Layered Composite Armor Shockwave Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional ballistic armor materials fail due to shockwave-induced fracture and spalling, leading to penetration, and existing solutions result in heavy, bulky armor systems that compromise mobility and survivability.
Innovation Solution
A composite material with alternating layers of different polymers, each 5 μm to 500 μm thick, bonded with sharp interfaces to control shockwave behavior and dissipate energy, reducing the amplitude of tensile waves below the material's tensile strength and guiding lattice waves laterally to prevent fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional brittle ballistic armor materials are used to stop projectiles, then penetration resistance is provided, but shockwave-induced fracture and spalling occur leading to failure
Solution Approach 1:
The armor material is segmented into multiple layers with alternating high and low acoustic impedance materials. Each layer thickness is controlled to be between λ/4 and 3λ/4 of the shockwave wavelength. This segmentation creates multiple interfaces that reflect and scatter shockwaves, preventing the formation of continuous failure waves and spalling that occur in monolithic materials.
Solution Approach 2:
The invention uses composite materials consisting of alternating layers of high acoustic impedance materials (such as ceramics or metals) and low acoustic impedance materials (such as polymers or foams). This composite structure exploits acoustic impedance mismatch at each interface to reflect and dissipate shockwave energy, thereby preventing the catastrophic failure modes of traditional single-material armor.
2Strength
If more armor material is added to improve ballistic protection, then penetration resistance increases, but weight and bulk increase compromising mobility
Solution Approach 1:
By segmenting the armor into thin alternating layers of different impedance materials, the design achieves high ballistic protection with reduced total thickness. The layered structure creates multiple shockwave reflection interfaces within a compact volume, providing equivalent or superior protection to thicker monolithic armor while significantly reducing weight.
Solution Approach 2:
The invention changes the acoustic impedance parameter distribution through alternating material layers. By optimizing the impedance contrast and layer thickness ratios, the structure achieves enhanced shockwave management efficiency, providing improved ballistic protection per unit weight compared to traditional homogeneous armor materials.
3Reliability
If shockwave energy is allowed to propagate through armor material, then material fracture occurs, but controlling shockwave behavior requires complex multi-layer structures
Solution Approach 1:
The complex shockwave control problem is solved by segmenting the armor into repeating units of alternating impedance layers. This regular segmentation creates predictable shockwave reflection and scattering patterns at each interface, systematically preventing fracture without requiring irregular or overly complex structures.
Solution Approach 2:
By carefully controlling the acoustic impedance parameters and layer thickness ratios of the alternating materials, the invention optimizes shockwave management. The parameter optimization allows for simplified layer designs that achieve effective shockwave control while minimizing structural complexity.
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 improves ballistic performance by reducing size, weight, and volume of armor, achieving a 45% improvement in ballistic protection while minimizing spalling and fracture, and can be applied to both transparent and opaque armor systems.
Implementation Method 1
Both of these failure mechanisms are directly associated with the shockwave created by a ballistic impact
Implementation Method 2
Spalling on the back of armor result from a large high to low impedance mismatch between the back of the armor and what is behind it; generally air which has very low impedance. The behavior of shockwaves within a medium is largely controlled by the acoustic impedance of that medium.
Implementation Method 3
The propagating acoustic phonon waves are termed lattice waves. As the shockwave moves through the material, it loses energy by generating lattice waves.
Implementation Method 4
These oscillations are arbitrarily quantized and are called phonons. There are two general types. Optical phonons have very high energy and vibrate at frequencies where the atoms cannot vibrate in a coherent form.
Data Source
AI summary
A transparent composite armor is made of tens to hundreds or even thousands of thin layers of material each with a thickness of 10-500 μm. An appropriate amount of impedance mismatch between the layers causes some reflection at each interface but limit the amplitude of the resulting tensile wave below the tensile strength of the constituent materials. The result is an improvement in ballistic performance and that will result is a significant impact in reducing size, weight, and volume of the armor.