enables the system to address both force and impulse transmission effectively, overcoming the limitation of using elastic impedance mismatch alone.

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional protective designs are used, then structural protection is provided, but energy dissipation efficiency is insufficient

Engineering Contradiction:
Improvestructural protectionVSAvoidenergy dissipation efficiency
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The invention introduces dynamic frequency modulation through the elastic layer, transforming the static protective design into a dynamic system that adapts to impact conditions. The elastic layer modulates stress wave frequencies in real-time to match the viscoelastic layer's dissipative properties, significantly improving energy dissipation efficiency while maintaining structural protection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system utilizes mechanical vibration principles where the elastic layer modulates the frequency content of stress waves, creating resonant conditions that maximize energy dissipation in the viscoelastic layer. This vibration-based approach resolves the contradiction by enhancing energy dissipation efficiency without compromising structural protection.

Inventive Principle:
Principle #18Mechanical vibration

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 approach significantly reduces peak acceleration and impulse transmission to the brain, offering enhanced protection by dissipating up to 96% of kinetic energy, making it more effective than conventional designs in mitigating impact forces and impulses.

Implementation Method 1

a viscoelastic layer to dissipate energy at that frequency

Methodology Applied
Scientific EffectViscoelastic damping: Viscoelasticity

Implementation Method 2

efficiently dissipates the energy transmitted through the composite

Methodology Applied
Scientific EffectEnergy dissipation: Damping

Implementation Method 3

uses one or more elastic layers to modulate the frequency content of the stress wave traveling through the composite

Methodology Applied
Scientific EffectStress wave modulation: Elasticity

Data Source

PatentEP3517883B1Method for blast mitigation
Publication Date: 2022.04.20 THE RGT UNIV OF MICHIGAN
  • EP3517883B1 patent drawingFigure 1~2
  • EP3517883B1 patent drawingFigure 3~5
  • EP3517883B1 patent drawingFigure 6A~6B

AI summary

A tuning and mitigation system for mitigating a blast or impact event having a tuning layer assembly having an acoustic impedance chosen to tune stress waves resulting from the blast or impact to one or more specific tuned frequencies, and a dissipative layer assembly made of a viscoelastic material having a critical damping frequency that matches at least one or more specific tuned frequencies.