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LangMod is an interactive software implementation of a modified Langlie sequential test strategy. Similar to the Up and Down (Bruceton) method, the Langlie strategy can be used in V50 ballistic limit testing to select test shot velocities based on previous velocities and responses. The software includes graph frames to show the data in shot sequence and the response curve as a function of velocity when the appropriate data is obtained. Parameter estimates are also provided to include the mean and standard deviation of the response curve as well as the V50 estimate and V50 standard deviation., The original document contains color images.

Decreasing the weight of protective systems, while minimizing the decrease in ballistic performance, is an ongoing goal of the Army. Ceramic materials are currently combined with other materials in these types of structures in order to decrease weight without losing ballistic performance. This includes structures in which the ceramic material is confined in some way or completely encapsulated. Confinement or encapsulation of ceramic material within a structure generally adds complexity and cost. Relatively simple panel specimens fabricated with ceramic tiles on aluminum backings and side confinement using steel were evaluated using nondestructive methods, including x-ray computed tomography and ultrasonic testing. The nondestructive evaluation results are discussed and compared, including the detectability and mapping of the fabrication features., The original document contains color images.

The goals of this research are to communicate the challenges of adhesive bonding for Army applications, present empirical correlations between relatively simple quasi-static coupon level testing and observed ballistic damage modes, present academic challenges that must be overcome, and outline a course for minimal preliminary qualification standards that must be fulfilled for any adhesive to be considered for potential Army ground vehicle applications that encourage novel research and development into Army unique property regions., Published in the Proceedings of the 34th Annual Meeting of the Adhesion Society, Savannah, GA, 13 16 February 2011. The original document contains color images.

This report presents an architectural framework for utilizing commercially available magnetic sensors to investigate magnetic field perturbations associated with ballistic events. Specifically, the Honeywell HMC1043 three-axis magnetoresistive field sensor is considered along with required circuitry to provide signal offset compensation, signal amplification, and set/reset strap capability. Conditions are quantified for which active offset compensation is desirable, and a method for achieving this compensation is discussed along with the constraints that active compensation imposes on signal amplification. A method for realizing optimal magnetic sensor performance through sensor conditioning set/reset operations is presented. A scheme for integrating an array of 32 HMC1043 magnetic field sensors into a microprocessor-controlled data acquisition and storage system is outlined, and fabrication details are provided., The original document contains color images.

The Army High Performance Computing Research Center, a collaboration between the U.S. Army and a consortium of university and industry partners, develops and applies high performance computing capabilities to address the Army s most difficult scientific and engineering challenges.

A lightweight castable alloy was sought to reduce the MIL-PRF-32269 class II cast steel perforated armor's weight with the requirement that the material had to be manufactured utilizing existing foundry technology and without incurring large alloy cost increases to meet property requirements. Literature on wrought age hardenable Fe-Mn-Al-C alloys suggested this alloy system could achieve weight reduction through high aluminum concentrations with the highest reported strengths exceeding 2 GPa for a Fe-30Mn-9Al-0.9C composition. Even though ballistic testing had not been conducted on this system, high strain rate data of wrought alloys showed excellent work hardenability; greater than existing ballistic metals. Cast material property information was severely limited, thus, a systematic approach was employed to develop casting and processing techniques and assess related structure property relationships of a nominal silicon modified Fe-30Mn-9Al-0.9C-0.5Mo alloy for ballistic use. Castability was addressed first as this information was crucial for making test coupons and assisting foundries with production of MIL-PRF-32269 ballistic test plates. Four silicon concentrations were investigated for fluidity, microstructure, liquidus, solidus and dendrite coherency point. Silicon was added because it is known to increase fluidity of other ferrous alloys and has also been shown to eliminate a brittle β-Mn phase in wrought Fe-Mn-Al-C alloys. Of the four silicon modified fluidity compositions, two were selected for heat treat property evaluation on the basis of microstructure. Hardness, strength, and ductility were measured (hardness is the only MIL-PRF-32269 measured property). The alloy with the highest ductility was selected for high strain rate evaluation. The strain rate testing results were the final means to lock in the alloy composition and heat treatment foWhile conducting V50 ballistic testiThe culmination of this thesis work resulted with posit, The original document contains color images.

The US Army is replacing conventional armor with new types of ballistic protection which are lighter in weight than the materials they replace yet offer the same degree of protection. A key component of this new type of armor is called Multi Functional (MFA) or Sensor Enhanced Armor (SEA) because the armor provides more capabilities than traditional ballistic protection for the soldier and ground vehicle. In this paper we shall concentrate on the real-time health monitoring of SEA. We have developed a method which has been applied to several types of new ballistic protection. We use ultrasonic waves to excite the armor panel. We measure the response to the excitation when the ballistic protection is known to be undamaged and store the results in a database. To determine if the armor has been damaged, we measure it again and compare the new results to the contents of the database., Presented at the 2011 NDIA Vehicles Systems Engineering and Technology Symposium 9-11 August 2011, Dearborn, Michigan, USA. Prepared in collaboration with Booz Allen, Hamilton, NY.

