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Sample records for ballistic impact strength

  1. Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

    Science.gov (United States)

    Littell, Justin D.; Binienda, Wieslaw K.; Arnold, William A.; Roberts, Gary D.; Goldberg, Robert K.

    2010-01-01

    The reliability of impact simulations for aircraft components made with triaxial-braided carbon-fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Methods to characterize the material properties used in the analytical models from a systematically obtained set of test data are also lacking. A macroscopic finite element based analytical model to analyze the impact response of these materials has been developed. The stiffness and strength properties utilized in the material model are obtained from a set of quasi-static in-plane tension, compression and shear coupon level tests. Full-field optical strain measurement techniques are applied in the testing, and the results are used to help in characterizing the model. The unit cell of the braided composite is modeled as a series of shell elements, where each element is modeled as a laminated composite. The braided architecture can thus be approximated within the analytical model. The transient dynamic finite element code LS-DYNA is utilized to conduct the finite element simulations, and an internal LS-DYNA constitutive model is utilized in the analysis. Methods to obtain the stiffness and strength properties required by the constitutive model from the available test data are developed. Simulations of quasi-static coupon tests and impact tests of a represented braided composite are conducted. Overall, the developed method shows promise, but improvements that are needed in test and analysis methods for better predictive capability are examined.

  2. Small unmanned aircraft ballistic impact speed

    DEFF Research Database (Denmark)

    La Cour-Harbo, Anders

    2018-01-01

    A study of how smaller unmanned aircraft will fall in case of failure. The aim is to determine the impact speed of a drone givens its general shape and aerodynamic behavior. This will include both CFD simulations and real world test of ballistic drops of smaller drones.......A study of how smaller unmanned aircraft will fall in case of failure. The aim is to determine the impact speed of a drone givens its general shape and aerodynamic behavior. This will include both CFD simulations and real world test of ballistic drops of smaller drones....

  3. Experimental Investigation on the Ballistic Resistace of Metal Plates Subjected to Impact of Rigid Projectiles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; DENG Yun-fei; CAO Zong-sheng

    2012-01-01

    The ballistic performance of monolithic and multi-layered steel plates impacted by ogival-nosed projectiles was investigated by using a gas gun experimentally.The total thickness of in-contact multi-layered target was equally to that of monolithic target.The results show that,for the high strength targets,the monolithic targets have greater ballistic limit velocities than multi-layered targets,and also the ballistic limit velocities of targets decrease with the increase of the number of layers.However,for the low strength targets,the monolithic targets have lower ballistic limit velocities than multi-layered targets.The differences in target capacity between various impact conditions can be related to the transitions of perforation mechanisms and failure models.

  4. Towards reliable simulations of ballistic impact on concrete structures

    NARCIS (Netherlands)

    Khoe, Y.S.; Tyler Street, M.D.; Maravalalu Suresh,, R.S.; Weerheijm, J.

    2013-01-01

    Protection against weapon effects like ballistic impacts, fragmenting shells and explosions is the core business of the Explosions, Ballistics and Protection department of TNO (The Netherlands). Experimental and numerical research is performed to gain and maintain the knowledge to support the Dutch

  5. Deformation and Damage of Two Aluminum Alloys from Ballistic Impact

    Science.gov (United States)

    Anderson, Charles E., Jr.; Dannemann, Kathryn A.

    2002-07-01

    A series of impact experiments were conducted on 4.76-mm-thick aluminum plates to investigate the deformation and damage behavior of two aluminum alloys, 6061-T6 and 7075-T6. The Sierra 165 lead-filled bullet was used to load the plates. Impact velocities were varied from approximately 260 m/s to 370 m/s. The flow stress for 7075-T6 aluminum is approximately twice that for 6061-T6 aluminum; however, the ballistic limit velocities differ by only 10%. The 7075-T6 aluminum plates exhibit less deformation than the 6061-T6 plates at the same impact velocity, but at some critical velocity, a through-thickness crack appears in the 7075-T6 plate, ultimately leading to plate perforation. In contrast, the 6061-T6 plates continue to deform and fail by ductile tearing. These differences in damage/failure result in the two alloys having much closer ballistic limit velocities than expected based on differences in strength.

  6. Impacts of Deflection Nose on Ballistic Trajectory Control Law

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

  7. Injuries of the head from backface deformation of ballistic protective helmets under ballistic impact.

    Science.gov (United States)

    Rafaels, Karin A; Cutcliffe, Hattie C; Salzar, Robert S; Davis, Martin; Boggess, Brian; Bush, Bryan; Harris, Robert; Rountree, Mark Steve; Sanderson, Ellory; Campman, Steven; Koch, Spencer; Dale Bass, Cameron R

    2015-01-01

    Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed "behind armor blunt trauma" (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400-460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.

  8. Effects of Strength vs. Ballistic-Power Training on Throwing Performance.

    Science.gov (United States)

    Zaras, Nikolaos; Spengos, Konstantinos; Methenitis, Spyridon; Papadopoulos, Constantinos; Karampatsos, Giorgos; Georgiadis, Giorgos; Stasinaki, Aggeliki; Manta, Panagiota; Terzis, Gerasimos

    2013-01-01

    The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations. Key pointsBallistic-power training with 30% of 1RM is equally effective in increasing shot put performance as strength training, in novice throwers, during a short training cycle of six weeks.In novice shot putters with relatively low initial muscle strength/mass, short-term strength training might be more important since it can increase both muscle strength and shot put performance.The ballistic type of power training resulted in a significant increase of the mass of type IIx muscle fibres and no change in their proportion. Thus, this type of training might be used effectively during the last weeks before competition, when the strength training load is usually reduced, in order to increase muscle power and shot put performance in novice shot putters.

  9. EFFECTS OF STRENGTH VS. BALLISTIC-POWER TRAINING ON THROWING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Nikolaos Zaras

    2013-03-01

    Full Text Available The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9 and Power (n = 8 groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ, Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively. Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively, while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05. Muscle fibre Cross Sectional Area (fCSA increased in all fibre types after Strength training by 19-26% (p < 0.05, while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (% decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations

  10. Study on Titanium Alloy TC4 Ballistic Penetration Resistance Part Ⅰ: Ballistic Impact Tests

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tao; CHEN Wei; GUAN Yupu; GAO Deping

    2012-01-01

    Ballistic impact test of different-scale casings is an efficient way to demonstrate the casing containment capability at the preliminary design stage of the engine.For the sake of studying the titanium alloy TC4 casing performance,the ballistic tests of flat and curved simulation casing are implemented by using two flat blades of different sizes as the projectile.The impact mechanism and failure of the target are discussed.Impact of the projectile is a highly nonlinear transient process with the large deformation of the target.On the impact,failures of the flat casing and the subscale casing are similar,concluding two parts,the global dishing and localized ductile tearing.The main localized failure mode combines plugging (shear) and petaling (shear) if the projectile perforates or penetrates,while crater (shear) if the projectile rebounds.The ballistic limit equation is verified by the test data and the results show that this empirical equation could be a practical way to estimate the critical velocity.

  11. Numerical Simulation of Ballistic Impact of Layered Aluminum Nitride Ceramic

    Science.gov (United States)

    2015-09-01

    sufficient for cessation of relative motion of the projectile to that of the target. Impact velocities of 1,030; 1,100; and 1,160 m/s were considered...estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington...Distribution List 12 iv List of Figures Fig. 1 Ballistic impact problem: a) projectile and target (3 tiles) and b) finite element mesh

  12. Effects of equal channel angular extrusion on microstructure, strength and ballistic performance of AA5754 plates

    DEFF Research Database (Denmark)

    Mishin, Oleg; Hong, Chuanshi; Toftegaard, Helmuth Langmaack

    2014-01-01

    The microstructure, hardness, tensile properties and ballistic performance have been investigated in thick plates of the AA5754 alloy both in a coarse-grained as-received condition and after 4 passes of equal channel angular extrusion (ECAE) conducted at elevated temperatures. It is found that ECAE...... refines the microstructure to an average subgrain size of 0.3 μm, which results in significantly increased hardness and strength. Although ductility decreases due to ECAE, the uniform elongation is still fairly large, ~10%. The ballistic performance of the ECAE-processed material is found...

  13. Ballistic strength training compared with usual care for improving mobility following traumatic brain injury: protocol for a randomised, controlled trial

    Directory of Open Access Journals (Sweden)

    Gavin Williams

    2016-07-01

    Discussion: Strength training in neurological rehabilitation is highly topical because muscle weakness has been identified as the primary impairment leading to mobility limitations in many neurological populations. This project represents the first international study of ballistic strength training after traumatic brain injury. The novelty of ballistic strength training is that the exercises attempt to replicate how lower limb muscles work, by targeting the high angular velocities attained during walking and higher level activities.

  14. Excellent Ballistic Impact Properties Demonstrated By New Fabric

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.; Hopkins, Dale A.

    2002-01-01

    Recently, a relatively new industrial fiber known by the trade name Zylon has been under commercial development by Toyobo Co., Ltd., Japan. In ballistic impact tests conducted at the NASA Glenn Research Center, it was found that dry fabric braided of Zylon had greater ballistic impact capacity than comparable (braid style and weight) fabric braided of Kevlar. To study the potential use of Zylon fabric in jet engine containment systems, the fabric was tested in Glenn's Structures and Acoustics Division Ballistic Impact Facility under conditions simulating those which occur in a jet engine blade-out event. Circular ring test specimens were fabricated by wrapping five layers of braided Zylon or Kevlar fabric around an inner ring made of a thin sheet of aluminum and a 1-in.-thick layer of aluminum honeycomb. The test specimens had an inner diameter of 40 in., an axial length of 10 in., and a wall thickness of approximately 1.5in. A test specimen is shown in the photograph.

  15. The relationship between strength, power and ballistic performance.

    Science.gov (United States)

    Wrbaskić, N; Dowling, J J

    2009-04-01

    The purpose of this investigation was to answer the question, "Does Stronger Mean Faster?". After a screening for elbow strength and speed, four groups of 8 subjects were selected for further investigation that fell into the extreme quartiles of the strength and speed continuums. The main investigation employed an apparatus that could freely rotate in the sagittal plane. Three isometric trials were performed at 60 degrees , 90 degrees and 120 degrees of elbow extension. Dynamic trials were performed with relative resistances (0, 20, 40, 60 and 80%), determined from the lowest maximum isometric torque produced from the three joint angles mentioned above, and absolute resistances of 1.1 kg and 2.2 kg. A 1:1 relationship between strength and speed was not established (r=0.498). Normalized peak power proved to be the best kinetic variable for predicting peak velocity (r ranging between 0.793 and 0.918). Individuals with similar peak torques were compared and the patterns of torque development, whether torques peaked early or late during the movement, physiologically agreed with known theoretically established mechanical responses. Similar velocities were also achieved with different peak torques demonstrating a timing issue. Estimated fibre-typing could not account for the performance differences.

  16. Yarn Pull-Out as a Mechanism for Dissipation of Ballistic Impact Energy in Kevlar KM-2 Fabric, Part 2: Prediction of Ballistic Performance

    Science.gov (United States)

    2004-05-01

    fabrics made from high-strength fibers, such as Kevlar,* Zylon ,† Armos,‡ and Spectra,§ have been widely used in flexible armors such as ballistic vests...pull-out during low velocity (< 300 m/s) impacts of Zylon fabrics, especially when at least two boundaries were unclamped, when impact occurred near the...Kevlar is a registered trademark of DuPont. † Zylon is a registered trademark of Toyobo. ‡ Armos is a registered trademark of Kamenskvolokno JSC

  17. Ultrasonic Imaging of Ballistically Impacted Composite Armour

    Directory of Open Access Journals (Sweden)

    S.S. Samant

    2013-12-01

    Full Text Available The ability of Kevlar-Polypropylene composite armour to withstand the impact of projectile (calibre 7.62 mm is investigated using immersion type ultrasonic c- scan method. The Kevlar polypropylene composite laminate is made of 36 Kevlar and 74 polypropylene layers having thickness 20 mm and are subjected to bullet impact with different striking velocities. At each location of the probe ultrasonic features peak amplitude and signal amplitude are extracted from digitized data and stored in controlling PC. Using UPGMA clustering technique, c-scan images of impacted zones of Kevlar polypropylene composite plate has been generated. The extent of core damage zone in the laminates correlated to the impact velocities of projectile. It is observed that areas of core damage zone are found to increase with the energy loss of the bullet. The area of core damage zone increases rapidly in case of shot lodging. Also peak amplitude and signal energy features are more reliable and sensitive for evaluation of damage in composite laminates.

  18. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    Science.gov (United States)

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  19. Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

    Directory of Open Access Journals (Sweden)

    Elias Randjbaran

    2014-01-01

    Full Text Available Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  20. Ballistic Impact on Glass/Epoxy Composite Laminates

    Directory of Open Access Journals (Sweden)

    R. Velmurugan

    2014-07-01

    Full Text Available Glass/epoxy composite laminates are subjected to impact loading and the energy absorbing capacity of the laminates is studied. In the present study, laminates with four different orientations and thickness values are considered. Analytical study is carried out based on energy method and results are compared with FE results obtained from Abaqus/Explicit software. Results obtained from the analytical methods are showing good agreement with the FE results. It is found that cross-ply laminates are most efficient in ballistic resistance when compared with the laminates of other orientations. It is also noticed that the energy absorbing capacity is decreasing with increase in velocity of the projectile for a given lay-up and thickness value.Defence Science Journal, Vol. 64, No. 4, July 2014, pp. 393-399, DOI:http://dx.doi.org/10.14429/dsj.64.3882 

  1. Acute Effects of Static vs. Ballistic Stretching on Strength and Muscular Fatigue Between Ballet Dancers and Resistance-Trained Women.

    Science.gov (United States)

    Lima, Camila D; Brown, Lee E; Wong, Megan A; Leyva, Whitney D; Pinto, Ronei S; Cadore, Eduardo L; Ruas, Cassio V

    2016-11-01

    Lima, CD, Brown, LE, Wong, MA, Leyva, WD, Pinto, RS, Cadore, EL, and Ruas, CV. Acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. J Strength Cond Res 30(11): 3220-3227, 2016-Stretching is used to increase joint range of motion, but the acute effects can decrease muscle strength. However, this may depend on the population or mode of stretching. The purpose of this study was to compare the acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. Fifteen resistance-trained women (age 23.8 ± 1.80 years, mass 67.47 ± 7.77 kg, height 168.30 ± 5.53 cm) and 12 ballet dancers (age 22.8 ± 3.04 years, mass 58.67 ± 5.65 kg, height 168.00 ± 7.69 cm) performed 5 days of testing. The first day was control (no stretching), whereas the other 4 days were static or ballistic stretching in a counterbalanced order. Range of motion, strength, and fatigue tests were also performed. Both groups demonstrated a significant decrease in hamstrings strength after static (102.71 ± 2.67 N·m) and ballistic stretching (99.49 ± 2.61 N·m) compared with control (113.059 ± 3.25 N·m), with no changes in quadriceps strength. For fatigue, only ballet dancers demonstrated a decrease from control (71.79 ± 4.88%) to ballistic (65.65 ± 8.19%), but no difference with static (65.01 ± 12.29%). These findings suggest that stretching decreases hamstrings strength similarly in ballet dancers and resistance-trained women, with no differences between modes of stretching. However, ballistic stretching only decreased muscular fatigue in ballet dancers, but not in resistance-trained women. Therefore, no stretching should be performed before strength performance. However, ballistic stretching may decrease acute muscular fatigue in ballet dancers.

  2. Fiber-Level Modeling of Dynamic Strength of Kevlar® KM2 Ballistic Fabric

    Science.gov (United States)

    Grujicic, M.; Hariharan, A.; Pandurangan, B.; Yen, C.-F.; Cheeseman, B. A.; Wang, Y.; Miao, Y.; Zheng, J. Q.

    2012-07-01

    In recent years, modeling of the high-performance ballistic fabric has gradually shifted from the continuum and yarn length scales to the sub-yarn length scale which enabled establishment of the relationships between the fabric penetration resistance and various fiber-level phenomena such as fiber-fiber friction, fiber twist, transverse properties of the fibers, and the stochastic nature of fiber strength. In general, these sub-yarn modeling schemes involve special numerical techniques (e.g., digital-element method) and customized computational codes. This status of the sub-yarn fabric-modeling methods and tools makes them not readily available to wider academic and industrial research communities. In the present work, an attempt is made to use conventional finite-element methods and tools in order to carry out sub-yarn numerical analysis of the penetration resistance of Kevlar® KM2 ballistic fabric. The goal was to demonstrate that results could be obtained which are comparable to their digital-element method = based counterparts. Specifically, a series of transient nonlinear dynamics finite-element analyses was carried out in order to investigate the role of the following two important sub-yarn phenomena on the penetration resistance of Kevlar® KM2 fabric: (a) fiber transverse properties including nonlinear elastic and plastic response and (b) fiber-fiber friction within the context of stochastically distributed fiber axial strength. It is generally found that the results obtained are consistent with their digital-element method-based counterparts.

  3. Ballistic Impact Properties of Zr-Based Amorphous Alloy Composites Reinforced with Woven Continuous Fibers

    Science.gov (United States)

    Kim, Gyeong Su; Son, Chang-Young; Lee, Sang-Bok; Lee, Sang-Kwan; Song, Young Buem; Lee, Sunghak

    2012-03-01

    This study aims at investigating ballistic impact properties of Zr-based amorphous alloy (LM1 alloy) matrix composites reinforced with woven stainless steel or glass continuous fibers. The fiber-reinforced composites with excellent fiber/matrix interfaces were fabricated without pores and misinfiltration by liquid pressing process, and contained 35 to 41 vol pct of woven continuous fibers homogeneously distributed in the amorphous matrix. The woven-STS-continuous-fiber-reinforced composite consisted of the LM1 alloy layer of 1.0 mm in thickness in the upper region and the fiber-reinforced composite layer in the lower region. The hard LM1 alloy layer absorbed the ballistic impact energy by forming many cracks, and the fiber-reinforced composite layer interrupted the crack propagation and blocked the impact and traveling of the projectile, thereby resulting in the improvement of ballistic performance by about 20 pct over the LM1 alloy. According to the ballistic impact test data of the woven-glass-continuous-fiber-reinforced composite, glass fibers were preferentially fragmented to form a number of cracks, and the amorphous matrix accelerated the fragmentation of glass fibers and the initiation of cracks. Because of the absorption process of ballistic impact energy by forming very large amounts of cracks, fragments, and debris, the glass-fiber-reinforced composite showed better ballistic performance than the LM1 alloy.

  4. Effects of Heat Treatment on the Ballistic Impact Properties of Inconel 718 for Jet Engine Fan Containment Applications

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2001-01-01

    The effects of heat treating Inconel 718 on the ballistic impact response and failure mechanisms were studied. Two different annealing conditions and an aged condition were considered. Large differences in the static properties were found between the annealed and the aged material, with the annealed condition having lower strength and hardness and greater elongation than the aged. High strain rate tests show similar results. Correspondingly large differences were found in the velocity required to penetrate material in the two conditions in impact tests involving 12.5 mm diameter, 25.4 mm long cylindrical Ti-6-4 projectiles impacting flat plates at velocities in the range of 150 to 300 m/sec. The annealed material was able to absorb over 25 percent more energy than the aged. This is contrary to results observed for ballistic impact response for higher velocity impacts typically encountered in military applications where it has been shown that there exists a correlation between target hardness and ballistic impact strength. Metallographic examination of impacted plates showed strong indication of failure due to adiabatic shear. In both materials localized bands of large shear deformation were apparent, and microhardness measurements indicated an increase in hardness in these bands compared to the surrounding material. These bands were more localized in the aged material than in the annealed material. In addition the annealed material underwent significantly greater overall deformation before failure. The results indicate that lower elongation and reduced strain hardening behavior lead to a transition from shear to adiabatic shear failure, while high elongation and better strain hardening capabilities reduce the tendency for shear to localize and result in an unstable adiabatic shear failure. This supports empirical containment design methods that relate containment thickness to the static toughness.

  5. Effect of High Velocity Ballistic Impact on Pretensioned Carbon Fibre Reinforced Plastic (CFRP) Plates

    Science.gov (United States)

    Azhar KAMARUDIN, Kamarul; HAMID, Iskandar ABDUL

    2017-01-01

    This work describes an experimental investigation of the pretensioned thin plates made of Carbon Fibre Reinforced Plastic (CFRP) struck by hemispherical and blunt projectiles at various impact velocities. The experiments were done using a gas gun with combination of pretension equipment positioned at the end of gun barrel near the nozzle. Measurements of the initial and residual velocities were taken, and the ballistic limit velocity were calculated for each procedures. The pretension target results in reduction of ballistic limit compared to non-pretension target for both flat and hemispherical projectiles. Target impacted by hemispherical projectile experience split at earlier impact velocity compared to target by flat projectile. C-Scan images analysis technique was used to show target impact damaged by hemispherical and flat projectiles. The damage area was shown biggest at ballistic limit velocity and target splitting occurred most for pretention plate.

  6. Prediction of Final Velocity of Aramid Fabric-Resin Composite Laminates Subjected to Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    熊杰; 萧庆亮; 刘冠峰; 顾伯洪; 王善元

    2003-01-01

    The strain rate effects of aramid fiber material,quasi-static and ballistic impact perforation of composite laminates made of aramid fabric and phenolic resin/PVB are investigated respectively by means of MTS, split Hopkinson tension bars and ballistic impact apparatus. The tensile impact experiments on aramid fiber material are performed in strain rate range from 0.01/ s to 1 000/ s. Experinental results show that the mechanical properties of aramid fiber material are insensitive to strain rate in the range from 0. 01/s to 1 000/s. An energy model to predict final velocity of composite laminates subjected to ballistic impact is proposed on the basis of experimental data of quasi-static perforation through the targets. The predicted final velocities show good agreement with the experimental final velocity.

  7. Modeling and Experiments on Ballistic Impact into UHMWPE Yarns Using Flat and Saddle-Nosed Projectiles

    Directory of Open Access Journals (Sweden)

    Stuart Leigh Phoenix

    2017-03-01

    Full Text Available Yarn shooting experiments were conducted to determine the ballistically-relevant, Young’s modulus and tensile strength of ultra-high molecular weight polyethylene (UHMWPE fiber. Target specimens were Dyneema® SK76 yarns (1760 dtex, twisted to 40 turns/m, and initially tensioned to stresses ranging from 29 to 2200 MPa. Yarns were impacted, transversely, by two types of cylindrical steel projectiles at velocities ranging from 150 to 555 m/s: (i a reverse-fired, fragment simulating projectile (FSP where the flat rear face impacted the yarn rather than the beveled nose; and (ii a ‘saddle-nosed projectile’ having a specially contoured nose imparting circular curvature in the region of impact, but opposite curvature transversely to prevent yarn slippage off the nose. Experimental data consisted of sequential photographic images of the progress of the triangular transverse wave, as well as tensile wave speed measured using spaced, piezo-electric sensors. Yarn Young’s modulus, calculated from the tensile wave-speed, varied from 133 GPa at minimal initial tension to 208 GPa at the highest initial tensions. However, varying projectile impact velocity, and thus, the strain jump on impact, had negligible effect on the modulus. Contrary to predictions from the classical Cole-Smith model for 1D yarn impact, the critical velocity for yarn failure differed significantly for the two projectile types, being 18% lower for the flat-faced, reversed FSP projectile compared to the saddle-nosed projectile, which converts to an apparent 25% difference in yarn strength. To explain this difference, a wave-propagation model was developed that incorporates tension wave collision under blunt impact by a flat-faced projectile, in contrast to outward wave propagation in the classical model. Agreement between experiment and model predictions was outstanding across a wide range of initial yarn tensions. However, plots of calculated failure stress versus yarn pre

  8. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  9. Ballistic impact behaviour of woven fabric composite: Finite element analysis and experiments

    Science.gov (United States)

    Phadnis, V. A.; Pandya, K. S.; Naik, N. K.; Roy, A.; Silberschmidt, V. V.

    2013-07-01

    A mechanical behaviour of plain-weave E-glass fabric/epoxy laminate composite plate exposed to ballistic impact is studied using a finite-element (FE) code Abaqus/Explicit. A ply-level FE model is developed, where a fabric-reinforced ply is modelled as a homogeneous orthotropic elastic material with potential to sustain progressive stiffness degradation due to fiber/matrix cracking, and plastic deformation under shear loading. The model is implemented as a VUMAT user subroutine. Ballistic experiments were carried out to validate the FE model. A parametric study for varying panel thickness is performed to compare impact resistance of the studied composite.

  10. Hazard map for volcanic ballistic impacts at El Chichón volcano (Mexico)

    Science.gov (United States)

    Alatorre-Ibarguengoitia, Miguel; Ramos-Hernández, Silvia; Jiménez-Aguilar, Julio

    2014-05-01

    The 1982 eruption of El Chichón Volcano in southeastern Mexico had a strong social and environmental impact. The eruption resulted in the worst volcanic disaster in the recorded history of Mexico, causing about 2,000 casualties, displacing thousands, and producing severe economic losses. Even when some villages were relocated after the 1982 eruption, many people still live and work in the vicinities of the volcano and may be affected in the case of a new eruption. The hazard map of El Chichón volcano (Macías et al., 2008) comprises pyroclastic flows, pyroclastic surges, lahars and ash fall but not ballistic projectiles, which represent an important threat to people, infrastructure and vegetation in the case of an eruption. In fact, the fatalities reported in the first stage of the 1982 eruption were caused by roof collapse induced by ashfall and lithic ballistic projectiles. In this study, a general methodology to delimit the hazard zones for volcanic ballistic projectiles during volcanic eruptions is applied to El Chichón volcano. Different scenarios are defined based on the past activity of the volcano and parameterized by considering the maximum kinetic energy associated with ballistic projectiles ejected during previous eruptions. A ballistic model is used to reconstruct the "launching" kinetic energy of the projectiles observed in the field. The maximum ranges expected for the ballistics in the different explosive scenarios defined for El Chichón volcano are presented in a ballistic hazard map which complements the published hazard map. These maps assist the responsible authorities to plan the definition and mitigation of restricted areas during volcanic crises.

  11. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact : Experimental Investigation II

    OpenAIRE

    S. N. Dikshit

    1999-01-01

    The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° obliquity, the plate offers protection up to a striking velocity of 800 mls. At zero obliquity, the plate provides protection below 6~ m/s. The depth of penetration decreases with...

  12. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact: Experimental Investigation .

    OpenAIRE

    S. N. Dikshit

    1998-01-01

    The ballistic behaviour of thick steel amlOW- plate has been investigated at different obliquity when impacted by an ogive-shaped steel projectile. The ballistic experiments have been conducted in the velocity range 300-800 m/s. Both the thickness of the target plate and the diameter of the projectile were 20 Inm. At 30 and 45. obliquity 20 mm plate provides full protection at 800 m/s, whereas at 0 and 15. obliquity, the plate provides protection up to 600 m/s. At 15 and 30° obliquity, the pl...

  13. An experimental study of the self-healing behavior of ionomeric systems under ballistic impact tests

    Science.gov (United States)

    Grande, A. M.; Coppi, S.; Di Landro, L.; Sala, G.; Giacomuzzo, C.; Francesconi, A.; Rahman, M. A.

    2012-04-01

    This research deals with the investigation of the self-healing behavior after ballistic damage of ethylene-methacrylic acid ionomers and theirs blends with epoxidized natural rubber (ENR). The self-healing capability was studied by ballistic puncture tests under different experimental conditions as sample thickness, bullet speed, diameter and shape. Bullet speed ranging from few hundreds meters per second to few km/s were employed. The healing efficiency was evaluated by applying a pressure gradient trough the plates and by checking for possible flow at the damage zone. A morphology analysis of the impact area was made observing all samples by scanning electron microscope.

  14. Fractographic Analysis of High Performance Fabric Reinforced Composites after Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua-peng; SHI Mei-wu; ZHANG Jian-chun; WANG Shan-yuan

    2002-01-01

    To improve the ballistic resistance of the ballistic resistant composites, this paper deals with the microscopically fractographic analysis of their failure caused by Fragments Simulated Projectiles (FSP) and bullet with the objective to clarify the failure modes of the compoosites, and to further improve the ballistic resistance of the ballistic systems by hybridizing based on the currently market available materials.After the analysis, it has been found that the penetration of the FSP into the panels causes shear failure in the impact side of the target but extensive tension failure in the distal side of the composite target. The failure modes also include matrix fragmentation, and delamination, and with resin content as high as 30%,more filaments are broken by cutting in the composite.Compared with the failure caused by bullet, there are more cutting or shearing for the failure caused by FSP,but more compressive failure caused by bullet. This paper also discusses the effects of hybridizing different types of fabrics on the ballistic resistance of the composite based on the observations and numerical simulation.

  15. Hazard map for volcanic ballistic impacts at Popocatépetl volcano (Mexico)

    Science.gov (United States)

    Alatorre-Ibargüengoitia, Miguel A.; Delgado-Granados, Hugo; Dingwell, Donald B.

    2012-11-01

    During volcanic explosions, volcanic ballistic projectiles (VBP) are frequently ejected. These projectiles represent a threat to people, infrastructure, vegetation, and aircraft due to their high temperatures and impact velocities. In order to protect people adequately, it is necessary to delimit the projectiles' maximum range within well-defined explosion scenarios likely to occur in a particular volcano. In this study, a general methodology to delimit the hazard zones for VBP during volcanic eruptions is applied to Popocatépetl volcano. Three explosion scenarios with different intensities have been defined based on the past activity of the volcano and parameterized by considering the maximum kinetic energy associated with VBP ejected during previous eruptions. A ballistic model is used to reconstruct the "launching" kinetic energy of VBP observed in the field. In the case of Vulcanian eruptions, the most common type of activity at Popocatépetl, the ballistic model was used in concert with an eruptive model to correlate ballistic range with initial pressure and gas content, parameters that can be estimated by monitoring techniques. The results are validated with field data and video observations of different Vulcanian eruptions at Popocatépetl. For each scenario, the ballistic model is used to calculate the maximum range of VBP under optimum "launching" conditions: ballistic diameter, ejection angle, topography, and wind velocity. Our results are presented in the form of a VBP hazard map with topographic profiles that depict the likely maximum ranges of VBP under explosion scenarios defined specifically for Popocatépetl volcano. The hazard zones shown on the map allow the responsible authorities to plan the definition and mitigation of restricted areas during volcanic crises.

  16. An experimental study to estimate ballistic limit velocity for glass epoxy composite under high velocity impact with two different projectile geometry.

    Directory of Open Access Journals (Sweden)

    Erfan Ebadi Afshar

    2016-12-01

    Full Text Available In this research a study in estimating velocity ballistic in glass epoxy composite sheet with construction process of padding-manually, under high velocity impact was conducted for laboratory with gas gun device and ballistic limit velocity for composite sheet with a thickness 2 mm were obtained under geometry of projectile. So that result is obtained in construction of military armor, aerospace industry, automotive, and general any industry to be used with impact challenges and faced dealt. That is down strength and toughness and resistance to crack growth in structural weight. Glass epoxy composite (three layers made and for build projectile of steel rod VCN200 (Brand steel 1.6580 was used to manually peeling method; amounting to 16 gas gun device was performed to dimensions of 65 × 65 mm on the samples. With results analysis obtained ballistic tests were two important conclusions: first, in compare of two projectile geometry together, projectile with spherical tip compared to projectile with conical tip for better performance in penetrate and pass of this armor; second ballistic limit velocity for armor was obtained under spherical tip projectile 136.6 (meters per second and under conic tip projectile 143.6 (meters per second.

  17. Failure analysis of high performance ballistic fibers

    OpenAIRE

    Spatola, Jennifer S

    2015-01-01

    High performance fibers have a high tensile strength and modulus, good wear resistance, and a low density, making them ideal for applications in ballistic impact resistance, such as body armor. However, the observed ballistic performance of these fibers is much lower than the predicted values. Since the predictions assume only tensile stress failure, it is safe to assume that the stress state is affecting fiber performance. The purpose of this research was to determine if there are failure mo...

  18. KevlarTM Fiber-Reinforced Polybenzoxazine Alloys for Ballistic Impact Application

    Directory of Open Access Journals (Sweden)

    Chanchira Jubsilp

    2011-10-01

    Full Text Available A light weight ballistic composites from KevlarTM-reinforcing fiber having polybenzoxazine (BA/urethane prepolymer (PU alloys as a matrix were investigated in this work. The effect of alloy compositions on the ballistic composite properties was determined. The results revealed that the enhancement in the glass transition temperature (Tg of the KevlarTM-reinforced BA/PU composites compared to that of the KevlarTM-reinforced polybenzoxazine composite was observed. The increase of the elastomeric PU content in the BA/PU alloy resulted in samples with tougher characteristics. The storage modulus of the KevlarTM-reinforced BA/PU composites increased with increasing the mass fraction of polybenzoxazine. A ballistic impact test was also performed on the KevlarTM-reinforced BA/PU composites using a 9 mm handgun. It was found that the optimal contents of PU in the BA/PU alloys should be approximately 20wt%. The extent of the delaminated area and interfacial fracture were observed to change with the varied compositions of the matrix alloys. The appropriate thickness of KevlarTM-reinforced 80/20 BA/PU composite panel was 30 plies and 50 plies to resist the penetration from the ballistic impact equivalent to levels II-A and III-A of NIJ standard. The arrangement of composite panels with the higher stiffness panel at the front side also showed the best efficiency of ballistic penetration resistance.

  19. Fiber-Level Modeling of Dynamic Strength of Kevlar (registered trademark) KM2 Ballistic Fabric

    Science.gov (United States)

    2012-07-01

    systems). Flexible lightweight materials have been used, throughout history , in body-armor systems to provide protection against specified threats, at...focused on fibers and the associated materials, it should be recognized that flexible-armor structures are made of fabric/ textiles containing these...specific patterns through weaving or braiding processes. It is important to note that fabric ballistic-penetration resistance is influenced not only by

  20. Penetration of sandwich plates with hybrid-cores under oblique ballistic impact

    Directory of Open Access Journals (Sweden)

    Changye Ni

    2014-01-01

    Full Text Available The oblique penetration performance of lightweight hybrid-cored sandwich plates are investigated numerically. To compose the hybrid-core, ceramic prisms are inserted into pyramidal metal lattice trusses and fixed using epoxy resin. Three-dimensional finite element simulations are carried out for the hybridcored sandwich impacted at 15°, 30°, 45°, and 60° obliquity by a hemispherical projectile. The ballistic limit, the energy absorbed by the constituting elements, and the critical oblique angle are quantified. The physical mechanisms underlying the failure and the influence of fundamental system parameters are explored. The angle of obliquity is found to have significant influence on the ballistic trajectory and erosion of the projectile, thus it is important for the impact response and penetration resistance of the sandwich. For oblique angles equal to or larger than 45°, the projectile moves mainly horizontally and can not effectively penetrate across the sandwich.

  1. Densification and Devitrification of Fused Silica Induced by Ballistic Impact: A Computational Investigation

    Science.gov (United States)

    2015-03-25

    and P. G. Dehmer, “Effect of the tin- vs. air-side plate-glass orientation on the impact response and penetration resistance of a laminated ...the multi-hit ballistic-protection performance of laminated transparent-armor systems,” Journal of Materials Engineering and Performance, vol. 21, no...www.hindawi.com Volume 2014 Nanoscience Journal of Textiles Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 Journal of Nanotechnology

  2. The impact of defect scattering on the quasi-ballistic transport of nanoscale conductors

    Energy Technology Data Exchange (ETDEWEB)

    Esqueda, I. S., E-mail: isanchez@isi.edu; Fritze, M. [Information Sciences Institute, University of Southern California, Marina del Rey, California 90292 (United States); Cress, C. D. [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States); Cao, Y.; Che, Y.; Zhou, C. [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States)

    2015-02-28

    Using the Landauer approach for carrier transport, we analyze the impact of defects induced by ion irradiation on the transport properties of nanoscale conductors that operate in the quasi-ballistic regime. Degradation of conductance results from a reduction of carrier mean free path due to the introduction of defects in the conducting channel. We incorporate scattering mechanisms from radiation-induced defects into calculations of the transmission coefficient and present a technique for extracting modeling parameters from near-equilibrium transport measurements. These parameters are used to describe degradation in the transport properties of nanoscale devices using a formalism that is valid under quasi-ballistic operation. The analysis includes the effects of bandstructure and dimensionality on the impact of defect scattering and discusses transport properties of nanoscale devices from the diffusive to the ballistic limit. We compare calculations with recently published measurements of irradiated nanoscale devices such as single-walled carbon nanotubes, graphene, and deep-submicron Si metal-oxide-semiconductor field-effect transistors.

  3. Combined Structural and Compositional Evolution of Planetary Rings Due to Micrometeoroid Impacts and Ballistic Transport

    Science.gov (United States)

    Estrada, Paul R.; Durisen, Richard H.; Cuzzi, Jeffrey N.; Morgan, Demitri A.

    2015-01-01

    We introduce improved numerical techniques for simulating the structural and compositional evolution of planetary rings due to micrometeoroid bombardment and subsequent ballistic transport of impact ejecta. Our current, robust code is capable of modeling structural changes and pollution transport simultaneously over long times on both local and global scales. In this paper, we describe the methodology based on the original structural code of Durisen et al. (1989, Icarus 80, 136-166) and on the pollution transport code of Cuzzi and Estrada (1998, Icarus 132, 1-35). We provide demonstrative simulations to compare with, and extend upon previous work, as well as examples of how ballistic transport can maintain the observed structure in Saturn's rings using available Cassini occultation optical depth data. In particular, we explicitly verify the claim that the inner B (and presumably A) ring edge can be maintained over long periods of time due to an ejecta distribution that is heavily biased in the prograde direction through a balance between the sharpening effects of ballistic transport and the broadening effects of viscosity. We also see that a "ramp"-like feature forms over time just inside that edge. However, it does not remain linear for the duration of the runs presented here unless a less steep ejecta velocity distribution is adopted. We also model the C ring plateaus and find that their outer edges can be maintained at their observed sharpness for long periods due to ballistic transport. We hypothesize that the addition of a significant component of a retrograde-biased ejecta distribution may help explain the linearity of the ramp and is probably essential for maintaining the sharpness of C ring plateau inner edges. This component would arise for the subset of micrometeoroid impacts which are destructive rather than merely cratering. Such a distribution will be introduced in future work.

  4. Modelling of Ballistic Impact over a Ceramic-Metal Protection System

    Directory of Open Access Journals (Sweden)

    Leandro Neckel

    2013-01-01

    Full Text Available The behavior of ceramic-metal protection against a projectile impact is modeled. The model takes into account the mass and velocity for each stage of the phenomenon. A former model was modified considering more realistic parameters such as geometries and deformation profile. To analyze the model, simulations on different parameters have been run. The impact results of different ballistic projectiles were simulated, and the movement was plotted. In addition, a deterministic simulation on the mechanical properties of the back metal plate properties was done.

  5. Ballistics for the neurosurgeon.

    Science.gov (United States)

    Jandial, Rahul; Reichwage, Brett; Levy, Michael; Duenas, Vincent; Sturdivan, Larry

    2008-02-01

    Craniocerebral injuries from ballistic projectiles are qualitatively different from injuries in unconfined soft tissue with similar impact. Penetrating and nonpenetrating ballistic injuries are influenced not only by the physical properties of the projectile, but also by its ballistics. Ballistics provides information on the motion of projectiles while in the gun barrel, the trajectory of the projectile in air, and the behavior of the projectile on reaching its target. This basic knowledge can be applied to better understand the ultimate craniocerebral consequences of ballistic head injuries.

