Opportunities in Protection Materials Science and Technology for Future Army Applications

This book explores the current theoretical and experimental understanding of the key issues surrounding protection materials, identifies the major challenges and technical gaps for developing the future generation of lightweight protection materials, and recommends a path forward for their development. It examines multiscale shockwave energy transfer mechanisms and experimental approaches for their characterization over short timescales, as well as multiscale modeling techniques to predict mechanisms for dissipating energy.



Armor plays a significant role in the protection of warriors. During the course of history, the introduction of new materials and improvements in the materials already used to construct armor has led to better protection and a reduction in the weight of the armor. But even with such advances in materials, the weight of the armor required to manage threats of ever-increasing destructive capability presents a huge challenge.

The report also considers exemplary threats and design philosophy for the three key applications of armor systems:
1) personnel protection, including body armor and helmets,
2) vehicle armor, and
3) transparent armor.

Contents
SUMMARY
OVERVIEW
Introduction
The Challenge
Scope of the Study
Statement of Task
Study Methodology
Report Organization
Other Issues
Overarching Recommendation
2 FUNDAMENTALS OF LIGHTWEIGHT ARMOR SYSTEMS
Armor System Performance and Testing in General
Definition of Armor Performance
Testing of Armor Systems
Exemplary Threats and Armor Designs
Personnel Protection
Threat
Design Considerations for Fielded Systems
Vehicle Armor
Threat
Design Considerations for Fielded Systems
Transparent Armor
Threat
Design Considerations for Fielded Systems
From Armor Systems to Protection Materials
Existing Paradigm
Security and Export Controls
3 MECHANISMS OF PENETRATION IN PROTECTIVE MATERIALS
Penetration Mechanisms in Metals and Alloys
Penetration Mechanisms in Ceramics and Glasses
Penetration Mechanisms in Polymeric Materials
Failure Mechanisms in Cellular-Sandwich Materials Due to Blasts
Conclusions
4 INTEGRATED COMPUTATIONAL AND EXPERIMENTAL METHODS FOR THE DESIGN OF PROTECTION MATERIAL AND PROTECTION SYSTEMS: CURRENT STATUS AND FUTURE OPPORTUNITIES
Three Examples of Current Capabilities for Modeling and Testing
Projectile Penetration of High-Strength Aluminum Plates
Projectile Penetration of Bilayer Ceramic-Metal Plates
All-Steel Sandwich Plates for Enhanced Blast Protection: Design, Simulation, and Testing
The State of the Art in Experimental Methods
Definition of the Length Scales and Timescales of Interest
Evaluating Material Behavior at High Strain Rates
Investigating Shock Physics
Investigating Dynamic Failure Processes
Investigating Impact Phenomenology
Modeling and Simulation Tools
Background and State of the Art
New Protection Materials and Material Systems: Opportunities and Challenges
Computational Materials Methods
Overall Recommendations
5 LIGHTWEIGHT PROTECTIVE MATERIALS: CERAMICS, POLYMERS, AND METALS
Overview and Introduction
Ceramic Armor Materials
Crystalline Ceramics: Phase Behavior, Grain Size or Morphology, and Grain Boundary Phases
Crystalline Structure of Silicon Carbide
Availability of Ceramic Powders
Processing and Fabrication Techniques for Armor Ceramics
“Green” Compaction
Sintering
Transparent Armor
Transparent Crystalline Ceramics
Fibers
Effect of Fiber Diameter on Strength in High-Performance Fibers
Relating Tensile Properties to Ballistic Performance
Approaching the Theoretical Tensile Strength and Theoretical Tensile Modulus
The Need for Mechanical Tests at High Strain Rates
Ballistic Fabrics
Ballistic Testing and Experimental Work on Fabrics
Failure Mechanisms of Fabrics
Important Issues for Ballistic Performance of Fabrics
Metals and Metal-Matrix Composites
Desirable Attributes of Metals as Protective Materials
Nonferrous Metal Alternatives
Adhesives for Armor and for Transparent Armor
General Considerations for the Selection of an Adhesive Interlayer
Important Issues Surrounding Adhesives for Lightweight Armor Applications
Types of Adhesive Interlayers
Testing, Simulation, and Modeling of Adhesives
Joining
Other Issues in Lightweight Materials
Nondestructive Evaluation Techniques
Fiber-Reinforced Polymer Matrix Composites
Overall Findings
6 THE PATH FORWARD
A New Paradigm
Recommendations for Protection Materials by Design
Element 1—Fundamental Understanding of Mechanisms of Deformation and Failure Due to Ballistic and Blast Threats
Element 2—Advanced Computational and Experimental Methods
Element 3—Development of New Materials and Material Systems
Element 4—Organizational Approach
Critical Success Factors for the Recommended New Organizations
DoD Center for the PMD Initiative
Open PMD Collaboration Center
Time Frame for Anticipated Advances
APPENDIXES
A Background and Statement of Task
B Biographical Sketches of Committee Members
C Committee Meetings
D Improving Powder Production
E Processing Techniques and Available Classes of Armor Ceramics
F High-Performance Fibers
G Failure Mechanisms of Ballistic Fabrics and Concepts for Improvement
H Metals as Lightweight Protection Materials
I Nondestructive Evaluation for Armor
J Fiber-Reinforced Polymer Matrix Composites