We are performing a series of Interceptor Body Armor audits in response to a congressional request. This audit evaluated product quality assurance for seven Army contracts, valued at $2.5 billion, for ballistic inserts awarded between 2004 and 2006. Specifically, we determined whether the results for First Article Tests (FATs) and Lot Acceptance Tests (LATs) met contract requirements and whether quality assurance personnel performed the product quality surveillance in accordance with contract requirements. What We Found The Army Program Manager Soldier Equipment (PM SEQ) could provide only limited assurance that approved ballistic materials for approximately 5 million inserts on seven contracts met the contract requirements. This occurred because PM SEQ did not consistently enforce the requirements for testing the body armor ballistic inserts. Specifically on two contracts, PM SEQ did not conduct all the required tests because they had no protection performance concerns on these inserts. On all seven contracts, PM SEQ did not always use the correct size ballistic insert for FATs, use a consistent methodology for measuring the proper velocity, or enforce the humidity and temperature requirements. In addition, PM SEQ did not require weathered and altitude tests on six of the seven contracts.

This report documents the theory and use of the BOOM computer program. BOOM is an exterior ballistics simulation program specifically designed to predict atmospheric flight of smart projectiles. The software contains a projectile dynamic model coupled to an open structure flight control system. The code can be run on PC, Unix, or Mac systems., The original document contains color images.

The objective of this research is to evaluate the effectiveness and feasibility of modifying conventional steel stud track wall systems to more effectively utilize the strength and ductility of the material without significantly increasing the cost of construction. The approach of this research is to evaluate the strength of various modifications to the standard connection detail for steel stud wall systems. All of the proposed modifications were selected to be a moderate change to traditional details so that any strength increase would be practically implemented. Results of lighter gauge samples show that tensile membrane action is fairly easily obtained and can be very useful in blast design. Heavier gauge stud wall systems still have untapped strength that would drastically raise the practicality of using steel stud wall systems for blast design. The Unified Facilities Criteria (UFC) limits can perhaps be re-evaluated based on the results of this project and the desired levels of protection.

A conformable self-healing ballistic armor protective structure has a shell formed of a laminated cloth material having outer and inner lamellae. The outer lamella of the laminated material is a ballistic cloth and the inner lamella is a soft, conformable self-healing, rubber compound. The shell is filled preferably with multiplicity of ceramic particles disposed in a fluid., Supersedes PAT-APPL-11 879 519-07.

Submitted for publication in Journal of Shock and Vibration - Disclaimer: Reference herein to any specific commercial company, product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the Department of the Army (DoA). The opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or the DoA, and shall not be used for advertising or product endorsement purposes., Submitted for publication to the Journal of Shock and Vibration.

The audit objective was to evaluate the product quality assurance for six Interceptor Body Armor (IBA) contracts awarded to Point Blank Body Armor, Inc. (Point Blank) for Outer Tactical Vests (OTVs) and components. Specifically, we determined whether the ballistic test results for first article tests (FATs) and lot acceptance tests (LATs) met the contract requirements. Further, we determined whether quality assurance personnel performed the product quality surveillance in accordance with the contract requirements. See Appendix A for a discussion of scope and methodology and prior coverage. Finding A discusses the ballistic test results for five of the six contracts awarded to Point Blank. Finding A does not discuss the sixth contract, W91CRB-05-F-0072, because it did not require ballistic testing. That contract was to convert the current camouflage pattern to the Universal Camouflage pattern of all OTV and components. Finding B discusses the product quality surveillance for all six contracts.

Occupant safety is a top priority of military vehicle designers. Recent trends have shifted safety emphasis from the threats of ballistics and missiles toward those of underbody explosives. For example, the MRAP vehicle is increasingly replacing the HMMWV, but it is much heavier and consumes twice as much fuel as its predecessor. Recent reports have shown that fuel consumption is no longer solely an environmental or economic issue, but also a safety concern; a significant cant percentage of fuel convoys that supply current field operations experience casualties en route. While heavier vehicles tend to fare better for safety in blast situations, they contribute to casualties elsewhere by requiring more fuel convoys. This study develops an optimization framework that uses physics-based simulations of vehicle blast events and empirical fuel consumption data to calculate and minimize combined total expected injuries from blast events and fuel convoys. Results are presented by means of two parametric studies, and the utility of the framework is discussed in a dynamic context and for evaluating casualty-reduction strategies., Presented at the 9th World Congress on Structural and Multidisciplinary Optimization Held 13-17 Jun 2011 in Shizuoka, Japan. Preepared in collaboration with University of Michigan, Ann Arbor, MI.

As part of the Lightweight Integrally Armored Floor agreement between the Aviation Applied Technology Directorate and United Technologies Research Center, ballistic testing was conducted on six armored floor system test specimens. The purpose of this ballistic testing was twofold: to evaluate the performance of test specimen configurations against the 7.62x39 mm PS Ball projectile, and to provide data for improved ballistic modeling capability. The general configuration for each of the six tested armored floor test specimens consists of a strike face, a layer of ultra-high-molecular-weight polyethylene, and a mini-core sandwich structure which serves as the walking surface of the floor system. Four of the six specimens failed to stop the projectiles; however, two of the six were able to stop the projectiles. Those two specimens were subjected to additional shots at higher velocity after demonstrating initial stopping capability.

