Tech Briefs

Reduced Order Modeling for Rapid Simulation of Blast Events of a Military Ground Vehicle and its Occupants

Improvised Explosive Devices (IEDs) pose a significant threat to military ground vehicles and soldiers in the field. Full-system end-to-end models, as well as Reduced Order Modeling and Simulation (M&S) methodologies, are extensively used for the development of blast-worthy ground vehicles.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Test & Measurement, Computer simulation, Hazards and emergency management, Injuries, Military vehicles and equipment

Software Tool Enables High-Fidelity Simulation of Explosive Device Effects

High-fidelity simulation tools are used as an acceptable surrogate for real-world tests. These tools accelerate development and reduce cost, while informing weapons development and systems survivability for defense and homeland security applications. As weapons grew in complexity, analytical methods became insufficient and high-fidelity computational methods became necessary.

Posted in: Briefs, Aerospace, Defense, Simulation Software, Software, Test & Measurement, Computer simulation, Hazards and emergency management

Continuous Sputter Deposition Coating of Long Monofilaments

A thin, uniform coating on long segments of monofilament could drastically improve the functionality of many complex fibers. A length of fishing line, microtubing, or polylactic acid (PLA) coated with copper could be left to cure within an epoxy, and upon removal of the monofilament, a narrow channel with a thin outer wall of copper would remain. That channel would be open for fluid flow, and also have a conductive shell. The “vascularized” material could be used for thermal management or self-healing composites.

Posted in: Briefs, Aerospace, Defense, Coatings & Adhesives, Materials, Thermal management, Adhesives and sealants, Coatings Colorants and Finishes, Copper, Fibers, Hoses

Hydrolytic Stability of Polyurethane-Coated Fabrics Used for Collapsible Fuel Storage Containers

Collapsible fabric fuel tanks have provided critical tactical bulk petroleum storage for military operations for over 50 years. Beginning in the 1940s with the 900 to 3,000-gallon pillow tanks, collapsible fabric tanks have evolved into the primary tactical fuel storage vessels now used by all of the military services.

Posted in: Briefs, Aerospace, Defense, Coatings & Adhesives, Materials, Containers, Storage, Coatings Colorants and Finishes, Fabrics, Fuel tanks, Military vehicles and equipment

Materials Design Principles for the Dynamic Fracture of Laminar Composite Structures

Crack bridging (e.g., from stitches or pins) and friction have profound and potentially very useful effects on delamination crack growth, controlling growth rates (damage levels) and the energy absorbed. However, the implications for structural design principles have remained quite obscure. The difficulty is that no simple analogue of crack toughness, which underpins static structural design, exists for dynamic cases with large-scale bridging effects. The external shape of the structure and the loading configuration dictate stress waves, frictional contact zones, and crack tip stress intensity factors in a way that is very difficult to approach, other than by brute case-specific numerical simulation. The problem is compounded by the common occurrence of multiple cracking, a complexity that is rarely entertained in laboratory fracture specimen design. Physically sound material models for the important structural problem of multiple, nonlinear cracking in laminated structures with large-scale bridging due to friction and reinforcement had previously remained undeveloped, in spite of the technological importance of these systems.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Materials, Finite element analysis, Composite materials

Development of Hydrophobic Coatings for Water-Repellent Surfaces Using Hybrid Methodology

Coatings that impart hydrophobic properties are of considerable interest. For applications such as aircraft windows, optical components, protective eyewear, and clothing, this type of surface is desired for the material to be soil-repellent and waterresistant. A prime model of a surface with these characteristics can be found in nature – the leaves of the lotus flower have super-hydrophobic properties as a means of self-cleaning.

Posted in: Briefs, Aerospace, Defense, Coatings & Adhesives, Materials, Windows and windshields, Optics, Coatings Colorants and Finishes, Protective equipment

Developing and Validating Statistical Cyber Defenses

Enterprise business processes are more connected than ever before, driven by the ability to share the right information with the right partners at the right time. While this interconnectedness and situational awareness is crucial to success, it also opens the possibility for misuse of the same capabilities by sophisticated adversaries to spread attacks and corrupt critical, sensitive information. This is particularly true for an insider threat scenario in which adversaries have legitimate access to some resources and unauthorized access to other resources that is not directly controlled by a fine-grained policy.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Statistical analysis, Collaboration and partnering, Cyber security, Data acquisition