  6. SPH Simulation of Ballistic Impact on Ceramic Plate

    Directory of Open Access Journals (Sweden)

    Chetan Swaroop

    2013-06-01

    Full Text Available This paper studies the use of smooth particle hydrodynamics (SPH numerical technique to simulate the impact, penetration and perforation of Ceramic plate (Al2O3-99.7% by Lead Round Nose (LRN projectile. The general discussion of the SPH solver is introduced first then AUTODYN 2D simulation of penetration and perforation of ceramic plate. The numerical prediction of the time history of velocity of bullet is investigated for a range of impact velocity between 400m/s to 800m/s and an empirical relation is derived between impact velocity and residual velocity. For this type of problem, the SPH approach can provide significant advantages over more traditional numerical methods.

  7. Using Hertzian Indentation to Understand the Strength and Ballistic Resistance of Silicon Carbide

    Energy Technology Data Exchange (ETDEWEB)

    Holmquist, T J [Network Computing Services, Inc., Minneapolis; Wereszczak, Andrew A [ORNL

    2010-01-01

    This article presents an initial evaluation of the usefulness of spherical or Hertzian indentation for the determination and/or validation of constitutive models and for a potential link to ballistic resistance (interface defeat). Recent advancements in producing more confident elevated stress levels in Hertzian indentation make the usefulness of this test much more feasible. There are very few experimental techniques that can produce the high stresses, strains, and pressures produced in Hertzian indentation tests. Additionally, they are also relatively simple, repeatable, timely, and inexpensive. There is still the disadvantage that the stresses, strains, and pressures are not explicit outputs of the experiments requiring the constitutive response to be inferred by performing computations and comparing the computed force-deflection results to the experiment. Preliminary results indicate that Hertzian indentation can be used to help define the constitutive response but it is still uncertain if it can be used to rank a ceramic's ability to produce interface defeat.

  8. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is nonexistent but necessary to protect the heart and lungs. In tests against ballistic projectiles, protective apparel is placed over ballistic clay and the projectiles are fired into the armor/clay target. The clay represents the human torso and its behind-armor, permanent deflection is the principal metric used to assess armor protection. Although this approach provides relative merit assessment of protection, it does not examine the behind-armor blunt trauma to crucial torso organs. We propose a modeling and simulation (M&S) capability for wound injury scenarios to the head, neck, and torso of the warfighter. We will use this toolset to investigate the consequences of, and mitigation against, blast exposure, blunt force impact, and ballistic projectile penetration leading to damage of critical organs comprising the central nervous, cardiovascular, and respiratory systems. We will leverage Sandia codes and our M&S expertise on traumatic brain injury to develop virtual anatomical models of the head, neck, and torso and the simulation methodology to capture the physics of wound mechanics. Specifically, we will investigate virtual wound injuries to the head, neck, and torso without and with protective armor to demonstrate the advantages of performing injury simulations for the development of body armor. The proposed toolset constitutes a significant advance over current methods by providing a virtual simulation capability to investigate wound injury and optimize armor design without the need for extensive field testing.

  9. Characteristics of Impact Damage and Post-Impact Strength in Glass-Fibre-Reinforced Plastics with Different Reinforcement Architecture

    Directory of Open Access Journals (Sweden)

    Michał BARCIKOWSKI

    2013-12-01

    Full Text Available Fiber-reinforced plastics (FRP are nowadays used commonly for constructions subjected to impacts of different energies and velocities; therefore, the problem of impact resistance is crucial. This paper presents the results of high-velocity impact tests and post-impact evaluation of damage in glass-fiber-reinforced plastics, depending on the architecture of reinforcing material (different woven fabrics, mat. Composites reinforced with continuous-filament mat, woven roving, roving fabric and twisted-yarn fabric were prepared and subjected to intermediate- and high-velocity impact. After the ballistic impact, damage extent and residual strength, as well as water leakage through the composites, were evaluated. The damage was also investigated under a microscope. The damage extent was confirmed to be linearly dependent on impact energy. The addition of rubber was found to decrease damage extent and increase post-impact residual strength, as well as decrease water leakage rate.

  10. Ballistic Impact Response of Woven Hybrid Coir/Kevlar Laminated Composites

    Directory of Open Access Journals (Sweden)

    Azrin Hani A.R

    2016-01-01

    Full Text Available The effects of different laminated hybrid composites stacking configuration subjected to ballistic impact were investigated. The hybrid composites consist of woven coir (C and woven Kevlar (K layers laminated together. The samples of woven coir were prepared using handloom device. The composites were produced by stacking the laminated woven coir and Kevlar alternately with the presence of the binder. The samples were tested under ballistic impact with different stacking configuration. The results obtained had successfully achieved the National Institute of Justice (NIJ standard level IIA with energy absorption of 435.6 kJ and 412.2 kJ under the projectile speed of between 330 m/s and 321 m/s respectively. Samples that having Kevlar layer at the front face and woven coir layer as back face achieved partial penetration during projectile impact. This orientation is proven to have good impact energy absorption and able to stop projectile at the second panel of the composites.

  11. Influence of obliquity effect on the ballistic performance of high strength steel plate%倾角效应对高强度钢板抗弹性能的影响

    Institute of Scientific and Technical Information of China (English)

    肖红亮; 李晓源; 时捷; 韩赟; 曹文全; 雍岐龙

    2011-01-01

    选择53式7.62 mm普通弹和53式7.62 mm穿燃弹两种弹型,对不同厚度的高强度马氏体均质钢板和有孔结构钢板进行抗弹性能试验.研究对应不同的弹丸类型和钢板结构时,倾角效应对抗弹性能的影响.结果表明,53普通弹和53穿燃弹冲击时,倾斜角增大,均质钢板抗弹性能均提高.钢板防护53普通弹时的抗弹性能对倾斜角不敏感,而钢板防护53穿燃弹时的抗弹性能对倾斜角敏感.弹丸以跳飞角入射时,钢板防护53普通弹和53穿燃弹的临界厚度基本相当.有孔结构钢板在大角度倾斜抗弹时,抗弹性能较好;在垂直抗弹时,孔结构导致的边缘效应明显降低钢板的抗弹性能.%Ballistic resistance tests were carried out on high-strength martensitic homogeneous steel plates with different thickness and the perforated steel plates, using 53-type ordinary ball and 53-type armor-piercing incendiary. The influence of obliquity effect on the ballistic performance under the different types of bullet and the structure of plates was studied. The results show that with the oblique angle increasing, the ballistic performance of homogeneous steel plates against the 53-type ordinary ball and 53-type armor-piercing incendiary increases. Moreover, ballistic performance against the 53-type ordinary ball is not sensitive to oblique angle, while it is contrary for 53-type armor-piercing incendiary. When the steel plate is impacted at ricochet angle, the critical thickness of plate against 53-type ordinary ball and 53-type armor-piercing incendiary is roughly equal. The perforated steel plate impacted at large oblique angle has preferable ballistic performance; while at normal impact, the ballistic performance of the perforated steel plate deteriorates obviously by edge effect.

  12. Experimental study of the coupling parameters influencing the terminal effects of thoracic blunt ballistic impacts.

    Science.gov (United States)

    Pavier, Julien; Langlet, André; Eches, Nicolas; Prat, Nicolas; Bailly, Patrice; Jacquet, Jean-François

    2015-07-01

    The objective of the study is to better understand how blunt projectile ballistic parameters and material properties influence the events leading to injuries. The present work focuses on lateral thoracic impacts and follows an experimental approach. The projectiles are made with a soft foam nose assembled with a rigid rear plastic part. The dynamic properties of the foams were first determined using the Split Hopkinson Pressure Bar (SHPB) system. The impact forces on a rigid wall were then measured to provide reference load data. Lastly, shots were made on isolated thoraxes of porcine cadavers to investigate the response in the vicinity of the impact (wall displacements, rib accelerations and strains, rib fractures). Results show that the severity of the response appears to be mainly correlated with the impulse and with the pre-impact momentum.

  13. Analysis of the ballistic impact response of a composite material using FAST Infrared Imagery

    Science.gov (United States)

    Marcotte, Frederick; Ouellet, Simon; Farley, Vincent

    2013-05-01

    The level of protection offered by a given ballistic material is typically evaluated in terms of a set of projectiles and their associated velocity at which a certain percentage of the projectiles are expected to perforate. (i.e. FSP 17gr : V50 = 500m/s, 9mm FMJ; V0=500m/s). These metrics give little information about the physical phenomena by which energy is dispersed, spread or absorbed in a specific target material. Aside from post-test inspection of the impacted material, additional information on the target response is traditionally obtained during a test from the use of high speed imaging, whether it is from a single camera aimed at the impact surface or the backface, or from a set of camera allowing full 3-D reconstruction of a deformed surface. Again, this kind of data may be difficult to interpret if the interest is in the way energy is managed in the target in real time. Recent technological progress in scientific grade high-speed infrared (IR) camera demonstrated that these phenomena can straightforwardly be measured using IR thermal imaging. This paper presents promising results obtained from Telops FAST-IR 1500 infrared camera on an aramid-based ballistic composite during an impact from a small caliber fragment simulating projectile (FSP).

  14. Ballistic impact behavior of carbon nanotube and nanosilica dispersed resin and composites

    Science.gov (United States)

    Pandya, K. S.; Akella, K.; Joshi, M.; Naik, N. K.

    2012-12-01

    Experimental studies are presented on the ballistic impact behavior of nanoparticle dispersed materials viz. symmetric balanced cross-ply laminates made using unidirectional E-glass fabric with epoxy resin and neat epoxy resin. The nanoparticles used are nanosilica and multi-walled carbon nanotube for polymer matrix composites and nanosilica for epoxy resin. For comparison, studies are carried out on symmetric balanced cross-ply E-glass/epoxy and neat epoxy resin without nanoparticles. Effect of nanoparticle dispersion on ballistic limit velocity, V50 and energy absorbed has been studied. It is observed that V50 can be enhanced up to 6.3% for polymer matrix composites and up to 7.3% for neat resin on addition of nanoparticles. Also, energy absorbed can be increased up to 13.0% for polymer matrix composites and up to 15.2% for neat resin on addition of nanoparticles. Damage and energy absorbing mechanisms for different types of materials studied is also presented. Further, it is observed that the damage size on the target around the point of impact decreases on addition of nanoparticles. Quantitative data are given for high velocity impact behavior of the five types of specimens studied.

  15. A computational study of influence of helmet padding materials on the human brain under ballistic impacts.

    Science.gov (United States)

    Salimi Jazi, Mehdi; Rezaei, Asghar; Karami, Ghodrat; Azarmi, Fardad; Ziejewski, Mariusz

    2014-01-01

    The results of a computational study of a helmeted human head are presented in this paper. The focus of the work is to study the effects of helmet pad materials on the level of acceleration, inflicted pressure and shear stress in a human brain model subjected to a ballistic impact. Four different closed cell foam materials, made of expanded polystyrene and expanded polypropylene, are examined for the padding material. It is assumed that bullets cannot penetrate the helmet shell. Finite element modelling of the helmet, padding system, head and head components is used for this dynamic nonlinear analysis. Appropriate contacts and conditions are applied between the different components of the head, as well as between the head and the pads, and the pads and the helmet. Based on the results of simulations in this work, it is concluded that the stiffness of the foam has a prominent role in reducing the level of the transferred load to the brain. A pad that is less stiff is more efficient in absorbing the impact energy and reducing the sudden acceleration of the head and consequently lowers the brain injury level. Using the pad with the least stiffness, the influence of the angle of impacts as well as the locations of the ballistic strike is studied.

  16. Response Simulation of a Micro Reinforced Concrete Target Under Ballistic Impact

    Science.gov (United States)

    Mohan, V.; Rajasankar, J.; Iyer, N. R.

    2014-05-01

    The response of concrete structures subjected to impact loading has received extensive attention in both civil and military applications. Research on improving the shock resistance of concrete has led to the development of cementitious composites. Micro Reinforced Concrete (MRC), a type of cementitious composite, is a concrete matrix embedded with multilayered steel wire meshes. This paper presents 3D hydrocode simulations of MRC panels subjected to impact under a ballistic range. A finite element model based on Lagrange formulation is used to represent both a 300 mm × 300 mm × 100 mm target with 30 layers of wire mesh and a 5.56 × 45 mm projectile in simulations. Penetration depth and damage patterns of the MRC mesh cement composite panel are numerically compared with those of the field experiment. The results show a relatively good agreement.

  17. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Candice Frances [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burnett, Damon J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is virtually nonexistent but necessary to ensure adequate protection against injury to the heart and lungs. In this report, we discuss the development of a high-fidelity human torso model, it's merging with the existing Sandia Human Head-Neck Model, and development of the modeling & simulation (M&S) capabilities necessary to simulate wound injury scenarios. Using the new Sandia Human Torso Model, we demonstrate the advantage of virtual simulation in the investigation of wound injury as it relates to the warfighter experience. We present the results of virtual simulations of blast loading and ballistic projectile impact to the tors o with and without notional protective armor. In this manner, we demonstrate the ad vantages of applying a modeling and simulation approach to the investigation of wound injury and relative merit assessments of protective body armor without the need for trial-and-error testing.

  18. Forensic Evidence and Criminal Investigations: The Impact of Ballistics Information on the Investigation of Violent Crime in Nine Cities().

    Science.gov (United States)

    King, William R; Campbell, Bradley A; Matusiak, Matthew C; Katz, Charles M

    2017-01-23

    We explore the impact of information from ballistics imaging hit reports on the investigation into violent crimes. Ballistics imaging hits link two crimes involving the same firearm by forensically matching tool marks on the fired bullets or cartridge cases. Interview data collected from detectives who received a hit report were used to explore the relationship between the presence of a hit report and outcomes in 65 gun-related violent crime investigations in nine U.S. police agencies. Findings indicate hit reports rarely contribute to identification, arrest, charging, or sentencing of suspects, because of delays in producing hit reports. On average, hit reports were completed 181.4 days after the focal crime. This delay forces investigations to proceed without the benefit of information from ballistics analysis. Additionally, hit reports rarely contained detailed information that was immediately useful to investigators. Instead, hit reports required additional research by the investigator to unlock useful information.

  19. Ballistic Impact Response of Ceramic-Faced Aramid Laminated Composites Against 7.62 mm Armour Piercing Projectiles

    Directory of Open Access Journals (Sweden)

    Nityananda Nayak

    2013-07-01

    Full Text Available Ballistic impact response of ceramic- composite armor, consisting of zirconia toughened alumina (ZTA ceramic front and aramid laminated composite as backing, against 7.62 mm armor piercing (AP projectiles has been studied. Two types of backing composite laminates i.e. Twaron-epoxy and Twaron-polypropylene (PP of 10 mm and 15 mm thickness were used with a ceramic face of 4mm thick ZTA. The ceramic- faced and the stand alone composite laminates were subjected to ballistic impact of steel core 7.62 mm AP projectiles with varying impact velocities and their V50 ballistic limit (BL was determined. A sharp rise in BL was observed due to addition of ceramic front layer as compared to stand alone ones. The impact energy was absorbed during penetration primarily by fracture of ceramic, deformation and fracture of projectile and elastic-plastic deformation of flexible backing composite layer. The breaking of ceramic tiles were only limited to impact area and did not spread to whole surface and projectile shattering above BL and blunting on impact below BL was observed. The ceramic- faced composites showed higher BL with Twaron-PP as backing than Twaron-epoxy laminate of same thickness. This combination of ceramic-composite laminates exhibited better multi-hit resistance capability; ideal for light weight armor.Defence Science Journal, 2013, 63(4, pp.369-375, DOI:http://dx.doi.org/10.14429/dsj.63.2616

  20. Effects of Various Heat Treatments on the Ballistic Impact Properties of Inconel 718 Investigated

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2000-01-01

    Uncontained failures of aircraft engine fan blades are serious events that can cause equipment damage and loss of life. Federal Aviation Administration (FAA) certification requires that all engines demonstrate the ability to contain a released fan blade with the engine running at full power. However, increased protection generally comes at the expense of weight. Proper choice of materials is therefore imperative to an optimized design. The process of choosing a good casing material is done primarily through trial and error. This costly procedure could be minimized if there was a better understanding of the relationships among static material properties, impact properties, and failure mechanisms. This work is part of a program being conducted at the NASA Glenn Research Center at Lewis Field to study these relationships. Ballistic impact tests were conducted on flat, square sheets of Inconel 718 that had been subjected to different heat treatments. Two heat treatments and the as-received condition were studied. In addition, results were compared with those from an earlier study involving a fourth heat treatment. The heat treatments were selected on the basis of their effects on the static tensile properties of the material. The impact specimens used in this study were 17.8-cm square panels that were centered and clamped over a 15.2-cm square hole in a 1.27-cm-thick steel plate. Three nominal plate thickness dimensions were studied, 1.0, 1.8, and 2.0 mm. For each thickness, all the specimens were taken from the same sheet of material. The projectile was a Ti-6Al-4V cylinder with a length of 25.4 mm, a diameter of 12.7 mm, and a mass ranging from 14.05 to 14.20 g. The projectiles were accelerated toward the specimens at normal incidence using a gas gun with a 2-m-long, 12.7-mm inner-diameter barrel. The ballistic limit for each heat treatment condition and thickness was determined by conducting a number of impact tests that bracketed as closely as possible the velocity

  1. Models of the SL9 Impacts I. Ballistic Monte-Carlo Plume

    CERN Document Server

    Harrington, J; Harrington, Joseph; Deming, Drake

    2001-01-01

    We model the Comet Shoemaker-Levy 9 - Jupiter impact plumes to calculate synthetic plume views, atmospheric infall fluxes, and debris patterns. Our plume is a swarm of ballistic particles with one of several mass-velocity distributions (MVD). The swarm is ejected instantaneously and uniformly into a cone from its apex. Upon falling to the ejection altitude, particles slide with horizontal deceleration following one of several schemes. The model ignores hydrodynamic and Coriolis effects. We adjust plume tilt, opening angle, and minimum velocity, and choose MVD and sliding schemes, to create impact patterns that match observations. Our best match uses the power-law MVD from the numerical impact model of Zahnle and Mac Low, with velocity cutoffs at 4.5 and 11.8 km/sec, cone opening angle of 75 degrees, cone tilt of 30 degrees from vertical, and a sliding constant deceleration of 1.74 m/sec^2. A mathematically-derived feature of Zahnle and Mac Low's published cumulative MVD is a thin shell of mass at the maximum ...

  2. Hybrid carbon-glass fiber/toughened epoxy thick composites subject to drop-weight and ballistic impacts

    Science.gov (United States)

    Sevkat, Ercan

    The goals of this study are to investigate the low velocity and ballistic impact response of thick-section hybrid fiber composites at room temperature. Plain-woven S2-Glass and IM7 Graphite fabrics are chosen as fiber materials reinforcing the SC-79 epoxy. Four different types of composites consisting of alternating layers of glass and graphite woven fabric sheets are considered. Tensile tests are conducted using 98 KN (22 kip) MTS testing machine equipped with environmental chamber. Low-velocity impact tests are conducted using an Instron-Dynatup 8250 impact test machine equipped with an environmental chamber. Ballistic impact tests are performed using helium pressured high-speed gas-gun. Tensile tests results were used to define the material behavior of the hybrid and non-hybrid composites in Finite Element modeling. The low velocity and ballistic impact tests showed that hybrid composites performance was somewhere between non-hybrid woven composites. Using woven glass fabrics as outer skin improved the impact performance of woven graphite composite. However hybrid composites are prone to delamination especially between dissimilar layers. The ballistic limit velocity V50 hybrid composites were higher that of woven graphite composite and lower than that of woven glass composite. Both destructive cross-sectional micrographs and nondestructive ultrasonic techniques are used to evaluate the damage created by impact. The Finite Element code LS-DYNA is chosen to perform numerical simulations of low velocity and ballistic impact on thick-section hybrid composites. The damage progression in these composites shows anisotropic nonlinearity. The material model to describe this behavior is not available in LS-DYNA material library. Initially, linear orthotropic material with damage (Chan-Chan Model) is employed to simulate some of the experimental results. Then, user-defined material subroutine is incorporated into LS-DYNA to simulate the nonlinear behavior. The

  3. Ballistic Impact Response of Kevlar 49 and Zylon under Conditions Representing Jet Engine Fan Containment

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    A ballistic impact test program was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situation. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  4. Simulation of depth of penetration during ballistic impact on thick targets using a one-dimensional discrete element model

    Indian Academy of Sciences (India)

    Rajesh P Nair; C Lakshmana Rao

    2012-04-01

    One-dimensional discrete element model for the ballistic impact is used to determine the depth of penetration of a bullet on a thick target. Discrete Element Method (DEM) is a numerical tool where a continuum is modelled as a network of masses connected by normal springs. A one-dimensional discrete element model is developed to obtain the displacements and forces associated with the ballistic impact on a thick target. The depth of penetration of the penetrator into the target is calculated from these DEM results. The simulated results of depth of penetration are found to be in reasonable agreement with the simulation results of other numerical approaches that are available in the literature.

  5. Effect of oblique impact on impact strength of planetesimals

    Science.gov (United States)

    Yasui, Minami; Yoshida, Yusaku; Matsue, Kazuma; Takano, Shota; Arakawa, Masahiko; Ogawa, Kazunori; Okamoto, Chisato

    2016-10-01

    Collisional processes among planetesimals have played an important role for the formation and the evolution of the bodies in the solar system. Some researchers conducted impact experiments to examine the effects of target material, impact velocity, etc., on the impact strength. Planetesimals could collide with each other at various impact angles. Therefore, the effect of impact angle on the impact strength should be examined, but there are only a few studies about oblique impact experiments. In this study, we conducted oblique impact experiments of porous gypsum and glass spheres simulating planetesimals and examined the effect of the impact angle on the impact strength.We used a porous gypsum sphere and a glass sphere as a target. We carried out impact experiments by using two-stage H2 gas gun at Kobe University. A polycarbonate spherical projectile was accelerated at 2 to 7 km/s. The impact angle, θ, changed from 10° to 90° (90° at a head-on impact). The impact phenomena were observed by a high-speed camera to measure the fragment velocities.The impact strength Q* is defined as an energy density Q, which is the kinetic energy of impactor normalized by the target mass, when the largest fragment mass is half of the original target mass. In both cases of porous gypsum and glass targets, the Q* became larger as the θ decreased. We reanalyzed our results by using the effective energy density, Qc*, defined as Qsin2θ and we found that the results of oblique impacts matched with those of a head-on impact. Furthermore, the relationship between the Qc and the normalized largest fragment mass, ml/Mt, could be fitted by ml/Mt=A×Qc-p and the parameters, A and p, were 82.2 and 0.72 for a porous gypsum target and 1.1×106 and 2.12 for a glass target, respectively. We defined the impact strength Qc* by using the Qc, and the Qc* was about 1000 J/kg for both targets. The power p for a glass target was about 3 times larger than that for a porous gypsum target. This means

  6. Analysis of Energy Dissipation Mechanisms of Woven Fabrics Subjected to Ballistic Impact

    OpenAIRE

    IŞIK, Halil; DEĞİRMENCİ, Ercan; EVCİ, Celal

    2013-01-01

    It is important for combat vehicles and technological defense systems used in the battlefield to be lightweight for maneuverability while they still provide effective protection for survivability. Desired ballistic protection of defense systems may be attained by armor systems developed with different materials. The most important factor in the design of armor is the optimization of ballistic protection/weight ratio. The protection degree needed for sufficient survivability is limited by the ...

  7. Morphoscopic analysis of experimentally produced bony wounds from low-velocity ballistic impact.

    Science.gov (United States)

    Kieser, Jules A; Tahere, Joy; Agnew, Caitlin; Kieser, David C; Duncan, Warwick; Swain, Michael V; Reeves, Matthew T

    2011-12-01

    Understanding how bone behaves when subjected to ballistic impact is of critical importance for forensic questions, such as the reconstruction of shooting events. Yet the literature addressing microscopic anatomical features of gunshot wounds to different types of bone is sparse. Moreover, a biomechanical framework for describing how the complex architecture of bone affects its failure during such impact is lacking. The aim of this study was to examine the morphological features associated with experimental gunshot wounds in slaughtered pig ribs. We shot the 4th rib of 12 adult pigs with .22 mm subsonic bullets at close range (5 cm) and examined resultant wounds under the light microscope, scanning electron microscope SEM and micro tomograph μCT. In all cases there was a narrow shot channel followed by spall region, with evidence of plastic deformation with burnishing of the surface bone in the former, and brittle fracture around and through individual Haversian systems in the latter. In all but one case, the entrance wounds were characterized by superficially fractured cortical bone in the form of a well-defined collar, while the exit wounds showed delamination of the periosteum. Inorganic residue was evident in all cases, with electron energy dispersive spectroscopy EDS confirming the presence of carbon, phosphate, lead and calcium. This material appeared to be especially concentrated within the fractured bony collar at the entrance. We conclude that gunshot wounds in flat bones may be morphologically divided into a thin burnished zone at the entry site, and a fracture zone at the exit.

  8. Terminal ballistics

    CERN Document Server

    Rosenberg, Zvi

    2016-01-01

    This book comprehensively discusses essential aspects of terminal ballistics, combining experimental data, numerical simulations and analytical modeling. Employing a unique approach to numerical simulations as a measure of sensitivity for the major physical parameters, the new edition also includes the following features: new figures to better illustrate the problems discussed; improved explanations for the equation of state of a solid and for the cavity expansion process; new data concerning the Kolsky bar test; and a discussion of analytical modeling for the hole diameter in a thin metallic plate impacted by a shaped charge jet. The section on thick concrete targets penetrated by rigid projectiles has now been expanded to include the latest findings, and two new sections have been added: one on a novel approach to the perforation of thin concrete slabs, and one on testing the failure of thin metallic plates using a hydrodynamic ram.

  9. Ballistic Fracturing of Carbon Nanotubes.

    Science.gov (United States)

    Ozden, Sehmus; Machado, Leonardo D; Tiwary, ChandraSekhar; Autreto, Pedro A S; Vajtai, Robert; Barrera, Enrique V; Galvao, Douglas S; Ajayan, Pulickel M

    2016-09-21

    Advanced materials with multifunctional capabilities and high resistance to hypervelocity impact are of great interest to the designers of aerospace structures. Carbon nanotubes (CNTs) with their lightweight and high strength properties are alternative to metals and/or metallic alloys conventionally used in aerospace applications. Here we report a detailed study on the ballistic fracturing of CNTs for different velocity ranges. Our results show that the highly energetic impacts cause bond breakage and carbon atom rehybridizations, and sometimes extensive structural reconstructions were also observed. Experimental observations show the formation of nanoribbons, nanodiamonds, and covalently interconnected nanostructures, depending on impact conditions. Fully atomistic reactive molecular dynamics simulations were also carried out in order to gain further insights into the mechanism behind the transformation of CNTs. The simulations show that the velocity and relative orientation of the multiple colliding nanotubes are critical to determine the impact outcome.

  10. Effect of Mesoscale and Multiscale Modeling on the Performance of Kevlar Woven Fabric Subjected to Ballistic Impact: A Numerical Study

    Science.gov (United States)

    Jia, Xin; Huang, Zhengxiang; Zu, Xudong; Gu, Xiaohui; Xiao, Qiangqiang

    2013-12-01

    In this study, an optimal finite element model of Kevlar woven fabric that is more computational efficient compared with existing models was developed to simulate ballistic impact onto fabric. Kevlar woven fabric was modeled to yarn level architecture by using the hybrid elements analysis (HEA), which uses solid elements in modeling the yarns at the impact region and uses shell elements in modeling the yarns away from the impact region. Three HEA configurations were constructed, in which the solid element region was set as about one, two, and three times that of the projectile's diameter with impact velocities of 30 m/s (non-perforation case) and 200 m/s (perforation case) to determine the optimal ratio between the solid element region and the shell element region. To further reduce computational time and to maintain the necessary accuracy, three multiscale models were presented also. These multiscale models combine the local region with the yarn level architecture by using the HEA approach and the global region with homogenous level architecture. The effect of the varying ratios of the local and global area on the ballistic performance of fabric was discussed. The deformation and damage mechanisms of fabric were analyzed and compared among numerical models. Simulation results indicate that the multiscale model based on HEA accurately reproduces the baseline results and obviously decreases computational time.

  11. Ballistic Impact Behavior of Nacre-Like Laminated Composites Consisting of B4C Tablets and Polyurea Matrix

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Ramaswami, S.

    2016-03-01

    A nacre-like composite armor consisting of B4C tablets and polyurea matrix is modeled, and its ballistic impact behavior and penetration resistance (under a normal and a 15°-oblique impact by a solid right circular cylindrical projectile) were analyzed using a series of transient, nonlinear dynamic, finite-element analyses. Nacre is a biological material constituting the innermost layer of the shells of gastropods and bivalves. It consists of polygonal tablets of aragonite, tessellated to form individual layers and having the adjacent layers as well as the tablets within a layer bonded by a biopolymer. Due to its highly complex hierarchical microstructure, nacre possesses an outstanding combination of mechanical properties, the properties which are far superior to the ones that are predicted using the homogenization techniques such as the rule of mixtures. The results of the transient nonlinear dynamic analysis pertaining to the ballistic impact response and the penetration resistance of the modeled nacre-like armor are compared with their counterparts for the B4C single-block armor having an identical areal density. Furthermore, the effect of various nacre microstructural features (e.g., surface profiling, micron-scale asperities, mineral bridges between the overlapping tablets lying in adjacent layers) on the ballistic penetration resistance of the nacre-like composite armor is investigated in order to identify an optimal nacre-like composite-armor architecture having the largest penetration resistance. The results obtained clearly show that a nacre-like armor possesses a superior penetration resistance relative to its monolithic counterpart, and that the nacre microstructural features considered play a critical role in the armor penetration resistance.

  12. Ballistic impact damage and penetration mechanics of fiber-reinforced composite laminates

    Science.gov (United States)

    Patts, Henry Michael

    2000-10-01

    Experimental and theoretical studies were performed to characterize and model the processes of damage evolution and resulting penetration failure of graphite fiber-reinforced epoxy resin composite laminates ("structural grade") under ballistic impact. In contrast to the local yielding demonstrated by ductile isotropic materials, the penetration failure of fiber-reinforced composites produced extensive fragmentation of material with multiple modes of damage propagation such as "delamination," "interfiber matrix splitting," "transverse fiber cuts," and "through-the-thickness plugging." Due to the formation of damage zones in three-dimensional scale, the increase in target thickness raised the amount of kinetic energy absorption for full penetration in a "non-linear" fashion in fiber composites unlike the linear correlation for isotropic material such as polycarbonate and aluminum. Interfiber matrix splitting and delamination were found to be the first sign of structural deterioration occurring far below V50 and precede transverse cutting of fibers and plugging. The development of interfiber splitting into delamination of composites is explained by relying on the contact mechanics of a spherical indentor. Matrix splits on adjacent plies formed one pair of geometrical "wedges" at the ply interface, resulting in a delamination zone connected through an "isthmus." Contained in this free ply region, stress concentration readily led to transverse cutting (approximately at 85 percent of the V50) of plies when longitudinal stress of the reinforcing fibers reaches a critical level for fracture. The observed distribution of the damage leading to transverse fiber cuts was modeled by idealizing a circular target panel of staircase laminate into three zones with different values of bending stiffness due to the progression of damage. In "three-zone" model, the energy absorbed by the panel were represented in three forms of potential energy; surface free energy due to delamination

  13. 两种不同强塑性薄钢板抗弹性能的试验和数值模拟%Experiment and Numerical Simulation on Ballistic Performance of Two Thin Steel Plates With Different Strength and Ductility

    Institute of Scientific and Technical Information of China (English)

    肖红亮; 时捷; 曹文全; 雍岐龙; 董瀚

    2012-01-01

    51B-type 7.62mm pistol bullets were fired at thin steel plates with different strength and ductility. And the numerical simulation for the experiments was carried on by ANSYS/LS-DYNA too. The macro-appearance in the process of testing and numerical simulation were compared, such as the impact craters, bulge height and residual projectile size. At last, combined with the energy absorption of the steel plate and the bullet, the influence of the strength and ductility on ballistic performance was analyzed. The results show that: two tested steel plates almost have the same ballistic performance against the 5113 type 7.62 mm pistol bullets, although the very different tensile strength and elongation they have. The numerical simulation result is consistent with the experiment, and it can re- flect the process of the bullets impact target rightly. To the higher strength steel plate, energy absorption by making the projectile deformation is greater than the lower strength one, and to the higher ductility steel plate, energy absorption though its own deformation is larger than the lower ductility one. Thus, the result of two tested steel plates almost have the same ballistic performance is explained.%利用51B式7.62mm手枪弹对不同强度和塑性的薄钢板进行枪击试验,采用ANSYS/LS-DYNA软件对试验过程进行数值模拟,对试验和数值模拟过程的钢板破坏形貌、背凸高度、残余弹丸长度等宏观形貌进行比较。结合抗弹过程中弹丸和钢板消耗的能量,分析了强度和塑性对钢板抗弹性能的影响。结果表明:尽管两种钢板的抗拉强度和断后伸长率差异较大,但其抗51B式7.62mm手枪弹性能相当。试验和数值模拟结果吻合较好,模拟方法能够正确地反映弹丸冲击靶板过程。因较高强度钢板使弹丸变形消耗的能量大于较低强度钢板,塑性较好钢板本身变形消耗的能量大于较低塑性钢板,从而解释了两种钢板抗弹性能相当的试验结果。

  14. Influence of Material Properties on the Ballistic Performance of Ceramics for Personal Body Armour

    Directory of Open Access Journals (Sweden)

    Christian Kaufmann

    2003-01-01

    Full Text Available In support of improved personal armour development, depth of penetration tests have been conducted on four different ceramic materials including alumina, modified alumina, silicon carbide and boron carbide. These experiments consisted of impacting ceramic tiles bonded to aluminum cylinders with 0.50 caliber armour piercing projectiles. The results are presented in terms of ballistic efficiency, and the validity of using ballistic efficiency as a measure of ceramic performance was examined. In addition, the correlation between ballistic performance and ceramic material properties, such as elastic modulus, hardness, spall strength and Hugoniot Elastic Limit, has been considered.

  15. FAA Development of Reliable Modeling Methodologies for Fan Blade Out Containment Analysis. Part 2; Ballistic Impact Testing

    Science.gov (United States)

    Revilock, Duane M.; Pereira, J. Michael

    2008-01-01

    This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situations. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  16. Capabilities of Helmets for Preventing Head Injuries Induced by Ballistic Impacts

    Directory of Open Access Journals (Sweden)

    D.V. Balandin

    2004-01-01

    Full Text Available The limiting performance of ballistically loaded helmets designed to reduce head injuries is studied analytically. The projectile does not penetrate the helmet. This analysis evaluates the absolute minimum of the peak displacement of the helmet shell relative to the head, provided that criteria measuring the severity of head injuries lie within prescribed limits. Rather than optimize a specific design configuration, e.g. a viscoelastic foam liner, characteristics of a time-dependent force representing the helmet liner are calculated. The formulation reduces the limiting performance analysis to an optimal control problem.

  17. Impact of Hydrodynamics on Oral Biofilm Strength

    NARCIS (Netherlands)

    Paramonova, E.; Kalmykowa, O. J.; van der Mei, H. C.; Busscher, H. J.; Sharma, P. K.

    2009-01-01

    Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of S

  18. Investigation on Impact Strength Properties of Kevlar Fabric using Different Shear Thickening Fluid Composition

    Directory of Open Access Journals (Sweden)

    R. Joselin

    2014-05-01

    Full Text Available Great interest has aroused in developing high impact resistant fabrics based on the incorporation of a shear thickening fluid (STF into high performance fabrics (Kevlar. This work developed a shear thickening fluid enhanced fabrics and the influence of the shear thickening fluid types against spike impact and the impact resistance performance were investigated. Silica nano-particle impregnated Kevlar fabrics exhibit significantly enhanced ballistic performance while retaining flexibility. It was found that fabrics impregnated with functionalized nanoparticles offer multiple resistance to the penetration of a sharp impactor. The improvement in protection is traced by the formation of siloxane bonds during functionalization. It exhibits significant improvement in shear stiffness and aslight increase in tensile stiffness. The impact strength properties of all samples were tested using impact testingand quasi-static testing apparatuses. Chemical compositions and microscopic structures were analyzed with Fouriertransform infrared spectroscopy and scanning electron microscopy. The current study clearly displays a significant enhancement in penetration resistance of Kevlar fabric impregnated with different combination of STF’s.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 236-243, DOI:http://dx.doi.org /10.14429/dsj.64.7322

  19. IMPACT STRENGTH AND FAILURE ANALYSIS OF WELDED DAMASCUS STEEL

    Directory of Open Access Journals (Sweden)

    Rastislav Mintách

    2012-01-01

    Full Text Available The aim of this work was the experimental research of damascus steel from point of view of the structural analyze, impact strength and failure analyzes. The damascus steel was produced by method of forged welding from STN 41 4260 spring steel and STN 41 9312 tool steel. The damascus steel consisted of both 84 and 168 layers. The impact strength was experimentally determined for original steels and damascus steels after heat treatment in dependence on temperature in the range from -60 to 160 °C. It has been found that the impact strength of experimental steels decreased with decreasing temperature behind with correlated change of damage mode. In the case of experimental tests performed at high temperature ductile fracture was revealed and with decreasing temperature proportion of cleavage facets increased. Only the STN 41 9312 steel did not show considerable difference in values of the impact strength with changing temperature.

  20. Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems

    Science.gov (United States)

    Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

    1997-01-01

    Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

  1. FEM SIMULATION OF THE EFFECTS OF STRENGTH MISMATCH ON THE BALLISTIC PERFORMANCE OF ALUMINUM WELD JOINT%强度失配对铝合金板焊接接头抗弹性能影响的有限元分析

    Institute of Scientific and Technical Information of China (English)

    刘文辉; 黄浩

    2012-01-01

    通过建立7.62mm穿甲弹侵彻铝合金板的模型,采用Johnson.Cook材料模型模拟研究了焊接接头的强度失配对铝合金板抗弹性能的影响。研究结果表明:当子弹侵彻铝合金焊接接头附近时,由于材料的不均匀变形,子弹会改变侵彻方向,其方向角的改变大小与子弹速度、侵入位置、弹头形状、强度失配比、靶板厚度有关;当子弹以低速侵彻铝合金板中间的软焊缝材料时,由于变形局部化,出现材料的抗弹性能低于纯焊缝材料的情况;由于子弹侵彻方向的改变,出现部分区域的抗弹性能高于铝合金基体材料的情况。研究结果为不均匀材料的抗弹性能研究提供参考。%To analyze the effect of strength mismatch on the ballistic performance of aluminum welded joint, a model of aluminum alloy plate penetrated by 7.62mm bullet was created, and the Johnson-Cook constitutive equation was adopted. Results show that the penetration direction will change due to the heterogeneous deformation as the projectile penetrates the aluminum weld joint, and the magnitude of angle change of penetration direction relates to the penetration position, impact velocity, projectile geometry, the rate of strength mismatch and target thickness. When the projectile only penetrates the region of weld seam at a small impact velocity, material's ballistic performance may be worse than that of pure weld seam material due to material deformation localization. There are some regions whose ballistic performances are better than that of aluminum base due to the change of penetration direction. It is useful for the ballistic performance analysis of heterogeneous materials.