Fires onboard aircraft are leading mechanisms for mishaps and losses during peacetime and combat operations. Typical ignition sources causing fires onboard aircraft include electrical sparks and hot surfaces. However, impact and penetration of common threats encountered during combat operations, such as armor piercing incendiary projectiles and missile fragments, generate short-lived, but thermally-intense clouds (flashes) capable of igniting fires. Fire simulations supporting system-level survivability analyses depend on accurate characterization of these flash clouds, however, such accurate representations are not currently available. This research presents the modeling approach developed to estimate the boundary model representations of impact flashes. The research presents generalized meta-modeling approaches to estimate flash size radii (in both the X and Y dimension), flash position, flash size duration, and flash orientation. The empirical model was developed using actual test data obtained via live-fire testing conducted by the 46th Test Group, Aerospace Survivability Analysis Branch. The time series response data from a set of live-fire test events were validated, analytical methods used to develop that response data based on impact event image processing were refined, and the data were then used to create fourth-order time series models of the response data for each of the test events. The collective of these time series models were then characterized by their parameter sets and a meta-model of those parameterizations was built as a function of test event setup parameters (e.g., projectile speed, angle of attack, and impact material) These final models were transitioned to the customer and are being linked to physics-based thermal models. The end result will be a first-ever projectile impact flash cloud representation suitable for survivability analyses., The original document contains color images.

Recent Army research has focused on the use of thermoplastic-based polymer laminates for mass-efficient ballistic helmets. The focus of this work was to develop an understanding of how hybridization of ultra-high molecular weight polyethylene (UHMWPE) thermoplastic with various other thermoplastic and thermoset materials would affect ballistic performance and back face deformation. Panels of various material combinations and of varying architectures were processed and tested. Architecturally hybridized panels of UHMWPE exhibited the highest resistance to dynamic backface deformation. Generally, there were tradeoffs between ballistic performance and backface deformation within the variations of architecturally hybridized composites. However, several of the panels (the 50/50 and 90/10 hybrid series) exhibited projectile resistances comparable, and in a few cases superior, to that of the [0/90] plate while still exhibiting a higher level of deformation resistance., The original document contains color images.

The Phase I deliverable is a physic-based model which represents a CMC gas turbine component concomitantly at the material level and the structural level. CMCs are currently being considered and used for aeroengine applications with a goal of increased specific power. A ceramic material must display sufficient capability to withstand the degrading effects that arise from external events such as FOD impacts. In addition to withstanding impact events, the CMC must be able to resist crack propagation through the thickness resulting from FOD induced surface flaws. Further issues of concern: 1) the possibility of impacting materials scratching off the environmental barrier coating (EBC) coating and the subsequent consequences. 2) Given constant environmental attack of a CMC combustor liner due to the vaporization of salty air/water, the rate and sizes of EBC debris that loosen and then impact on turbine nozzle guide vanes. The delivered phase I tool provides the means to cost effectively investigate and resolve these issues in a phase II effort., Prepared in collaboration with Univ. of Arizona, Tucson, AZ.

The identification of ballistics specimens from imaging systems is of paramount importance in criminal investigation. Binarization plays a key role in preprocess of recognizing cartridges in the ballistic imaging systems. Unfortunately, it is very difficult to get the satisfactory binary image using existing binary algorithms. In this paper, we utilize the global and local thresholds to enhance the image binarization. Importantly, we present a novel criterion for effectively detecting edges in the images. Comprehensive experiments have been conducted over sample ballistic images. The empirical results demonstrate the proposed method can provide a better solution than existing binary algorithms.

The identification of ballistics specimens from imaging systems is of paramount importance in criminal investigation. Binarization plays a key role in preprocess of recognizing cartridges in the ballistic imaging systems. Unfortunately, it is very difficult to get the satisfactory binary image using existing binary algorithms. In this paper, we utilize the global and local thresholds to enhance the image binarization. Importantly, we present a novel criterion for effectively detecting edges in the images. Comprehensive experiments have been conducted over sample ballistic images. The empirical results demonstrate the proposed method can provide a better solution than existing binary algorithms.

As part of a US Army supported project to establish appropriate NDE modalities for inspecting layered ceramic-composite armor, a series of 84 40 cm (16-inch) square by 50 mm (2-inch) thick, multi-layered ceramic composite armor specimens has been prepared. Some of these have had designed defects located in the interior-some do not. All samples are to be ballistically impacted and are to be inspected before and after ballistic testing. The question to be answered is-which NDE modality might best be used to quantify ballistically-induced damage. NDE modalities under present study include: 1)-immersion phased array ultrasonics, 2)- through-transmission, direct-digital x-ray imaging, 3)-non-contact scanning microwaves, 4)-air-coupled ultrasound and 5)-immersion, through-transmission and pulse-echo single-transducer ultrasound. At this time, all 84 samples have been inspected prior to ballistic testing. This paper will discuss these NDE techniques, issues that have been uncovered and will present results obtained.

A meso-scale ballistic material model for a prototypical plain-woven single-ply flexible armor is developed and implemented in a material user subroutine for the use in commercial explicit finite element programs. The main intent of the model is to attain computational efficiency when calculating the mechanical response of the multi-ply fabric-based flexible-armor material during its impact with various projectiles without significantly sacrificing the key physical aspects of the fabric microstructure, architecture, and behavior. To validate the new model, a comparative finite element method analysis is carried out in which: (a) the plainwoven single-ply fabric is modeled using conventional shell elements and weaving is done in an explicit manner by snaking the yarns through the fabric and (b) the fabric is treated as a planar continuum surface composed of conventional shell elements to which the new meso-scale unit-cell based material model is assigned. The results obtained show that the material model provides a reasonably good description for the fabric deformation and fracture behavior under different combinations of fixed and free boundary conditions. Finally, the model is used in an investigation of the ability of a multi-ply soft-body armor vest to protect the wearer from impact by a 9-mm round nose projectile. The effects of inter-ply friction, projectile/yarn friction, and the far-field boundary conditions are revealed and the results explained using simple wave mechanics principles, high-deformation rate material behavior, and the role of various energy absorbing mechanisms in the fabric-based armor systems., Published in the Journal of Materials Engineering and Performance, v19 n1 p22-39, 2010. Supported in part by the U.S. Army/Clemson University Coopertive Agreements Contract nos. W911NF-04-2-0024 and W911NF-06-2-0042. The original document contains color images.

The Electric Arc Shock Tube (EAST) facility and the Hypervelocity Free Flight Aerodynamic Facility (HFFAF) at NASA Ames Research Center are described. These facilities have been in operation since the 1960s and have supported many NASA missions and technology development initiatives. The facilities have world-unique capabilities that enable experimental studies of real-gas aerothermal, gas dynamic, and kinetic phenomena of atmospheric entry., See also ADA569031. Aerothermodynamic Design, Review on Ground Testing and CFD (Conception aerothermodynamique, revue sur les essais au sol et dynamique des fluides informatisee). Prepared in cooperation with ELORET, Inc., Moffett Field, CA.

The identification of ballistics specimens from imaging systems is of paramount importance in criminal investigation. Binarization plays a key role in preprocess of recognizing cartridges in the ballistic imaging systems. Unfortunately, it is very difficult to get the satisfactory binary image using existing binary algorithms. In this paper, we utilize the global and local thresholds to enhance the image binarization. Importantly, we present a novel criterion for effectively detecting edges in the images. Comprehensive experiments have been conducted over sample ballistic images. The empirical results demonstrate the proposed method can provide a better solution than existing binary algorithms.

Fourier theory of thermal transport considers heat transport as a diffusive process where energy flow is driven by a temperature gradient. However, this is not valid at length scales smaller than the mean free path for the energy carriers in a material, which can be hundreds of nanometres in crystalline materials at room temperature. In this case, heat flow will become 'ballistic'--driven by direct point-to-point transport of energy quanta. Past experiments have demonstrated size-dependent ballistic thermal transport through nanostructures such as thin films, superlattices, nanowires and carbon nanotubes. The Fourier law should also break down in the case of heat dissipation from a nanoscale heat source into the bulk. However, despite considerable theoretical discussion and direct application to thermal management in nanoelectronics, nano-enabled energy systems and nanomedicine, this non-Fourier heat dissipation has not been experimentally observed so far. Here, we report the first observation and quantitative measurements of this transition from diffusive to ballistic thermal transport from a nanoscale hotspot, finding a significant (as much as three times) decrease in energy transport away from the nanoscale heat source compared with Fourier-law predictions., Published in Nature Materials, v9 p26-30, January 2010. Sponsored in part DOE and NSF grant 0846561.

This report examines the dependence of the ballistic performance of silicon carbide on the third invariant of the stress tensor by use of numerical simulations and test data. The JHB ceramic model is modified to account for the influence of the third invariant, and the modification includes a material parameter defined as the ratio of yield in tri-axial extension to yield in tri-axial compression. Simulations of high-velocity impact are performed systematically with several values of the parameter to determine the influence of the third invariant. The simulation results are also compared to test data to determine the degree of influence that provide s the best agreement. Simulations include tensile and compressive plate-impact tests, long-rod penetration of prestressed targets, long-rod penetration of confined targets, long-rod penetration of unconfined targets, and ballistic impact of thin targets with substrates.

The Vice Chief of Staff of the Army (VCSA) directed that Soldier combat helmets be fitted with electronic sensor technologies to sense and record helmet response to dynamic events. These events could be exposure to blast events (IEDs), ballistic impacts, and/or blunt impacts. The sensors record orthogonal accelerations and blast overpressure levels. However, since helmets are not rigidly coupled to the head, and are not rigid bodies and often experience local deformations during impact, the measured helmet response will be different from the head response. The objective of this effort is the characterize the differences between helmet and head responses by conducting controlled physical tests; and then use these results to develop appropriate transfer functions (numerical equations or models) that approximate head exposures based on the observed helmet response. The physical testing included ballistic impact and blast overpressure tests. This report provides a description of the tests performed and an assessment of the quality of the data collected for the purpose of validating the transfer function and model., The original document contains color images.