  2. BALLISTIC RESISTANT ARTICLES COMPRISING TAPES

    NARCIS (Netherlands)

    VAN DER EEM, JORIS; HARINGS, JULES; JANSE, GERARDUS; TJADEN, HENDRIK

    2015-01-01

    The invention pertains to a ballistic-resistant moulded article comprising a compressed stack of sheets comprising reinforcing tapes having a tensile strength of at least 1.0 GPa, a tensile modulus of at least 40 GPa, and a tensile energy-to-break of at least 15 J/g, the direction of the tapes withi

  3. Effect of microstructure on adiabatic shear band bifurcation in Ti–6Al–4V alloys under ballistic impact

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials under Shock and Impact, Beijing Institute of Technology, Beijing 100081 (China); Yu, Xiaodong [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials under Shock and Impact, Beijing Institute of Technology, Beijing 100081 (China); Laboratory of Advanced Materials Behavior Characteristics, Beijing Institute of Technology and Institute of Space Medico-Engineering, Beijing 100081 (China); Tan, Chengwen, E-mail: tanchengwen@126.com [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials under Shock and Impact, Beijing Institute of Technology, Beijing 100081 (China); Laboratory of Advanced Materials Behavior Characteristics, Beijing Institute of Technology and Institute of Space Medico-Engineering, Beijing 100081 (China); Ma, Honglei [Laboratory of Advanced Materials Behavior Characteristics, Beijing Institute of Technology and Institute of Space Medico-Engineering, Beijing 100081 (China); Wang, Fuchi; Cai, Hongnian [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials under Shock and Impact, Beijing Institute of Technology, Beijing 100081 (China)

    2014-02-10

    Adiabatic shear band (ASB) bifurcations in Ti–6Al–4V alloys with equiaxed, bimodal, and lamellar microstructures under ballistic impact were studied using transmission electron microscopy (TEM). Focused ion beam (FIB) technology was used to accurately prepare TEM samples in the ASB regions, which contained the regions in front of the ASB bifurcation, behind the ASB bifurcation, and the bifurcation regions. ASB consisted of dynamically recrystallized equiaxed grains and incompletely and dynamically recrystallized striped subgrains. ASB bifurcation occurred when the deformation incongruity between striped subgrains and surrounding equiaxed grains intensified sufficiently. Microstructure has an important effect on the number and morphology of ASB bifurcations. More ASB bifurcations formed in Ti–6Al–4V alloys with bimodal and lamellar microstructures than in the alloy with equiaxed microstructure because of the different amounts and distributions of striped subgrains. In the equiaxed microstructure, fewer subgrains were preserved in ASBs. Thus, forming deformation incongruities sufficiently intense to induce ASB bifurcation was difficult. In the bimodal microstructure, numerous striped subgrains and deformation incongruity locations were observed. More randomly distributed deformation incongruity locations would ultimately lead to more random ASB bifurcations. In the lamellar microstructure, the striped subgrains arranged along different directions in different colonies caused more intense deformation incongruity than when the subgrains were in the same colony. ASB bifurcation more commonly occurred at colony boundaries.

  4. INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Saman GHAHRI

    2014-03-01

    Full Text Available In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP composites was investigated. The PP (virgin and recycled polypropylene and wood flour (WF were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA and ethylene/propylene/diene terpolymer (EPDM, to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier. The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites

  5. Psychological impact of identifying character strengths in people with psychosis.

    Science.gov (United States)

    Sims, Anna; Barker, Chris; Price, Claire; Fornells-Ambrojo, Miriam

    2015-04-03

    A one group pre-post test design investigated the impact of identifying character strengths using the Values In Action Inventory of Strengths (VIA-IS) with individuals with early psychosis (N = 29). Post-test improvements in positive affect and cognitive performance were observed. Neither self-esteem nor self-efficacy improved. The technique appears feasible for use within early intervention services. Adverse consequences should be monitored and additional components considered to enhance benefits.

  6. Modeling the Ballistic Behavior of Solid Ejecta from the Deep Impact Cratering Event

    Science.gov (United States)

    Richardson, J. E.; Melosh, H. J.

    2006-03-01

    We describe results from a forward model of the first-order, solid ejecta particle behavior from the impact produced by the Deep Impact mission. The expansion rate of the plume places constraints on the gravity field, mass, and density of Tempel 1.

  7. Prediction of Behavior of Ceramic/Metal Composite Panels Under Two Consecutive Ballistic Impacts

    Science.gov (United States)

    Prakash, A.; Rajasankar, J.; Iyer, N. R.; Anandavalli, N.; Biswas, S. K.; Mukhopadhyay, A. K.

    2014-05-01

    This article presents a numerical investigation to predict the behavior of ceramic (Al2O3 99.5)/metal (Al5083 H116) composite panels under two consecutive high-velocity impacts of 7.62 mm sharp-nosed small projectiles. A numerical model is developed using the advanced nonlinear software AUTODYN. The aim of the study is to predict the impact behavior of ceramic/metal composite panels. The study mainly focuses on the effect of arrangement of front ceramic tiles having collinear and non-collinear joints on the impact damage pattern. The novelty of the study presented in this article is the prediction of high-velocity-impact response under two consecutive and closely spaced hits on composite panels carried out in a more realistic manner. Numerical responses, such as depth of penetration, and deformation in back plate and crack patterns, are found to match well with the experimental results. It is believed that the outcome of this study is helpful in the design of a ceramic tile joint arrangement to minimize damage in the target panel.

  8. Penetration resistance and ballistic-impact behavior of Ti/TiAl3 metal/intermetallic laminated composites (MILCs: A computational investigation

    Directory of Open Access Journals (Sweden)

    Jennifer S. Snipes

    2016-06-01

    Full Text Available A comprehensive computational engineering analysis is carried out in order to assess suitability of the Ti/TiAl3 metal/intermetallic laminated composites (MILCs for use in both structural and add-on armor applications. This class of composite materials consists of alternating sub-millimeter thick layers of Ti (the ductile and tough constituent and TiAl3 (the stiff and hard constituent. In recent years, this class of materials has been investigated for potential use in light-armor applications as a replacement for the traditional metallic or polymer-matrix composite materials. Within the computational analysis, an account is given to differing functional requirements for candidate materials when used in structural and add-on ballistic armor. The analysis employed is of a transient, nonlinear-dynamics, finite-element character, and the problem investigated involves normal impact (i.e. under zero obliquity angle of a Ti/TiAl3 MILC target plate, over a range of incident velocities, by a fragment simulating projectile (FSP. This type of analysis can provide more direct information regarding the ballistic limit of the subject armor material, as well as help with the identification of the nature and the efficacy of various FSP material-deformation/erosion and kinetic-energy absorption/dissipation phenomena and processes. The results obtained clearly revealed that Ti/TiAl3 MILCs are more suitable for use in add-on ballistic, than in structural armor applications.

  9. Predicting The Compression Strength Of Impact-Damaged Sandwich Panels

    Science.gov (United States)

    Ratcliffe, James; Jackson, Wade; Schaff, Jeffery

    1990-01-01

    The objective of this work was to develop a technique for predicting the residual compression strength of sandwich panels containing impact damage in one facesheet. The technique was tailored to predict the strength of specimens that exhibit a failure mode involving the formation of kink bands at locations of peak strain in the region of impact damage. Under continued compression loading, the kink bands propagate in a stable manner perpendicular to the applied load. When a critical kink-band length is reached, growth becomes unstable corresponding to panel failure. The analysis follows in two sections. The first section calculates the far-field stress required for stable kink-band growth and the second calculates that required for unstable growth. The residual strength prediction is made when the stress for stable growth becomes equal to that for unstable kink-band growth. Initial comparisons between analysis and experiment show good agreement.

  10. Concrete under Impact Loading, Tensile Strength and Bond

    NARCIS (Netherlands)

    Reinhardt, H.W.

    1982-01-01

    Uniaxial impact tensile tests on plain concrete were carried out with the aid of Split Hopkinson Bar equipment with stress rates of up to 60000 N/mm2. s. Various concrete mixes were investigated under. dry and wet conditions. All the concretes showed an increase in strength with increasing stress ra

  11. Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

    Science.gov (United States)

    2013-01-01

    Sheet) Continuation for Block 13 ARO Report Number Friction Stir Weld Failure Mechanisms in Alumin Block 13: Supplementary Note © 2013 . Published in...nose, steel jacketed, hard tungsten core (1400 Hv), armor piercing (AP) projectile (Ref 1). As mentioned above, this failure mechanism is often...zones being impacted with blunt, lower hardness projectiles [e.g., 20-mm caliber, 53 g, blunt, chamfered right circular cylindrical steel fragment

  12. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    Science.gov (United States)

    2007-12-01

    Composite Materials 1988; 22: 518-532. 111. Liaw BM, Pierides AM and Liu YX. Ultrasonic assessment of impact damage in aluminum /acrylic sandwich plates...Ninth International Conference on Composite Materials , ICCM/9, Vol. V: Composites Behaviour , Miravete A (Ed), Madrid, Spain, July 12-16, 1993: 311-320...line loading. J. of Composite Materials 1993; 27: 1443-64. 148. Mouritz AP, Gallagher J and Goodwin AA. Flexural strength and interlaminar shear

  13. Low velocity impact behaviour of ultra high strength concrete panels

    Indian Academy of Sciences (India)

    Smitha Gopinath; R Ayashwarya; V Ramesh Kumar; Prabhat Ranjan Prem; A Rama Chandra Murthy; C K Madheswaran; R Nagesh Iyer

    2014-12-01

    This paper presents the results of an investigation carried out on Ultra High Strength Concrete (UHSC) panels subjected to low velocity projectile impact to assess impact resistance. UHSC panel of size 350 × 350 mm and thickness 15 mm is studied under drop weight impact loading for three different pre-determined drop heights ranging from 100 mm to 300 mm. The response of UHSC panel in terms of acceleration vs time is obtained experimentally. Numerical model has been developed to simulate the impact behaviour of UHSC panel. The Brittle cracking model is used to simulate the behaviour of UHSC panel under impact loading and to perform parametric studies by varying the volume fraction of steel fibres.

  14. Coupling strength versus coupling impact in nonidentical bidirectionally coupled dynamics

    Science.gov (United States)

    Laiou, Petroula; Andrzejak, Ralph G.

    2017-01-01

    The understanding of interacting dynamics is important for the characterization of real-world networks. In general, real-world networks are heterogeneous in the sense that each node of the network is a dynamics with different properties. For coupled nonidentical dynamics symmetric interactions are not straightforwardly defined from the coupling strength values. Thus, a challenging issue is whether we can define a symmetric interaction in this asymmetric setting. To address this problem we introduce the notion of the coupling impact. The coupling impact considers not only the coupling strength but also the energy of the individual dynamics, which is conveyed via the coupling. To illustrate this concept, we follow a data-driven approach by analyzing signals from pairs of coupled model dynamics using two different connectivity measures. We find that the coupling impact, but not the coupling strength, correctly detects a symmetric interaction between pairs of coupled dynamics regardless of their degree of asymmetry. Therefore, this approach allows us to reveal the real impact that one dynamics has on the other and hence to define symmetric interactions in pairs of nonidentical dynamics.

  15. IMPACT OF COOKING HOMOGENEITY ON PULP STRENGTH PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Bofeng Mao

    2004-01-01

    Cooking homogeneity of kraft pulping can have significant impact on pulp strength properties. We have studied cooking homogeneity of two kraft digesters within Stora Enso. One of the digesters is a one-vessel hydraulic continuous digester (digester A)and the other one is a two-vessel vapor/liquor phase continuous digester (digester B). They are located in the same mill and use the same softwood chip quality. Due to the differences in chip pre-steaming and cooking facilities and conditions, significant differences in pulp strength properties, reject contents and kappa variations have been found between the pulps produced in the two digesters. Digester A has a modem chip bin with efficient pre-heating and air removal, whereas digester B has poor chip pre-steaming conditions. Our strength delivery studies show that although the two digesters produce pulps with the same kappa number and viscosity, the pulp produced in digester A has about 20% higher strength delivery, l%-unit (based on wood) lower reject content and lower kappa variations based on FTIR spectra analysis on pulp sheet than the pulp produced in digester B.Results of the studies indicate that more homogeneous cooking, i.e., lower lignin/kappa variation in the fibers, leads to improved pulp strength properties. Efficient chip pre-steaming is important/essential for achieving homogeneous cooking. Rebuilding the equipment for improving chip pre-steaming conditions of digester B is to be carried out.

  16. Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems, Phase II. Part 2; Ballistic Impact Testing

    Science.gov (United States)

    Revilock, D. M.; Pereira, J. M.

    2009-01-01

    This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade-out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar(TradeName) 49 and Zylon(TradeName) AS (as spun) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation, and velocity of the projectile were varied and recorded. In most cases, the tests were designed so the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models to predict the response of fabrics under conditions that simulate those of a jet engine blade-release situation. In addition, some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different fabric materials.

  17. Ballistic Applications of Glass and Kevlar Fibre Vinylester Composites

    Directory of Open Access Journals (Sweden)

    S. P. Panda

    1994-10-01

    Full Text Available Void-free E-glass and Kevlar-49 fibre reinforced vinylester laminates prepared under compression moulding were found to have Charpy impact strength of 576 KJlm2 and 304 KJlm2, respectively. Ballistic immunisation tests carried out on the glass reinforced vinylester laminates with thickness ranging from 12 mm to 54 mm against 7.62 mm rifle bullets produced an exponential relationship between the per cent attenuation in bullet velocity and the areal density of the laminates; whereas the relationship was linear for 9 mm carbine fire with laminate thicknessvarying from 5.5 mm to 12 mm .

  18. Assessment of Ballistic Performance for Transparent Material

    Directory of Open Access Journals (Sweden)

    Basim M. Fadhil

    2014-05-01

    Full Text Available A finite element method was used to investigate the ballistic behavior of Polymethylmethacrylate (PMMA under impact loading by spherical steel projectile with different ranges of velocities. Three different target thicknesses were used in the experimental and the numerical works. A mathematical model has been used for the ballistic limit based on the experimental results. It has been found that projectile velocity and target thickness play an important role in the ballistic behavior of PMMA. A good agreement was found between the numerical, experimental, and the analytical result.

  19. Feasibility of ballistic strengthening exercises in neurologic rehabilitation.

    Science.gov (United States)

    Williams, Gavin; Clark, Ross A; Hansson, Jessica; Paterson, Kade

    2014-09-01

    Conventional methods for strength training in neurologic rehabilitation are not task specific for walking. Ballistic strength training was developed to improve the functional transfer of strength training; however, no research has investigated this in neurologic populations. The aim of this pilot study was to evaluate the feasibility of applying ballistic principles to conventional leg strengthening exercises in individuals with mobility limitations as a result of neurologic injuries. Eleven individuals with neurologic injuries completed seated and reclined leg press using conventional and ballistic techniques. A 2 × 2 repeated-measures analysis of variance was used to compare power measures (peak movement height and peak velocity) between exercises and conditions. Peak jump velocity and peak jump height were greater when using the ballistic jump technique rather than the conventional concentric technique (P exercises, the incorporation of ballistic principles was associated with increased peak height and peak velocities.

  20. IMPACT OF COOKING HOMOGENEITY ON PULP STRENGTH PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    BofengMao

    2004-01-01

    Cooking homogeneity of kraft pulping can havesignificant impact on pulp strength properties. Wehave studied cooking homogeneity of two kraftdigesters within Stora Enso. One of the digesters is aone-vessel hydraulic continuous digester (digester A)and the other one is a two-vessel vapor/liquor phasecontinuous digester (digester B). They are located inthe same mill and use the same softwood chipquality. Due to the differences in chip pre-steamingand cooking facilities and conditions, significantdifferences in pulp strength properties, reject contentsand kappa variations have been found between thepulps produced in the two digesters. Digester A has amodem chip bin with efficient pre-heating and airremoval, whereas digester B has poor chippre-steaming conditions. Our strength deliverystudies show that although the two digesters producepulps with the same kappa number and viscosity, thepulp produced in digester A has about 20% higherstrength delivery, l%-unit (based on wood) lowerreject content and lower kappa variations based onFTIR spectra analysis on pulp sheet than the pulpproduced in digester B.Results of the studies indicate that morehomogeneous cooking,variation in the fibers,i.e., lower lignin/kappa leads to improved pulpstrength properties. Efficient chip pre-steaming isimportant/essential for achieving homogeneouscooking. Rebuilding the equipment for improvingchip pre-steaming conditions of digester B is to becarded out.

  1. Relationship between Ballistic Coefficient and Static Mechanical Properties for Armor Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The relationship between the ballistic coefficient and the static mechanical properties of armor materials was studied. The results show that the ballistic coefficient is determined by the strength, hardness and the toughness of materials. According to the Martel rule, the equation of the relationship between ballistic coefficient and static mechanical properties satisfies the following formula: . From the mixture law of composite, the prerequisite, for which ballistic coefficient has maximum to reinforcement volume fraction, is obtained by the following equation: .

  2. Behavior of steel fiber high strength concrete under impact of projectiles

    Directory of Open Access Journals (Sweden)

    Cánovas, M. F.

    2012-09-01

    Full Text Available This paper presents the results of the investigation carried out by the authors about the behavior of 80 MPa characteristic compression strength concrete reinforced with different amount of high carbon content steel fiber, submit to impact of different caliber projectiles, determining the thickness of this type of concrete walls needs to prevent no perforation, as well as the maximum penetration to reach into them, so that in the event of no perforation and only penetration, "scabbing" phenomena does not take place on the rear surface of the wall. Prior to ballistic testing was necessary to design the high-strength concrete with specific mechanical properties, especially those related to ductility, since these special concrete must absorb the high energy of projectiles and also the shock waves that accompany them.Este trabajo presenta los resultados de la investigación llevada a cabo por los autores sobre el comportamiento de hormigón de 80 MPa de resistencia característica a compresión reforzado con diferentes cuantías de fibras de acero de alto contenido en carbono sometido al impacto de proyectiles de distintos calibres, determinando el espesor de muros de este tipo de hormigón que sería preciso disponer para impedir su perforación por dichos proyectiles, así como los valores máximos de penetración, para que en el caso de no producirse perforación y sólo penetración, no se genera cráter, “scabbing”, en el trasdós de los mismos. Previamente a los ensayos balísticos fue preciso diseñar los hormigones para que, presentaran determinadas características mecánicas, especialmente las relacionadas con la ductilidad, dado que estos hormigones especiales deben absorber la elevada energía que le transmiten los proyectiles y las ondas de choque que los acompañan.

  3. INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

    OpenAIRE

    Saman GHAHRI; Saeed KAZEMI NAJAFI; Mohebby, Behbood

    2014-01-01

    In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP) composites was investigated. The PP (virgin and recycled polypropylene) and wood flour (WF) were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA) and ethylene/propylene/diene terpolymer (EPDM)), to produce wood flour-PP composites specimen. The results showed t...

  4. The impact of water content and ionic diffusion on the uniaxial compressive strength of shale

    OpenAIRE

    Talal AL-Bazali

    2013-01-01

    Experimental data showed that water content has a profound influence on the uniaxial compressive strength of shale. Testing has shown a great decrease in the uniaxial compressive strength as the water content increases. Regression analysis was used in this work to develop a general equation for predicting uniaxial compressive strength of shale from the available information on its water content and dry uniaxial compressive strength. The impact of ionic diffusion on the compressive strength...

  5. Influence of Impact Modifier and Coupling Agent on Impact Strength of Wood Flour/Recycled Plastic Composites

    Directory of Open Access Journals (Sweden)

    Saman GHAHRI

    2014-03-01

    Full Text Available In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP composites was investigated. The PP (virgin and recycled polypropylene and wood flour (WF were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA and ethylene/propylene/diene terpolymer (EPDM, to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier. The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites.

  6. The Truth About Ballistic Coefficients

    CERN Document Server

    Courtney, Michael

    2007-01-01

    The ballistic coefficient of a bullet describes how it slows in flight due to air resistance. This article presents experimental determinations of ballistic coefficients showing that the majority of bullets tested have their previously published ballistic coefficients exaggerated from 5-25% by the bullet manufacturers. These exaggerated ballistic coefficients lead to inaccurate predictions of long range bullet drop, retained energy and wind drift.

  7. The impact of water content and ionic diffusion on the uniaxial compressive strength of shale

    Directory of Open Access Journals (Sweden)

    Talal AL-Bazali

    2013-12-01

    Finally, the impact of ionic diffusion on the compressive strength of shale was carried out in the absence of both chemical osmosis and capillary forces. Results show that the invasion of sodium and calcium ions into shale reduced its compressive strength considerably while the invasion of potassium ions enhanced its compressive strength.

  8. Ballistic Response of Fabrics: Model and Experiments

    Science.gov (United States)

    Orphal, Dennis L.; Walker Anderson, James D., Jr.

    2001-06-01

    Walker (1999)developed an analytical model for the dynamic response of fabrics to ballistic impact. From this model the force, F, applied to the projectile by the fabric is derived to be F = 8/9 (ET*)h^3/R^2, where E is the Young's modulus of the fabric, T* is the "effective thickness" of the fabric and equal to the ratio of the areal density of the fabric to the fiber density, h is the displacement of the fabric on the axis of impact and R is the radius of the fabric deformation or "bulge". Ballistic tests against Zylon^TM fabric have been performed to measure h and R as a function of time. The results of these experiments are presented and analyzed in the context of the Walker model. Walker (1999), Proceedings of the 18th International Symposium on Ballistics, pp. 1231.

  9. Metamaterials for Ballistic Electrons

    CERN Document Server

    Dragoman, D; Dragoman, Daniela; Dragoman, Mircea

    2007-01-01

    The paper presents a metamaterial for ballistic electrons, which consists of a quantum barrier formed in a semiconductor with negative effective electron mass. This barrier is the analogue of a metamaterial for electromagnetic waves in media with negative electrical permittivity and magnetic permeability. Besides applications similar to those of optical metamaterials, a nanosized slab of a metamaterial for ballistic electrons, sandwiched between quantum wells of positive effective mass materials, reveals unexpected conduction properties, e.g. single or multiple room temperature negative differential conductance regions at very low voltages and with considerable peak-to-valley ratios, while the traversal time of ballistic electrons can be tuned to larger or smaller values than in the absence of the metamaterial slab. Thus, slow and fast electrons, analogous to slow and fast light, occur in metamaterials for ballistic electrons.

  10. Ballistic Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Ballistic Test Facility is comprised of two outdoor and one indoor test ranges, which are all instrumented for data acquisition and analysis. Full-size aircraft...

  11. Analysis of Multiple-Impact Ballistic Performance of a Tempered Glass Laminate with a Strike Face Film

    Science.gov (United States)

    2014-02-01

    strengthened glass as exterior or strike faces. Initial impact by a single projectile typically produces a quasi-symmetrical crater exhibiting the typical...during subsequent impacts. Should an impact from a second projectile occur on the damaged glass , loosely constrained fragments would be forced in a...Should an impact from a second projectile occur on the damaged glass , loosely constrained fragments would be forced in a direction away from the strike

  12. Factors affecting miniature Izod impact strength of tungsten-fiber-metal-matrix

    Science.gov (United States)

    Winsa, E. A.; Petrasek, D. W.

    1973-01-01

    The miniature Izod and Charpy impact strengths of copper, copper-nickel, and nickel-base superalloy uniaxially reinforced with continuous tungsten fibers were studied. In most cases, impact strength was increased by increasing fiber or matrix toughness, decreasing fibermatrix reaction, increasing test temperature, hot working, or heat treating. Notch sensitivity was reduced by increasing fiber content or matrix toughness. An equation relating impact strength to fiber and matrix properties and fiber content was developed. Program results imply that tungsten alloy-fiber/superalloy matrix composites can be made with adequate impact resistance for turbine blade or vane applications.

  13. Tests for determining impact resistance and strength of glass used for nuclear waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Bunnell, L.R.

    1979-05-01

    Tests are described for determining the impact resistance (Section A) and static tensile strength (Section B) of glasses containing simulated or actual nuclear wastes. This report describes the development and use of these tests to rank different glasses, to assess effects of devitrification, and to examine the effect of impact energy on resulting surface area. For clarity this report is divided into two sections, Impact Resistance and Tensile Strength.

  14. Effect of Clamping Rigidity of the Armour on Ballistic Performance

    Directory of Open Access Journals (Sweden)

    S. N. Dikshit

    1992-04-01

    Full Text Available Influence of the manner in which the armour plates are held during their ballistic testing on the armour performance, has been evaluated. One armour plate was clamped rigidly to the test stand while a second plate of identical composition, hardness, and dimensions was hung loosely from the target holder. Both these plates were impacted with the same type of projectiles and over the same impact velocity range. The nature of ballistic damage evaluated indicates that the manner in which the armour is held during ballistic testing has a negligible influence on its performance at least when the mass of the plate is substantially higher than that of the projectile.

  15. Areca Fiber Reinforced Epoxy Composites: Effect of Chemical Treatments on Impact Strength

    Directory of Open Access Journals (Sweden)

    S. Dhanalakshmi

    2015-06-01

    Full Text Available In this research work, impact strength of untreated, alkali treated, potassium permanganate treated, benzoyl chloride treated and acrylic acid treated areca fiber reinforced epoxy composites were studied under 40%, 50%, 60% and 70% fiber loadings. Impact strength increased with increase in fiber loading up to 60% and then showed a decline for all untreated and chemically treated areca fiber reinforced epoxy composites. The acrylic acid treated areca fiber reinforced epoxy composites with 60% fiber loading showed highest impact strength of 28.28 J/mm2 amongst all untreated and chemically treated areca/epoxy composites with same 60% fiber loading.

  16. Assessment of the impact strength of the denture base resin polymerized by various processing techniques

    Directory of Open Access Journals (Sweden)

    Rajashree Jadhav

    2013-01-01

    Full Text Available Aim : To measure the impact strength of denture base resins polymerized using short and long curing cycles by water bath, pressure cooker and microwave techniques. Materials and Methods: For impact strength testing, 60 samples were made. The sample dimensions were 60 mm × 12 mm × 3 mm, as standardized by the American Standards for Testing and Materials (ASTM. A digital caliper was used to locate the midpoint of sample. The impact strength was measured in IZOD type of impact tester using CEAST Impact tester. The pendulum struck the sample and it broke. The energy required to break the sample was measured in Joules. Data were analyzed using Student′s " t" test. Results: There was statistically significant difference in the impact strength of denture base resins polymerized by long curing cycle and short curing cycle in each technique, with the long curing processing being the best. Conclusion: The polymerization technique plays an important role in the influence of impact strength in the denture base resin. This research demonstrates that the denture base resin polymerized by microwave processing technique possessed the highest impact strength.

  17. Damage Characteristics and Residual Strength of Composite Sandwich Panels Impacted with and Without Compression Loading

    Science.gov (United States)

    McGowan, David M.; Ambur, Damodar R.

    1998-01-01

    The results of an experimental study of the impact damage characteristics and residual strength of composite sandwich panels impacted with and without a compression loading are presented. Results of impact damage screening tests conducted to identify the impact-energy levels at which damage initiates and at which barely visible impact damage occurs in the impacted facesheet are discussed. Parametric effects studied in these tests include the impactor diameter, dropped-weight versus airgun-launched impactors, and the effect of the location of the impact site with respect to the panel boundaries. Residual strength results of panels tested in compression after impact are presented and compared with results of panels that are subjected to a compressive preload prior to being impacted.

  18. Design aspects of high strength steel welded structures improved by high frequency mechanical impact (HFMI) treatment

    OpenAIRE

    Yildirim, Halid Can

    2013-01-01

    This doctoral study is concerned with the fatigue strength of welded steel structures which are improved by high frequency mechanical impact (HFMI) treatment. A comprehensive evaluation of 417 HFMI test data obtained from the literature and 24 HFMI fatigue data tested as a part of this work are studied. According to the statistical analyses an S-N slope of five (5) is proposed. A yield strength correction procedure which relates the material yield strength (fy) to fatigue is presented and ver...

  19. Impact strength of denture polymethyl methacrylate reinforced with continuous glass fibers or metal wire.

    Science.gov (United States)

    Vallittu, P K; Vojtkova, H; Lassila, V P

    1995-12-01

    The impact strength of heat-cured acrylic resin test specimens that had been reinforced in various ways was compared in this study. Ten rectangular test specimens were fabricated for each test group. The strengtheners included 1.0-mm-diameter steel wire and continuous E-glass fibers. Both notched and unnotched test specimens were tested in a Charpy-type impact test. In a further analysis the concentration of glass fibers in the test specimens was determined and plotted against the impact strength of the test specimens. The results showed that, compared with the unreinforced specimens, both types of reinforcement increased the impact strength of the test specimens considerably (p < 0.001). There was no clear difference between the mean impact strength value of the test specimens reinforced with metal wire and that of the specimens reinforced with glass fiber. The correlation coefficient between the fiber concentration of the test specimens and their impact strength was 0.818 (p < 0.005). Specimens with fiber concentrations greater than 25 wt% yielded to the higher impact strength more readily than those with metal wire reinforcement did.

  20. Missile Defense Agency Ballistic Missile Defense System (BMDS): Programmatic Environmental Impact Statement. Volume 1 Final BMDS PEIS

    Science.gov (United States)

    2007-01-01

    dwarfed shrubs and miniature wildflowers adapted to a short growing season. Species resident in arctic tundra have evolved adaptations peculiar to high...strong northeast winds, the likelihood of pollutants remaining in the ambient air is low. Heavy industrial activities, high automobile traffic, and...bodies. Some perennial surface waters could be impacted following a flight termination. However, the probability of any individual water body, spring

  1. Prediction of the ballistic limit of an aluminium sandwich panel

    Science.gov (United States)

    Campbell, J.; De Vuyst, T.; Vignjevic, R.; Hughes, K.

    2016-08-01

    This paper presents research on modelling the impact of a 150g projectile on a 35mm thick aluminium sandwich panel. The objective of the work is a predictive modelling capability for the ballistic limit of the panel. A predictive modelling capability supports the design of capture and deorbit missions for large items of space debris such as satellites and rocket upper stages. A detailed explicit finite element model was built using the LSDYNA software and results were compared with experimental data for the projectile exit velocity to establish key parameters. The primary parameters influencing the model behaviour were the strength and failure of the aluminium face sheets and the friction between projectile and panel. The model results showed good agreement with experimental results for ogive nose projectiles, but overestimated the exit velocity for flat nose projectiles.

  2. Impact Craters on Asteroids: Does Gravity or Strength Control Their Size?

    Science.gov (United States)

    Nolan, Michael C.; Asphaug, Erik; Melosh, H. Jay; Greenberg, Richard

    1996-12-01

    The formation of kilometer-size craters on asteroids is qualitatively different from the formation of meter-size (laboratory- and weapons-scale) craters on Earth. A numerical hydrocode model is used to examine the outcomes of various-size cratering impacts into spheres and half-spaces. A shock wave fractures the target in advance of the crater excavation flow; thus, for impactors larger than 100 m, impacting at typical asteroid impact velocities, target tensile strength is irrelevant to the impact outcome. This result holds whether the target is initially intact or a “rubble pile,” even ignoring the effects of gravity. Because of the shock-induced fracture, crater excavation is controlled by gravity at smaller sizes than would otherwise be predicted. Determining the strength-gravity transition by comparing the physical strength of the material to the force of gravity will not work, because strength is eliminated by the shock wave.

  3. Impact strength and abrasion resistance of high strength concrete with rice husk ash and rubber tires

    Directory of Open Access Journals (Sweden)

    M. B. Barbosa

    Full Text Available The paper discusses the application of High Strength Concrete (HSC technology for concrete production with the incorporation of Rice Husk Ash (RHA residues by replacing a bulk of the material caking and rubber tires with partial aggregate volume, assessing their influence on the mechanical properties and durability. For concrete with RHA and rubber, it was possible to reduce the brittleness by increasing the energy absorbing capacity. With respect to abrasion, the RHA and rubber concretes showed lower mass loss than the concrete without residues, indicating that this material is attractive to be used in paving. It is thus hoped that these residues may represent a technological and ecological alternative for the production of concrete in construction works.

  4. Impact cratering: The effect of crustal strength and planetary gravity

    OpenAIRE

    O'Keefe, John D.; Ahrens, Thomas J.

    1981-01-01

    Upon impact of a meteorite with a planetary surface the resulting shock wave both ‘processes’ the material in the vicinity of the impact and sets a larger volume of material than was subjected to high pressure into motion. Most of the volume which is excavated by the impact leaves the crater after the shock wave has decayed. The kinetic energy which has been deposited in the planetary surface is converted into reversible and irreversible work, carried out against the planetary gravity field a...

  5. Simulation of ultra thin film SOI transistors using a non-local ballistic model for impact ionisation

    Science.gov (United States)

    Armstrong, G. A.; French, W. D.

    1992-12-01

    To model bipolar snapback in thin film SOI transistors accurately, it is necessary to employ a non-local model of impact ionisation. Such a model, based on the "Lucky electron" theory, has been incorporated in a two-dimensional device simulator. Accurate prediction of bipolar holding voltage has been obtained for SOI transistors with sub-micron gate lengths. The model has been applied to analyse separately the effects of both lightly doped source and lightly doped drain in maximising the holding voltage. The advantage of using ultra thin highly doped SOI films in conjunction with a lightly doped drain is discussed.

  6. Ballistic hole magnetic microscopy

    NARCIS (Netherlands)

    Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

    2005-01-01

    A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs. Spin-dependen

  7. The stress and ballistic properties of granular materials

    Science.gov (United States)

    Proud, William G.; Chapman, David J.; Eakins, Daniel E.

    2017-01-01

    Granular materials are widespread in nature and in manufacturing. Their particulate nature gives a compressive strength of a similar order of magnitude as many continuous solids, a vanishingly small tensile strength and variable shear strength, highly dependent on the loading conditions. Previous studies have shown the effect of composition, morphology and particle size, however, compared to metals and polymers, granular materials are not so well understood. This paper will present some recent results for granular materials, placing these within the wider context. Two areas will be dealt with (i) the effect of the skeletal strength of the material and (ii) the displacements associated with ballistic impact. One clear observation is the similarity of behavior of quartz-sands in compression across a range of particle size. However, the precise pathway of compression is strongly dependent on the initial conditions e.g. density and connectivity within the granular bed, as emphasized by some data for quasi-static compression of sand. To fully embrace the range of behaviours seen requires the development of a suitable parameter to describe the material, the paper concludes with a discussion of one of those approaches.

  8. The application of a calibrated 3D ballistic trajectory model to ballistic hazard assessments at Upper Te Maari, Tongariro

    Science.gov (United States)

    Fitzgerald, R. H.; Tsunematsu, K.; Kennedy, B. M.; Breard, E. C. P.; Lube, G.; Wilson, T. M.; Jolly, A. D.; Pawson, J.; Rosenberg, M. D.; Cronin, S. J.

    2014-10-01

    On 6 August, 2012, Upper Te Maari Crater, Tongariro volcano, New Zealand, erupted for the first time in over one hundred years. Multiple vents were activated during the hydrothermal eruption, ejecting blocks up to 2.3 km and impacting ~ 2.6 km of the Tongariro Alpine Crossing (TAC) hiking track. Ballistic impact craters were mapped to calibrate a 3D ballistic trajectory model for the eruption. This was further used to inform future ballistic hazard. Orthophoto mapping revealed 3587 impact craters with a mean diameter of 2.4 m. However, field mapping of accessible regions indicated an average of at least four times more observable impact craters and a smaller mean crater diameter of 1.2 m. By combining the orthophoto and ground-truthed impact frequency and size distribution data, we estimate that approximately 13,200 ballistic projectiles were generated during the eruption. The 3D ballistic trajectory model and a series of inverse models were used to constrain the eruption directions, angles and velocities. When combined with eruption observations and geophysical observations, the model indicates that the blocks were ejected in five variously directed eruption pulses, in total lasting 19 s. The model successfully reproduced the mapped impact distribution using a mean initial particle velocity of 200 m/s with an accompanying average gas flow velocity over a 400 m radius of 150 m/s. We apply the calibrated model to assess ballistic hazard from the August eruption along the TAC. By taking the field mapped spatial density of impacts and an assumption that an average ballistic impact will cause serious injury or death (casualty) over an 8 m2 area, we estimate that the probability of casualty ranges from 1% to 16% along the affected track (assuming an eruption during the time of exposure). Future ballistic hazard and probabilities of casualty along the TAC are also assessed through application of the calibrated model. We model a magnitude larger eruption and illustrate

  9. Comparison of impact strength of acrylic resin reinforced with kevlar and polyethylene fibres.

    Science.gov (United States)

    Kamath, G; Bhargava, K

    2002-01-01

    The present study was done to evaluate the impact strengths of heat-activated acrylic resins reinforced with Kevlar fibres, polyethylene fibres and unreinforced heat activated acrylic resin. Each of three groups had 25 specimens. Brass rods of uniform length of 40 mm and diameter of 8 mm were used to prepare the moulds. A combination of long fibres (40 mm length) and short fibres (6 mm length) were used. The total amount of fibres incorporated was limited to 2% by weight of the resin matrix. Short and long fibres of equal weight were incorporated. The short fibres were mixed with polymer and monomer and packed into the mould, while, the long axis of the specimen, perpendicular to the applied force. The specimens were then processed. Impact strength testing was done on Hounsfield's impact testing machine. Kevlar fibre reinforced heat activated acrylic resin specimens recorded higher mean impact strength of 0.8464 Joules, while polyethylene fibres reinforced heat activated acrylic resin recorded mean impact strength of 0.7596 joules. The unreinforced heat activated acrylic resin recorded mean impact strength of 0.3440 Joules.

  10. A Residual Mass Ballistic Testing Method to Compare Armor Materials or Components (Residual Mass Ballistic Testing Method)

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin Langhorst; Thomas M Lillo; Henry S Chu

    2014-05-01

    A statistics based ballistic test method is presented for use when comparing multiple groups of test articles of unknown relative ballistic perforation resistance. The method is intended to be more efficient than many traditional methods for research and development testing. To establish the validity of the method, it is employed in this study to compare test groups of known relative ballistic performance. Multiple groups of test articles were perforated using consistent projectiles and impact conditions. Test groups were made of rolled homogeneous armor (RHA) plates and differed in thickness. After perforation, each residual projectile was captured behind the target and its mass was measured. The residual masses measured for each test group were analyzed to provide ballistic performance rankings with associated confidence levels. When compared to traditional V50 methods, the residual mass (RM) method was found to require fewer test events and be more tolerant of variations in impact conditions.

  11. The sensitivity of the burst performance of impact damaged pressure vessels to material strength properties

    Science.gov (United States)

    Lasn, K.; Vedvik, N. P.; Echtermeyer, A. T.

    2016-07-01

    This numerical study is carried out to improve the understanding of short-term residual strength of impacted composite pressure vessels. The relationship between the impact, created damage and residual strength is predicted by finite element (FE) analysis. The burst predictions depend largely on the strength properties used in the material models. However, it is typically not possible to measure all laminate properties on filament wound structures. Reasonable testing efforts are concentrated on critical properties, while obtaining other less sensitive parameters from e.g. literature. A parametric FE model is hereby employed to identify the critical strength properties, focusing on the cylindrical section of the pressure vessel. The model simulates an impactor strike on an empty vessel, which is subsequently pressurized until burst. Monte Carlo Simulations (MCS) are employed to investigate the correlations between strength related material parameters and the burst pressure. The simulations indicate the fracture toughness of the composite, hoop layer tensile strength and the yield stress of the PE liner as the most influential parameters for current vessel and impact configurations. In addition, the conservative variation in strength parameters is shown to have a rather moderate effect (COV ca. 7%) on residual burst pressures.