In this study, a cavity previously used as part of the Navy Internal Carriage and Separation (NICS) experiments will be used in conjunction with the Mark 82 (500 lb class) store to compare previously obtained wind tunnel data to CFD results for an internal bay/store configuration. Forces and moments for the store along the horizontal traverse will be found using a specific single equation turbulence model (Spalart-Allmaras) in order to better understand the nature of the flow and its affect on the store with an emphasis on the region in the vicinity of the shear layer. The CFD results will be compared with existing wind tunnel data on the same configurations in order to jude the efficacy of using Euler, Navier-Stokes, and time-accurate Navier-Stokes flow solvers to provide mean force data for the store., The original document contains color images.

The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co) perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM) which included energy-dispersive (X-ray) spectrometry (EDS). Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549), a model for lung tissue, to particulates (especially nanoparticulates) collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate) mix has not yet allowed any particular chemical composition to be identified., Pub. in International Journal Environmental Research and Public Health, v7, p3313-3331, Sep 2010. Government or Federal Purpose Rights License.. The original document contains color images. ISSN-1660-4601

A probability of hit (PHit) methodology has been developed to characterize the overall performance of the C6 General Purpose Machine Gun (GPMG) and 40 mm Automatic Grenade Launcher (AGL) Integrated on a Remote Weapon Station (RWS) Mounted on a Tactical Armoured Patrol Vehicle (TAPV) Platform. The methodology takes into account four (4) different scenarios (static/moving vehicle to engage a static/moving target) to develop an error budget of the weapon system. The error budget analysis breaks down the total dispersion, i.e., the standard deviation (SD) of the impact point position, into four (4) main error sources: weather, gun, projectile and the Fire Control System (FCS) Dispersion. The weather dispersion can be developed to see the individual contributions of the standard deviation of the wind speed, atmospheric temperature and atmospheric pressure. The Gun dispersion can be developed to see the individual contributions to the standard deviation of the gun support and the gun barrel. The projectile dispersion can be developed to see the individual contributions to the standard deviation of the ammunition dispersion, muzzle velocity, drag-mass ratio and tracer effect. The FCS dispersion can be developed to see the individual contributions to the standard deviation of the gun laying, target tracking, vehicle movement and mutual interaction effects. The PRODAS (PROjectile and Design and Analysis System) budget error and simulation package were used to model the weapon system performance for different firings conditions. The experimental data from the static/moving vehicle against static/moving target scenarios necessary to validate the PRODAS modeling is being obtained in the CFB (Canadian Forces Base).

As modern helmets have become quite capable of defeating the penetration capabilities of ballistic threats, Soldiers may experience head injuries due to blunt trauma caused by helmet back face deformation (BFD). Possible resulting injuries include skull fracture, hematoma, concussion,contusion, diffuse axonal injury, etc. Some of these injuries have been associated with traumatic brain injury.

Fragmentation of metals due to high strain rate loading is a relevant topic for explosively driven metals, high velocity impacts and other energetic material scenarios. The ability to perform relevant and well-controlled experiments is a challenge. The ability to predictively model such failure and fragmentation events in dynamic continuum mechanics codes or hydrocodes is even more of a challenge. A collection of three papers are presented on the design, analysis and experiments of an explosively driven cylinder fragmentation event. The first paper describes the background of the problem and provides details of an explosively loaded cylinder geometry that establishes either plane strain or uniaxial stress conditions for failure. Parametric variations of cylinder material, initiation configuration, and cylinder dimensions are addressed. The results of this initial paper are then used to manufacture items and conduct physical experiments, which are reported in the second paper. Experiments of free-air expansion and water-recovery are conducted to extract all necessary engineering measures from which to calibrate and utilize the Johnson-Cook damage model. Experimental data obtained includes the strain-to-failure, strain-rate, fragment velocity, fragment mass, mass distributions, size distributions and approximate time of fragmentation. Diagnostics of photonic Doppler velocimetry and ultra-high speed framing cameras provide a coupled data set for high-confidence and meaningful input to the model. The last paper takes the experiment data and invokes a Weibull compensated Johnson-Cook model to explicitly calculate fragment distributions. These distributions are compared with that actually recovered., Prepared in collaboration with Naval Surface Warfare Center, Dahlgren, VA and General Dynamics, Niceville, FL.

Ocean wave propagation causes random change of ocean surface slope and in turn affects the underwater bomb trajectory deviation (r) through water column. This trajectory deviation is crucial for the clearance of obstacles such as sea mines or maritime improvised explosive device (IED) in coastal oceans using bombs. A nonlinear six degrees of freedom (6-DOF) model has been recently developed and verified at the Naval Postgraduate School with various surface impact speeds and surface slopes as model inputs. The surface slope (s) randomly changes between 0 and pi/2 with a probability density function (PDF) p(s), or called the s-PDF. After s is discretized into I intervals by s1, s2,..., si,... sI+1, the 6-DOF model is integrated with a given surface impact speed (v0) and each slope si to get bomb trajectory deviation ri at depth (h) as a model output. The calculated series of {ri} is re-arranged into monotonically increasing order (rj}. The bomb trajectory deviation r within (rj, rj+1) may correspond to one interval or several intervals of s. The probability of r falling into (rj, rj+1) can be obtained from the probability of s, and in turn the PDF of r, or called the r-PDF. Change of the r-PDF versus features of the s-PDF, water depth, and surface impact speed is also investigated., To be published in Journal of Dynamic Systems, Measurement and Control (American Society of Mechanical Engineers), in press. The original document contains color images.

The purpose of this research is to simulate and test nanomaterial reinforced composites for potential applications in Army vehicles, especially for improved ballistic and blast protection. The resultant simulation and design system can address major concerns in functional requirements of nanomaterials in Army's ground vehicles such as strength, durability, ballistic and blast impact resistance. An important part of this research is to develop a comprehensive modeling tool to predict nano-composite behaviors. Based on a unit cell model developed for nanoclay-epoxy composites, the effect of nanomaterial distribution on the maximum stress developed in an epoxy resin was investigated by including modeling of the nanoclay-polymer interface. Tests were conducted on composite laminate/armor coupons that were reinforced by nanocomposites, including quasi-static mechanical tests, drop tower tests, shock tube tests, and ballistic tests. The ballistic tests indicate that armor with nanoclay insertion can survive more rounds of projectile impact. Shock tube tests showed that the damage in the laminate is less severe for samples with nanoclay reinforced epoxy resin than for those without nanoclay reinforcement. In addition, deflection was reduced about 43% with the usage of nanoclay reinforcement in the epoxy resin., The original document contains color images.

An Reactive Structure Technology (RST) is being developed, where a Reactive Structure is defined as a new class of smart structure that can react to external excitations (such as a ballistic or blast impact) in a carefully designed way to counteract the hazardous loading or perform other desired tasks. Two prototypes of the reactive structure have been designed and fabricated for proving the concept of RST. The prototype basically consists of three integrated modules: 1) a structure with changeable configuration embedded with piezoelectric sensors for sensing the impact load; 2) an electronic control module capable of detecting external impacts and driving actuator to change the configuration of the structure; 3) a mechanism used to simulate the ballistic object. Also, an innovative sensor network using piezoelectric pillars has been developed, which can be used in smart armor for detecting the impact location in real time. The technologies developed in this research are expected to be used in applications of the protection of future ground vehicle., Presented at the Army Science Conference (27th), held in Orlando, FL on 29 Nov-2 Dec 2010. The original document contains color images.

Understanding the detailed ignition, flame-spreading, and combustion processes inside of a granular solid-propellant bed is vital for accurate interior ballistic modeling, and for the development of ballistic propulsion systems. Experiments were conducted to investigate both the penetration characteristics of pyrotechnic igniter jets, and the subsequent flame spreading processes in a granular bed. The experiments utilized both live and inert propellant, in conjunction with high-speed photography and photodetectors. A singular igniter jet was discharged axially into an inert granular bed. This setup was designed to study the region of particles coated by the condensed-phase products of the igniter jet. This information is very useful since the ignition behavior of live propellants is dependent upon both convective heating by the igniter jet as well as conductive heating by the deposited condensed-phase products. Three correlations were developed that describe the region of the granular bed coated by the condensed-phase products from the igniter jet; these include: 1) the axial depth of penetration, 2) maximum radial penetration, and 3) the volume of the coated region. These parameters were found as functions of the Reynolds number based on the operating conditions of the igniter jet and granular bed., The original document contains color images.

Influences of microstructure and properties of an aluminium alloy on resistance to dynamic perforation are predicted using a decoupled multi-scale modelling approach. At the scale of individual grains, a crystal plasticity model is developed accounting for finite elastic and plastic deformations, thermal softening and energy storage mechanisms linked to microscopic residual stress fields induced by line defects and second-phase particles. An averaging scheme is invoked to compute macroscopic stress-deformation responses corresponding to various microstructures. The results of the averaging process motivate choices of parameters entering a macroscopic plasticity model, with different parameter sets corresponding to different microstructures. This macroscopic model, with various parameter sets, is in turn used to simulate impact and perforation of a thin plate of the aluminium alloy by a cylindrical projectile. The results provide quantitative assessments of possible benefits of texturing, insertion of strengthening and energy storage mechanisms and enhancement of ductility on performance of the alloy., The original document contains color images. Published in International Journal of Materials and Structural Integrity, v4 n2-4 p116-140, 2010.

This report provides a literature review of the area of battle damage prediction and vulnerability reduction methods in the land and maritime domains and will provide input into the strategic planning process for Maritime Platforms Division's (MPD) long range research program., The original document contains color images.