  12. Ballistic negatron battery

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M.S.R. [Koneru Lakshmiah Univ.. Dept. of Electrical and Electronics Engineering, Green fields, Vaddeswaram (India)

    2012-07-01

    If we consider the Statistics there is drastic increase in dependence of batteries from year to year, due to necessity of power storage equipment at homes, power generating off grid and on grid Wind, PV systems, etc.. Where wind power is leading in renewable sector, there is a need to look at its development. Considering the scenario in India, most of the wind resource areas are far away from grid and the remaining areas which are near to grid are of low wind currents which is of no use connecting these equipment directly to grid. So, there is a need for a power storage utility to be integrated, such as the BNB (Ballistic Negatron Battery). In this situation a country like India need a battery which should be reliable, cheap and which can be industrialized. So this paper presents the concept of working, design, operation, adaptability of a Ballistic Negatron Battery. Unlike present batteries with low energy density, huge size, more weight, more charging time and low resistant to wear level, this Ballistic Negatron Battery comes with, 1) High energy storage capability (many multiples more than the present most advanced battery). 2) Very compact in size. 3) Almost negligible in weight compared to present batteries. 4) Charges with in very less time. 5) Never exhibits a wear level greater than zero. Seems like inconceivable but adoptable with simple physics. This paper will explains in detail the principle, model, design, construction and practical considerations considered in making this battery. (Author)

  13. Survivability Armor Ballistic Laboratory (SABL)

    Data.gov (United States)

    Federal Laboratory Consortium — The SABL provides independent analysis, ballistic testing, data collection, data reduction and qualification of current and advanced armors. Capabilities: The SABL...

  14. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Paz, Rene Anisio; Araujo, Edcleide Maria; Tomas Jeferson Alves; Amanda Damiao; Medeiros, Vanessa da Nobrega [Federal University of Campina Grande (CCT/UFCG), Campina Grande, PB (Brazil). Centro de Ciencias e Tecnologia; Pessan, Luiz Antonio [Federal University of Sao Carlos (DEMa/UFSCar), SP (Brazil). Materials Engineering Department

    2012-07-15

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that it affects the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD) results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM). By thermogravimetry (TG), the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness. (author)

  15. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Rene Anisio Paz

    2012-08-01

    Full Text Available Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that it affects the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM. By thermogravimetry (TG, the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness.

  16. Strength of a thick graphite/epoxy rocket motor case after impact by a blunt object

    Science.gov (United States)

    Poe, C. C., Jr.; Illg, W.

    1987-01-01

    The National Aeronautics and Space Administration is developing graphite/epoxy filament-wound cases (FWC) for the solid rocket motors of the Space Shuttle. The membrane region is about 36 mm thick. A study was made to determine the reduction in strength of the FWC due to accidental damage caused by low-velocity impacts. Two 76.2 cm diameter by 30.5 cm long cylinders were impacted every 5 cm of circumference with 1.27 cm radius impacters of various mass. The impacters represented tools and equipment dropped from various heights. One cylinder was empty and the other was filled with inert propellant. Five cm wide test specimens were cut from the cylinder. Each was centered on an impact sight. The specimens were X-rayed and loaded to failure in uniaxial tension. The strengths and depths of impact damage were analyzed in terms of maximum impact force. Rigid body mechanics and the Hertz law were used to derive an equation for impact force in terms of kinetic energy and the masses of the impacter and target. The depth of damage was predicted in terms of impact force using Love's solution of pressure applied on part of the boundary of a semi-infinite body.

  17. The "Strength" of Cometary Surface Material: Relevance of Deep Impact Results for Future Comet Missions

    Science.gov (United States)

    Biele, J.; Ulamec, S.; Richter, L.; Kührt, E.; Knollenberg, J.; Möhlmann, D.

    In the view of the ongoing Rosetta Mission which was launched in March 2004 and will arrive at the target comet 67P Churyumov-Gerasimenko in 2014 where a Lander is going to be delivered the results of the Deep Impact Mission in particular regarding comet surface properties have been acknowledged with highest interest Analysis of the velocity of dust ejecta indicates very soft surface material of comet Tempel 1 with strength of only 65 Pa A Hearn M F et al Deep Impact Excavating Comet Tempel 1 Science 310 258-264 14 Oct 2005 It appears however necessary to discuss three principal issues in the interpretation of the data 1 By the impact shock itself the material is stressed fractured and its tensile strength is modified Thus the pristine material properties can most likely not be determined with the applied method 2 Due to the impact a non-negligible amount of gas has been released from an extended source modifying the velocity distribution of the ejected dust particles Thus the detection of a minimum velocity of dust grains cannot be directly related to the material strength 3 The definition of strength in A Hearn et al 2005 needs to be defined more clearly in order to draw conclusions on e g the penetration of a lander device with an impact speed of 1 m s Slow penetration into cometary material is depending primarily on the compressive strength which is typically at least one order of magnitude higher than the tensile strength We will discuss the three issues stated above and estimate the real compressive

  18. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels

    Science.gov (United States)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-01-01

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400–450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0–1.2 GPa at room temperature, which is nearly 3–5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry. PMID:28150692

  19. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels.

    Science.gov (United States)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-02-02

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400-450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0-1.2 GPa at room temperature, which is nearly 3-5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry.

  20. Q235钢板对平头弹抗侵彻特性研究%Ballistic performance of Q235 metal plates subjected to impact by blunt-nosed projectiles

    Institute of Scientific and Technical Information of China (English)

    邓云飞; 张伟; 孟凡柱

    2015-01-01

    In order to investigate the influence of configuration of target on the ballistic performance, monolithic and three⁃layered targets were normally impacted by blunt⁃nosed projectiles in the velocity range of 190~450 m/s with the help of a gas gun, and also the photos of the impact process were obtained. Based on the tests, the residual velocity versus the initial velocity curves of the projectiles were constructed, and also ballistic limit velocities were obtained. The influence of combination configuration of target on the ballistic characteristic, including the ballistic resistance and failure models were investigated. Moreover, the penetration process of metal plates impacted by rod projectiles had been studied with numerical simulation code ABAQUS/EXPLICIT, and also the validation of models and parameters of materials had been proved by comparing the experiment results with numerical simulations. The results indicated that the ballistic limit velocity of multi⁃layered target was higher than that of monolithic target, and also there were differences between failure models of multi⁃layered targets and monolithic target. Moreover, the failure models of plates of multi⁃layered targets were in relation to their order.%为分析靶体结构对其抗侵彻特性的影响,利用轻气炮进行平头杆弹正撞击单层板和等厚接触式三层板的实验,获取相关的撞击过程图片.通过撞击实验,得到这两种结构靶体的初始-剩余速度曲线以及弹道极限,撞击速度为190~450 m/s.研究靶体结构对抗侵彻特性的影响,包括靶板的失效模式和抗侵彻性能.最后,采用ABAQUS/EXPLICIT软件对杆弹撞击金属板的过程进行数值模拟研究,通过对比数值模拟和实验结果,验证了数值模拟材料模型和参数的有效性.结果表明:多层板的弹道极限高于等厚单层板,并且多层板和单层板的主要失效模式之间存在差异.对于多层板

  1. A Numerical Investigation of the influence of Yarn-Level Finite-Element Model on Energy Absorption by a Flexible Fabric Armour During Ballistic Impact

    Science.gov (United States)

    2008-01-01

    clamping pressure on the ballistic performance of soft body armor. Compos. B, in press. 13 Kawabata , S., Niwa, M., and Kawai, H. The finite...deformation theory of plain-weave fabrics part I: the biaxial-deformation theory. J. Text. Inst., 1973, 64, 21–46. 14 Kawabata , S., Niwa, M., and Kawai, H...The finite- deformation theory of plain-weave fabrics. Part II. The uniaxial-deformation theory. J. Text. Inst., 1973, 64, 47–61. 15 Kawabata , S., Niwa

  2. FE analysis of the effect of friction on ballistic impact performance of woven fabrics%摩擦力对织物防弹性能影响的有限元分析

    Institute of Scientific and Technical Information of China (English)

    王莹; 陈晓刚

    2013-01-01

    纱线之间的摩擦力对织物的防弹性能有很大影响,但是始终缺少对失效机制了解。例如,多大的摩擦力有利于织物吸收能量,纱线间的摩擦力对应力分布的影响等。本文采用有限元分析的方法对摩擦力影响的机理进行了系统的研究,采用ABAQUS建立织物的有限元分析模型。研究表明,织物的防弹性能随纱线之间摩擦力的增大而增加。应力在纱线上的分布随摩擦力的变化而改变。增大摩擦力能减少接触区边缘的应力。因此,摩擦力较大的织物需要更多的时间才能被穿透,这将有助于吸收更多的能量。研究还表明摩擦力的增加会导致纵向波速下降,能量吸收会因此而减少。但是,增加摩擦力会产生较大的横向波,能量吸收会因此而增加。%Many attempts have been done to investigate the effect of friction on ballistic impact response of woven fabrics .It has been shown that friction plays an important role in determi-ning the ballistic impact performance of fabrics .Currently ,there is little fundamental under-standing of impact failure mechanisms in woven fabrics .For example ,what levels of inter-yarn friction are beneficial to energy absorption capacity of the fabrics , how friction affects the stress distributions w hich are crucial important in determining the failure modes of yarns and energy absorption .In this paper ,a detailed study using finite element analysis has been carried out .The purpose of the paper is to study numerically the way in which friction affects the im-pact behaviour of ballistic fabrics and to determine the distribution and magnitude of the stres-ses .The finite element model was created using ABAQUS to simulate the transverse impact onto woven fabrics . The calculated results show that the ballistic impact performance of woven fabrics increa-ses with increasing levels of friction .The stress distributions on the yarns are sensitive to the

  3. ON RESIDUAL COMPRESSIVE STRENGTH PREDICTION OF COMPOSITE SANDWICH PANELS AFTER LOW-VELOCITY IMPACT DAMAGE

    Institute of Scientific and Technical Information of China (English)

    Xie Zonghong; Anthony J. Vizzini; Tang Qingru

    2006-01-01

    This paper introduces a nonlinear finite element analysis on damage propagation behavior of composite sandwich panels under in-plane uniaxial quasi-static compression after a low velocity impact. The major damage modes due to the impact, including the residual indentation on the impacted facesheet, the initially crushed core under the impacted area, and the delamination are incorporated into the model. A consequential core crushing mechanism is incorporated intothe analysis by using an element deactivation technique. Damage propagation behavior, which corresponds to those observed in sandwich compression after impact (SCAI) tests, has been successfully captured in the numerical simulation. The critical far field stress corresponding to the onset of damage propagation at specified critical locations near the damage zone are captured successfully. They show a good correlation with experimental data. These values can be used to effectively predict the residual compressive strength of low-velocity impact damaged composite sandwich panels.

  4. Quantitative evaluation of smoke source strengths and impacts by infusing satellite fire- strength measurements in transport models.

    Science.gov (United States)

    Ichoku, C.; Chin, M.; Diehl, T.; Wooster, M.; Roberts, G.; Giglio, L.

    2007-05-01

    Chemical transport models currently derive their smoke emission sources from counts of fire hot spots detected from satellites, usually with single daily overpasses. However, fires vary in size and strength, with a significant diurnal trend, making the use of pixel counts measured at the same time of day very unreliable for estimating smoke sources. Fortunately, the Moderate-resolution Imaging Spectro-radiometer (MODIS) twin sensors onboard the Terra and Aqua satellites, not only detect fires everywhere at four strategic times of day, but also measure their strength in the form of fire radiative power (FRP) or rate of release of fire radiative energy (FRE). FRP is now also being derived from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor onboard the geostationary Meteosat-8 platform, which observes Africa and Europe virtually every 15 mins. The SEVIRI measurements show that MODIS 4-times-a-day measurements capture the essence of the fire diurnal cycle. Therefore, MODIS is currently the only satellite data source ideal for estimating daily smoke emissions globally. In a number of recent studies, FRP has been found to be directly proportional to both the rate of biomass consumption and the rate of smoke aerosol emission. Indeed, (1) a combustion factor (Fc), which relates FRE to burned biomass was established, and (2) a FRE-based emission coefficient (Ce), which is a simple coefficient to convert FRP (or FRE) to smoke aerosol emissions was derived for different parts of the world. The results obtained from satellite have been reproduced in the laboratory, and the ingestion of FRP in models is now being tested using the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. Although MODIS has been in operation since the last 6 years, regrettably, this rare but formidable data resource it provides (FRP) has been left largely unutilized. In this presentation, we will show the preliminary results of using FRP to improve the

  5. Effect of Impact Damage and Open Hole on Compressive Strength of Hybrid Composite Laminates

    Science.gov (United States)

    Hiel, Clement; Brinson, H. F.

    1993-01-01

    Impact damage tolerance is a frequently listed design requirement for composites hardware. The effect of impact damage and open hole size on laminate compressive strength was studied on sandwich beam specimens which combine CFRP-GFRP hybrid skins and a syntactic foam core. Three test specimen configurations have been investigated for this study. The first two were sandwich beams which were loaded in pure bending (by four point flexure). One series had a skin damaged by impact, and the second series had a circular hole machined through one of the skins. The reduction of compressive strength with increasing damage (hole) size was compared. Additionally a third series of uniaxially loaded open hole compression coupons were tested to generate baseline data for comparison with both series of sandwich beams.

  6. THE IMPACT OF A STRENGTH GRADING PROCESS ON SAWMILL PROFITABILITY AND PRODUCT QUALITY

    Directory of Open Access Journals (Sweden)

    Mattias Brännström

    2009-11-01

    Full Text Available A strength grading process, starting with log grading, was studied with respect to grading yield, impact on quality, and economic efficiency when visual grades according to Nordic grading rules were used for alternate product comparison. Pine (Pinus sylvestris and spruce (Picea abies logs and boards were graded with several varieties of commercial grading and strength-grading equipment. The boards were destructively tested, and the European grade-determining properties strength, stiffness, and density were measured. Models for these were made by partial least squares and validated. A method for the derivation of settings for multiple indicating properties, which increased yield in some cases, was proposed and evaluated. Grading to grade combinations of C40, C30, and C18 was done. The impact of visual override based on deformations was also studied. A simplified economic and sensitivity analysis was done. The outcome was that log grading can be used for strength grading with good economic and quality results. Strength pregrading on logs improves sawmill economy, depending on the species and market situation. Drying quality greatly influences the yield through visual override grading on deformations. Market prices of high grades (>C30 must improve in order to stimulate supply, as it is more economical to produce lower grades.

  7. Impacts of Soil Moisture Content and Vegetation on Shear Strength of Unsaturated Soil

    Institute of Scientific and Technical Information of China (English)

    YANG Yong-hong; ZHANG Jian-guo; ZHANG Jian-hui; LIU Shu-zhen; WANG Cheng-hua; XIAO Qing-hua

    2005-01-01

    It is analyzed that the impacts of vegetation type and soil moisture content on shear strength of unsaturated soil through direct shearing tests for various vegetation types, different soil moisture contents and different-depth unsaturated soil. The results show that the cohesion of unsaturated soil changes greatly, and the friction angle changes a little with soil moisture content. It is also shown that vegetation can improve shear strength of unsaturated soil, which therefore provides a basis that vegetation can reinforce soil and protect slopes.

  8. Design and Manufacturing Process for a Ballistic Missile

    Directory of Open Access Journals (Sweden)

    Zaharia Sebastian Marian

    2016-12-01

    Full Text Available Designing a ballistic missile flight depends on the mission and the stress to which the missile is subject. Missile’s requests are determined by: the organization of components; flight regime type, engine configuration and aerodynamic performance of the rocket flight. In this paper has been developed a ballistic missile with a smooth fuselage type, 10 control surfaces, 8 directional surfaces for cornering execution, 2 for maneuvers of execution to change the angle of incidence and 4 stabilizers direction. Through the technology of gluing and clamping of the shell and the use of titanium components, mass of ballistic missile presented a significant decrease in weight and a structure with high strength.

  9. Research on ballistic missile laser SIMU error propagation mechanism

    Institute of Scientific and Technical Information of China (English)

    Wei Shihui; Xiao Longxu

    2008-01-01

    It is necessary that the laser inertial system is used to further improve the fire accuracy and quick reaction capability in the ballistic missile strapdown inertial navigation system. According to the guidance con-trolling method and the output and error model of ballistic missile laser SIMU, the mathematical model of error propagation mechanism is set up and any transfer environmental function of error coefficient that affects the fire accuracy is deduced. Also, the missile longitudinal/lateral impact point is calculated using MATLAB. These estab-lish the technical foundation for further researching the dispersion characteristics of impact point and reducing the laser guidance error.

  10. Improving Impact Strength Recovery of Fractured and Healed Rice Husks Fibre Reinforced Polypropylene Composites.

    Directory of Open Access Journals (Sweden)

    Odhong, O.V.E

    2016-10-01

    Full Text Available Rice husks fibre reinforced polypropylene composite (rhfrpc is a natural plant fibre reinforced polymer composite having advantages of high strength, light weight and affordability. They are commonly used for light load structural and non structural applications. They are mainly used as particle boards, for fencing post, roofing tiles, for interiors of car and aircrafts among other usages. This material once cracked by impact forces cannot be repaired using traditional repair methods for engineering materials such as metals or other composites that can be repaired by welding or by patch repair methods respectively, thus a method of repair of rice husks fibre reinforced polypropylene composites by refilling the damaged volume by injection of various healing agents has been investigated. The composite coupons were produced by injection moulding, cooled sufficiently and prepared for charpy impact tests. Test results for pristine coupons were a maximum of 48 J/mm2 . The destroyed coupons were then subjected to healing in a fabricated healing fixture. Healing agents such as epoxy resin, ethyl cyanoacrylate, and tannin gum have been investigated for their use as possible healing agents to fill the damaged volume and perform healing action at the fractured surfaces. The impact test results were recorded and compared with those of unhealed pristine coupons. The recovered strengths were a maximum of 60 J/mm2 translating into a 125% impact strength recovery, and this is good enough for the healed composites to be recommended for reuse in their second lives of their respective original functions.

  11. Investigating the Impact of Acetone Vapor Smoothing on the Strength and Elongation of Printed ABS Parts

    Science.gov (United States)

    Gao, Harry; Kaweesa, Dorcas V.; Moore, Jacob; Meisel, Nicholas A.

    2017-03-01

    Acetone vapor smoothing is a chemical treatment that "melts" the surface of additively manufactured acrylonitrile butadiene styrene parts. The process fuses layers together and allows them to reform when vapor is removed, resulting in a smooth surface finish. Although commonly used to improve aesthetics, recent work has begun to investigate the effects of vapor smoothing on part strength. Nevertheless, most of this work has failed to take into account the anisotropic nature of printed parts. Prior research has shown that vapor smoothing reduces strength under best-case loading conditions, when the tensile load is parallel with the direction of the layers. In this article, the authors hypothesize that vapor smoothing may increase strength under nonoptimal loading conditions as a result of increased cohesion between layers and a reduction in stress concentrations. They use a design of experiments approach to identify the combined impact of printing and vapor smoothing parameters on part material properties.

  12. The Impact of Arthroscopic Capsular Release in Patients with Primary Frozen Shoulder on Shoulder Muscular Strength

    Directory of Open Access Journals (Sweden)

    Michał Waszczykowski

    2014-01-01

    Full Text Available The aim of this study was to evaluate the impact of arthroscopic capsular release in patients with primary frozen shoulder on muscular strength of nonaffected and treated shoulder after at least two-year follow-up after the surgery. The assessment included twenty-seven patients, who underwent arthroscopic capsular release due to persistent limitation of range of passive and active motion, shoulder pain, and limited function of upper limb despite 6-month conservative treatment. All the patients underwent arthroscopic superior, anteroinferior, and posterior capsular release. After at least two-year follow-up, measurement of muscular strength of abductors, flexors, and external and internal rotators of the operated and nonaffected shoulder, as well as determination of range of motion (ROM and function (ASES in the operated and nonaffected shoulder, was performed. Measurement of muscular strength in the patient group did not reveal statistically significant differences between operated and nonaffected shoulder. The arthroscopic capsular release does not have significant impact on the decrease in the muscular strength of the operated shoulder.

  13. Ballistic Missile Defense System (BMDS)

    Science.gov (United States)

    2015-12-01

    Estimate RDT&E - Research , Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined TY - Then...all ranges and in all phases of flight. Following guidance from the President, the Secretary of Defense approved the Ballistic Missile Defense (BMD...based Midcourse Defense (GMD) system to enhance our capability against Intercontinental Ballistic Missiles. We are currently sustaining 30

  14. Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

    Directory of Open Access Journals (Sweden)

    C. Labrecque

    2011-02-01

    Full Text Available A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT, 16 J (-20°C and 11 J (-40°C. The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation.

  15. The Dynamic Behaviour of Ballistic Gelatin

    Science.gov (United States)

    Shepherd, C. J.; Appleby-Thomas, G. J.; Hazell, P. J.; Allsop, D. F.

    2009-12-01

    In order to characterise the effect of projectiles it is necessary to understand the mechanism of both penetration and resultant wounding in biological systems. Porcine gelatin is commonly used as a tissue simulant in ballistic tests because it elastically deforms in a similar manner to muscular tissue. Bullet impacts typically occur in the 350-850 m/s range; thus knowledge of the high strain-rate dynamic properties of both the projectile and target materials are desirable to simulate wounds. Unlike projectile materials, relatively little data exists on the dynamic response of flesh simulants. The Hugoniot for a 20 wt.% porcine gelatin, which exhibits a ballistic response similar to that of human tissues at room temperature, was determined using the plate-impact technique at impact velocities of 75-860 m/s. This resulted in impact stresses around three times higher than investigated elsewhere. In US-uP space the Hugoniot had the form US = 1.57+1.77 uP, while in P-uP space it was essentially hydrodynamic. In both cases this was in good agreement with the limited available data from the literature.

  16. A new experimental setup to characterize the dynamic mechanical behaviour of ballistic yarns

    Science.gov (United States)

    Chevalier, C.; Kerisit, C.; Boussu, F.; Coutellier, D.; Faderl, N.; Klavzar, A.

    2016-10-01

    Fabrics have been widely used as part of ballistic protections since the 1970s and the development of new ballistic solutions made from fabrics need numerical simulations, in order to predict the performance of the ballistic protection. The performances and the induced mechanisms in ballistic fabrics during an impact depend on the weaving parameters and also on the inner parameters of the yarns used inside these structures. Thus, knowing the dynamic behaviour of yarn is essential to determine the ballistic behaviour of fabrics during an impact. Two major experimental devices exist and are used to test ballistic yarns in a dynamic uniaxial tension. The first one corresponds to the Split Hopkinson Tensile Bars device, which is commonly used to characterize the mechanical properties of materials in uniaxial tension and under high loading. The second one is the transversal impact device. The real conditions of ballistic impact can be realized with this device. Then, this paper deals with a new experimental setup developed in our laboratory and called the ‘tensile impact test for yarn’ (TITY) device. With this device, specific absorbed energy measurements of para-aramid yarns (336 Tex, Twaron™, 1000 filaments) have been carried out and revealed that static and dynamic properties of para-aramid are different.

  17. The Impact of Weld Metal Creep Strength on the Overall Creep Strength of 9% Cr Steel Weldments

    OpenAIRE

    Mayr, Peter; Mitsche, Stefan; Cerjak, Horst; Allen, Samuel Miller

    2010-01-01

    In this work, three joints of a X11CrMoWVNb9-1-1 (P911) pipe were welded with three filler metals by conventional arc welding. The filler metals varied in creep strength level, so that one overmatched, one undermatched, and one matched the creep strength of the P911 grade pipe base material. The long-term objective of this work was to study the influence of weld metal creep strength on the overall creep behavior of the welded joints and their failure mechanism. Uniaxial creep tests at 600°C a...

  18. Gunshot wounds: A review of ballistics related to penetrating trauma

    Directory of Open Access Journals (Sweden)

    Panagiotis K. Stefanopoulos

    2014-01-01

    Full Text Available Civilian gunshot injuries from handgun and rifle ammunition vary in severity depending on the anatomic location involved and the different effects from the ballistic properties of the penetrating projectiles. Ballistic factors such as the impact velocity and energy should not be considered in isolation, as their specific effects are determined by the interaction between the projectile and tissues. Increased tissue damage can result from tumbling of non-deforming rifle bullets and deformation of expanding bullets. Both of these mechanisms increase substantially the energy transfer to the wound and its diameter, also producing a pulsating temporary cavity associated with pressure changes within tissue.

  19. Optimizing Ballistic Imaging Operations.

    Science.gov (United States)

    Wang, Can; Beggs-Cassin, Mardy; Wein, Lawrence M

    2017-04-03

    Ballistic imaging systems can help solve crimes by comparing images of cartridge cases, which are recovered from a crime scene or test-fired from a gun, to a database of images obtained from past crime scenes. Many U.S. municipalities lack the resources to process all of their cartridge cases. Using data from Stockton, CA, we analyze two problems: how to allocate limited capacity to maximize the number of cartridge cases that generate at least one hit, and how to prioritize the cartridge cases that are processed to maximize the usefulness (i.e., obtained before the corresponding criminal case is closed) of hits. The number of hits can be significantly increased by prioritizing crime scene evidence over test-fires, and by ranking calibers by their hit probability and processing only the higher ranking calibers. We also estimate that last-come first-served increases the proportion of hits that are useful by only 0.05 relative to first-come first-served.

  20. Chicxulub High-Altitude Ballistic Ejecta from Central Belize

    Science.gov (United States)

    Pope, K. O.; Ocampo, A. C.

    2000-01-01

    Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.

  1. Evaluation of interlaminar shear strength of a unidirectional carbon/epoxy laminated composite under impact loading

    Science.gov (United States)

    Yokoyama, T.; Nakai, K.

    2006-08-01

    The interlaminar shear strength (ILSS) of a unidirectional carbon/epoxy (T700/2521) laminated composite under impact loading is determined using the conventional split Hopkinson pressure bar. Double-notch shear (DNS) specimens with lateral constraint from a supporting jig are used in the static and impact interlaminar compressive shear tests. Short-beam shear specimens are also used under static 3-point bending. Numerical stress analyses are performed to determine the shear stress and normal stress distributions on the expected failure plane in the DNS specimen using the MSC/NASTRAN package. The effect of deformation rate on the ILSS and failure mode is investigated. It is observed that the ILSS is independent of the deformation rate up to nearly 1.5m/s (dotγ ≈ 780/s). The validity of the test results is confirmed by microscopic examinations of both static and impact failure surfaces for the DNS specimens.

  2. Finite Element Modelling Full Vehicle Side Impact with Ultrahigh Strength Hot Stamped Steels

    Science.gov (United States)

    Taylor, T.; Fourlaris, G.; Cafolla, J.

    2016-10-01

    "Hot stamped boron steel" 22MnB5 has been imperative in meeting the automotive industry's demand for materials exhibiting higher tensile strength in the final component. In this paper, the crash performance of three experimental grades developed for automotive hot stamping technologies, exhibiting wider tensile property ranges than 22MnB5, was validated by finite element modelling full vehicle side impact with the experimental material data applied to the B-pillar reinforcement. The superior anti-intrusive crash performance of grade 38MnB5 was demonstrated, with 11 mm less intrusion of the B-pillar reinforcement compared to 22MnB5. Moreover, the superior "impact-energy absorptive" crash performance of grade 15MnCr5 was demonstrated, with 0.15 kJ greater impact-energy absorption by the B-pillar reinforcement compared to 22MnB5.

  3. Impact of Inertial Training on Strength and Power Performance in Young Active Men.

    Science.gov (United States)

    Naczk, Mariusz; Naczk, Alicja; Brzenczek-Owczarzak, Wioletta; Arlet, Jarosław; Adach, Zdzisław

    2016-08-01

    Naczk, M, Naczk, A, Brzenczek-Owczarzak, W, Arlet, J, and Adach, Z. Impact of inertial training on strength and power performance in young active men. J Strength Cond Res 30(8): 2107-2113, 2016-This study evaluated how 5 weeks of inertial training using 2 different loads influenced strength and power performance. Fifty-eight male physical education students were randomly divided into training and control groups. The 2 training groups (T0 and T10) performed inertial training 3 times per week for 5 weeks using the new Inertial Training and Measurement System (ITMS). Each training session included 3 exercise sets involving the knee extensors muscles. The T0 group used only the mass of the ITMS flywheel (19.4 kg), whereas the T10 group had an additional 10 kg on the flywheel. Before and after training, we evaluated maximum force and power of knee extensors muscles, countermovement jump (CMJ), squat jump (SJ), maximal power output achieved during ergometer test PVT, electromyography of quadriceps, and muscle mass. In T0 and T10, respectively, ITMS training induced significant increases in muscle force (25.2 and 23.3%), muscle power (33.2 and 27%), CMJ (3.8 and 6.7%), SJ (2.2 and 6.1%), PVT (8 and 7.4%), and muscle mass (9.8 and 15%). The changes did not significantly differ between T0 and T10. A 16% significant increase of electromyography amplitude (quadriceps muscle) was noted only in T0. The novel ITMS training method is effective for improving muscular strength and power. Improvements in PVT, CMJ, and SJ indicate that the increased strength and power elicited by ITMS training can translate to improvements in sport performance. The ITMS training can also be useful for building muscle mass.

  4. In-situ caustic generation from sewage: the impact of caustic strength and sewage composition.

    Science.gov (United States)

    Pikaar, Ilje; Rozendal, René A; Rabaey, Korneel; Yuan, Zhiguo

    2013-10-01

    Periodic caustic dosage is a commonly used method by the water industry to elevate pH levels and deactivate sewer biofilms responsible for hydrogen sulfide generation. Caustic (NaOH) can be generated in-situ from sewage using a divided electrochemical cell, which avoids the need for transport, handling and storage of concentrated caustic solutions. In this study, we investigated the impact of caustic strength in the cathode compartment and the impact of sodium concentration in sewage on the Coulombic efficiency (CE) for caustic generation. The CE was found to be independent of the caustic strength produced in the range of up to ~3 wt%. Results showed that a caustic solution of ~3 wt% could be produced directly from sewage at a CE of up to 75 ± 0.5%. The sodium concentration in sewage had a significant impact on the CE for caustic generation as well as on the energy requirements of the system, with a higher sodium concentration leading to a higher CE and lower energy consumption. The proton, calcium, magnesium and ammonium concentrations in sewage affected the CE for caustic generation, especially at low sodium concentrations. Economical assessment based on the experimental results indicated that sulfide control in sewers using electrochemically-generated caustic from sewage is an economically attractive strategy.

  5. Relationships between the fibromyalgia impact questionnaire, tender point count, and muscle strength in female patients with fibromyalgia: a cohort study

    DEFF Research Database (Denmark)

    Henriksen, Marius; Lund, Hans; Christensen, Robin;

    2009-01-01

    OBJECTIVE: To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength. METHODS: A total of 840 FM patients and 122 healthy subjects were evaluated between 1998 and 2005. All of the patie......OBJECTIVE: To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength. METHODS: A total of 840 FM patients and 122 healthy subjects were evaluated between 1998 and 2005. All...... of the patients completed version 1 of the Fibromyalgia Impact Questionnaire (FIQ) and were assessed for tender points and knee muscle strength. All subjects underwent bilateral isokinetic knee muscle strength testing in flexion and extension. Normative knee muscle strength values were calculated from the healthy...

  6. A Study of Transport and Impact Strength of Fukushima Nuclear Pollutants in the North Pacific Surface

    Institute of Scientific and Technical Information of China (English)

    FU Hongli; LI Wei; ZHANG Xuefeng; HAN Guijun; WANG Xidong; WU Xinrong; ZHANG Lianxin

    2014-01-01

    Based on the statistics of surface drifter data of 1979-2011 and the simulation of nuclear pollutant particulate move-ments simulated using high quality ocean reanalysis surface current dataset, the transport pathways and impact strength of Fuku-shima nuclear pollutants in the North Pacific have been estimated. The particulates are used to increase the sampling size and en-hance the representativeness of statistical results. The trajectories of the drifters and particulates are first examined to identify typical drifting pathways. The results show that there are three types of transport paths for nuclear pollutants at the surface: 1) most pollutant particles move eastward and are carried by the Kuroshio and Kuroshio-extension currents and reach the east side of the North Pacific after about 3.2-3.9 years;2) some particles travel with the subtropical circulation branch and reach the east coast of China after about 1.6 years according to one drifter trajectory and about 3.6 years according to particulate trajectories;3) a little of them travel with local, small scale circulations and reach the east coast of China after about 1.3-1.8 years. Based on the par-ticulates, the impact strength of nuclear pollutants at these time scales can be estimated according to the temporal variations of relative concentration combined with the radioactive decay rate. For example, Cesium-137, carried by the strong North Pacific current, mainly accumulates in the eastern North Pacific and its impact strength is 4%of the initial level at the originating Fuku-shima area after 4 years. Due to local eddies, Cesium-137 in the western North Pacific is 1%of the initial pollutant level after 1.5 years and continuously increases to 3%after 4 years. The vertical movement of radioactive pollutants is not taken into account in the present study, and the estimation accuracy would be improved by considering three-dimensional flows.

  7. The Effect of Temperature and Nanoclay on the Low Velocity and Ballistic Behavior of Woven Glass-Fiber Reinforced Composites

    Science.gov (United States)

    Patrin, Lauren

    The objective of this research was to study the effect of nanoclay and temperature on the behavior of woven glass-fabric reinforced epoxy composite under low velocity and ballistic impacts. The materials used in manufacturing the composite were S2 (6181) glass-fibers, epoxy resin (EPON 828), hardener (Epikure 3230), nanoclay and Heloxy 61 modifier. The nanoclay addition was 0%, 1%, 3% and 5% by weight, with respect to the resin. All specimens were manufactured at the City College facilities using vacuum infusion. Tensile tests were conducted to characterize the material and obtain the Young's modulus, ultimate stress, failure strain, Poisson's ratio, shear modulus and shear strength and their variation with nanoclay percentage and temperature. The tests were conducted at room temperature (21°C/70°F), -54°C (-65°F), -20°C (-4°F), 49°C (120°F) and 71°C (160°F). Next composite specimens with 0%, 1%, 3% and 5% nanoclay by weight, with respect to the resin, were subjected to low velocity impact at the previously specified temperatures to determine dynamic force, displacement and energy correlations. The extent of damage was studied using the ultrasound technique. Then ballistic tests were conducted on the nanoclay infused specimens at room temperature to obtain the ballistic limit (V50) and the damage behavior of the composite. The dynamic finite element analysis (FEA) software LS-DYNA was used to model and simulate the results of low velocity impact tests. Good agreement was obtained between experimental and numerical (FEA) results. Analytical analyses were undertaken to compare the results from the tensile experiments. The finite element analysis (FEA) allowed for further analytical comparison of the results. The FEA platform used was LS-DYNA due to its proficient dynamic and damage capabilities in composite materials. The FEA was used to model and simulate the low velocity impacts and compare the results to experiments.

  8. Numerical simulation of ballistic impact on composite armours%复合装甲抗侵彻性能的数值分析

    Institute of Scientific and Technical Information of China (English)

    过超强; 赵桂平

    2013-01-01

    用数值分析的方法分别对金属、陶瓷、纤维增强复合材料组成的层合板和由陶瓷球填充的金属四边形蜂窝夹芯结构在冲击载荷作用下的抗侵彻性能进行了模拟计算.其中冲击载荷由12.7mm直径的刚性穿甲弹模拟.研究了不同构型靶板在侵彻过程中对动能量的吸收机理,分析了两种复合靶板各组分材料的吸能特性,并比较了不同靶板的弹道极限速度V50.研究结果表明:在相同面密度条件下,层合复合靶板中具有最强抗弹性能的陶瓷层与纤维层的最佳比例是2.22,其与4340钢均质靶板相比质量减轻了33%;蜂窝填充陶瓷结构的靶板中灌注环氧树脂后其弹道极限速度提高了13%.%Finite element analysis using LS-DYNA has been performed to investigate the penetration-resistance properties of composite armours.A 3-D model consisting of the various discrete layers of the armour has been built and subjected to transient dynamic loading.The projectile is a bullet with 12.7mm diameter.The dynamic responses of the integral armour having two different types of core topology: multi-component layers of 4340 steel,B4C ceramic and FRP core and square honeycomb filled with ceramic ball and epoxy core are simulated and analyzed.Numerical modeling is used to obtain an estimate for the ballistic limit velocity (V50) and simulate penetration processes.The focus is placed on the energy absorption capabilities of different component layers with same density per unit area.Results of the study indicate that the composite armour having thickness ratio of 2.22 between ceramic and FRP layers is an excellent one with highest ballistic limit velocity in all laminated composite armours and its mass is 33% lighter than that of 4340 steel target.Furthermore,it is found that the V50 of composite armour with square honeycomb filled with ceramic ball and epoxy cores is 13% higher than that without epoxy filled.

  9. Modeling Of Ballistic Missile Dynamics

    Directory of Open Access Journals (Sweden)

    Salih Mahmoud Attiya

    2013-05-01

    Full Text Available Aerodynamic modeling of ballistic missile in pitch plane is performed and the open-loop transfer function related to the jet deflector angle as input and pitch rate, normal acceleration as output has been derived with certain acceptable assumptions. For typical values of ballistic missile parameters such as mass, velocity, altitude, moment of inertia, thrust, moment and lift coefficient show that, the step time response and frequency response of the missile is unstable. The steady state gain, damping ratio and undraped natural frequency depend on the missile parameters. To stabilize the missile a lead compensator must be added to the forward loop.

  10. 抗冲ABS树脂的研究%Study on high impact strength ABS

    Institute of Scientific and Technical Information of China (English)

    朱伟平; 韩晔

    2001-01-01

    介绍了采用物理共混改性提高ABS树脂的抗冲击性的方法,确定了抗冲击改性剂的种类和用量,并研究了改性剂对ABS的抗冲性能、耐热性能和熔融流动性能的影响。%The modifier was used to improve the impact strength of ABS resin by blending.The type and dosage of the modifier were confirmed,and the effects of modifier on the impact stength,heat resistance and melting fluxion ahility were also studied.

  11. A Finite Element Analysis for Predicting the Residual Compressive Strength of Impact-Damaged Sandwich Panels

    Science.gov (United States)

    Ratcliffe, James G.; Jackson, Wade C.

    2008-01-01

    A simple analysis method has been developed for predicting the residual compressive strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compressive loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core material is represented using spring elements, aligned in the thickness direction of the core. The nonlinear crush response of the core material used in the analysis is based on data from flatwise compression tests. A comparison with a previous analysis method and some experimental data shows good agreement with results from this new approach.

  12. A Finite Element Analysis for Predicting the Residual Compression Strength of Impact-Damaged Sandwich Panels

    Science.gov (United States)

    Ratcliffe, James G.; Jackson, Wade C.

    2008-01-01

    A simple analysis method has been developed for predicting the residual compression strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compression loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core material is represented using spring elements, aligned in the thickness direction of the core. The nonlinear crush response of the core material used in the analysis is based on data from flatwise compression tests. A comparison with a previous analysis method and some experimental data shows good agreement with results from this new approach.