The purpose of this research is to simulate and test nanomaterial reinforced composites for potential applications in Army vehicles, especially for improved ballistic and blast protection. The resultant simulation and design system can address major concerns in functional requirements of nanomaterials in Army's ground vehicles such as strength, durability, ballistic and blast impact resistance. An important part of this research is to develop a comprehensive modeling tool to predict nano-composite behaviors. Based on a unit cell model developed for nanoclay-epoxy composites, the effect of nanomaterial distribution on the maximum stress developed in an epoxy resin was investigated by including modeling of the nanoclay-polymer interface. Tests were conducted on composite laminate/armor coupons that were reinforced by nanocomposites, including quasi-static mechanical tests, drop tower tests, shock tube tests, and ballistic tests. The ballistic tests indicate that armor with nanoclay insertion can survive more rounds of projectile impact. Shock tube tests showed that the damage in the laminate is less severe for samples with nanoclay reinforced epoxy resin than for those without nanoclay reinforcement. In addition, deflection was reduced about 43% with the usage of nanoclay reinforcement in the epoxy resin., To be presented at The 27th Army Science Conference (ASC), sponsored by the Assistant Secretary of the Army (Acquisition, Logistics and Technology), will be held at the JW Marriott Grande Lakes, Orlando, Florida, November 29-December 2, 2010. The original document contains color images.

In the calculation of the velocity of primary fragments a number of important parameters are involved. Some of these parameters are standard and seemingly well-defined [1-14]. Included in this group would be the drag coefficient, C(sub 0), the fragment density, rho(sub f), the ambient air density, rho(sub air), the fragment diameter, d(sub f), and the fragment mass, m(sub f). In addition to these standard parameters there exist a number of other parameters, which are not completely standard and/or not well-defined. The most important of these is the velocity decay coefficient, k(sub v) [1, 2, 4, 8, 13, 14]*. In three of these references [1, 2, 13] the parameter "caliber density," D, is also introduced. Another parameter is the "presented area," A(sub f) [1-14], along with the "shape factor or ballistic density," k [3, 4, 8], and the "L" parameter [3, 4]. In addition, the fragment "form factor" is utilized in a number of references [2, 10-13]. In a recent study [5], a methodology taken from Reference 4 introduces an "L(sub 1)" parameter, along with a specific value of the shape factor, k. In the development and application of these parameters, both standard and nonstandard, certain apparent discrepancies have developed. The discussion which follows represents a summary of these discrepancies. A complete description of all such parameters and related discrepancies is beyond the scope of this discussion, but such a description is available elsewhere [15]., See also ADM002313. Department of Defense Explosives Safety Board Seminar (34th) held in Portland, Oregon on 13-15 July 2010. Document contains briefing charts. The original document contains color images.

Numerical simulations of compression Hopkinson bar tests on soft, nearly incompressible materials were performed in an effort to understand inertial effects in these tests. The specimen was modeled as either a linear elastic or a nonlinear elastic solid; the nonlinear model was calibrated to ballistic gelatin data. The simulations revealed a previously unreported phenomenon, namely, for sufficiently high strain rates in the specimen and sufficiently short rise times to the final strain rate, small gaps formed at both the specimen-incident bar and the specimen-transmission bar interfaces. The size of these gaps ranged from sub-micron to as large as 43 m. Gaps formed at small specimen strains but persisted out to large strains, closing and re-opening multiple times. At some instants the gaps extended over most of the face of the specimen. Unloading of the specimen and the pressure bars accompanied these gaps. In an effort to rule out numerical artifacts, the sensitivity of these results to mesh size and contact algorithm parameters was studied., The original document contains color images.

This report documents research that was conducted to analytically investigate the relationships between dynamic energy absorption of plain-woven fabrics commonly used in protective systems and the architectural parameters used to describe their construction including, for example, crimp contents, yarn density ratios, and yarn-yarn friction. The research results showed that for plain-woven fabrics subject to ballistic impacts, highly crimp-imbalanced, plain-woven fabrics performed in a manner far superior to that of crimp-balanced, plain-woven fabrics. These analytical solutions resulted in the ability to parametrically study the effect of crimp imbalance on the dynamic energy absorbability of plain-woven fabrics.

The Navy is in need of an organic, inexpensive, swift method to neutralize or sweep waterborne mines. This paper presents an alternative to current mine countermeasure technologies that fulfill this criteria - the use of the Joint Direct Attack Munition (JDAM) to clear a minefield. Our experimental and modeling study strongly suggest high efficiency of the JABS for mine clearance in the very shallow water (depth less than 12.2 m)., Presented at the International Symposium on Technology and Mine Problem, (9th), held in Monterey, CA on 17-20 May 2010.

In order to reduce weight while maintaining ballistic performance, modern armored vehicles often use ceramic-based armor solutions. Ceramic solutions are typically made of a close-fitting periodic array of ceramic tiles, maintaining a specific gap dimension between the tiles. The gap separation distance is critical to the ballistic performance of the system and it is important to have a reliable means of quantitative inspection. This report presents results of a study of a non-destructive quantitative X-ray gap width measurement method commonly used to measure and inspect array gaps. It was found that this X-ray method gives a good portrayal of array quality and gap widths, but that gap measurement accuracy likely can be improved. The X-ray method was found to skew gap width measurements higher, between 2 and 20%, and was dependent on image blur. An X-ray system designed specifically for gap measurement will significantly improve measurement accuracy. Obtaining such a system is recommended, with digital X-ray radiography being the preferred path forward., The original document contains color images. Prepared in collaboration with SURVICE Engineering Co., Dyanmic Science, Inc. and BAE Systems U.S. Combat Systems.