  13. Ballistic Performance of Coconut Shell Powder/Twaron Fabricagainst Non-armour Piercing Projectiles

    Directory of Open Access Journals (Sweden)

    M.S. Risby

    2008-03-01

    Full Text Available Body armour technologists over the years are seeking to develop protective systems whichare both effective and lightweight. However these hard armour materials are very expensive andhave certain weight constraints. From this point of view, natural fibres and fillers have attractedthe attention of researchers due to their low density with high specific strengths, abundance,availability, renewability and being environmental-friendly. This paper reports the potential useof coconut shell powder-epoxy composite (COEX panel bonded with Twaron CT716 fabric asa hard armour material and the characteristics of its fracture imprints from a specific threat levelwhen subjected to ballistic tests1 (NIJ Standard 0108.01. It was observed that the imprint patternson the particulate composite (COEX could be identified according to effectiveness in impactenergy dissipation. COEX/Twaron test panel was found to withstand impact equivalent to NIJLevel IIIA using 9 mm FMJ ammunition but perforated at NIJ Level III of 7.62 mm FMJ bulletimpacts. Test results showed that COEX panel do possess shock absorbance characteristics andcan be utilised as  an armour component in the hard-body armour system. Dependency onTwaron fabric layers as ballistic reinforcements has been reduced up to 3-time with 170 per centimprovement on energy-absorption capabilities when using COEX composite as the frontalcomponent of the armour.

  14. Kevlar-129纤维复合材料的弹道侵彻数值仿真%Ballistic impact simulation of Kevlar-1 29 fiber reinforced composite material

    Institute of Scientific and Technical Information of China (English)

    张明; 原梅妮; 向丰华; 王振兴

    2015-01-01

    The penetration resistance of Kevlar-129 fiber reinforced composite materials was investigated with AUTODYN soft-ware.The ballistic limits of the fragment that pierced 6 kinds of target plates were obtained by finite element simulation when the 10 g fragment simulation projectile (FSP)impacting to the target plates of different thickness values of 8,10,12,14,16 and 1 8 mm with appropriate velocity,respectively,and the influences of thickness on the ballistic limits and the specific energy absorption were analyzed.The results show that the ballistic limit of Kevlar-129 fiber reinforced composite plates presents line-ar growth with the increase of the target thickness in the range from 8 to 1 8 mm.The specific energy absorption of plates pres-ents approximately linear growth,but there is slightly slow growth in the range from 10 to 16 mm of the target thickness.It al-so can be found that the influences of plate thickness and surface density on the varying pattern of specific energy absorption are almost the same.Therefore,both of them can be used to characterize the variation of specific energy absorption under the im-pact of the FSP fragment.%基于 AUTODYN有限元软件,研究了Kevlar-129纤维增强复合材料的抗侵彻性能。通过质量为10 g的 FSP破片对厚度为8、10、12、14、16以及18 mm 的六组 Kevlar 纤维靶板进行撞击模拟,获得了 FSP破片贯穿6组靶板的弹道极限,并分析了靶板的弹道极限、比吸收能随板厚的变化关系。结果表明,在板厚8-18 mm范围内,Kevlar纤维靶板的弹道极限随板厚的增加呈线性增长;在此范围内,靶板的比吸收能也呈近似线性增长,但在板厚为10-16 mm时,增长稍缓。对比还发现,比吸收能随板厚的变化规律与靶板面密度的变化规律几乎相同,二者都可用于描述Kevlar-129纤维复合材料靶板在 FSP 破片碰撞下比吸收能的变化。

  15. Effects of Microstructure on CVN Impact Toughness in Thermomechanically Processed High Strength Microalloyed Steel

    Science.gov (United States)

    Jia, Tao; Zhou, Yanlei; Jia, Xiaoxiao; Wang, Zhaodong

    2017-02-01

    Investigation on the correlation between microstructure and CVN impact toughness is of practical importance for the microstructure design of high strength microalloyed steels. In this work, three steels with characteristic microstructures were produced by cooling path control, i.e., steel A with granular bainite (GB), steel B with polygonal ferrite (PF) and martensite-austenite (M-A) constituent, and steel C with the mixture of bainitic ferrite (BF), acicular ferrite (AF), and M-A constituent. Under the same alloy composition and controlled rolling, similar ductile-to-brittle transition temperatures were obtained for the three steels. Steel A achieved the highest upper shelf energy (USE), while large variation of impact absorbed energy has been observed in the ductile-to-brittle transition region. With apparently large-sized PF and M-A constituent, steel B shows the lowest USE and delamination phenomenon in the ductile-to-brittle transition region. Steel C exhibits an extended upper shelf region, intermediate USE, and the fastest decrease of impact absorbed energy in the ductile-to-brittle transition region. The detailed CVN impact behavior is studied and then linked to the microstructural features.

  16. The effect of high-pressure devitrification and densification on ballistic-penetration resistance of fused silica

    Science.gov (United States)

    Avuthu, Vasudeva Reddy

    perhaps alpha-quartz) within fused silica during ballistic impact. To rationalize the findings obtained, the all-atom molecular-level computational analysis is complemented by a series of quantum-mechanics density functional theory (DFT) computations. The latter computations enable determination of the relative potential energies of the fused silica, alpha-quartz and stishovite under ambient pressure (i.e. under their natural densities) as well as under imposed (as high as 50 GPa) pressures (i.e. under higher densities) and shear strains. In addition, the transition states associated with various fused-silica devitrification processes were identified. In the second part of the present work, the molecular-level computational results obtained in the first portion of the work are used to enrich a continuum-type constitutive model (that is, the so-called Johnson-Holmquist-2, JH2, model) for fused silica. Since the aforementioned devitrification and permanent-densification processes modify the response of fused silica to the pressure as well as to the deviatoric part of the stress, changes had to be made in both the JH2 equation of state and the strength model. To assess the potential improvements with respect to the ballistic-penetration resistance of this material brought about by the fused-silica devitrification and permanent-densification processes, a series of transient non-linear dynamics finite element analyses of the transverse impact of a fused-silica test plate with a solid right-circular cylindrical steel projectile was conducted. The results obtained revealed that, provided the projectile incident velocity and, hence, the attendant pressure, is sufficiently high, fused silica can undergo impact-induced energy-consuming devitrification, which improves its ballistic-penetration resistance.

  17. Ballistics examination of air rifle.

    Science.gov (United States)

    Bogiel, G

    2014-01-01

    The aim of this paper is to determine the velocity, energy, maximum range and distance at which pellets fired from an air rifle of kinetic energy below 17 J can pose a threat to unprotected human skin. Doppler radar equipment and exterior ballistics software were used in this examination.

  18. Ballistics examination of air rifle

    Directory of Open Access Journals (Sweden)

    Grzegorz Bogiel

    2014-08-01

    Full Text Available The aim of this paper is to determine the velocity, energy, maximum range and distance at which pellets fired from an air rifle of kinetic energy below 17 J can pose a threat to unprotected human skin. Doppler radar equipment and exterior ballistics software were used in this examination.

  19. Ballistics examination of air rifle

    OpenAIRE

    2014-01-01

    The aim of this paper is to determine the velocity, energy, maximum range and distance at which pellets fired from an air rifle of kinetic energy below 17 J can pose a threat to unprotected human skin. Doppler radar equipment and exterior ballistics software were used in this examination.

  20. Electron transport properties in InAs four-terminal ballistic junctions under weak magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, M.; Fujiwara, K.; Amano, N.; Maemoto, T.; Sasa, S.; Inoue, M. [Nanomaterials Microdevices Research Center, Osaka Institute of Technology (JP)u, Osaka 535-8585 (Japan)

    2009-06-15

    We report on the electron transport properties based on ballistic electrons under magnetic fields in four-terminal ballistic junctions fabricated on an InAs/AlGaSb heterostructure. The four-terminal junction structure is composed of two longitudinal stems with two narrow wires slanted with 30 degree from the perpendicular axis. The electron focusing peak was obtained with the bend resistance measurement. Then it was investigated the nonlinear electron transport property of potential difference between longitudinal stems due to ballistic electrons with applying direct current from narrow wires. Observed nonlinearity showed clear rectification effects which have negative polarity regardless of input voltage polarity. Although this nonlinearity was qualitatively changed due to the Lorentz force under magnetic fields, the degradation of ballistic effects on nonlinear properties were observed when the current increased to higher strength. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Investigation about the influence of the mechanical properties of lead core and brass jacket of a NATO 7.62 mm ball bullet in numerical simulations of ballistic impacts

    Directory of Open Access Journals (Sweden)

    Scapin M.

    2012-08-01

    Full Text Available In the present work a validated numerical approach has been used in order to build a robust and reliable FE model of the impact of a NATO 7.62 mm ball bullet, against an aluminium transmission shaft. The bullet is a full metal jacket type, with a lead alloy core and a brass jacket. Target shaft is made by an Al6061-T6 aluminium alloy. According to the soft core (lead alloy of the bullet, most effort has been spent in order to evaluate the effect of bullet materials mechanical properties on the numerical results. Numerical analyses, carried out using the non-linear dynamic finite element solver Abaqus∖Explicit 6.10, have been performed focusing on core and jacket material behaviour (target material, Al6061-T6, has been previously calibrated by the authors. Thus numerical analyses have been performed considering for the mechanical behaviour of the bullet both a simplified approach (as reported in literature and new material data (with strain rate effect obtained by means of experimental tests on the two materials (lead and brass with specimens cut directly from the bullet. Finally the results of the analyses have been compared with real experimental ballistic tests.

  2. Investigation about the influence of the mechanical properties of lead core and brass jacket of a NATO 7.62 mm ball bullet in numerical simulations of ballistic impacts

    Science.gov (United States)

    Giglio, M.; Gilioli, A.; Manes, A.; Peroni, L.; Scapin, M.

    2012-08-01

    In the present work a validated numerical approach has been used in order to build a robust and reliable FE model of the impact of a NATO 7.62 mm ball bullet, against an aluminium transmission shaft. The bullet is a full metal jacket type, with a lead alloy core and a brass jacket. Target shaft is made by an Al6061-T6 aluminium alloy. According to the soft core (lead alloy) of the bullet, most effort has been spent in order to evaluate the effect of bullet materials mechanical properties on the numerical results. Numerical analyses, carried out using the non-linear dynamic finite element solver Abaqus∖Explicit 6.10, have been performed focusing on core and jacket material behaviour (target material, Al6061-T6, has been previously calibrated by the authors). Thus numerical analyses have been performed considering for the mechanical behaviour of the bullet both a simplified approach (as reported in literature) and new material data (with strain rate effect) obtained by means of experimental tests on the two materials (lead and brass) with specimens cut directly from the bullet. Finally the results of the analyses have been compared with real experimental ballistic tests.

  3. Impact of quality of evidence on the strength of recommendations: an empirical study

    Directory of Open Access Journals (Sweden)

    Trikalinos Thomas A

    2009-07-01

    Full Text Available Abstract Background Evidence is necessary but not sufficient for decision-making, such as making recommendations by clinical practice guideline panels. However, the fundamental premise of evidence-based medicine (EBM rests on the assumed link between the quality of evidence and "truth" and/or correctness in making guideline recommendations. If this assumption is accurate, then the quality of evidence ought to play a key role in making guideline recommendations. Surprisingly, and despite the widespread penetration of EBM in health care, there has been no empirical research to date investigating the impact of quality of evidence on the strength of recommendations made by guidelines panels. Methods The American Association of Blood Banking (AABB has recently convened a 12 member panel to develop clinical practice guidelines (CPG for the use of fresh-frozen plasma (FFP for 6 different clinical indications. The panel was instructed that 4 factors should play a role in making recommendation: quality of evidence, uncertainty about the balance between desirable (benefits and undesirable effects (harms, uncertainty or variability in values and preferences, and uncertainty about whether the intervention represents a wise use of resources (costs. Each member of the panel was asked to make his/her final judgments on the strength of recommendation and the overall quality of the body of evidence. "Voting" was anonymous and was based on the use of GRADE (Grading quality of evidence and strength of recommendations system, which clearly distinguishes between quality of evidence and strength of recommendations. Results Despite the fact that many factors play role in formulating CPG recommendations, we show that when the quality of evidence is higher, the probability of making a strong recommendation for or against an intervention dramatically increases. Probability of making strong recommendation was 62% when evidence is "moderate", while it was only 23% and 13

  4. 树脂含量对芳纶防弹复合材料性能的影响%Influence of Different Resin Content on Twaron Ballistic Material Properties

    Institute of Scientific and Technical Information of China (English)

    方心灵; 吴中伟; 高虹; 刘元坤; 张静

    2012-01-01

    对不同树脂含量的芳纶纤维无纬布的力学性能和防弹性能进行了分析和测试,确定了最佳的树脂含量.结果表明:树脂含量在15% ~25%时,无纬布的拉伸强度、层间剥离强度以及冲击强度三项性能均表现优异,对应的防弹性能最好,这可为今后防弹复合材料的设计研究提供参考.%The paper studies mechanical properties and ballistic performance of different resin content of Twaron fiber no-woven cloth, the optimum resin content is determined. The results show that; the resin content is 15% -25% , the tensile strength, peeling strength and impact strength of no-woven cloth are better, ballistic performance of no-woven cloth is also better. This can provid useful information for the studies of ballistic material.

  5. Scale-up model describing the impact of lubrication on tablet tensile strength.

    Science.gov (United States)

    Kushner, Joseph; Moore, Francis

    2010-10-31

    Lubrication of 2:1 and 1:1 blends of microcrystalline cellulose and spray-dried lactose or dibasic calcium phosphate (DCP) with 0.33% or 1% magnesium stearate, as model free-flowing pharmaceutical formulations, was performed in rotary drum blenders. Blender process parameters examined in this study included type (Bin, V, and Turbula), volume (0.75-Quart to 200-L), fraction of headspace in the blender after the blend is loaded (30-70%), speed (6-202 rpm), and time (up to 225 min). Based on analysis of the experimental data, the following model for the impact of the lubrication process on tablet tensile strength at 0.85 solid fraction, TS(SF=0.85), was obtained, TS(SF=0.85)=TS(SF=0.85,0) [βexp(-γ×V(1/3)×F(headspace)×r)+(1-β)], where V is blender volume, F(headspace) is the headspace fraction, r is the number of revolutions (i.e. speed × time), TS(SF=0.85,0) is the initial tensile strength of the blend, β is the sensitivity of the blend to lubrication, and γ is the lubrication rate constant of the formulation. This model can be used to maintain tensile strength during scale-up, by ensuring that (V(1/3)F(headspace)r)(1)=(V(1/3)F(headspace)r)(2). The model also suggests that formulations with DCP are less sensitive to lubrication and more slowly lubricated than formulations with spray-dried lactose (i.e. smaller β and γ values).

  6. STUDY ON HIGH WELD STRENGTH OF IMPACT PROPYLENE COPOLYMER/HIGH DENSITY POLYETHYLENE LAMINATES

    Institute of Scientific and Technical Information of China (English)

    Chun-hui Zhang; Rui-fen Chen; Feng Chen; Yong-gang Shangguan; Qiang Zheng; Guo-hua Hu

    2011-01-01

    The impact propylene copolymer (IPC) and isotactic polypropylene (iPP) were separately selected to prepare laminates with high density polyethylene (HDPE) by hot press. The peel forces of IPC/HDPE and iPP/HDPE laminates were examined, and it was found that the welded joint strength in IPC/HDPE laminate was dramatically higher than that of iPP/HDPE laminate. According to the special microstructure of IPC, the co-crystallization of the ethylene segments in ethylene-propylene block copolymer (EbP) component of IPC and the PE chain in HDPE was proposed to explain the highstrength welding. The DSC results indicated that there indeed existed some interaction between IPC and HDPE, and the crystallizable PE component in IPC could affect the crystallization of HDPE. The scanning electron microscope (SEM) observations of IPC/HDPE blends demonstrated that HDPE tended to stay with the PE-rich EbP chains to form the dispersed phase, indicating the good miscibility between HDPE and EbP components of IPC. According to the above results, the effect of co-crystallization of the PE components of theIPC and HDPE on the high weld strength of IPC/HDPE laminate was confirmed.

  7. Springback Prediction and Compensation for a High Strength Steel Side Impact Beam

    Science.gov (United States)

    Dutton, Trevor; Edwards, Richard; Blowey, Andrew

    2005-08-01

    Prediction of formability for sheet metal pressings has advanced to a high state of confidence in recent years. The major challenge is now to predict springback and, moreover, to assist in the design of tooling to correctly compensate for springback. This is particularly the case for materials now being routinely considered for automotive production, such as aluminium and ultra high strength steels, which are prone to greater degrees of springback than traditional mild steels. This paper presents a case study based on the tool design for an ultra high strength steel side impact beam. The forming and springback simulations, carried out using eta/DYNAFORM (based on the LS-DYNA solver), are reported and compared to measurements from the prototype panels. The analysis parameters used in the simulation are presented, and the sensitivity of the results to variation in physical properties is also reviewed. The process of compensating the tools based on the analysis prediction is described; finally, an automated springback compensation method is also applied and the results compared with the final tool design.

  8. The ballistic performance of the bombard Mons Meg

    Directory of Open Access Journals (Sweden)

    Ian Lewtas

    2016-04-01

    Full Text Available The bombard Mons Meg, located in Edinburgh Castle, with a diameter of 19 inches (48 cm, was one of the largest calibre cannons ever built. Constructed in 1449 and presented to King James II of Scotland in 1454, Mons Meg was used in both military and ceremonial roles in Scotland until its barrel burst in 1680. This paper examines the history, internal, external and terminal ballistics of the cannon and its shot. The likely muzzle velocity was estimated by varying the propellant type and the cannon profile was investigated to identify weak spots in the design that may have led to its failure. Using the muzzle velocity calculated from the internal ballistics, simulations were performed with granite and sandstone shot for varying launch angle and ground temperature. The likely trajectory and range of the cannonballs are described. The internal and external ballistics informed the initial conditions of the terminal ballistic impact scenarios. The performance of the cannonball against both period and modern targets, in the form of a pseudo-castle wall and a monolithic concrete target, respectively, were simulated and are presented and discussed.

  9. The ballistic performance of the bombard Mons Meg

    Institute of Scientific and Technical Information of China (English)

    Ian LEWTAS; Rachael MCALISTER; Adam WALLIS; Clive WOODLEY; Ian CULLIS

    2016-01-01

    The bombard Mons Meg, located in Edinburgh Castle, with a diameter of 19 inches (48 cm), was one of the largest calibre cannons ever built. Constructed in 1449 and presented to King James II of Scotland in 1454, Mons Meg was used in both military and ceremonial roles in Scotland until its barrel burst in 1680. This paper examines the history, internal, external and terminal ballistics of the cannon and its shot. The likely muzzle velocity was estimated by varying the propellant type and the cannon profile was investigated to identify weak spots in the design that may have led to its failure. Using the muzzle velocity calculated from the internal ballistics, simulations were performed with granite and sandstone shot for varying launch angle and ground temperature. The likely trajectory and range of the cannonballs are described. The internal and external ballistics informed the initial conditions of the terminal ballistic impact scenarios. The performance of the cannonball against both period and modern targets, in the form of a pseudo-castle wall and a monolithic concrete target, respectively, were simulated and are presented and discussed.

  10. Influence of reprocessing on fibre length distribution, tensile strength and impact strength of injection moulded cellulose fibre-reinforced polylactide (PLA composites

    Directory of Open Access Journals (Sweden)

    N. Graupner

    2016-08-01

    Full Text Available The present study focuses on the reprocessing behaviour of recycled injection moulded polylactide (PLA composites. The composites are reinforced with regenerated cellulose fibres (lyocell of variable fineness and a fibre mass content of 30%. They were reprocessed up to three times. The influence of reprocessing on the fibre length distribution and the resulting composite mechanical properties (tensile and impact strength was analysed. While the first reprocessing cycle does not affect the mechanical characteristics of the neat PLA matrix, the strength of the composites decreases significantly due to a decreasing fibre aspect ratio. It was shown that fibres having a larger cross-sectional area display a lower aspect ratio than finer fibres, after reprocessing. This phenomenon leads to a larger decrease in tensile strength of composites reinforced with coarser fibres when compared to composites reinforced with finer fibres. A comparison of virgin composites and threefold reprocessed composites with a similar fibre length distribution resulted in a significantly higher tensile strength compared to the virgin sample. This result leads to the conclusion that not only the fibre length is drastically reduced by reprocessing but also that the fibres and the matrix were damaged.

  11. Differential oscillator strengths for chlorine dioxide, OClO, produced by electron impact energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J.A.; Mason, N.J. [University Coll., London (United Kingdom). Dept. of Physics and Astronomy; Marston, G.; Wayne, R.P. [Oxford Univ. (United Kingdom). Physical Chemistry Lab.

    1995-09-28

    Electron impact spectroscopy has been used for the first time to obtain energy-loss spectra for chlorine dioxide, OC10, over an energy range 2.5 {yields} 12.5 eV. The differential oscillator strength (DOS) obtained from the energy-loss spectrum is compared with the DOS obtained from optical measurements. Oscillator strengths for several transitions have been calculated from a summation of the DOS and comparisons are also made with previous optical data. (author).

  12. One Dimensional Ballistic Electron Transport

    Directory of Open Access Journals (Sweden)

    Thomas K J

    2009-10-01

    Full Text Available Research in low-dimensional semiconductor systems over the last three decades has been largely responsible for the current progress in the areas of nanoscience and nanotechnology. The ability to control and manipulate the size, the carrier density, and the carrier type in two-, one-, and zero- dimensional structures has been widely exploited to study various quantum transport phenomena. In this article, a brief introduction is given to ballistic electron transport in one-dimensional quantum wires.

  13. Reference ballistic imaging database performance.

    Science.gov (United States)

    De Kinder, Jan; Tulleners, Frederic; Thiebaut, Hugues

    2004-03-10

    Ballistic imaging databases allow law enforcement to link recovered cartridge cases to other crime scenes and to firearms. The success of these databases has led many to propose that all firearms in circulation be entered into a reference ballistic image database (RBID). To assess the performance of an RBID, we fired 4200 cartridge cases from 600 9mm Para Sig Sauer model P226 series pistols. Each pistol fired two Remington cartridges, one of which was imaged in the RBID, and five additional cartridges, consisting of Federal, Speer, Winchester, Wolf, and CCI brands. Randomly selected samples from the second series of Remington cartridge cases and from the five additional brands were then correlated against the RBID. Of the 32 cartridges of the same make correlated against the RBID, 72% ranked in the top 10 positions. Likewise, of the 160 cartridges of the five different brands correlated against the database, 21% ranked in the top 10 positions. Generally, the ranking position increased as the size of the RBID increased. We obtained similar results when we expanded the RBID to include firearms with the same class characteristics for breech face marks, firing pin impressions, and extractor marks. The results of our six queries against the RBID indicate that a reference ballistics image database of new guns is currently fraught with too many difficulties to be an effective and efficient law enforcement tool.

  14. Comparing ballistic wounds with experiments on body simulator.

    Science.gov (United States)

    Bresson, F; Franck, O

    2010-05-20

    This paper demonstrates how ballistic experiments on body simulator can bring a key information in the forensic science field. In the investigated case, a hunter was shot by accident in the back. Two hunters were suspected of having inadvertently shot towards the victim. The deadly bullet left the body and cannot be found on the scene neither in the body. The only way to discriminate the two options was to perform ballistic tests in body simulators. Even though the knowledge about body simulators is not enough advanced yet to expect accurate quantitative results, it was supposed to fully discriminate the two investigated cases as its respective impact energy are highly different (respectively 1200J and 2400J). For each investigated possibility, bullet's expansion state and body wounds were simulated. Bullet impact characteristics were determined by measuring the muzzle velocity, compute the impact velocity in the considered range (the position of each hunter is accurately known). Reloading cartridges allowed to reproduce accuretaly the corresponding velocity. The body was simulated by 3 different means in order to explore the accuracy of the simulation process. We demonstrated that the reported case is situated in a velocity/energy range in which body simulators do not need to be particularly accurate to reproduce the bullet expansion/non-expansion state. It furthermore demonstrated that only one case is compatible with the ballistic wounds of the victim. In the other case, the bullet's expansion would lead to a completely different wound shape.

  15. A new approach in treating the ballistic coefficient in the differential correction fitting program

    Science.gov (United States)

    Barker, William N.; Eller, Thomas J.; Herder, Leland E.

    This paper describes the results of study to improve the accuracy of tracking and impact prediction special perturbations software in use at the Space Surveillance Center. First, historical data are considered for a wide range of decayed satellites. In general, this data indicate that the satellite ballistic coefficient (a model parameter in the directional correction process) varies as a function of time in the last days prior to decay. At present, this effect is not modeled and the ballistic coefficient is held constant over the differential correction observation span. The new approach presented here is a parameterization of the ballistic coefficient in the form of a simple linear function with time. The slope of this function is the time derivative of the ballistic coefficient which is treated as a new model parameter. Numerical results obtained from processing two important historical satellite decay cases are presented.

  16. Impact of Particle Size of Ceramic Granule Blends on Mechanical Strength and Porosity of 3D Printed Scaffolds

    Directory of Open Access Journals (Sweden)

    Sebastian Spath

    2015-07-01

    Full Text Available 3D printing is a promising method for the fabrication of scaffolds in the field of bone tissue engineering. To date, the mechanical strength of 3D printed ceramic scaffolds is not sufficient for a variety of applications in the reconstructive surgery. Mechanical strength is directly in relation with the porosity of the 3D printed scaffolds. The porosity is directly influenced by particle size and particle-size distribution of the raw material. To investigate this impact, a hydroxyapatite granule blend with a wide particle size distribution was fractioned by sieving. The specific fractions and bimodal mixtures of the sieved granule blend were used to 3D print specimens. It has been shown that an optimized arrangement of fractions with large and small particles can provide 3D printed specimens with good mechanical strength due to a higher packing density. An increase of mechanical strength can possibly expand the application area of 3D printed hydroxyapatite scaffolds.

  17. Ballistic transport in planetary ring systems due to particle erosion mechanisms. I - Theory, numerical methods, and illustrative examples

    Science.gov (United States)

    Durisen, Richard H.; Murphy, Brian W.; Cramer, Nichael Lynn; Cuzzi, Jeffrey N.; Mullikin, Thomas L.

    1989-01-01

    Ballistic transport, defined as the net radial transport of mass and angular momentum due to exchanges of meteoroid hypersonic-impact ejecta by neighboring planetary ring regions on time-scales orders-of-magnitude shorter than the age of the solar system, is presently considered as a problem in mathematical physics. The preliminary results of a numerical scheme for following the combined effects of ballistic transport and viscous diffusion demonstrate that ballistic transport generates structure near sharp edges already present in the ring-mass distribution; the entire ring system ultimately develops an undulatory structure whose length scale is typically of the order of the radial excursion of the impact ejecta.

  18. Impact behaviors of poly-lactic acid based biocomposite reinforced with unidirectional high-strength magnesium alloy wires

    Directory of Open Access Journals (Sweden)

    Xuan Li

    2014-10-01

    Full Text Available A novel poly-lactic acid (PLA based biocomposite reinforced with unidirectional high-strength magnesium alloy (Mg-alloy wires for bone fracture fixation was fabricated by hot-compressing process. The macroscopical and microscopical impact behaviors of the biocomposite were investigated using impact experiments and finite element method (FEM, respectively. The results indicated that the biocomposite had favorable impact properties due to the plastic deformation behavior of Mg-alloy wires during impact process. While the content of Mg-alloy wires reached 20 vol%, the impact strength of the composite could achieve 93.4 kJ/m2, which is approximate 16 times larger than that of pure PLA fabricated by the same process. According to FEM simulation results, the complete destruction life of the composites during impact process increased with increasing volume fraction of Mg-alloy wires, indicating a high impact-bearing ability of the composite for bone fracture fixation. Simultaneously, the energy absorbed by Mg-alloy wires in the composites had a corresponding increase. In addition, it denoted that the impact properties of the composites are sensitive to the initial properties of the matrix material.

  19. Impact behaviors of poly-lactic acid based biocomposite reinforced with unidirectional high-strength magnesium alloy wires

    Institute of Scientific and Technical Information of China (English)

    Xuan Li; Chao Guo; Xiaokai Liu; Lei Liu; Jing Bai; Feng Xue; Pinghua Lin; Chenglin Chu

    2014-01-01

    A novel poly-lactic acid (PLA) based biocomposite reinforced with unidirectional high-strength magnesium alloy (Mg-alloy) wires for bone fracture fixation was fabricated by hot-compressing process. The macroscopical and microscopical impact behaviors of the biocomposite were investigated using impact experiments and finite element method (FEM), respectively. The results indicated that the biocomposite had favorable impact properties due to the plastic deformation behavior of Mg-alloy wires during impact process. While the content of Mg-alloy wires reached 20 vol%, the impact strength of the composite could achieve 93.4 kJ/m2, which is approximate 16 times larger than that of pure PLA fabricated by the same process. According to FEM simulation results, the complete destruction life of the composites during impact process increased with increasing volume fraction of Mg-alloy wires, indicating a high impact-bearing ability of the composite for bone fracture fixation. Simultaneously, the energy absorbed by Mg-alloy wires in the composites had a corresponding increase. In addition, it denoted that the impact properties of the composites are sensitive to the initial properties of the matrix material.

  20. The Cooperative Ballistic Missile Defence Game

    NARCIS (Netherlands)

    Evers, L.; Barros, A.I.; Monsuur, H.

    2013-01-01

    The increasing proliferation of ballistic missiles and weapons of mass destruction poses new risks worldwide. For a threatened nation and given the characteristics of this threat a layered ballistic missile defence system strategy appears to be the preferred solution. However, such a strategy involv

  1. Ballistic transport in Saturn's rings - An analytic theory

    Science.gov (United States)

    Lissauer, J. J.

    1984-01-01

    Ejecta from impacts of micrometeoroids on Saturn's ring particles will, in most cases, remain in orbit about Saturn and eventually be reaccreted by the rings, possibly at a different radial location. The resulting mass transport has been suggested as the cause of some of the features observed in Saturn's rings. Previous attempts to model this transport have used numerical simulations which have not included the effects of the angular momentum transport coincident with mass transport. An analytical model for ballistic mass transport in Saturn's rings is developed. The model includes the effects of angular momentum advection and shows that the net material movement due to angular momentum advection is comparable to that caused by direct ballistic mass transport.

  2. Strength training prior to endurance exercise: impact on the neuromuscular system, endurance performance and cardiorespiratory responses.

    Science.gov (United States)

    Conceição, Matheus; Cadore, Eduardo Lusa; González-Izal, Miriam; Izquierdo, Mikel; Liedtke, Giane Veiga; Wilhelm, Eurico Nestor; Pinto, Ronei Silveira; Goltz, Fernanda Reistenbach; Schneider, Cláudia Dornelles; Ferrari, Rodrigo; Bottaro, Martim; Kruel, Luiz Fernando Martins

    2014-12-09

    This study aimed to investigate the acute effects of two strength-training protocols on the neuromuscular and cardiorespiratory responses during endurance exercise. Thirteen young males (23.2 ± 1.6 years old) participated in this study. The hypertrophic strength-training protocol was composed of 6 sets of 8 squats at 75% of maximal dynamic strength. The plyometric strength-training protocol was composed of 6 sets of 8 jumps performed with the body weight as the workload. Endurance exercise was performed on a cycle ergometer at a power corresponding to the second ventilatory threshold until exhaustion. Before and after each protocol, a maximal voluntary contraction was performed, and the rate of force development and electromyographic parameters were assessed. After the hypertrophic strength-training and plyometric strength-training protocol, significant decreases were observed in the maximal voluntary contraction and rate of force development, whereas no changes were observed in the electromyographic parameters. Oxygen uptake and a heart rate during endurance exercise were not significantly different among the protocols. However, the time-to-exhaustion was significantly higher during endurance exercise alone than when performed after hypertrophic strength-training or plyometric strength-training (p strength-training, with no oxygen uptake or heart rate changes during the exercise.

  3. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    Directory of Open Access Journals (Sweden)

    Maria J. Gerschutz, PhD

    2011-10-01

    Full Text Available Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn Rigid and Orfitrans Stiff check socket materials produced significantly lower tensile strength and impact resistance than polyethylene terephthalate glycol (PETG. Copolymer socket materials exhibited greater resistance to impact forces than the check socket materials but lower tensile strengths than PETG. The heated molding processes, for the check socket and copolymer materials, reduced both tensile strength and elongation at break. Definitive laminated sockets were sorted according to fabrication techniques. Nyglass material had significantly higher elongation, indicating a more ductile material than carbon-based laminations. Carbon sockets with pigmented resin had higher tensile strength and modulus at break than nonpigmented carbon sockets. Elongation at yield and elongation at break were similar for both types of carbon-based laminations. The material properties determined in this study provide a foundation for understanding and improving the quality of prosthetic sockets using current fabrication materials and a basis for evaluating future technologies.

  4. Computational Analysis of the Compressible Flow Driven by a Piston in a Ballistic Range

    Institute of Scientific and Technical Information of China (English)

    G. Rajesh; R. Mishra; H. G. Kang; H. D. Kim

    2007-01-01

    The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics and aeroballistics, since it can create an extremely high-pressure state in very short time. Since the operation of the ballistic range includes many complicated phenomena, each process should be understood in detail for the performance enhancement of the device. One of the main processes which have significant influence on the device performance is the compression process of the driver gas. Most of the studies available in this field hardly discuss this phenomenon in detail and thus lack a proper understanding of its effect on the whole system performance. In the present study, a computational analysis has been made to investigate the fluid dynamic aspects of the compression process in the pump tube of a ballistic range and to assess how it affects the performance of the ballistic range, The results obtained are validated with the available experimental data. In order to evaluate the system performance, several performance parameters are defined. Effect of a shock tube added in between the pump tube and launch tube on the performance of the ballistic range is also studied analytically. Performance of the ballistic range could be significantly improved by the proper selection of the pump tube and high-pressure tube parameters and the addition of the shock tube.

  5. Potentiation Effects of Half-Squats Performed in a Ballistic or Nonballistic Manner.

    Science.gov (United States)

    Suchomel, Timothy J; Sato, Kimitake; DeWeese, Brad H; Ebben, William P; Stone, Michael H

    2016-06-01

    Suchomel, TJ, Sato, K, DeWeese, BH, Ebben, WP, and Stone, MH. Potentiation effects of half-squats performed in a ballistic or nonballistic manner. J Strength Cond Res 30(6): 1652-1660, 2016-This study examined and compared the acute effects of ballistic and nonballistic concentric-only half-squats (COHSs) on squat jump performance. Fifteen resistance-trained men performed a squat jump 2 minutes after a control protocol or 2 COHSs at 90% of their 1 repetition maximum (1RM) COHS performed in a ballistic or nonballistic manner. Jump height (JH), peak power (PP), and allometrically scaled peak power (PPa) were compared using three 3 × 2 repeated-measures analyses of variance. Statistically significant condition × time interaction effects existed for JH (p = 0.037), PP (p = 0.041), and PPa (p = 0.031). Post hoc analysis revealed that the ballistic condition produced statistically greater JH (p = 0.017 and p = 0.036), PP (p = 0.031 and p = 0.026), and PPa (p = 0.024 and p = 0.023) than the control and nonballistic conditions, respectively. Small effect sizes for JH, PP, and PPa existed during the ballistic condition (d = 0.28-0.44), whereas trivial effect sizes existed during the control (d = 0.0-0.18) and nonballistic (d = 0.0-0.17) conditions. Large statistically significant relationships existed between the JH potentiation response and the subject's relative back squat 1RM (r = 0.520; p = 0.047) and relative COHS 1RM (r = 0.569; p = 0.027) during the ballistic condition. In addition, large statistically significant relationship existed between JH potentiation response and the subject's relative back squat strength (r = 0.633; p = 0.011), whereas the moderate relationship with the subject's relative COHS strength trended toward significance (r = 0.483; p = 0.068). Ballistic COHS produced superior potentiation effects compared with COHS performed in a nonballistic manner. Relative strength may contribute to the elicited potentiation response after ballistic and

  6. Modeling and Simulation of Ballistic Penetration of Ceramic-Polymer-Metal Layered Systems

    Directory of Open Access Journals (Sweden)

    J. D. Clayton

    2015-01-01

    Full Text Available Numerical simulations and analysis of ballistic impact and penetration by tungsten alloy rods into composite targets consisting of layers of aluminum nitride ceramic tile(s, polymer laminae, and aluminum backing are conducted over a range of impact velocities on the order of 1.0 to 1.2 km/s. Computational results for ballistic efficiency are compared with experimental data from the literature. Simulations and experiments both demonstrate a trend of decreasing ballistic efficiency with increasing impact velocity. Predicted absolute residual penetration depths often exceed corresponding experimental values. The closest agreement between model and experiment is obtained when polymer interfaces are not explicitly represented in the numerical calculations, suggesting that the current model representation of such interfaces may be overly compliant. The present results emphasize the importance of proper resolution of geometry and constitutive properties of thin layers and interfaces between structural constituents for accurate numerical evaluation of performance of modern composite protection systems.

  7. Inelastic deformation and failure of tungsten carbide under ballistic-loading conditions

    NARCIS (Netherlands)

    Hazell, P.J.; Appleby-Thomas, G.J.; Herlaar, K.; Painter, J.

    2010-01-01

    High-speed photography has been used to investigate the dynamic behaviour of similar grades of WC-Co hardmetals during ballistic impacts with velocities in the range of 28-484. m/s. Key features of the failure of similar grades of WC-Co materials during complimentary impacts have been observed and d

  8. Numerical and experimental evaluation of the impact performance of advanced high-strength steel sheets based on a damage model

    Science.gov (United States)

    Ma, Ning; Park, Taejoon; Kim, Dongun; Kim, Chongmin; Chung, Kwansoo

    2010-06-01

    The impact performance in a Charpy impact test was experimentally and numerically studied for the advanced high-strength steel sheets (AHSS) TWIP940 and TRIP590 as well as the high-strength grade known as 340R. To characterize the mechanical properties, uni-axial simple tension tests were conducted to determine the anisotropic properties and strain rate sensitivities of these materials. In particular, the high-speed strain-rate sensitivity of TRIP590 and 340R (rate sensitive) was also characterized to account for the high strain rates involved in the Charpy impact test. To evaluate fracture behavior in the Charpy impact test, a new damage model including a triaxiality-dependent fracture criterion and hardening behavior with stiffness deterioration was introduced. The model was calibrated via numerical simulations and experiments involving simple tension and V-notch tests. The new damage model along with the anisotropic yield function Hill 1948 was incorporated into the ABAQUS/Explicit FEM code, which performed reasonably well to predict the impact energy absorbed during the Charpy impact test.

  9. A Comparative Study of Ballistic Resistance of Sandwich Panels with Aluminum Foam and Auxetic Honeycomb Cores

    Directory of Open Access Journals (Sweden)

    Shu Yang

    2013-01-01

    Full Text Available An innovative auxetic-cored sandwich panel (AXP is proposed. Its perforation resistant performance under high-velocity projectile impact was numerically analyzed using the validated finite element simulation techniques and compared with that of the aluminum foam-cored sandwich panel (AFP of identical dimensions and weight. It has been found that the AXP is far superior to the AFP in ballistic resistance because of the material concentration at the impacted area due to the negative Poisson's ratio (NPR effect. A parametric study was carried out to investigate the effects of several key parameters, including impact velocity, face and core thicknesses, and core density, on the ballistic resistance of the AXP and AFP. The results show that the ballistic limit and perforation energy of the AXP is greatly affected by these parameters. Meanwhile, the advantages of AXP over AFP being used as ballistic resistant structures are highlighted. The primary outcome of this research is new information on the development and design of advanced ballistic resistant structures containing auxetic materials.

  10. A model for evaluating the ballistic resistance of stratified packs

    Science.gov (United States)

    Pirvu, C.; Georgescu, C.; Badea, S.; Deleanu, L.