This paper reviews the scientific support for a ballistic pressure wave radiating outward from a penetrating projectile and causing injury and incapacitation. This phenomenon is known colloquially as "hydrostatic shock." The idea apparently originates with Col. Frank Chamberlin, a World War II trauma surgeon and wound ballistics researcher. The paper reviews claims that hydrostatic shock is a myth and considers supporting evidence through parallels with blast, describing the physics of the pressure wave, evidence for remote cerebral effects, and remote effects in the spine and other internal organs. Finally, the review considers the levels of energy transfer required for the phenomenon to be readily observed.

This report outlines a relatively straightforward technique to incorporate the effect of liquid payloads on the numerical prediction of projectile trajectories. The key to this method is the addition of liquid moments imparted onto the projectile body. The first step to include the effects of liquid payloads is to model a low-viscosity liquid while undergoing typical projectile translational and angular motions. Since most projectiles carrying liquid payloads are spin stabilized with high spin rates, the moment contribution of the liquid to the angular motion of the projectile can be found using linear theory. After developing an integrated dynamic model for a projectile with a liquid payload, example trajectory characteristics are shown that exhibit typical dynamic behavior of a projectile with a liquid payload. Results comparing solid projectiles with a similar liquid-filled projectile are presented as well as a discussion of flight stability caused by a liquid payload., The original document contains color images.

The Aegis ballistic missile defense (BMD) program, which is carried out by the Missile Defense Agency (MDA) and the Navy, gives Navy Aegis cruisers and destroyers a capability for conducting BMD operations. Under current MDA and Navy plans, the number of BMD-capable Navy Aegis ships is scheduled to grow from 20 at the end of FY2010 to 38 at the end of FY2015. MDA and Navy plans also call for an increasing portion of the Navy's BMD-capable Aegis ships to be equipped with newer and more capable versions of the Aegis BMD system. BMD-capable Aegis ships operate in the Western Pacific and the Persian Gulf to provide regional defense against potential ballistic missile attacks from countries such as North Korea and Iran. The Administration's Phased Adaptive Approach (PAA) for BMD operations, announced in September 2009, calls for operating BMD-capable Aegis ships in European waters to defend Europe from potential ballistic missile attacks from countries such as Iran. Some observers are concerned-particularly following the Administration's announcement of its intention to use Aegis-BMD ships to defend Europe against potential ballistic missile attacks- that demands from U.S. regional military commanders for BMD-capable Aegis ships are growing faster than the number of BMD-capable Aegis ships. They are also concerned that demands from U.S. regional military commanders for Aegis ships for conducting BMD operations could strain the Navy's ability to provide regional military commanders with Aegis ships for performing non-BMD missions. There is also some concern regarding the adequacy of planned numbers of SM-3 missiles-the interceptor missiles used by Aegis ships for conducting BMD operations., CRS Report for Congress

The prediction of damage to a target caused by the ballistic impact of projectiles has long been a goal of military analysts. One of the more widely accepted approaches to this problem is the shotline method. This method involves projecting rays of a specified direction through a target and describing the interactions along each ray. The Fast Shotline Generator (FASTGEN) is computer program that executes the shotline method. The user inputs a geometric description of the desired target and specifies a threat type (whether KE or HE). The code then uses this information to generate rays representing the threat and traces these rays through the target. The end result of this process is the generation of files containing shotlines, ordered lists of components intersected by each ray. This manual describes how to use the FASTGEN5 legacy mode of the COVART6 computer program.

This paper discusses the details of a program to develop and test a family of Improved Container Delivery Systems (ICDS) capable of airdropping 2,000-10,000-lb payloads, the intricacies of developing a parachute model of the Joint Precision Airdrop System -- Mission Planner (JPADS-MP), and the results from testing. The systems are being developed by the U.S. Army Natick Soldier Research, Development and Engineering Center (NSRDEC) in conjunction with the Joint Improvised Explosive Device Defeat Organization (JIEDDO). They were designed to be low cost and one time use and to use components already in the U.S. Army inventory. Readily available parachutes were used, and a low cost plywood platform was designed, submitted, and approved for use on U.S. Air Force C-17 and C-130E/H/J model aircrafts. These ballistic parachute systems use a high altitude low opening (HALO) design to meet the threshold requirement of 400 m accuracy when airdropped from an altitude of 24,500 ft Mean Sea Level (MSL). The wireless activation device (WAD) is a key component of these systems and is responsible for the staging of the low opening parachutes. This device is wirelessly programmed for a specific time period, calculated based on weather and parachute characteristics using the JPADS-MP. Empirical data such as rate of descent as a function of weight and altitude, stabilization time, altitude loss, forward throw, and inflation times for each system configuration were collected during test drops. A database was generated for each parachute configuration and this data was combined with pre-existing parachute data to build system models into the JPADS-MP., The original document contains color images. Prepared in collaboration with Ignition Technology Inc., Sudbury, MA and TRAX Test Services, Yuma, AZ.