    2016-08-01

    Models for evaluating the ballistic performance of stratified packs are useful in reducing the time for laboratory tests, understanding the failure process and identifying key factors to improve the architecture of the packs. The authors present the results of simulating the bullet impact on a packs made of 24 layers, taking into consideration the friction between layers (μ = 0.4) and the friction between bullet and layers (μ = 0.3). The aim of this study is to obtain a number of layers that allows for the bullet arrest in the packs and to have several layers undamaged in order to offer a high level of safety for this kind of packs that could be included in individual armors. The model takes into account the yield and fracture limits of the two materials the bullet is made of and those for one layer, here considered as an orthotropic material, having maximum equivalent plastic strain of 0.06. All materials are considered to have bilinear isotropic hardening behavior. After documentation, the model was designed as isothermal because thermal influence of the impact is considered low for these impact velocities. The model was developed with the help of Ansys 14.5. Each layer has 200 mm × 200 × 0.35 mm. The bullet velocity just before impact was 400 m/s, a velocity characterizing the average values obtained in close range with a ballistic barrel and the bullet model is following the shape and dimensions of the 9 mm FMJ (full metal jacket). The model and the results concerning the number of broken layers were validated by experiments, as the number of broken layers for the actual pack (made of 24 layers of LFT SB1) were also seven...eight. The models for ballistic impact are useful when they are particularly formulated for resembling to the actual system projectile - target.

  11. Shape and size effects of ceria nanoparticles on the impact strength of ceria/epoxy resin composites

    Institute of Scientific and Technical Information of China (English)

    Xiaoqiang He; Dengsong Zhang; Hongrui Li; Jianhui Fang; Liyi Shi

    2011-01-01

    Ceria nanoparticles with various shapes (rods,cubes,and plates) and sizes were controllably synthesized and then introduced into epoxy resin. Subsequently,we investigated correlations between the shape and size of ceria nanostructures and the mechanical performance of composites. The samples were characterized by transmission electron microscopy,scanning electron microscopy,and X-ray diffraction. Compared with commercial ceria filled composites,the composites made with morphology-controlled ceria nanostructures show a higher impact strength. It is found that epoxy resins made with high-aspect-ratio ceria nanorods show the highest impact strength,up to 17.27 kJ/m2,which is about four times that of the neat epoxy resin.

  12. Impact of New Gamow-Teller Strengths on Explosive Type Ia Supernova Nucleosynthesis

    CERN Document Server

    Mori, Kanji; Kajino, Toshitaka; Suzuki, Toshio; Hidaka, Jun; Honma, Michio; Iwamoto, Koichi; Nomoto, Ken'ichi; Otsuka, Takaharu

    2016-01-01

    Recent experimental results have confirmed a possible reduction in the GT$_+$ strengths of pf-shell nuclei. These proton-rich nuclei are of relevance in the deflagration and explosive burning phases of Type Ia supernovae. While prior GT strengths result in nucleosynthesis predictions with a lower-than-expected electron fraction, a reduction in the GT$_+$ strength can result in an slightly increased electron fraction compared to previous shell model predictions, though the enhancement is not as large as previous enhancements in going from rates computed by Fuller, Fowler, and Newman based on an independent particle model. A shell model parametrization has been developed which more closely matches experimental GT strengths. The resultant electron-capture rates are used in nucleosynthesis calculations for carbon deflagration and explosion phases of Type Ia supernovae, and the final mass fractions are compared to those obtained using more commonly-used rates.

  13. Preservation and storage of prepared ballistic gelatine.

    Science.gov (United States)

    Mattijssen, E J A T; Alberink, I; Jacobs, B; van den Boogaard, Y

    2016-02-01

    The use of ballistic gelatine, generally accepted as a human muscle tissue simulant in wound ballistic studies, might be improved by adding a preservative (Methyl 4-hydroxybenzoate) which inhibits microbial growth. This study shows that replacing a part of the gelatine powder by the preservative does not significantly alter the penetration depth of projectiles. Storing prepared blocks of ballistic gelatine over time decreased the penetration depth of projectiles. Storage of prepared gelatine for 4 week already showed a significant effect on the penetration depth of projectiles.

  14. Electron impact excitation collision strengths for neon-like Ni XIX calculated using the relativistic R-matrix method

    Indian Academy of Sciences (India)

    K M Aggarwal; F P Keenan

    2006-09-01

    In a recent paper [Pramana - J. Phys. 64, 129 (2005)] results have been presented for electron impact excitation collision strengths for transitions among the fine-structure levels of the 2s22p6 and 2s22p53s configurations of Ni XIX. In this paper we demonstrate through an independent calculation with the relativistic -matrix code that those results are unreliable and the conclusions drawn are invalid.

  15. Strengthening of oxidation resistant materials for gas turbine applications. [treatment of silicon ceramics for increased flexural strength and impact resistance

    Science.gov (United States)

    Kirchner, H. P.

    1974-01-01

    Silicon nitride and silicon carbide ceramics were treated to form compressive surface layers. On the silicon carbide, quenching and thermal exposure treatments were used, and on the silicon nitride, quenching, carburizing, and a combination of quenching and carburizing were used. In some cases substantial improvements in impact resistance and/or flexural strength were observed. The presence of compressive surface stresses was demonstrated by slotted rod tests.

  16. [Development of a ballistic furnace for shell production]. Annual report 1998

    Energy Technology Data Exchange (ETDEWEB)

    Cook, R; Isakov, A I

    1998-12-31

    During the fourth contract year, the authors continued to develop Ballistic technology of shell formation. A new upgraded version of Ballistic Furnace with longer hot zone (1.56m) and cooling one (1.2m) had been finally assembled, and a lot of shell formation experiments had been carried out. The change of the Ballistic Furnace configuration has led to significant changing in operational conditions suitable for shells production. They had found optimal operational conditions for some grades of initial granules giving them high yield of good shells. Serious attention was paid on initial granules preparation. In the experiments some unexpected results were obtained--first of all it was a strong influence of temperature profile, an initial granule velocity and a trajectory angle on good quality shells yield. Those observations made them consider some additional physical phenomena (initial granule defragmentation and gas convection inside hot zone) to explain good shell formation. Appropriate estimations of the velocity of possible convectional gas currents in the hot zone, strength of formed shells, thermal stress in an initial granule caused by its fast heating in the ballistic furnace etc. were made. Good quality shells up to 2mm in diameters with high yield were produced. Although a production of good quality shells in diameter range > 1.8 mm stays an easy job, their experience led them to declare that Ballistic technology hasn't reach its boundaries, and future development will allow them to obtain perfect results.

  17. The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

    Science.gov (United States)

    Tomlinson, D J; Erskine, R M; Morse, C I; Winwood, K; Onambélé-Pearson, Gladys

    2016-06-01

    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.

  18. Review of Ballistic Limit Equations for Composite Structure Walls of Satellites

    Science.gov (United States)

    Schaefer, Frank K.*; Schneider, E.; Lambert, M.

    2004-08-01

    In this paper a review of existing ballistic limit equations for CFRP (Carbon Fibre Reinforced Plastics) structure walls of satellites is given, and two new ballistic limit equations are presented. The predictive capabilities of the equations are compared to a set of experimental hypervelocity impact test data of CFRP plates and CFRP honeycomb sandwich panels (satellite structure wall) from ENVISAT, AXAF, and a generic technology program. In the literature, three ballistic limit equations for sandwich panels (SP) made from CFRP face-sheets and Al- honeycomb (H/C) core were found and analyzed (Frost's approach, Approach using Christiansen's Whipple shield Ballistic Limit Equation (BLE), and Taylor's approach). Furthermore, in this paper, a new ballistic limit equation was proposed for CFRP H/C SP (Modified ESA Triple Wall Equation) and for composite panels (plates) with and without MLI attached to the surface. The amount of impact data on CFRP structure walls of satellites found in the literature was rather scarce. The new BLE for CFRP plates makes good predictions to the available set of test data. For the BLE for CFRP H/C SP, it was found that Frost's approach and application of Christiansen's BLE to CFRP H/C SP lead to an overprediction of the ballistic limit diameters for ENVISAT structure walls and the samples of the generic technology program. Taylor's approach and the newly designed MET ballistic limit equation have both yielded good predictions for all samples except for the AXAF samples that had rather thin-walled face-sheets and a thin Al H/C core: for these samples the predictions were conservative. Thus, for use in risk analysis tools for satellites (e. g. ESA's ESABASE/DEBRIS tool or NASA's BUMPER code), it is recommended to use either the MET or Taylor equation.

  19. Enhanced Thermal Performance and Impact Strength of UHMWPE/Recycled-PA6 Blends Synthesized via a Melting Extrusion Route

    Directory of Open Access Journals (Sweden)

    Xiuying Yang

    2016-01-01

    Full Text Available The blends of ultra-high molecular weight polyethylene (UHMWPE and recycled-polyamide 6 (R-PA6 were prepared via a melting extrusion route using high-density polyethylene-graft-maleic anhydride (HDPE-g-MAH as the compatibilizer. The morphologies and distributions of the chemical components of the blends were characterized by scanning electron microscopy and synchrotron Fourier transform infrared microspectroscopy. The effects of R-PA6 content on the Vicat softening temperature (VST, heat distortion temperature (HDT, and impact strength of the blends were studied. Remarkably, in comparison with those of UHMWPE, the VST and HDT of UHMWPE/R-PA6 blends with 44 wt% R-PA6 were increased to 165.1 and 98.4°C, respectively, and the Charpy impact strength and Izod impact strength of the blends were enhanced to 33.9 and 16.2 kJ/m2, respectively. In addition, it was found that the blending system containing 44 wt% R-PA6 and 48 wt% UHMWPE exhibited the best compatibility when it was prepared using 8 wt% HDPE-g-MAH. The distribution of the phases of UHMWPE and R-PA6 was uniform, and no obvious phase separation was observed in the blends.

  20. EFFECT OF PROCESSING METHOD ON THE IMPACT STRENGTH OF POM/TPU/CaCO3 TERNARY COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Xiao-ling Gao; Cheng Qu; Qin Zhang; Rong-ni Du; Qiang Fu

    2005-01-01

    Polyoxymethylene (POM)/elastomer/filler ternary composites were prepared, in which thermoplastic polyurethane (TPU) and inorganic filler, namely, CaCO3, were used to achieve balanced mechanical properties of POM. The dispersion and phase morphology of POM/elastomer/filler composites were found to depend largely on processing method, CaCO3content in masterbatch and the filler size. Two processing methods were employed to prepare POM/elastomer/filler ternary composites. One is called the one-step method, in which elastomer and the filler directly melt blended with POM matrix. The other is called the two-step method, in which the elastomer and the filler were mixed to get masterbatch first, which was then melt blended with pure POM of different content. The effect of phase morphology and processing method on impact strength was investigated. It was found that the two-step method results in an increase in impact strength but not for the one-step method. Additionally, the impact strength of POM ternary composites decreases with the increase in the size of CaCO3particles.

  1. Wave propagation in ballistic gelatine.

    Science.gov (United States)

    Naarayan, Srinivasan S; Subhash, Ghatu

    2017-01-23

    Wave propagation characteristics in long cylindrical specimens of ballistic gelatine have been investigated using a high speed digital camera and hyper elastic constitutive models. The induced transient deformation is modelled with strain rate dependent Mooney-Rivlin parameters which are determined by modelling the stress-strain response of gelatine at a range of strain rates. The varying velocity of wave propagation through the gelatine cylinder is derived as a function of prestress or stretch in the gelatine specimen. A finite element analysis is conducted using the above constitutive model by suitably defining the impulse imparted by the polymer bar into the gelatine specimen. The model results are found to capture the experimentally observed wave propagation characteristics in gelatine effectively.

  2. Characterization of the ballistic limit curve for metallic Whipple shield

    Directory of Open Access Journals (Sweden)

    Lee M.

    2012-08-01

    Full Text Available It has been known that space debris or meteoroid impact damage can have significant effects on spacecraft. Experimental test has been conducted up to 7 km/s, and numerical simulations are performed at higher velocities. Studies on the hypervelocity impact onto single plate, double spaced plates (Whipple shield, and multiple plates (MS shield have been performed and ballistic limit curves (BLCs are proposed. Last 15 years SPH (Smoothed Particle Hydrodynamics has been applied to the hypervelocity impact problems because of cost of test and numerical efficiency especially in the hypervelocity impact regime. Although most of the simulations captured the debris shape well, somehow they do not seem to match well with the empirical ballistic limit curves. We have recently developed a new axisymmetric SPH hydrocode. In order to assess the confidence that should be placed in such simulations we simulated the hypervelocity impacts on aluminum Whipple shields and compared with the empirical BLCs. The SPH simulations indicated an improved accuracy compared with the previously published SPH simulation results. Other effort we put was using different types of equation of state, however no further improvement was achieved.

  3. Estimation of ballistic block landing energy during 2014 Mount Ontake eruption

    Science.gov (United States)

    Tsunematsu, Kae; Ishimine, Yasuhiro; Kaneko, Takayuki; Yoshimoto, Mitsuhiro; Fujii, Toshitsugu; Yamaoka, Koshun

    2016-05-01

    The 2014 Mount Ontake eruption started just before noon on September 27, 2014. It killed 58 people, and five are still missing (as of January 1, 2016). The casualties were mainly caused by the impact of ballistic blocks around the summit area. It is necessary to know the magnitude of the block velocity and energy to construct a hazard map of ballistic projectiles and design effective shelters and mountain huts. The ejection velocities of the ballistic projectiles were estimated by comparing the observed distribution of the ballistic impact craters on the ground with simulated distributions of landing positions under various sets of conditions. A three-dimensional numerical multiparticle ballistic model adapted to account for topographic effect was used to estimate the ejection angles. From these simulations, we have obtained an ejection angle of γ = 20° from vertical to horizontal and α = 20° from north to east. With these ejection angle conditions, the ejection speed was estimated to be between 145 and 185 m/s for a previously obtained range of drag coefficients of 0.62-1.01. The order of magnitude of the mean landing energy obtained using our numerical simulation was 104 J.

  4. Impact of backpack type on respiratory muscle strength and lung function in children.

    Science.gov (United States)

    Vieira, Ana Christina; Ribeiro, Fernando

    2015-01-01

    We examine the influence of backpack type on lung function and respiratory muscle strength in children. Thirty-seven children were assessed for lung function and inspiratory and expiratory muscle strength under four randomly determined conditions: unloaded erect standing and three conditions carrying 15% of the child's body weight. In these three conditions, children carried the weight on a backpack with bilateral shoulder straps carried over both shoulders, on a backpack with bilateral shoulder straps carried over one shoulder and on a backpack with a mono shoulder strap. Significantly lower forced vital capacity, forced expiratory volume in one second and maximal expiratory pressure were observed when children carried a backpack with a mono shoulder strap compared to the unloaded standing position. In conclusion, the restrictive effect and the decrease in expiratory muscle strength were more pronounced for the backpack with a mono shoulder strap, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack. Practitioner summary: There is little known about the effect of schoolbags on respiratory muscle function. We investigated the influence of backpack type on lung function and respiratory muscle strength. A backpack with a mono shoulder strap created a restrictive effect and a decrease in strength, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack.

  5. Impact of Selected Parameters on the Fatigue Strength of Splices on Multiply Textile Conveyor Belts

    Science.gov (United States)

    Bajda, Mirosław; Błażej, Ryszard; Hardygóra, Monika

    2016-10-01

    Splices are the weakest points in the conveyor belt loop. The strength of these joints, and thus their design as well as the method and quality of splicing, determine the strength of the whole conveyor belt loop. A special zone in a splice exists, where the stresses in the adjacent plies or cables differ considerably from each other. This results in differences in the elongation of these elements and in additional shearing stresses in the rubber layer. The strength of the joints depends on several factors, among others on the parameters of the joined belt, on the connecting layer and the technology of joining, as well as on the materials used to make the joint. The strength of the joint constitutes a criterion for the selection of a belt suitable for the operating conditions, and therefore methods of testing such joints are of great importance. This paper presents the method of testing fatigue strength of splices made on multi-ply textile conveyor belts and the results of these studies.

  6. Impact of dispersed coupling strength on the free running periods of circadian rhythms

    Science.gov (United States)

    Gu, Changgui; Rohling, Jos H. T.; Liang, Xiaoming; Yang, Huijie

    2016-03-01

    The dominant endogenous clock, named the suprachiasmatic nucleus (SCN), regulates circadian rhythms of behavioral and physiological activity in mammals. One of the main characteristics of the SCN is that the animal maintains a circadian rhythm with a period close to 24 h in the absence of a daily light-dark cycle (called the free running period). The free running period varies among species due to heterogeneity of the SCN network. Previous studies have shown that the heterogeneity in cellular coupling as well as in intrinsic neuronal periods shortens the free running period. Furthermore, as derived from experiments, one neuron's coupling strength is negatively associated with its period. It is unknown what the effects of this association between coupling strength and period are on the free running period and how the heterogeneity in coupling strength influences this free running period. In the present study we found that in the presence of a negative relationship between one neuron's coupling strength and its period, surprisingly, the dispersion of coupling strengths increases the free running period. Our present finding may shed new light on the understanding of the heterogeneous SCN network and provides an alternative explanation for the diversity of free running periods between species.

  7. Does Weak Turbulence Impact PMSEs' Strengths Closer To The Northern Pole?

    Science.gov (United States)

    Swarnalingam, N.; Hocking, W. K.; Janches, D.; Nicolls, M. J.

    2015-12-01

    Existing 51.0 MHz VHF radar at Eureka (80N, 86W) in northern Canada is located closer to both the northern magnetic and geomagnetic poles. A recent calibrated study of Polar Mesosphere Summer Echoes (PMSE) using this radar supports the previous results by other radars that the absolute signal strength of PMSE in this region is relatively weak compared with the radar observations located at high latitudes. Although very cold temperature and existence of charged ice particles are the most important ingredient required for PMSE to appear, several other factors could potentially influence the absolute signal strengths of these echoes. One of them is neutral air turbulence. Previous studies indicate that upper mesospheric turbulence's strength decreases with latitudes, especially in the very high latitudes [Becker, 2004; Lubken et. al., 2009]. In this study, we investigate long-term mesospheric turbulence strengths at Eureka and study how they could be associated with the weak PMSE signal strengths compared with other high latitude conditions, where PMSE are strong.

  8. Analysis of the Molecules Structure and Vertical Electron Affinity of Organic Gas Impact on Electric Strength

    Institute of Scientific and Technical Information of China (English)

    JIAO Juntao; XIAO Dengming; ZHAO Xiaoling; DENG Yunkun

    2016-01-01

    It is necessary to find an efficient selection method to pre-analyze the gas electric strength from the perspective of molecule structure and the properties for finding the alternative gases to sulphur hexafluoride (SF6).As the properties of gas are determined by the gas molecule structure,the research on the relationship between the gas molecule structure and the electric strength can contribute to the gas pre-screening and new gas development.In this paper,we calculated the vertical electron affinity,molecule orbits distribution and orbits energy of gas molecules by the means of density functional theory (DFT) for the typical structures of organic gases and compared their electric strengths.By this method,we find part of the key properties of the molecule which are related to the electric strength,including the vertical electron affinity,the lowest unoccupied molecule orbit (LUMO) energy,molecule orbits distribution and negativeion system energy.We also listed some molecule groups such as unsaturated carbons double bonds (C=C) and carbonitrile bonds (C≡N) which have high electric strength theoretically by this method.

  9. Analysis of the Molecules Structure and Vertical Electron Affinity of Organic Gas Impact on Electric Strength

    Science.gov (United States)

    Jiao, Juntao; Xiao, Dengming; Zhao, Xiaoling; Deng, Yunkun

    2016-05-01

    It is necessary to find an efficient selection method to pre-analyze the gas electric strength from the perspective of molecule structure and the properties for finding the alternative gases to sulphur hexafluoride (SF6). As the properties of gas are determined by the gas molecule structure, the research on the relationship between the gas molecule structure and the electric strength can contribute to the gas pre-screening and new gas development. In this paper, we calculated the vertical electron affinity, molecule orbits distribution and orbits energy of gas molecules by the means of density functional theory (DFT) for the typical structures of organic gases and compared their electric strengths. By this method, we find part of the key properties of the molecule which are related to the electric strength, including the vertical electron affinity, the lowest unoccupied molecule orbit (LUMO) energy, molecule orbits distribution and negative-ion system energy. We also listed some molecule groups such as unsaturated carbons double bonds (C=C) and carbonitrile bonds (C≡N) which have high electric strength theoretically by this method. supported by National Natural Science Foundation of China (Nos. 51177101 and 51337006)

  10. Ballistic Rail Gun Soft Recovery Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Ballistic Rail Gun Soft Recovery Facility accommodates a 155mm Howitzer, fired horizontally into a 104-foot long water trough to slow the projectile and recover...

  11. Constitutive equations of a ballistic steel alloy as a function of temperature

    Directory of Open Access Journals (Sweden)

    Coghe F.

    2012-08-01

    Full Text Available In the present work, dynamic tests have been performed on a new ballistic steel alloy by means of split Hopkinson pressure bars (SHPB. The impact behavior was investigated for strain rates ranging from 1000 to 2500 s−1, and temperatures in the range from − 196 to 300∘C. A robotized sample device was developed for transferring the sample from the heating or cooling device to the position between the bars. Simulations of the temperature evolution and its distribution in the specimen were performed using the finite element method. Measurements with thermocouples added inside the sample were carried out in order to validate the FEM simulations. The results show that a thermal gradient is present inside the sample; the average temperature loss during the manipulation of the sample is evaluated. In a last stage, optimal material constants for different constitutive models (Johnson-Cook, Zerilli-Amstrong, Cowper-Symonds has been computed by fitting, in a least square sense, the numerical and experimental stress-strain curves. They have been implemented in a hydrocode for validation using a simple impact problem: an adapted projectile geometry with a truncated nose (.50 calibre fragment simulating projectiles was fired directly against an armor plate. The parameters of the selected strength and failure models were determined. There is a good correspondence between the experimental and computed results. Nevertheless, an improved failure model is necessary to get satisfactory computed residual projectile velocities.

  12. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-12-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  13. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-09-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  14. An experimental investigation into the damage resistance and compression-after-impact strength of T800H/3900-2

    Science.gov (United States)

    Vietinghoff, H.; Poon, C.; Straznicky, P. V.; Gould, R.

    1993-01-01

    An experimental investigation was conducted into impact behavior of a Toray T800H/3900-2 material system, a system representative of the most recent generation of toughened graphite-epoxy composites selected for use in several new airframes. In the investigation, test specimens featuring quasi-isotropic and midplane symmetric layup with 24 plies were fabricated and impacted at five different impact energy levels, resulting in damage ranging from barely visible to severe. Damage was characterized using nondestructive and destructive inspection, including ultrasound and x-ray techniques, and the specimens were then compressively loaded to failure. The carefully controlled set of experiments resulted in a detailed three dimensional characterization of the damage induced in the selected laminate layup for a range of impact energies. Compression after impact testing resulted in a correlation of impact energy and damage area with residual compressive strength. The results will be used to calibrate and test the analytical prediction methods being developed as part of a project on impact resistance and tolerance of composite materials, and as reference data on the material system.

  15. Impact of zeolite-based nanomodified additive on the structure and strength of the cement stone

    Science.gov (United States)

    Egorova, A. D.; Filippova, K. E.

    2015-01-01

    Portland cement is the main binder in the building materials industry; its properties strongly influence properties of mortars and concretes. Some regions experience difficulties with delivery and storage of Portland cement, raising the need to develop an effective additive from the available raw materials. Such materials for the Republic of Sakha (Yakutia) are zeolite-containing rocks. Studies have shown that introducing of dibutylphthalate to the composition of modified additive during mechanochemical activation leads to achievement of up to 11% of total amount particles with the size of 3-30 nm. After introducing 0.5% of the obtained additives, the compressive strength of cement-sand slurry samples increases up to 28%. Positive effect of additives introduction is also observed at high flow rate of water (W / C = 0.7). Gaining strength reaches 23%, allowing the efficient use of additive for movable mixtures with enhanced strength properties. In general, the proposed supplement allows reducing the water flow in the solution without decreasing its mobility, and increasing strength properties, which makes it possible to obtain a whole class of solutions of modified cement binder. The market value of the developed additives is 18 rubles per 1 kg, making sound competition in the market of modifying additives.

  16. Fiber-matrix integrity, micromorphology and flexural strength of glass fiber posts: Evaluation of the impact of rotary instruments.

    Science.gov (United States)

    Pereira, Gabriel Kalil Rocha; Lançanova, Mateus; Wandscher, Vinicius Felipe; Kaizer, Osvaldo Bazzan; Limberger, Inácio; Özcan, Mutlu; Valandro, Luiz Felipe

    2015-08-01

    Several rotary instruments have been daily employed on clinic to promote cut aiming to adjust the length of fiber posts to the radicular conduct, but there is no information on the literature about the effects of the different rotary instruments and its impact on the micromorphology of surface and mechanical properties of the glass fiber post. This study aimed the impact of rotary instruments upon fiber-matrix integrity, micromorphology and flexural-strength of glass-fiber posts (GFP). GFP (N=110) were divided into 5 groups: Ctrl: as-received posts, DBc: coarse diamond-bur, DBff: extra-fine diamond-bur, CB: carbide-bur, DD: diamond-disc. Cutting procedures were performed under abundant irrigation. Posts exposed to rotary instruments were then subjected to 2-point inclined loading test (compression 45°) (n=10/group) and 3-point flexural-strength test (n=10/group). Fiber-matrix integrity and micromorphology at the cut surface were analyzed using a SEM (n=2/group). Cutting procedures did not significantly affect the 2-point (51.7±4.3-56.7±5.1 MPa) (p=0.0233) and 3-point flexural-strength (671.5±35.3-709.1±33.1 MPa) (p=0.0968) of the posts (One-way ANOVA and Tukey׳s test). Fiber detachment was observed only at the end point of the cut at the margins of the post. Cut surfaces of the CB group were smoother than those of the other groups. After 3-point flexural strength test, fiber-matrix separation was evident at the tensile side of the post. Rotary instruments tested with simultaneous water-cooling did not affect the resistance of the tested fiber posts but caused disintegration of the fibers from the matrix at the end of the cut, located at the margins.

  17. Design and Ballistic Performance of Hybrid Composite Laminates

    Science.gov (United States)

    Ćwik, Tomasz K.; Iannucci, Lorenzo; Curtis, Paul; Pope, Dan

    2016-10-01

    This paper presents an initial design assessment of a series of novel, cost-effective, and hybrid composite materials for applications involving high velocity impacts. The proposed hybrid panels were designed in order to investigate various physical phenomenon occurring during high velocity impact on compliant laminates from a previous study on Dyneema® and Spectra®. In the first, screening phase of the study twenty different hybrid composite laminates were impacted with 20 mm Fragment Simulating Projectiles at 1 km/s striking velocity. The best performing concepts were put forward to phase II with other hybrid concepts involving shear thickening fluids, commonly used in low velocity impacts. The results indicated that it is possible to design hybrid laminates of similar ballistic performance as the reference Dyneema® laminate, but with lower material costs. The optimal hybrid concept involves a fibre reinforced Polypropylene front and a Dyneema® backing.

  18. Influence of Various Process Parameters on Mechanical Properties and Ballistics of Nitramine-Based Advanced CMDB Propellants

    Directory of Open Access Journals (Sweden)

    S. N. Asthana

    1991-10-01

    Full Text Available This paper reports the influence of important process parameters, namely mixing time and batch size; on the mechanical properties and ballistics of nitramine-based advanced CMDB propellants. Considerable improvement to the tune of 67 per cent in tensile strength was observed at a mixing time increase of 60-135 min. Scaling up of batch size from 8 to 25 kg resulted in 30 per cent higher tensile strength. Recorded enhancement of burning rate was of the order of 8 per cent in both the sets of experiments. Ballistically modified composition revealed 11-12 per cent increase in burning rate at all the pressure ranges, on combined increase in mixing time (55 to 85 min and batch size(5-17kg. These findings are in line with those reported for composite and ballistically modified double-base propellants.

  19. Impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin: an in vitro study.

    Science.gov (United States)

    Stawarczyk, Bogna; Hartmann, Leonie; Hartmann, Rahel; Roos, Malgorzata; Ender, Andreas; Ozcan, Mutlu; Sailer, Irena; Hämmerle, Christoph H F

    2012-02-01

    This study tested the impact of Gluma Desensitizer on the tensile strength of zirconia crowns bonded to dentin. Human teeth were prepared and randomly divided into six groups (N = 144, n = 24 per group). For each tooth, a zirconia crown was manufactured. The zirconia crowns were cemented with: (1) Panavia21 (PAN), (2) Panavia21 combined with Gluma Desensitizer (PAN-G), (3) RelyX Unicem (RXU), (4) RelyX Unicem combined with Gluma Desensitizer (RXU-G), (5) G-Cem (GCM) and (6) G-Cem combined with Gluma Desensitizer (GCM-G). The initial tensile strength was measured in half (n = 12) of each group and the other half (n = 12) subjected to a chewing machine (1.2 Mio, 49 N, 5°C/50°C). The cemented crowns were pulled in a Universal Testing Machine (1 mm/min, Zwick Z010) until failure occurred and tensile strength was calculated. Data were analyzed with one-way and two-way ANOVA followed by a post hoc Scheffé test, t test and Kaplan-Meier analysis with a Breslow-Gehan analysis test (α = 0.05). After the chewing simulation, the self-adhesive resin cements combined with Gluma Desensitizer showed significantly higher tensile strength (RXU-G, 12.8 ± 4.3 MPa; GCM-G, 13.4 ± 6.2 MPa) than PAN (7.3 ± 1.7 MPa) and PAN-G (0.9 ± 0.6). Within the groups, PAN, PAN-G and RXU resulted in significantly lower values when compared to the initial tensile strength; the values of all other test groups were stable. In this study, self-adhesive resin cements combined with Gluma Desensitizer reached better long-term stability compared to PAN and PAN-G after chewing simulation.

  20. Effect of microstructure on the impact toughness of high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, I.

    2014-07-01

    One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design. (Author)

  1. Composite Concrete Modifier CM 02-10 and Its Impact on the Strength Characteristics of Concrete

    Directory of Open Access Journals (Sweden)

    Akimov Luka

    2016-01-01

    Full Text Available The main aim of this research is the investigation of effect of the composite additive (a mixture of hyperplasticizer and microsilica CM 02-10 (10 % of MS and 0.2 % of HP on strength characteristics of concrete. Interaction of concrete with plasticizing and siliceous additives individually depending on their percentage content by the weight of cement is also investigated. Results of experiments with such additives on the fluidity of concrete mix and strength of concrete are presented. Additives used in the experiment: superplasticizer S-3, fused microsilica FMS-85, hyperplasticizer PENTAFLOW AC 2, and composite additive CM 02-10. In this paper results of tests of samples aged 3, 7 and 28 days are presented.

  2. Factors that affect the fatigue strength of power transmission shafting and their impact on design

    Science.gov (United States)

    Leowenthal, S. H.

    1986-01-01

    A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

  3. Machining variability impacts on the strength of a 'chair-side' CAD-CAM ceramic.

    LENUS (Irish Health Repository)

    Addison, Owen

    2012-08-01

    To develop a novel methodology to generate specimens for bi-axial flexure strength (BFS) determination from a \\'chair-side\\' CAD-CAM feldspathic ceramic with surface defect integrals analogous to the clinical state. The hypotheses tested were: BFS and surface roughness (R(a)) are independent of machining variability introduced by the renewal or deterioration of form-grinding tools and that a post-machining annealing cycle would significantly modify BFS.

  4. Gunshot wounds:A review of ballistics related to penetrating trauma

    Institute of Scientific and Technical Information of China (English)

    SPanagiotis K Stefanopoulos; Georgios F Hadjigeorgiou; Konstantinos Filippakis; Dimitrios Gyftokostas

    2014-01-01

    Civilian gunshot injuries from handgun and rifle ammunition vary in severity depending on the anatomic location involved and the different effects from the ballistic properties of the penetrating projectiles.Ballistic factors such as the impact velocity and energy should not be considered in isolation, as their specific effects are determined by the interaction between the projectile and tissues.Increased tissue damage can result from tumbling of non-deforming rifle bullets and deformation of expanding bullets.Both of these mechanisms increase substantially the energy transfer to the wound and its diameter, also producing a pulsating temporary cavity associated with pressure changes within tissue.

  5. Modeling and Simulation of Ceramic Arrays to Improve Ballistic Performance (Briefing charts)

    Science.gov (United States)

    2014-02-28

    center impact DOP can on be achieved If at a gap size of 0.508 mm -In simulation the adhesive layer improves the ballistic efficiency of the target...Projectile, 762x39 PS Projectile, SPH, Aluminum 5083, SiC, DoP Expeminets, AutoDyn Sin 16. SECURITY CLASSIFICATION OF: UU a. REPORT b. ABSTRACT c

  6. Comparison of analytic Whipple bumper shield ballistic limits with CTH simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, E.S. Jr.

    1993-05-01

    A series of CTH simulations were conducted to assess the feasibility of using the hydrodynamic code for debris cloud formation and to predict any damage due to the subsequent loading on rear structures. Six axisymmetric and one 3-dimensional simulations were conducted for spherical projectiles impacting Whipple bumper shields. The projectile diameters were chosen to correlate with two well known analytic expressions for the ballistic limit of a Whipple bumper shield. It has been demonstrated that CTH can be used to simulate the debris cloud formation, the propagation of the debris across a void region, and the secondary impact of the debris against a structure. In addition, the results from the CTH simulations were compared to the analytic estimates of the ballistic limit. At impact velocities of 10 km/s or less, the CTH predicted ballistic limit lays between the two analytic estimates. However, for impact velocities greater than 10 km/s, CTH simulations predicted a ballistic limit larger than both analytical estimates. The differences at high velocities are not well understood. Structural failure at late times due to the time integrated loading of a very diffuse debris cloud has not been considered in the CTH model. In addition, the analytic predictions are extrapolated from relatively low velocity data and the extrapolation technique may not be valid. The discrepancy between the two techniques should be investigated further.

  7. Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins

    Directory of Open Access Journals (Sweden)

    Nour M. Ajaj-ALKordy

    2014-01-01

    Conclusion: Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture.

  8. How erosive drinks and enzyme inhibitors impact bond strength to dentin

    Directory of Open Access Journals (Sweden)

    Camila Moreira MACHADO

    2015-01-01

    Full Text Available Concern has been raised about the bonding of restorative procedures to an erosive lesion, given the change in organic and inorganic composition and structure of this substrate. This in vitro study evaluated the effect of erosive drinks and an enzyme inhibitor (2% chlorhexidine digluconate – 2% CHX on bond strength to dentin. Sixty sound human third molars were selected, and the occlusal enamel was flattened, exposing the dentin surface. The specimens were randomly divided into three groups: AS-Artificial saliva (control group, RC- Regular Cola and ZC- Zero Cola. Twenty specimens were immersed in their respective solution for 1 minute, 3 times a day, over the course of 5 days. After acid etching and before bonding with Adper Single Bond 2, half of the samples of each group (n = 10 were treated with 2% CHX, whereas the other half (n = 10 were not, forming the control group (CONV. All the specimens were restored with Filtek Z250 composite resin filled in Tygon tubes (0.48 mm2, yielding six microcylinders for microshear bond strength testing. Three composite resin microcylinders of each specimen were tested after 1 month, and the remaining microcylinders were tested after 6 months. Failure modes were determined using a stereomicroscope (40x. The data were statistically analyzed by three-way ANOVA and Tukey tests (α = 0.05. Overall bonding was reduced after 6 months, regardless of treatment. The 2% CHX enhanced bond strength after 1 month only in the ZC group, and did not enhance bonding performance to demineralized dentin by erosive protocol after 6 months in any group.

  9. Erodibility of Titan ice bedrock constrained by laboratory measurements of ice strength and erosion by sediment impacts

    Science.gov (United States)

    Sklar, L. S.; Collins, G. C.; Litwin, K. L.; Polito, P. J.; Zygielbaum, B. R.

    2012-12-01

    Saturn's moon Titan has a remarkably earth-like surface morphology, with branching fluvial networks draining elevated terrain. A paucity of impact craters suggests fluvial dissection is active and that the pace of landscape evolution is rapid. A key limitation on modeling rates of incision by Titan's rivers of liquid methane has been a lack of information on the erodibility of water-ice bedrock at ultra-cold temperatures. Here we report results from laboratory measurements of ice resistance to tensile fracture and rates of erosion of Titan bedrock analogs by low-velocity sediment impacts. We apply these experimental results to modeling fluvial incision, and explore constraints on rates and frequency of channel cutting on Titan. We made test samples of polycrystalline ice with a narrow and wide size distribution of seed ice grains. For some samples we added solid impurities composed of basalt, urea, and ammonium-sulfate, to account for the possibility that Titan's ice bedrock also contains silicates from meteors, organic polymers derived from Titan's atmosphere, and ammonia-based compounds formed by cryovolcanism. The experiments were conducted in a walk-in freezer and environmental chamber, where we varied temperature between 260 and 110 K using dry ice and liquid nitrogen (LN). For terrestrial rocks, resistance to erosion by sediment impacts depends on the kinetic energy required to detach a unit volume, which has been shown to scale with the square of tensile strength. We measured the tensile strength of Titan bedrock analogs using the Brazilian splitting test and found that strength increases with decreasing temperature at 7 kPa/K, for all ice types tested. Ice at Titan temperatures is thus roughly twice as strong as at terrestrial conditions; ice is strengthened by increasing impurity concentrations, finer grain-size distributions, and lower porosity. To replicate erosion of ice bedrock by bedload sediment impacts, we filled a 55-gallon drum with various ice

  10. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    Science.gov (United States)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  11. Tunable strength saddle-point contacts impact on quantum rings transmission

    Science.gov (United States)

    González, J. J.; Diago-Cisneros, L.

    2016-09-01

    A particular subject of investigation is the role of several sadle-point contact (QPC) parameters on the scattering properties of an Aharonov-Bohm-Aharonov-Casher quantum ring (QR) under Rashba-type spin orbit interaction. We discuss the interplay of the conductance with the confinement strengths and height of the QPC, which yields new and tunable harmonic and non-harmonics patterns, while one manipulates these constriction parameters. This phenomenology may be of utility to implement a novel way to modulate spin interference effects in semiconducting QRs, providing an appealing test-platform for spintronics applications.

  12. The pore characteristics of geopolymer foam concrete and their impact on the compressive strength and modulus

    Science.gov (United States)

    Zhang, Zuhua; Wang, Hao

    2016-08-01

    The pore characteristics of GFCs manufactured in the laboratory with 0-16% foam additions were examined using image analysis (IA) and vacuum water saturation techniques. The pore size distribution, pore shape and porosity were obtained. The IA method provides a suitable approach to obtain the information of large pores, which are more important in affecting the compressive strength of GFC. By examining the applicability of the existing models of predicting compressive strength of foam concrete, a modified Ryshkevitch’s model is proposed for GFC, in which only the porosity that is contributed by the pores over a critical diameter (>100 μm) is considered. This “critical void model” is shown to have very satisfying prediction capability in the studied range of porosity. A compression-modulus model for Portland cement concrete is recommended for predicting the compression modulus elasticity of GFC. This study confirms that GFC have similar pore structures and mechanical behavior as those Portland cement foam concrete and can be used alternatively in the industry for the construction and insulation purposes.

  13. A Predictive Explicit Guidance Scheme for Ballistic Missiles

    Directory of Open Access Journals (Sweden)

    N. Prabhakar

    2013-09-01

    Full Text Available A new approach to the design of ballistic missile guidance is presented in this paper. The proposed method uses the missile model to predict the likely impact point at every guidance cycle and apply course corrections based on the predicted impact point (PIP deviations. The algorithm also estimates the in-flight thrust variation from nominal and accordingly updates the model to reduce the uncertainty in the prediction of the impact point. The performance of the algorithm is tested through 6-DOF simulation. The simulation results show excellent performance of the proposed guidance scheme in nominal & off nominal cases.Defence Science Journal, 2013, 63(5, pp.456-461, DOI:http://dx.doi.org/10.14429/dsj.63.2575

  14. Effects of thermal aging on fracture toughness and Charpy-impact strength of stainless steel pipe welds

    Energy Technology Data Exchange (ETDEWEB)

    Gavenda, D.J.; Michaud, W.F.; Galvin, T.M.; Burke, W.F.; Chopra, O.K. [Argonne National Lab., IL (United States)

    1996-05-01

    Degradation of fracture toughness, tensile, and Charpy-impact properties of Type 304 and 304/308 SS pipe welds due to thermal aging was studied at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in charpy-impact strength and fracture toughness. Upper-shelf energy decreased by 50-80 J/cm{sup 2}. Decrease in fracture toughness J-R curve or J{sub IC} is relatively small. Thermal aging had no or little effect on tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.

  15. The effect of strain rate on the impact strength of the high-Mn steel

    Directory of Open Access Journals (Sweden)

    A. Śmiglewicz

    2015-10-01

    Full Text Available In the paper, results of impact bending tests of a high-manganese steel of Fe – 30 wt.%, Mn – 9 wt.%, Al – 0,65 wt.%, C grade are presented. The tests were carried out using a flywheel machine, suitable for dynamic stretching and impact bending tests in the range of linear velocity of the forcing element from 5 ÷ 40 m/s. The obtained test results were compared with the results of impact resistance of the studied steel determined using Charpy machine. Structural investigations were carried out using scanning transmission electron microscopy. Surfaces of fractures formed in the break point during bending tests were analyzed, and they indicate a presence of mixed transcrystalline fractures with a predominance of plastic fractures.

  16. Transverse isotropic modeling of the ballistic response of glass reinforced plastic composites

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P.A. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    The use of glass reinforced plastic (GRP) composites is gaining significant attention in the DoD community for use in armor applications. These materials typically possess a laminate structure consisting of up to 100 plies, each of which is constructed of a glass woven roving fabric that reinforces a plastic matrix material. Current DoD attention is focused on a high strength, S-2 glass cross-weave (0/90) fabric reinforcing a polyester matrix material that forms each ply of laminate structure consisting anywhere from 20 to 70 plies. The resulting structure displays a material anisotropy that is, to a reasonable approximation, transversely isotropic. When subjected to impact and penetration from a metal fragment projectile, the GRP displays damage and failure in an anisotropic manner due to various mechanisms such as matrix cracking, fiber fracture and pull-out, and fiber-matrix debonding. In this presentation, the author will describe the modeling effort to simulate the ballistic response of the GRP material described above using the transversely isotropic (TI) constitutive model which has been implemented in the shock physics code, CTH. The results of this effort suggest that the model is able to describe the delamination behavior of the material but has some difficulty capturing the in-plane (i.e., transverse) response of the laminate due to its cross-weave fabric reinforcement pattern which causes a departure from transverse isotropy.

  17. BALLISTICS TESTING OF THE 9977 SHIPPING PACKAGE FOR STORAGE APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Loftin, B.; Abramczyk, G.; Koenig, R.

    2012-06-06

    Radioactive materials are stored in a variety of locations throughout the DOE complex. At the Savannah River Site (SRS), materials are stored within dedicated facilities. Each of those facilities has a documented safety analysis (DSA) that describes accidents that the facility and the materials within it may encounter. Facilities at the SRS are planning on utilizing the certified Model 9977 Shipping Package as a long term storage package and one of these facilities required ballistics testing. Specifically, in order to meet the facility DSA, the radioactive materials (RAM) must be contained within the storage package after impact by a .223 caliber round. In order to qualify the Model 9977 Shipping Package for storage in this location, the package had to be tested under these conditions. Over the past two years, the Model 9977 Shipping Package has been subjected to a series of ballistics tests. The purpose of the testing was to determine if the 9977 would be suitable for use as a storage package at a Savannah River Site facility. The facility requirements are that the package must not release any of its contents following the impact in its most vulnerable location by a .223 caliber round. A package, assembled to meet all of the design requirements for a certified 9977 shipping configuration and using simulated contents, was tested at the Savannah River Site in March of 2011. The testing was completed and the package was examined. The results of the testing and examination are presented in this paper.

  18. Analysis of Environmental Impact for Concrete Using LCA by Varying the Recycling Components, the Compressive Strength and the Admixture Material Mixing

    Directory of Open Access Journals (Sweden)

    Taehyoung Kim

    2016-04-01

    Full Text Available Concrete is a type of construction material in which cement, aggregate, and admixture materials are mixed. When cement is produced, large amounts of substances that impact the environment are emitted during limestone extraction and clinker manufacturing. Additionally, the extraction of natural aggregate causes soil erosion and ecosystem destruction. Furthermore, in the process of transporting raw materials such as cement and aggregate to a concrete production company, and producing concrete in a batch plant, substances with an environmental impact are emitted into the air and water system due to energy use. Considering the fact that the process of producing concrete causes various environmental impacts, an assessment of various environmental impact categories is needed. This study used a life cycle assessment (LCA to evaluate the environmental impacts of concrete in terms of its global warming potential, acidification potential, eutrophication potential, ozone depletion potential, photochemical ozone creation potential, and abiotic depletion potential (GWP, AP, EP, ODP, POCP, ADP. The tendency was that the higher the strength of concrete, the higher the GWP, POCP, and ADP indices became, whereas the AP and EP indices became slightly lower. As the admixture mixing ratio of concrete increased, the GWP, AP, ODP, ADP, and POCP decreased, but EP index showed a tendency to increase slightly. Moreover, as the recycled aggregate mixing ratio of concrete increased, the AP, EP, ODP, and ADP decreased, while GWP and POCP increased. The GWP and POCP per unit compressed strength (1 MPa of high strength concrete were found to be about 13% lower than that for its normal strength concrete counterpart. Furthermore, in the case of AP, EP, ODP, and ADP per unit compressed strength (1 MPa, high-strength concrete was found to be about 10%~25% lower than its normal strength counterpart. Among all the environmental impact categories, ordinary cement was found to have

  19. Nutrition impact symptoms, handgrip strength and nutritional risk in hospitalized patients with gastroenterological and liver diseases

    DEFF Research Database (Denmark)

    Wilkens Knudsen, Anne; Naver, Astrid; Bisgaard, Karen;

    2015-01-01

    OBJECTIVE: Malnutrition is common among patients with diseases of the liver and gastrointestinal tract. Nutritional intake may be negatively affected by nutrition impact symptoms (NIS). Therefore, the aims were to assess: 1) the prevalence of NIS in this group of patients and 2) the relationship ...

  20. Impact of ionic strength on Cd(II) partitioning between alginate gel and Aqueous media

    NARCIS (Netherlands)

    Kalis, E.J.J.; Davis, T.A.; Town, R.M.; Leeuwen, van H.P.

    2009-01-01

    Alginate gel is representative of polysaccharide-based components of cell walls which contain a large number of negatively charged functional groups. The structural charge gives rise to a Donnan potential in the gel, which impacts significantly on the partitioning of ions between the aqueous medium

  1. [Studies of dental methacrylic resin. (Part 8) Flexural and impact adhesive strength of self-curing methacrylic resin to cross-linked polymethyl methacrylate resins (author's transl)].

    Science.gov (United States)

    Hirasawa, T; Hirabayashi, S; Harashima, I

    1981-10-01

    Heat-curing methacylic resins cross-linked with three kinds of dimethacrylates, i.e. EDMA, tri-EDMA and nona-EDMA, were prepared, and the flexural and the impact adhesive strength of the dough moulding type and the pour type self-curing methacrylic resins to them were examined. The results obtained were as follows. (1) The flexural and the impact adhesive strength of the pour type self-curing resin were higher and more stable than those of the dough moulding type one. (2) The flexural and the impact adhesive strength of self-curing resins to cross-linked adherent resins rised in order of nona-EDMA greater than tri-EDMA greater than EDMA in the range of higher concentration of cross-linking agents. This tendency was marked for the pour type resin. (3) When the dough moulding type resin was used as adhesive resin, to adherent resin cross-linked with EDMA or tri-EDMA which had relatively short chain, the respective adhesive strength of that decreased with increasing the concentration of cross-linking agent. While, to adherent resin cross-linked with nona-EDMA, which had relatively long and more flexible chain, the respective adhesive strength of the dough moulding type resin increased with increasing the concentration of cross-linking agent. (4) When the pour type resin was used as adhesive resin, to adherent resin cross-linked with EDMA or tri-EDMA, the respective adhesive strength of that showed the maximum at the concentration near 2 to 5 mole% and decreased with increasing the concentration. While, to adherent resin cross-linked with nona-EDMA, the flexural adhesive strength of the pour type resin was approximately constant without the effect of the concentration, but the impact adhesive strength of that increased with increasing the concentration. (5) The flexural adhesive strength of the dough moulding and the pour type resin under the wet condition decreased about 30 to 60% compared with under the dry condition, but the percentage of the falling for the impact

  2. Modelling of ultrasonic impact treatment (UIT of welded joints and its effect on fatigue strength

    Directory of Open Access Journals (Sweden)

    K.L. Yuan

    2015-10-01

    Full Text Available Ultrasonic impact treatment (UIT is a remarkable post-weld technique applying mechanical impacts in combination with ultrasound into the welded joints. In the present work, a 3D simulation method including welding simulation, numerical modelling of UIT-process and an evaluation of fatigue crack growth has been developed. In the FE model, the actual treatment conditions and local mechanical characteristics due to acoustic softening are set as input parameters. The plastic deformation and compressive stress layer are found to be more pronounced when acoustic softening takes place. The predicted internal residual stress distributions of welded joint before and after UIT are compared with experimental results, showing a fairly good agreement with each other. Finally, simulated results of fatigue crack growth in various residual stress fields are well compared with test results, so that the proposed model may provide an effective tool to simulate UIT-process in engineering structures.

  3. Effect of microstructure on the impact toughness of high strength steels

    Directory of Open Access Journals (Sweden)

    Gutiérrez, Isabel

    2014-12-01

    Full Text Available One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design.El desarrollo de nuevos grados de acero se tropieza con frecuencia con la necesidad de incrementar la resistencia mecánica al mismo tiempo que se reduce la temperatura de transición dúctil-frágil y se eleva la energía del palier dúctil. Hacer frente a este reto requiere un diseño microestructural. La tenacidad en aceros está controlada por diferentes constituyentes microestructurales. Algunos de ellos, como las inclusiones son intrínsecos, pero otros que se manifiestan a diferentes escalas microestructurales dependen de las condiciones de proceso. Existen algunas ecuaciones empíricas que permiten calcular para ferrita-perlita en aceros de bajo carbono la temperatura de transición como suma de contribuciones de elementos en solución sólida, nitrógeno libre, carburos, fracción de perlita, tamaño de grano y, eventualmente

  4. Strategic marketing management for health management: cross impact matrix and TOWS (threats, opportunities, weaknesses, strengths).

    Science.gov (United States)

    Proctor, T

    2000-01-01

    Organisations operate within a three-tiered environment--internal, micro and macro. The environment is a powerful force acting upon the effectiveness of strategic decision making. Failure to take cognisance of the influence of the three-tiered environment can have disastrous consequences. The cross-impact matrix and the TOWS matrix are two strategic decision-making aids that improve effective decision making. When used in conjunction with creative problem solving methods they can provide the basis of a powerful management tool.

  5. Impact toughness of high strength low alloy TMT reinforcement ribbed bar

    Indian Academy of Sciences (India)

    Bimal Kumar Panigrahi; Surendra Kumar Jain

    2002-08-01

    Charpy V-notch impact toughness of 600 MPa yield stress TMT rebars alloyed with copper, phosphorus, chromium and molybdenum has been evaluated. Subsize Charpy specimens were machined from the rebar keeping the tempered martensite rim intact. The copper–phosphorus rebar showed toughness of 35 J at room temperature. The toughness of copper–molybdenum and copper–chromium rebars was 52 J. The lower toughness of phosphorus steel is attributed to solid solution strengthening and segregation of phosphorus to grain boundaries. Due to superior corrosion resistance, copper–phosphorus TMT rebar is a candidate material in the construction sector.

  6. Graphene Triangular Ballistic Rectifier: Fabrication and Characterisation

    Science.gov (United States)

    Auton, Gregory; Kumar, Roshan Krishna; Hill, Ernie; Song, Aimin

    2016-09-01

    It has been shown that graphene can demonstrate ballistic transport at room temperature. This opens up a range of practical applications that do not require graphene to have a band gap, which is one of the most significant challenges for its use in the electronics industry. Here, the very latest high mobility graphene (>100,000 cm2 V-1 s-1) fabrication techniques will be demonstrated so that one such device, called the triangular ballistic rectifier (TBR), can be characterised. The TBR is a four-terminal device with a triangular anti-dot at their intersection; two sides of the triangle are positioned and angled such that ballistic carriers from the two input electrodes are redirected like billiard balls to one of the two output contacts irrespective of the instantaneous polarity of the input. A responsivity of 2400 mV mW-1 is demonstrated at room temperature from a low-frequency input signal. The ballistic nature of the device is justified and explained in more detail with low-temperature measurements.

  7. First Soviet Sea-Launched Ballistic Rockets

    Directory of Open Access Journals (Sweden)

    Yuri F. Katorin

    2013-03-01

    Full Text Available In the article it is told about the creation of the first generation of Soviet ballistic missiles for the armament of submarines. The basic stages of their development, tests and adoption for the armament are described. Are cited the data about the people, is most which actively participated in these processes.

  8. The Ballistic Cart on an Incline Revisited.

    Science.gov (United States)

    Serway, Raymond A.; And Others

    1995-01-01

    Presents the theory behind the mechanics demonstration that involves projecting a ball vertically upward from a ballistic cart moving along an inclined plane. The measured overshoot is believed to be due, in part, to the presence of rolling friction and the inertial properties of the cart wheels. (JRH)

  9. The Internal Ballistics of an Air Gun

    Science.gov (United States)

    Denny, Mark

    2011-01-01

    The internal ballistics of a firearm or artillery piece considers the pellet, bullet, or shell motion while it is still inside the barrel. In general, deriving the muzzle speed of a gunpowder firearm from first principles is difficult because powder combustion is fast and it very rapidly raises the temperature of gas (generated by gunpowder…

  10. Electron Interference in Ballistic Graphene Nanoconstrictions

    DEFF Research Database (Denmark)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes

    2016-01-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed...

  11. Impact Behavior of Composite Fan Blade Leading Edge Subcomponent with Thermoplastic Polyurethane Interleave

    Science.gov (United States)

    Miller, Sandi G.; Roberts, Gary D.; Kohlman, Lee W.; Heimann, Paula J.; Pereira, J. Michael; Ruggeri, Charles R.; Martin, Richard E.; McCorkle, Linda S.

    2015-01-01

    Impact damage tolerance and damage resistance is a critical metric for application of polymer matrix composites where failure caused by impact damage could compromise structural performance and safety. As a result, several materials and/or design approaches to improve impact damage tolerance have been investigated over the past several decades. Many composite toughening methodologies impart a trade-off between increased fracture toughness and compromised in-plane strength and modulus. In large part, mechanical tests to evaluate composite damage tolerance include static methods such as Mode I, Mode II, and mixed mode failures. However, ballistic impact damage resistance does not always correlate with static properties. The intent of this paper is to evaluate the influence of a thermoplastic polyurethane veil interleave on the static and dynamic performance of composite test articles. Static coupon tests included tension, compression, double cantilever beam, and end notch flexure. Measurement of the resistance to ballistic impact damage were made to evaluate the composites response to high speed impact. The interlayer material showed a decrease of in-plane performance with only a moderate improvement to Mode I and Mode II fracture toughness. However, significant benefit to impact damage tolerance was observed through ballistic tests.

  12. Principles of ballistics applicable to the treatment of gunshot wounds.

    Science.gov (United States)

    Swan, K G; Swan, R C

    1991-04-01

    Ballistics is the science of the motion of a projectile through the barrel of a firearm (internal ballistics), during its subsequent flight (external ballistics), and during its final complicated motion after it strikes a target (terminal ballistics). Wound ballistics is a special case of terminal ballistics. Although wound ballistics is at best sets of approximations, its principles enter usefully into an evaluation of a gunshot wound and its treatment. A special consideration in these cases is their medicolegal aspects. At a minimum, the medical team receiving the patient should exert care not to destroy the clothing and in particular to cut around and not through bullet holes, to turn over to law enforcement officials any metallic foreign body recovered from the patient, and to describe precisely, or even to photograph, any entrance or exit wounds.

  13. Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

    Directory of Open Access Journals (Sweden)

    Sanjib C. Chowdhury

    2017-02-01

    Full Text Available Ballistic impact induces multiaxial loading on Kevlar® and polyethylene fibers used in protective armor systems. The influence of multiaxial loading on fiber failure is not well understood. Experiments show reduction in the tensile strength of these fibers after axial and transverse compression. In this paper, we use molecular dynamics (MD simulations to explain and develop a fundamental understanding of this experimental observation since the property reduction mechanism evolves from the atomistic level. An all-atom MD method is used where bonded and non-bonded atomic interactions are described through a state-of-the-art reactive force field. Monotonic tension simulations in three principal directions of the models are conducted to determine the anisotropic elastic and strength properties. Then the models are subjected to multi-axial loads—axial compression, followed by axial tension and transverse compression, followed by axial tension. MD simulation results indicate that pre-compression distorts the crystal structure, inducing preloading of the covalent bonds and resulting in lower tensile properties.

  14. Development of a New Armor Steel and its Ballistic Performance

    Directory of Open Access Journals (Sweden)

    S. Hakan Atapek

    2013-05-01

    Full Text Available In this study, a boron added armor steel was developed according to standard rolled homogenous armor steel, MIL-A-12560, and metallographic-fractographic examinations were carried out to understand its deformation characteristics and perforation mode after interaction with a 7.62 mm armor piercing projectile. The microstructure of the developed steel was characterized by light and scanning electron microscope to evaluate its matrix after application of several heat treatments consisting of austenization, quenching and tempering. The mechanical properties of the developed steel were determined by tensile test at room temperature and notched impact test at -40 ºC. The ballistic performance of developed steel was determined by its V50 ballistic protection limit according to MIL-STD-662F standard and it was found to be higher than that of MIL-A-12560 steel. After perforation deformation induced adiabatic shear bands, that have an important role on the crack nucleation, were observed close to the penetration in the etched steel and perforation occurred by typical ductile hole enlargement with certain radial flows.Defence Science Journal, 2013, 63(3, pp.271-277, DOI:http://dx.doi.org/10.14429/dsj.63.1341

  15. Influence of Polymer Restraint on Ballistic Performanceof Alumina Ceramic Tiles

    Directory of Open Access Journals (Sweden)

    P.R.S. Reddy

    2008-03-01

    Full Text Available An experimental study has been carried out to evaluate the influence of confinement ofalumina ceramic tiles through polymer restraint, on its ballistic performance. Tiles of 99.5 per centpurity alumina were subjected to ballistic impact against 7.62 mm armour piercing projectiles atvelocities of about 820 m/s. The tiles of size 75 mm x 75 mm x 7 mm were confined on both facesby effectively bonding varying numbers of layers of polymer fabrics. These were then bondedto a 10 mm thick fibre glass laminate as a backing using epoxy resin. High performance polyethyleneand aramid polymer fabrics were used in the current set of experiments for restraining the tiles.Comparative effects of confinement on energy absorption of tiles with varied number of layersof fabrics were evaluated. It was observed that by providing effective confinement to the tile,energy absorption could be doubled with increase in areal density by about 13 per cent.Photographs of the damage and the effects of restraint on improvement in energy absorptionof ceramic tiles are presented and discussed.

  16. Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

    Directory of Open Access Journals (Sweden)

    M. F. Uddin

    2009-01-01

    Full Text Available We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscale TiO2 particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

  17. Optimization on Impact Strength of Woven Kenaf Reinforced Polyester Composites using Taguchi Method

    Science.gov (United States)

    Khalid, S. N. A.; Ismail, A. E.; Zainulabidin, M. H.

    2017-01-01

    This paper focuses on the effect of weaving patterns and orientations on the energy absorption of woven kenaf reinforced polyester composites. Kenaf fiber in the form of yarn is weaved to produce different weaving patterns such as plain, twill and basket. Three woven mats are stacked together and mixed with polyester resin before it is compressed to squeeze out any excessive resin. There is nine different orientations are used during stacking processes by following Taguchi orthogonal arrays method. The hardened composites are cured for 24 hours before it is shaped according to specific dimensions for impact tests. The composites are perforated with 1m/s blunted projectile. According to the experimental findings, weaving pattern and orientation have distinct potential effects on value of energy absorption. The optimization using Taguchi method reveals preferable orientation of each weaving pattern composites. Based on the fracture observation, the fragmentations after optimization indicating lower distance surface fracture perforated obtained.

  18. Relationships between the fibromyalgia impact questionnaire, tender point count, and muscle strength in female patients with fibromyalgia

    DEFF Research Database (Denmark)

    Henriksen, Marius; Lund, Hans Peter; Christensen, Robin

    2009-01-01

    To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength.......To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength....

  19. Use of an image converter camera for analysis of ballistic resistance of lightweight armor materials

    Science.gov (United States)

    van Bree, J. L.; van Riet, E. J.

    1991-04-01

    Experiments to measure the ballistic resistance of light weight armour materials normally comprise the determination of the ballistic limit velocity V50 for a standardized fragment simulating projectile. However, in order to characterize these materials in more detail, it is of great interest to know the dynamic response of armour materials at impact. To this end, high speed photography is used to monitor target behaviour during impact and subsequent perforation in a timeresolved manner. Moreover, in the field of personal protection it is of importance to know the maximum temporary indentation for nonpenetrating projectiles at impact velocities near the critical V50 velocity as a parameter for trauma-effect. Experiments, making use of a Imacon camera, are described in which materials for light weight armour applications were screened.

  20. Ballistic behavior of boron carbide reinforced AA7075 aluminium alloy using friction stir processing–An experimental study and analytical approach

    Institute of Scientific and Technical Information of China (English)

    I. SUDHAKAR; G. MADHUSUDHAN REDDY; K. SRINIVASA RAO

    2016-01-01

    High strength-to-weight ratio of non-ferrous alloys, such as aluminium, magnesium and titanium alloys, are considered to be possible replacement of widely accepted steels in transportation and automobile sectors. Among these alloys, magnesium is self explosive and titanium is costlier, and aluminium is most likely to replace steels. Application of aluminium or its alloys is also thought of as an appropriate replacement in defence field, especially to enhance the easiness in mobility of combat vehicles while maintaining the same standard as that of conventional armour grade steels. Hence most of the investigations have been confined to aluminium or its alloys as base material and open an era of developing the newer composite materials to address the major limitation, i.e. tribological properties. The surface composites can be fabricated by incorporating the ceramic carbides like silicon carbide, carbides of transition metals and oxides of aluminium using surface modification techniques, such as high energy laser melt treatment, high energy electron beam irradiation and thermal spray process which are based on fusion route. These techniques yield the fusion related problems, such as interfacial reaction, pin holes, shrinkage cavities or voids and other casting related defects, and pave the way to need of an efficient technique which must be based on solid state. Recently developed friction stir processing technique was used in the present investigation for surface modification of AA7075 aluminum alloy, which is an alternative to steels. In the present investigation, 160μm sized boron carbide powder was procured and was reduced to 60μm and 30μm using high energy ball mill. Subsequently these powders were used to fabricate the surface composites using friction stir processing. Ballistic performance testing as per the military standard (JIS.0108.01) was carried out. In the present work, an analytical method of predicting the ballistic behavior of surface composites

  1. Elevated Temperature, Residual Compressive Strength of Impact-Damaged Sandwich Structure Manufactured Out-of-Autoclave

    Science.gov (United States)

    Grimsley, Brian W.; Sutter, James K.; Burke, Eric R.; Dixon, Genevieve D.; Gyekenyesi, Thomas G.; Smeltzer, Stanley S.

    2012-01-01

    Several 1/16th-scale curved sandwich composite panel sections of a 10 m diameter barrel were fabricated to demonstrate the manufacturability of large-scale curved sections using minimum gauge, [+60/-60/0]s, toughened epoxy composite facesheets co-cured with low density (50 kilograms per cubic meters) aluminum honeycomb core. One of these panels was fabricated out of autoclave (OoA) by the vacuum bag oven (VBO) process using Cycom(Registered Trademark) T40-800b/5320-1 prepreg system while another panel with the same lay-up and dimensions was fabricated using the autoclave-cure, toughened epoxy prepreg system Cycom(Registered Trademark) IM7/977-3. The resulting 2.44 m x 2 m curved panels were investigated by non-destructive evaluation (NDE) at NASA Langley Research Center (NASA LaRC) to determine initial fabrication quality and then cut into smaller coupons for elevated temperature wet (ETW) mechanical property characterization. Mechanical property characterization of the sandwich coupons was conducted including edge-wise compression (EWC), and compression-after-impact (CAI) at conditions ranging from 25 C/dry to 150 C/wet. The details and results of this characterization effort are presented in this paper.

  2. Impact Strength of Different Weaving Patterns of Woven Kenaf Reinforced Polyester Composites

    Science.gov (United States)

    Khalid, S. N. A.; Ismail, A. E.; Zainulabidin, M. H.

    2017-01-01

    This paper focuses on the effect of weaving patterns and orientations on the energy absorption of woven kenaf reinforced polyester composites. Kenaf fiber in the form of yarn is weaved to produce different weaving patterns such as plain, twill and basket. Three woven mats are stacked together and mixed with polyester resin before it is compressed to squeeze out any excessive resin. There is 9 different orientations are used during stacking processes. The hardened composites are cured for 24 hours before it is shaped according to specific dimensions for imp act tests. The composites are perforated with 1m/s blunted projectile. According to the experimental findings, both weaving patterns and orientations have distinct potential effects on the force-displacement diagrams. However, fiber orientations have insignificant effect for plain woven especially in the first stage of deformations. Energy absorption performances for each composite condition are calculated and then plotted against fiber orientations for different weaving patterns. It is found there is no strong relationship between energy absorption and fiber orientations. However for each case of composites, higher energy absorption is found for the composites orientated using [+40°/-15°/+40°/+75°]. Based on the fracture observation, both plain and basket-type woven composites reveal large fragmentations occurred indicating lower energy absorption performances. While for twill condition, no obvious fragmentation is observed where the impact damage around the perforated hole is uniformly distributed leading to higher capability of energy absorptions.

  3. Experiments and modeling of ballistic penetration using an energy failure criterion

    Directory of Open Access Journals (Sweden)

    Dolinski M.

    2015-01-01

    Full Text Available One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968. In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB. Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006, according to whom shear bands initiate as a result of dynamic recrystallization (DRX, a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010, a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the

  4. Ballistic penetration test results for Ductal and ultra-high performance concrete samples.

    Energy Technology Data Exchange (ETDEWEB)

    Reinhart, William Dodd; Thornhill, Tom Finley, III (KTech)

    2010-03-01

    This document provides detailed test results of ballistic impact experiments performed on several types of high performance concrete. These tests were performed at the Sandia National Laboratories Shock Thermodynamic Applied Research Facility using a 50 caliber powder gun to study penetration resistance of concrete samples. This document provides test results for ballistic impact experiments performed on two types of concrete samples, (1) Ductal{reg_sign} concrete is a fiber reinforced high performance concrete patented by Lafarge Group and (2) ultra-high performance concrete (UHPC) produced in-house by DoD. These tests were performed as part of a research demonstration project overseen by USACE and ERDC, at the Sandia National Laboratories Shock Thermodynamic Applied Research (STAR) facility. Ballistic penetration tests were performed on a single stage research powder gun of 50 caliber bore using a full metal jacket M33 ball projectile with a nominal velocity of 914 m/s (3000 ft/s). Testing was observed by Beverly DiPaolo from ERDC-GSL. In all, 31 tests were performed to achieve the test objectives which were: (1) recovery of concrete test specimens for post mortem analysis and characterization at outside labs, (2) measurement of projectile impact velocity and post-penetration residual velocity from electronic and radiographic techniques and, (3) high-speed photography of the projectile prior to impact, impact and exit of the rear surface of the concrete construct, and (4) summarize the results.

  5. Simulation of ballistic performance of coarse-grained metals strengthened by nanotwinned regions

    Science.gov (United States)

    Yang, G.; Guo, X.; Weng, G. J.; Zhu, L. L.; Ji, R.

    2015-12-01

    Coarse-grained (CG) metals strengthened by nanotwinned (NT) regions have both ultrahigh strength and good ductility. The presence of the NT regions contributes to their ultrahigh strength, while their good ductility is attributed to the recrystallized coarse grains. These characteristics make them a potential candidate for bullet-proof material. In this paper, numerical simulations based on the mechanism-based strain gradient plasticity and the Johnson-Cook failure criterion are carried out to investigate the effects of twin spacing and microstructural attributes on the ballistic performance of CG copper strengthened by NT regions. We investigate the performance of fourteen idealized microstructures, and find that smaller twin spacing and regular distribution of NT regions are more conducive to the promotion of the ballistic performance. We also uncover that the role of the shape of NT regions is significantly affected by twin spacing. Furthermore, we make a comparison with its CG counterpart without NTs, and find that microstructures with array arrangement of NT regions have higher limit velocities and smaller relative displacements than the single phase CG structure. This makes them a strong candidate for helmets and other personal protective equipments. It is believed that the simulated results could provide useful insights into the development of this advanced class of metals for ballistic protection.

  6. Modeling ballistic effects in frequency-dependent transient thermal transport using diffusion equations

    Science.gov (United States)

    Maassen, Jesse; Lundstrom, Mark

    2016-03-01

    Understanding ballistic phonon transport effects in transient thermoreflectance experiments and explaining the observed deviations from classical theory remains a challenge. Diffusion equations are simple and computationally efficient but are widely believed to break down when the characteristic length scale is similar or less than the phonon mean-free-path. Building on our prior work, we demonstrate how well-known diffusion equations, namely, the hyperbolic heat equation and the Cattaneo equation, can be used to model ballistic phonon effects in frequency-dependent periodic steady-state thermal transport. Our analytical solutions are found to compare excellently to rigorous numerical results of the phonon Boltzmann transport equation. The correct physical boundary conditions can be different from those traditionally used and are paramount for accurately capturing ballistic effects. To illustrate the technique, we consider a simple model problem using two different, commonly used heating conditions. We demonstrate how this framework can easily handle detailed material properties, by considering the case of bulk silicon using a full phonon dispersion and mean-free-path distribution. This physically transparent approach provides clear insights into the nonequilibrium physics of quasi-ballistic phonon transport and its impact on thermal transport properties.

  7. The acute effects of dynamic and ballistic stretching on vertical jump height, force, and power.

    Science.gov (United States)

    Jaggers, Jason R; Swank, Ann M; Frost, Karen L; Lee, Chong D

    2008-11-01

    Stretching before performance is a common practice among athletes in hopes of increasing performance and reducing the risk of injury. However, cumulative results indicate a negative impact of static stretching and proprioceptive neuromuscular facilitation (PNF) on performance; thus, there is a need for evaluating other stretching strategies for effective warm-up. The purpose of this study was to compare the differences between two sets of ballistic stretching and two sets of a dynamic stretching routine on vertical jump performance. Twenty healthy male and female college students between the ages of 22 and 34 (24.8 +/- 3 years) volunteered to participate in this study. All subjects completed three individual testing sessions on three nonconsecutive days. On each day, the subjects completed one of three treatments (no stretch, ballistic stretch, and dynamic stretch). Intraclass reliability was determined using the data obtained from each subject. A paired samples t-test revealed no significant difference in jump height, force, or power when comparing no stretch with ballistic stretch. A significant difference was found on jump power when comparing no stretch with dynamic stretch, but no significant difference was found for jump height or force. Statistics showed a very high reliability when measuring jump height, force, and power using the Kistler Quattro Jump force plate. It seems that neither dynamic stretching nor ballistic stretching will result in an increase in vertical jump height or force. However, dynamic stretching elicited gains in jump power poststretch.

  8. Indirect decompression and vertebral body endplate strength after lateral interbody spacer impaction: cadaveric and foam-block models.

    Science.gov (United States)

    Kwon, Anthony J; Hunter, William D; Moldavsky, Mark; Salloum, Kanaan; Bucklen, Brandon

    2016-05-01

    OBJECTIVE The lateral transpsoas approach to the lumbar spine is a well-defined procedure for the management of discogenic spinal pathology necessitating surgical intervention. Intervertebral device subsidence is a postoperative clinical risk that can lead to recurrence of symptomatic pathology and the need for surgical reintervention. The current study was designed to investigate static versus expandable lateral intervertebral spacers in indirect decompression for preserving vertebral body endplate strength. METHODS Using a cadaveric biomechanical study and a foam-block vertebral body model, researchers compared vertebral body endplate strength and distraction potential. Fourteen lumbar motion segments (7 L2-3 and 7 L4-5 specimens) were distributed evenly between static and expandable spacer groups. In each specimen discectomy was followed by trialing and spacer impaction. Motion segments were axially sectioned through the disc, and a metal stamp was used to apply a compressive load to superior and inferior vertebral bodies to quantify endplate strength. A paired, 2-sample for means t-test was performed to determine statistically significant differences between groups (p ≤ 0.05). A foam-block endplate model was used to control simulated disc tension when a spacer with 2- and 3-mm desired distraction was inserted. One-way ANOVA and a post hoc Student Newman-Keuls test were performed (p ≤ 0.05) to determine differences in distraction. RESULTS Both static and expandable spacers restored intact neural foramen and disc heights after device implantation (p > 0.05). Maximum peak loads at endplate failure for static and expandable spacers were 1764 N (± 966 N) and 2284 N (± 949 N), respectively (p ≤ 0.05). The expandable spacer consistently produced greater desired distraction than was created by the static spacer in the foam-block model (p ≤ 0.05). Distraction created by fully expanding the spacer was significantly greater than the predetermined goals of 2 mm

  9. Ballistic model to estimate microsprinkler droplet distribution

    Directory of Open Access Journals (Sweden)

    Conceição Marco Antônio Fonseca

    2003-01-01

    Full Text Available Experimental determination of microsprinkler droplets is difficult and time-consuming. This determination, however, could be achieved using ballistic models. The present study aimed to compare simulated and measured values of microsprinkler droplet diameters. Experimental measurements were made using the flour method, and simulations using a ballistic model adopted by the SIRIAS computational software. Drop diameters quantified in the experiment varied between 0.30 mm and 1.30 mm, while the simulated between 0.28 mm and 1.06 mm. The greatest differences between simulated and measured values were registered at the highest radial distance from the emitter. The model presented a performance classified as excellent for simulating microsprinkler drop distribution.

  10. Ballistic Missile Silo Door Monitoring Analysis

    Energy Technology Data Exchange (ETDEWEB)

    EDENBURN,MICHAEL W.; TROST,LAWRENCE C.

    2000-01-01

    This paper compares the cost and effectiveness of several potential options that may be used to monitor silo-based ballistic missiles. Silo door monitoring can be used to verify that warheads removed to deactivate or download silo-based ballistic missiles have not been replaced. A precedent for monitoring warhead replacement using reentry vehicle on site inspections (RV-OSIs) and using satellites has been established by START-I and START-II. However, other monitoring options have the potential to be less expensive and more effective. Three options are the most promising if high verification confidence is desired: random monitoring using door sensors; random monitoring using manned or unmanned aircraft; and continuous remote monitoring using unattended door sensors.

  11. Ballistic penetration of Perma-Gel

    Science.gov (United States)

    Ryckman, Raymond Albert; Powell, David Arthur; Lew, Adrian

    2012-03-01

    In this study a number of experiments were performed by taking high-speed footage of the firing spherical steel bullets at different speeds into Perma-Gel, a new synthetic thermoplastic material touted to exhibit similar properties to ordnance ballistic gelatin. We found that the gel undergoes very large and recoverable elastic deformations, which could strongly affect the dynamics of the temporary cavity formed behind the projectile. As with ordnance ballistic gelatin, the diameter of the temporary cavity can be many times the diameter of the projectile, in contrast with that of the permanent cavity which is several times smaller.We also observed that the closure of the cavity chokes the air inside, which could affect its dynamics in noticeable ways. Finally, one of the experiments suggest that the precise model of material failure may not be important to determine the dynamics of the temporary cavity.

  12. Ballistic Missile Defense. Past and Future

    Science.gov (United States)

    2010-04-01

    and deployed. These are the two big questions of the anti-ballistic missile ( ABM ) debate. It must be emphasized that the...is the extreme polarization of the opposing positions that have been taken. Consider this statement: “The whole ABM question touched off so intense...earlier that same year by the Washington Post and ABC News11 reported that 80 percent of the American population was in favor of building a missile

  13. Attacking the Theater Mobile Ballistic Missile Threat

    Science.gov (United States)

    1993-06-01

    and Record, �Theater Ballistic Missile Defense and US Contingency Operations,� 13. 43Greg Myre, Associated Press, �De Klerk Reveals South African...possession). ____. Briefing, subject: �WarBreaker.� 17 December 1992. Myre, Greg. Associated Press. �De Klerk Reveals South African Nuclear...April�3 May 1992, 1,44. Ordway, Frederick I. III and Ronald C. Wakeford. International Missile and Spacecraft Guide. New York: McGraw

  14. Thermo-Electron Ballistic Coolers or Heaters

    Science.gov (United States)

    Choi, Sang H.

    2003-01-01

    Electronic heat-transfer devices of a proposed type would exploit some of the quantum-wire-like, pseudo-superconducting properties of single-wall carbon nanotubes or, optionally, room-temperature-superconducting polymers (RTSPs). The devices are denoted thermo-electron ballistic (TEB) coolers or heaters because one of the properties that they exploit is the totally or nearly ballistic (dissipation or scattering free) transport of electrons. This property is observed in RTSPs and carbon nanotubes that are free of material and geometric defects, except under conditions in which oscillatory electron motions become coupled with vibrations of the nanotubes. Another relevant property is the high number density of electrons passing through carbon nanotubes -- sufficient to sustain electron current densities as large as 100 MA/square cm. The combination of ballistic motion and large current density should make it possible for TEB devices to operate at low applied potentials while pumping heat at rates several orders of magnitude greater than those of thermoelectric devices. It may also enable them to operate with efficiency close to the Carnot limit. In addition, the proposed TEB devices are expected to operate over a wider temperature range

  15. Targeting Low-Energy Ballistic Lunar Transfers

    Science.gov (United States)

    Parker, Jeffrey S.

    2010-01-01

    Numerous low-energy ballistic transfers exist between the Earth and Moon that require less fuel than conventional transfers, but require three or more months of transfer time. An entirely ballistic lunar transfer departs the Earth from a particular declination at some time in order to arrive at the Moon at a given time along a desirable approach. Maneuvers may be added to the trajectory in order to adjust the Earth departure to meet mission requirements. In this paper, we characterize the (Delta)V cost required to adjust a low-energy ballistic lunar transfer such that a spacecraft may depart the Earth at a desirable declination, e.g., 28.5(white bullet), on a designated date. This study identifies the optimal locations to place one or two maneuvers along a transfer to minimize the (Delta)V cost of the transfer. One practical application of this study is to characterize the launch period for a mission that aims to launch from a particular launch site, such as Cape Canaveral, Florida, and arrive at a particular orbit at the Moon on a given date using a three-month low-energy transfer.

  16. Formation of Nanostructures in Severely Deformed High-Strength Steel Induced by High-Frequency Ultrasonic Impact Treatment

    Science.gov (United States)

    Dutta, R. K.; Malet, L.; Gao, H.; Hermans, M. J. M.; Godet, S.; Richardson, I. M.

    2015-02-01

    Surface modification by the generation of a nanostructured surface layer induced via ultrasonic impact treatment was performed at the weld toe of a welded high-strength quenched and tempered structural steel, S690QL1 (Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt pct)). Such high-frequency peening techniques are known to improve the fatigue life of welded components. The nanocrystallized structure as a function of depth from the top-treated surface was characterized via a recently developed automated crystal orientation mapping in transmission electron microscopy. Based on the experimental observations, a grain refinement mechanism induced by plastic deformation during the ultrasonic impact treatment is proposed. It involves the formation of low-angle misoriented lamellae displaying a high density of dislocations followed by the subdivision of microbands into blocks and the resulting formation of polygonal submicronic grains. These submicronic grains further breakdown into nano grains. The results show the presence of retained austenite even after severe surface plastic deformation. The average grain size of the retained austenite and martensite is 17 and 35 nm, respectively. The in-grain deformation mechanisms are different in larger and smaller grains. Larger grains show long-range lattice rotations, while smaller grains show plastic deformation through grain rotation. Also the smaller nano grains exhibit the presence of short-range disorder. Surface nanocrystallization also leads to an increased fraction of low angle and low energy coincident site lattice boundaries especially in the smaller grains ( nm).

  17. A preliminary study on the perforation resistance of high-strength steel plates

    Science.gov (United States)

    Børvik, T.; Dey, S.; Clausen, A. H.

    2006-08-01

    Thin plates of high-strength steel are frequently being used in ballistic protection systems. In this study, the perforation resistance of three different high-strength steel alloys impacted by 7.62 mm AP projectiles has been determined and compared against each other. The considered alloys are Weldox 500 E, Hardox 400 and Domex Protect 500. The yield stress in Domex Protect 500 is almost three times the yield stress in Weldox 500 E, while the opposite trend is found regarding strain to fracture in uniaxial tension. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit velocity of the steels using 6+6=12 mm thick targets. Moreover, a material test programme including high strain rate tests in a split-Hopkinson tension bar was carried out in order to be able to calibrate a proper constitutive equation and fracture criteria. Here, a simplified identification procedure was used together with a modified Johnson-Cook constitutive relation and the Cockcroft-Latham fracture criterion since it is considered important to limit the number of material tests in design. Finally, results from 2D axisymmetric numerical simulations using the non-linear FEM code LS-DYNA are included, and the different findings are compared.

  18. Using a Combination of Experimental and Computational Methods to Explore the Impact of Metal Identity and Ligand Field Strength on the Electronic Structure of Metal Ions

    Science.gov (United States)

    Pernicone, Naomi C.; Geri, Jacob B.; York, John T.

    2011-01-01

    In this exercise, students apply a combination of techniques to investigate the impact of metal identity and ligand field strength on the spin states of three d[superscript 5] transition-metal complexes: Fe(acac)[subscript 3], K[subscript 3][Fe(CN)[subscript 6

  19. Adhesive luting of all-ceramic restorations--the impact of cementation variables and short-term water storage on the strength of a feldspathic dental ceramic.

    LENUS (Irish Health Repository)

    Addison, Owen

    2008-08-01

    To investigate the impact of resin cement luting variables and short-term water storage on the strength of an adhesively luted all-ceramic restorative material. An understanding of the strengthening mechanisms will result in optimisation of operative techniques and materials selection criteria.

  20. Impact Strength and Flexural Properties Enhancement of Methacrylate Silane Treated Oil Palm Mesocarp Fiber Reinforced Biodegradable Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2014-01-01

    Full Text Available Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA/polycaprolactone (PCL/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  1. Impact strength and flexural properties enhancement of methacrylate silane treated oil palm mesocarp fiber reinforced biodegradable hybrid composites.

    Science.gov (United States)

    Eng, Chern Chiet; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  2. Strain Rate Effect on the Tensile Behavior of Fibers and Its Application to Ballistic Perforation of Multi-layered Fabrics

    Institute of Scientific and Technical Information of China (English)

    GU Bo-hong; PAN Xiong-qi

    2002-01-01

    Rate-dependent property of material is very important in analysis of ballistic impact. The tensile property of Twaron(R) filaments at strain rate range from 0.01/s to1 000/s was obtained by MTS materials testing and split Hopkinson tension bar. Rate sensitivity of Twaron(R) filaments is discussed. Application of high strain rate property to ballistic perforation of multi- layered fabrics conforms to the actual situation than that of quasi-static property. The revised analytical model can be used to calculate the process of ballistic penetration and perforation on soft armour, such as fabric target plate,at intuitive approach and simple algorithm with a little computer process time. Predictions of the residual velocities and energy absorbed by the multi- layered fabric show good agreement with experimental data.

  3. Large-scale QRPA calculation of E1-strength and its impact on the neutron capture cross section

    CERN Document Server

    Goriely, S

    2002-01-01

    Large-scale QRPA calculations of the E1-strength are performed as a first attempt to microscopically derive the radiative neutron capture cross sections for the whole nuclear chart. A folding procedure is applied to the QRPA strength distribution to take the damping of the collective motion into account. It is shown that the resulting E1-strength function based on the SLy4 Skyrme force is in close agreement with photoabsorption data as well as the available experimental E1-strength at low energies. The increase of the E1-strength at low energies for neutron-rich nuclei is qualitatively analyzed and shown to affect the corresponding radiative neutron capture cross section significantly. A complete set of E1-strength function is made available for practical applications in a table format for all 7

  4. Experimental study about the influence of adhesive stiffness to the bonding strengths of adhesives for ceramic/metal targets

    Institute of Scientific and Technical Information of China (English)

    W. SEIFERT; E. STRASSBURGER; S. GREFEN; S. SCHAARE

    2016-01-01

    The aim of the investigations presented here was to understand how the stiffness of the adhesive affects the failure of ceramic tiles adhered to metallic backings. The working hypothesis was that varying the adhesive stiffness could have the same effect on the ballistic performance as a variation of the adhesive thickness. Two different projectile/target combinations were utilized for ballistic tests in order to generate extremely different loading conditions. With targets consisting of 6 mm aluminum oxide ceramic and 6 mm aluminum backing, complete penetration occurred in each test with 7.62 mm tungsten carbide core AP ammunition at an impact velocity of 940 m/s. In contrast, with ceramic tiles of 20 mm thickness on 13 mm steel backing, no penetration of the ceramic occurred at the impact of a 7.62 mm ball round at 840 m/s. Four different types of adhesive (high-strength till high-flexible) were tested in both configurations. The elongation of the adhesive layer, the deformation of the metallic backing and the failure of the ceramics were observed by means of a high-speed camera during the projectile/target interaction. The results of the ballistic tests showed that a higher fracture strain caused a larger deformation of the backing compared to adhesives, which exhibit a high tensile strength and low fracture strains. The experimental results indicate that the damage behavior of the ceramic/metal composites depends on the absolute elongation of the adhesive layer. This can be controlled either by the thickness or the stiffness of the bonding layer.

  5. Development of data optimization methodology for nondestructive testing of concrete strength by the parameters of the electric response to impact excitation

    Science.gov (United States)

    Fursa, T. V.; Surzhikov, A. P.; Petrov, M. V.

    2016-02-01

    The paper presents the research results by the improvement of the non-destructive testing method of concrete strength by the parameters of the electric response to impact excitation. The electric response parameters from the set of identical concrete samples sized of 100×100×100 mm were studied. It is shown that the use of linear filtering procedure reduces the variance of diagnostic electric parameter for concrete strength determination and is in a good agreement with the elastic characteristics of the material.

  6. Promoting strength and balance in adolescents during physical education: effects of a short-term resistance training.

    Science.gov (United States)

    Granacher, Urs; Muehlbauer, Thomas; Doerflinger, Britta; Strohmeier, Ralf; Gollhofer, Albert

    2011-04-01

    Secular trends in strength and postural control have been reported for children and adolescents. Therefore, the objective of this study was to investigate the impact of a short-term ballistic strength training (BST) followed by detraining on measures of strength and postural control in adolescents. Twenty-eight high-school students participated in this study and were assigned to either an intervention (n = 14, age 16.7 ± 0.6 years, body mass index [BMI] 21.1 ± 1.7 kg · m) or a control group (n = 14, age 16.8 ± 0.7 years, BMI 19.9 ± 1.7 kg · m). The intervention class participated in a short-term (8 week) lower extremity BST program 2 times a week integrated in their regular physical education lessons. Pre, post, and follow-up tests included the measurements of maximal isometric force (MIF) and rate of force development (RFD) of the leg extensors on a leg press with the feet resting on a force platform, vertical jumping height (countermovement jump [CMJ]) on a force plate and the assessment of static (1-legged stance on a balance platform), and dynamic (mediolateral perturbation impulse on a balance platform) postural control. Ballistic strength training resulted in statistically significant improvements in MIF (p = 0.001) and CMJ height (p physical education lessons) that produced transient improvements in strength variables. These results could have an impact on improving the performance level in various motor fitness skills and sports activities in physical education.

  7. Development of an impact-reduction device by applying ultrasonic vibrations to a high-strength steel plate using a downsized transducer

    Science.gov (United States)

    Suzuki, Atsuyuki; Ikeoka, Shota; Tsujino, Jiromaru

    2016-07-01

    In this study, we attempted to downsize an ultrasonic impact-reduction device and studied its use in vehicles because the use of large devices increases the overall vehicle weight and size and reduces fuel economy. We downsized the ultrasonic transducer to 195 mm from 435 mm and measured the vibration, deformation, and impact-reduction characteristics. The resonant frequency changed after a bolt-clamped Langevin-type transducer was connected with the horn, and the motional admittance decreased. Upon application of ultrasonic vibrations to a high-strength steel plate, the deformation magnitude increased, the springback magnitude decreased by up to 25%, and the impact force decreased by 18%. While the downsized impact reduction system was found to be less effective, it still showed an impact reduction effect.

  8. Development and testing of a flexible ballistic neck protection

    NARCIS (Netherlands)

    Roebroeks, G.H.J.J.; Rensink, P.

    2016-01-01

    Sufficient ballistic protection of the neck area would significantly reduce the vulnerability of an infantry soldier. So far this protection is offered by extensions on the ballistic vest or combat helmet. However, the requirements for head agility and the various body to head positions combined wit

  9. Ballistic performance and microstructure of four armor ceramics

    NARCIS (Netherlands)

    Abadjieva, E.; Carton, E.P.

    2013-01-01

    The ballistic behavior of four different armor ceramic materials with thicknesses varying from 3 mm to 14 mm has been investigated. These are two types of alumina Al2O3 armor grades and two types of SiC armor grades produced by different armor ceramic producers. The ballistic study has been performe

  10. Ballistic Characterization of the Scalability of Magnesium Alloy AMX602

    Science.gov (United States)

    2015-07-01

    Magnesium Alloy AMX602 by Tyrone L Jones Weapons and Materials Research Directorate, ARL Katsuyoshi Kondoh Joining and Welding Research...formed a collaborative partnership with Osaka University Joining and Welding Research Institute (JWRI), Taber Extrusions, Epson Atmix, Pacific Sowa...Powder Metallurgy 4 5. Fabrication Procedure 4 6. Mechanical Property Analysis 5 7. Ballistic Experimental Procedures 6 8. Ballistic Experimental

  11. The reference ballistic imaging database revisited.

    Science.gov (United States)

    De Ceuster, Jan; Dujardin, Sylvain

    2015-03-01

    A reference ballistic image database (RBID) contains images of cartridge cases fired in firearms that are in circulation: a ballistic fingerprint database. The performance of an RBID was investigated a decade ago by De Kinder et al. using IBIS(®) Heritage™ technology. The results of that study were published in this journal, issue 214. Since then, technologies have evolved quite significantly and novel apparatus have become available on the market. The current research article investigates the efficiency of another automated ballistic imaging system, Evofinder(®) using the same database as used by De Kinder et al. The results demonstrate a significant increase in correlation efficiency: 38% of all matches were on first position of the Evofinder correlation list in comparison to IBIS(®) Heritage™ where only 19% were on the first position. Average correlation times are comparable to the IBIS(®) Heritage™ system. While Evofinder(®) demonstrates specific improvement for mutually correlating different ammunition brands, ammunition dependence of the markings is still strongly influencing the correlation result because the markings may vary considerably. As a consequence a great deal of potential hits (36%) was still far down in the correlation lists (positions 31 and lower). The large database was used to examine the probability of finding a match as a function of correlation list verification. As an example, the RBID study on Evofinder(®) demonstrates that to find at least 90% of all potential matches, at least 43% of the items in the database need to be compared on screen and this for breech face markings and firing pin impression separately. These results, although a clear improvement to the original RBID study, indicate that the implementation of such a database should still not be considered nowadays.

  12. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    OpenAIRE

    I. Sudhakar; V. Madhu; G. Madhusudhan Reddy; K. Srinivasa Rao

    2015-01-01

    Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to tha...

  13. Going ballistic: Graphene hot electron transistors

    Science.gov (United States)

    Vaziri, S.; Smith, A. D.; Östling, M.; Lupina, G.; Dabrowski, J.; Lippert, G.; Mehr, W.; Driussi, F.; Venica, S.; Di Lecce, V.; Gnudi, A.; König, M.; Ruhl, G.; Belete, M.; Lemme, M. C.

    2015-12-01

    This paper reviews the experimental and theoretical state of the art in ballistic hot electron transistors that utilize two-dimensional base contacts made from graphene, i.e. graphene base transistors (GBTs). Early performance predictions that indicated potential for THz operation still hold true today, even with improved models that take non-idealities into account. Experimental results clearly demonstrate the basic functionality, with on/off current switching over several orders of magnitude, but further developments are required to exploit the full potential of the GBT device family. In particular, interfaces between graphene and semiconductors or dielectrics are far from perfect and thus limit experimental device integrity, reliability and performance.

  14. More Inaccurate Specifications of Ballistic Coefficients

    Science.gov (United States)

    2012-01-02

    The rifles used in the study were all Remington 700s with factory barrels. The 223 Remington , 308 Winchester, and 30-06 were all ADLs with...Berger 62 grain flat base varmint bullet. This bullet demonstrates excellent accuracy (0.5 MOA) in the Remington 700 test rifle out to 300 yards and...factor. The earlier paper (Courtney and Courtney 2009) reported a BC of 0.308 +/- 0.010 for the 125 grain Nosler Ballistic Tip from the Remington

  15. Dynamic conductance of a ballistic quantum wire

    Energy Technology Data Exchange (ETDEWEB)

    Quan Jun [School of Physics Science and Technology, Zhanjiang Normal University, Zhanjiang 524048 (China); Tian Ying [Center of Liberal Education, Zhanjiang Normal University, Zhanjiang 524048 (China); Zhang, Jun, E-mail: ntu_submit@yahoo.c [School of Physics Science and Technology, Zhanjiang Normal University, Zhanjiang 524048 (China); Shenzhen Institute of Advanced Integration Technology, Shenzhen 518055 (China); Shao Lexi [School of Physics Science and Technology, Zhanjiang Normal University, Zhanjiang 524048 (China)

    2011-04-01

    Within the framework of exact linear response theory, we derive a general formula, with which the dynamic conductance of mesoscopic system can be determined in the absence of Coulomb interaction. In addition, we present a solution to the problem of current partition in the system. These allow the derivation of dynamic conductance in time-dependent case. As a natural consequence, the current (charge) conservation and gauge invariance conditions are fulfilled. To give an example, we discuss the dynamic conductance of a ballistic quantum wire, and the effect of contacts on the conductance is also discussed.

  16. Ballistic Behaviour of Tempered Steel Armour Plates under Plane Strain Condition .

    Directory of Open Access Journals (Sweden)

    S. N. Dikshit

    1998-04-01

    Full Text Available The present investigation deals with the ballistic behaviour of tempered steel armour plates under plane strain condition at normal angle of attack. A conical-shaped steel projectile of 6.1 mmdiameter was impacted on 20 mm thick steel annour plates of 350, 450 and 550 Hv hardness, in the velocity range 200 -700 m/s at zero obliquity. Ballistic performance measured in terms of the depthof penetration indicates that, under plane strain condition, behavio1Do" f 550 Hv steel plate is better than those of the other two plates. However, front spalling causes damageto the entry side of the high hardness plate, thus affecting its multihit capability in a limited manner.

  17. Multi Scale Modeling of Continuous Aramid Fiber Reinforced Polymer Matrix Composites Used in Ballistic Protection Applications

    Science.gov (United States)

    2014-11-16

    discussed within the context of p-phenylene terephthalamide (PPTA) polymeric filaments such as Kevlar ®, Twaron®, etc. Molecular level: A pictorial...Grujicic, M., Bell, W. C., Glomski, P. S., Pandurangan, B., Yen, C.-F. & Cheeseman, B. A. “Multi-length Scale Computational Derivation of Kevlar ® Yarn...Pandurangan, B., Yen, C-.F., Cheeseman, B. A., Wang, Y., Miao, Y. & Zheng, J. Q. “Fiber-level Modeling of Dynamic Strength of Kevlar ® KM2 Ballistic

  18. THE IMPACT OF REINFORCED CONDITIONS ON THE STRENGTH OF PALM REINFORCED SOIL%加筋条件对棕榈加筋土强度的影响

    Institute of Scientific and Technical Information of China (English)

    璩继立; 赵冬雪; 李贝贝

    2015-01-01

    To improve the characteristics of the low Shanghai clay strength and easy destroy, the dispersed palm was mixed into Shanghai clay with different mass reinforcement ratio and aspect ratio to do unconfined compressive strength test and Brazilian splitting test, then the impact of reinforced conditions on the compressive strength and tensile strength was explored.The results showed that compared with plain soil, palm reinforced soil could increase the compressive strength and tensile strength of Shanghai clay. The most appropriate reinforcement ratio of compressive strength and tensile strength in test was 1.00%.The best palm length was 4 mm, the optimum aspect ratio was 1∶3.Compared with plain soil, the improved degree of tensile strength by reinforcement was higher than that of the compressive strength.Meanwhile it was analyzed the mechanism of raising the strength of palm reinforced soil.%为改良上海黏土强度低,易发生破坏的特性,将分散的棕榈片以不同质量加筋率、长宽比等加入上海黏土中进行抗压强度试验和巴西劈裂试验,来探究加筋条件对棕榈加筋土抗压强度和抗拉强度的影响。试验结果表明:与素土相比,棕榈加筋土可提高上海黏土的抗压强度和抗拉强度。抗压强度和抗拉强度最适宜的加筋率为1.00%,最佳棕榈长度为4 mm,最优长宽比为1∶3。相对于素土,加筋对抗拉强度的提高幅度高于抗压强度。同时对棕榈加筋土强度提高的机理进行分析。

  19. Evaluation of the Impact of Hydrostatic Pressure and Lode Angle on the Strength of the Rock Mass Based on the Hoek–Brown Criterion

    Directory of Open Access Journals (Sweden)

    Marczak Halina

    2015-06-01

    Full Text Available Determination of the global uniaxial compressive strength of rock mass on the basis of the Hoek-Brown failure criterion requires knowledge of the strength parameters: cohesion and the angle of internal friction. In the conventional method for the determination of these parameters given by Balmer, they are expressed by the minimum principal stress. Thus, this method does not allow for the assessment of an impact of hydrostatic pressure and stress path on the value of cohesion, friction angle and global uniaxial compression of rock mass. This problem can be eliminated by using the Hoek-Brown criterion expressed by the invariants of the stress state. The influence of hydrostatic pressure and the Lode angle on the strength parameters of the rock mass was analysed.

  20. High-strength porous carbon and its multifunctional applications

    Science.gov (United States)

    Wojtowicz, Marek A; Rubenstein, Eric P; Serio, Michael A; Cosgrove, Joseph E

    2013-12-31

    High-strength porous carbon and a method of its manufacture are described for multifunctional applications, such as ballistic protection, structural components, ultracapacitor electrodes, gas storage, and radiation shielding. The carbon is produced from a polymer precursor via carbonization, and optionally by surface activation and post-treatment.

  1. Influence of the vacuum resin process, on the ballistic behaviour of lightweight armouring solutions

    Directory of Open Access Journals (Sweden)

    Coutellier D.

    2012-08-01

    Full Text Available The armour of vehicles against conventional threats is mainly composed with steel or aluminium panels. Efficient heavy solutions exist, but the involved industries require new lightweight structures. Moreover, unconventional threats as IEDs (Improvised Explosive Devices may cause severe damages on these structural and protective panel solutions. Thus, combination of aluminium or steel plates with textile composite structures used as a backing, leads to the mass reduction and better performance under delamination behaviour against these new threats. This paper is a part of a study dealing with the impact behaviour of three warp interlocks weaving structures under Fragment Simulating Projectile (FSP impact. During this research, several parameters has being studied as the influence of the yarns insertions [1–4], the degradation of the yarns during the weaving process [5–7], and the influence of the resin rate on the ballistic behaviour. The resin rate inside composite materials is dependant on the final application. In ballistic protection, we need to control the resin rate in order to have a deformable structure in order to absorb the maximum of energy. However, with the warp interlocks weaving structure, the yarns insertions induce empty spaces between the yarns where the resin takes place without being evacuated. The resin rate inside the warp interlocks structures is in the most of cases less than 50%, which lead to have brittle and hard material during the impact. Contrary to interlocks structures, the existing protection based on prepreg structure have a high fibres ratio around 88% of weight. That leads to have the best ballistic properties during the impact and good deformability of the structure. The aim of this paper is to evaluate the influence of the resin rate on the ballistic results of the composites materials. For that, we have chosen two kinds of warp interlocks fabrics which were infused with epoxy resin following two

  2. Ballistics of space launch by a rail gun

    Science.gov (United States)

    Panin, Alexander

    2010-10-01

    The idea of using a big gun to launch objects to space has been around for years -- even Isaac Newton considered the concept. However the technology of accelerating a payload with a gun only recently began approaching orbital velocity (8 km/sec). NASA is currently experimenting with a rail gun which utilizes a magnetic field powered by electricity to accelerate a projectile along a set of rails, similar to train rails. Velocities up to 3 km/sec have been reported for small projectiles, and it seems that orbital velocities can soon become a reality too. We model a launch of various projectiles from Earth surface into the elevation corresponding to the low Earth orbit (about 200-250 km above Earth's surface). The goal of this modeling is to study feasibility of such launch (and accelerations induced), and the ballistics of the flight via Earth's atmosphere (the trajectory, air drag induced, pressure and temperature generated by air drag, etc) and thus the requirements for a mass, size, strength, heat shield, and general design of a payload capsule.

  3. Ballistic quench-induced correlation waves in ultracold gases

    CERN Document Server

    Corson, John P

    2016-01-01

    We investigate the wave packet dynamics of a pair of particles that undergoes a rapid change of scattering length. The short-range interactions are modeled in the zero-range limit, where the quench is accomplished by switching the boundary condition of the wave function at vanishing particle separation. This generates a correlation wave that propagates rapidly to nonzero particle separations. We have derived universal, analytic results for this process that lead to a simple phase-space picture of the quench-induced scattering. Intuitively, the strength of the correlation wave relates to the initial contact of the system. We find that, in one spatial dimension, the $k^{-4}$ tail of the momentum distribution contains a ballistic contribution that does not originate from short-range pair correlations, and a similar conclusion can hold in other dimensionalities depending on the quench protocol. We examine the resultant quench-induced transport in an optical lattice in 1D, and a semiclassical treatment is found to...

  4. Short report of an unusual ballistic trauma

    Science.gov (United States)

    Inchingolo, Francesco; Tatullo, Marco; Marrelli, Massimo; Inchingolo, Alessio D.; Pinto, Giorgia; Inchingolo, Angelo M.; Dipalma, Gianna

    2011-01-01

    INTRODUCTION Portable firearms have a relevant medico-legal interest, being a major cause of injury. Bullet entry wounds generally have a particular appearance, including contusion, skin introflection, and simple or excoriated ecchymosis. The skin wound is typically a hole with frayed margins, whose diameter is smaller than that of the bullet. PRESENTATION OF CASE We report the case of a 19-year-old man with ballistic trauma. Examination of the patient's lesions indicated that the bullet had entered from the left mandibular parasymphysis, creating a small hole without the typical bullet wipe and blackening. Subsequently, the bullet seemed to have fractured the left chin region immediately below the lower alveolar process, and it finally stopped in the submandibular area in the suprahyoid region of the neck. DISCUSSION This case is peculiar because the distinctive features of a firearm injury were absent; the lack of bleeding and edema made the case difficult to interpret without additional diagnostic investigations. CONCLUSION Ballistic trauma can manifest in different ways; therefore, internal trauma should be suspected even in the absence of clear external signs. This case report shows how an unusual bullet entry hole can mask quite serious injuries. PMID:22096751

  5. Advanced geometries for ballistic neutron guides

    Science.gov (United States)

    Schanzer, Christian; Böni, Peter; Filges, Uwe; Hils, Thomas

    2004-08-01

    Sophisticated neutron guide systems take advantage of supermirrors being used to increase the neutron flux. However, the finite reflectivity of supermirrors becomes a major loss mechanism when many reflections occur, e.g. in long neutron guides and for long wavelengths. In order to reduce the number of reflections, ballistic neutron guides have been proposed. Usually linear tapered sections are used to enlarge the cross-section and finally, focus the beam to the sample. The disadvantages of linear tapering are (i) an inhomogeneous phase space at the sample position and (ii) a decreasing flux with increasing distance from the exit of the guide. We investigate the properties of parabolic and elliptic tapering for ballistic neutron guides, using the Monte Carlo program McStas with a new guide component dedicated for such geometries. We show that the maximum flux can indeed be shifted away from the exit of the guide. In addition we explore the possibilities of parabolic and elliptic geometries to create point like sources for dedicated experimental demands.

  6. Advanced geometries for ballistic neutron guides

    Energy Technology Data Exchange (ETDEWEB)

    Schanzer, Christian E-mail: christian.schanzer@frm2.tum.de; Boeni, Peter; Filges, Uwe; Hils, Thomas

    2004-08-21

    Sophisticated neutron guide systems take advantage of supermirrors being used to increase the neutron flux. However, the finite reflectivity of supermirrors becomes a major loss mechanism when many reflections occur, e.g. in long neutron guides and for long wavelengths. In order to reduce the number of reflections, ballistic neutron guides have been proposed. Usually linear tapered sections are used to enlarge the cross-section and finally, focus the beam to the sample. The disadvantages of linear tapering are (i) an inhomogeneous phase space at the sample position and (ii) a decreasing flux with increasing distance from the exit of the guide. We investigate the properties of parabolic and elliptic tapering for ballistic neutron guides, using the Monte Carlo program McStas with a new guide component dedicated for such geometries. We show that the maximum flux can indeed be shifted away from the exit of the guide. In addition we explore the possibilities of parabolic and elliptic geometries to create point like sources for dedicated experimental demands.

  7. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  8. Understanding juror perceptions of forensic evidence: investigating the impact of case context on perceptions of forensic evidence strength.

    Science.gov (United States)

    Smith, Lisa L; Bull, Ray; Holliday, Robyn

    2011-03-01

    The most widely accepted model of juror decision making acknowledges the importance of both the case-specific information presented in the courtroom, as well as the prior general knowledge and beliefs held by each juror. The studies presented in this paper investigated whether mock jurors could differentiate between evidence of varying strengths in the absence of case information and then followed on to determine the influence that case context (and therefore the story model) has on judgments made about the strength of forensic DNA evidence. The results illustrated that mock jurors correctly identified various strengths of evidence when it was not presented with case information; however, the perceived strength of evidence was significantly inflated when presented in the context of a criminal case, particularly when the evidence was of a weak or ambiguous standard. These findings are discussed in relation to the story model, and the potential implications for real juries.

  9. An experimental study on characteristics of cavitation and ballistic of axisymmetric slender body underwater movement

    Science.gov (United States)

    Zhao, Cheng-Gong; Wang, Cong; Wei, Ying-Jie; Zhang, Xiao-Shi

    2015-12-01

    An experimental study of the axisymmetric slender body underwater movement was conducted using high-speed photography technology. From the results of the experiment, the characteristics of cavitation and ballistic of the axisymmetric, including the formation, development, evolution and collapse of the cavity, are presented in the paper. The experimental results show that the axisymmetric slender body moves in a supercavity, and the slender body rotate in the supercavity on its head at the same time due to the perturbation of launching. The supercavity wall is transparent and smooth except the tail itself. The impact between the tail of slender body and supercavity wall resulted from the slender body's rotation is termed as tail- slap which is one way to keep the stabilization of the movement. Series of different flow mechanisms and the relationship between ballistic characteristics and cavity characteristics with defferent initial velocities are discussed. The slender bodies have different accelerations and ballistics with different initial velocity which means they have different drag forces.

  10. Performance of lead-free versus lead-based hunting ammunition in ballistic soap.

    Directory of Open Access Journals (Sweden)

    Felix Gremse

    Full Text Available BACKGROUND: Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. METHODS: We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. RESULTS: All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. CONCLUSION: The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion

  11. Balancing ballistic protection against physiological strain: evidence from laboratory and field trials.

    Science.gov (United States)

    Taylor, Nigel A S; Burdon, Catriona A; van den Heuvel, Anne M J; Fogarty, Alison L; Notley, Sean R; Hunt, Andrew P; Billing, Daniel C; Drain, Jace R; Silk, Aaron J; Patterson, Mark J; Peoples, Gregory E

    2016-02-01

    This project was based on the premise that decisions concerning the ballistic protection provided to defence personnel should derive from an evaluation of the balance between protection level and its impact on physiological function, mobility, and operational capability. Civilians and soldiers participated in laboratory- and field-based studies in which ensembles providing five levels of ballistic protection were evaluated, each with progressive increases in protection, mass (3.4-11.0 kg), and surface-area coverage (0.25-0.52 m(2)). Physiological trials were conducted on volunteers (N = 8) in a laboratory, under hot-dry conditions simulating an urban patrol: walking at 4 km·h(-1) (90 min) and 6 km·h(-1) (30 min or to fatigue). Field-based trials were used to evaluate tactical battlefield movements (mobility) of soldiers (N = 31) under tropical conditions, and across functional tests of power, speed, agility, endurance, and balance. Finally, trials were conducted at a jungle training centre, with soldiers (N = 32) patrolling under tropical conditions (averaging 5 h). In the laboratory, work tolerance was reduced as protection increased, with deep-body temperature climbing relentlessly. However, the protective ensembles could be grouped into two equally stressful categories, each providing a different level of ballistic protection. This outcome was supported during the mobility trials, with the greatest performance decrement evident during fire and movement simulations, as the ensemble mass was increased (-2.12%·kg(-1)). The jungle patrol trials similarly supported this outcome. Therefore, although ballistic protection does increase physiological strain, this research has provided a basis on which to determine how that strain can be balanced against the mission-specific level of required personal protection.

  12. Strength of Hard Alloys,

    Science.gov (United States)

    Partial replacement of titanium carbide by tantalum carbide in three-phase WC-TiC-Co alloys tends to have a favorable effect on mechanical properties such as fatigue strength under bending and impact durability.

  13. Ballistic energy transport in PEG oligomers

    Directory of Open Access Journals (Sweden)

    Kireev Victor V.

    2013-03-01

    Full Text Available Energy transport between the terminal groups of the azido-PEG-succinimide ester compounds with a number of repeating PEG units of 0, 4, 8, and 12 was studied using relaxation-assisted two-dimensional infrared spectroscopy. The through-bond energy transport time, evaluated as the waiting time at which the cross peak maximum is reached, Tmax, was found to be linearly dependent on the chain length for chain lengths up to 60 Å suggesting a ballistic energy transport regime. The through-bond energy transport speed is found to be ca. 500 m/s. The cross-peak amplitude at the maximum decays exponentially with the chain length with a characteristic decay distance of 15.7 ± 1 Å. Substantial mode delocalization across the PEG bridge is found, which can support the energy propagation as a wavepacket.

  14. Real-world ballistics: A dropped bucket

    CERN Document Server

    Hogg, David W

    2007-01-01

    I discuss an apparently simple ballistics problem: the time it takes an object to fall a small vertical distance near the surface of the Earth. It turns out to be not so simple; I spend a great deal of time on the quantitative assessment of the assumptions involved, especially with regards to the influence of the air. The point is \\emph{not} to solve the problem; indeed I don't even end up solving the problem exactly. I introduce dimensional analysis to perform all of the calculations approximately. The principal theme of the lecture is that \\emph{real} physics can be very different from ``textbook'' physics, since in the real world you aren't ever told what equations are appropriate, or why.

  15. Gate tuneable beamsplitter in ballistic graphene

    Energy Technology Data Exchange (ETDEWEB)

    Rickhaus, Peter; Makk, Péter, E-mail: Peter.Makk@unibas.ch; Schönenberger, Christian [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Liu, Ming-Hao; Richter, Klaus [Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg (Germany)

    2015-12-21

    We present a beam splitter in a suspended, ballistic, multiterminal, bilayer graphene device. By using local bottomgates, a p-n interface tilted with respect to the current direction can be formed. We show that the p-n interface acts as a semi-transparent mirror in the bipolar regime and that the reflectance and transmittance of the p-n interface can be tuned by the gate voltages. Moreover, by studying the conductance features appearing in magnetic field, we demonstrate that the position of the p-n interface can be moved by 1 μm. The herein presented beamsplitter device can form the basis of electron-optic interferometers in graphene.

  16. Ballistic miniband conduction in a graphene superlattice

    Science.gov (United States)

    Lee, Menyoung; Wallbank, John R.; Gallagher, Patrick; Watanabe, Kenji; Taniguchi, Takashi; Fal'ko, Vladimir I.; Goldhaber-Gordon, David

    2016-09-01

    Rational design of long-period artificial lattices yields effects unavailable in simple solids. The moiré pattern in highly aligned graphene/hexagonal boron nitride (h-BN) heterostructures is a lateral superlattice with high electron mobility and an unusual electronic dispersion whose miniband edges and saddle points can be reached by electrostatic gating. We investigated the dynamics of electrons in moiré minibands by measuring ballistic transport between adjacent local contacts in a magnetic field, known as the transverse electron focusing effect. At low temperatures, we observed caustics of skipping orbits extending over hundreds of superlattice periods, reversals of the cyclotron revolution for successive minibands, and breakdown of cyclotron motion near van Hove singularities. At high temperatures, electron-electron collisions suppress focusing. Probing such miniband conduction properties is a necessity for engineering novel transport behaviors in superlattice devices.

  17. Ballistic Missile Defense: New Plans, Old Challenges

    Directory of Open Access Journals (Sweden)

    Elizabeth Zolotukhina

    2010-01-01

    Full Text Available On September 17, 2009—the 70th anniversary of the Soviet invasion of Poland in 1939 that marked the beginning of World War II—the Obama Administration announced its intention to shelve plans for the U.S. Ballistic Missile Defense (BMD that had been developed under former President George W. Bush. Pointing to a new intelligence assessment, President Obama argued that his predecessor's plan to deploy an X-band radar station outside of Prague, Czech Republic, and 10 two-stage interceptor missiles in Poland would not adequately protect America and its European allies from the Iranian threat and reiterated his opposition to utilizing unproven technology in any European BMD architecture.

  18. Ballistics firearm identification by digital holography

    Institute of Scientific and Technical Information of China (English)

    LI Dong-guang

    2009-01-01

    The need for firearm identification systems by police services continues to increase with greater accessibility to weapons in the national and international contexts. The difficulties associated with traditional imaging of ballistics specimens are numerous, and include the smallness of the samples, the nature of the surfaces and shapes for the cartridge cases and projectiles. The digital holography has been introduced to create the 3D image of the fired bullets in order to identify firearms. In digital holography a CCD camera records optically generated holograms which is then reconstructed numerically by a calculation of scalar diffraction in the Fresnel approximation. The digital photography facilitates real time transmission of the message via traditional communication methods. In this paper the principle of digital holography and its application to the 3D image encryption-decryption were reviewed. The experimental results of firearm identification recording using digital holography and their numerical reconstruction were presented.

  19. Absence of cross-limb transfer of performance gains following ballistic motor practice in older adults.

    Science.gov (United States)

    Hinder, Mark R; Schmidt, Matthew W; Garry, Michael I; Carroll, Timothy J; Summers, Jeffery J

    2011-01-01

    The phenomenon of cross-limb transfer, in which unilateral strength training can result in bilateral strength gains, has recently been tested for ballistic movements. Performance gains associated with repetitive motor practice, and the associated transfer, occur within a few minutes. In this study, young and older adults were trained to perform ballistic abductions of their dominant (right) index finger as quickly as possible. Performance was assessed bilaterally before, during, and after this training. Both groups exhibited large performance gains in the right hand as a result of training (P performance improvements were accompanied by increases in excitability, together with decreases in intracortical inhibition, of the projections to both the trained muscle and the homologous muscle in the contralateral limb (P performance improvements as a result of cross-limb transfer in the left (untrained) hand (P performance increase in the trained hand. In contrast, there were no significant performance gains in the left hand for the older group (P = 0.23). This was surprising given that the older group exhibited a significantly greater degree of mirror activity than the young group (P < 0.01) in the left first dorsal interosseus muscle (FDI) during right hand movements. Our findings suggest that older adults exhibit a reduced capacity for cross-limb transfer, which may have implications for motor rehabilitation programs after stroke.

  20. The impact of endodontic irrigating solutions on the push-out shear bond strength of glass fiber posts luted with resin cements.

    Science.gov (United States)

    Bueno, Carlos Eduardo da Silveira; Pelegrine, Rina Andrea; Silveira, Cláudia Fernandes de Magalhães; Bueno, Vanessa Castro Pestana da Silveira; Alves, Vanessa de Oliveira; Cunha, Rodrigo Sanches; Pereira, Gisele Damiana da Silveira; Paulillo, Luis Alexandre Maffei Sartini

    2016-01-01

    Resin-based restorative materials, widely used to cement posts, may be influenced by irrigants used during endodontic chemical-mechanical preparation. This study evaluated the impact of endodontic irrigating solutions and adhesive cement systems on the push-out shear bond strength of glass fiber posts to root dentin. Ninety-six bovine incisors were divided into 12 groups (4 irrigants × 3 resin cements; n = 8). Prepared canals were irrigated with saline solution, 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl, or 2% chlorhexidine gel, and posts were cemented with RelyX ARC, Panavia F, or RelyX U100. The bond strength was evaluated by means of the push-out test, and results were subjected to analysis of variance. The mean bond strength observed for the combination of 5.25% NaOCl irrigant and RelyX U100 cement was significantly lower (8.82 MPa) than the values found for the other groups (P < 0.05). The other combinations of irrigating solution and resin cement had no adverse effect on the bond strength of the glass fiber posts to dentin.

  1. MODEL FOR PREDICTING SHEAR STRENGTH OF SATURATED SOFT CLAY AFTER IMPACT LOADING%冲击荷载作用下饱和软粘土强度预测模型

    Institute of Scientific and Technical Information of China (English)

    白冰

    2004-01-01

    Previous studies showed that the samples of saturated soft clay undergoing several stages of impact loading and reconsolidation show obvious quasi-overconsolidation state,and have an increased shear strength. In this paper,the definition of quasi-overconsolidation ratio is given,and furthermore a model for predicting the shear strength of saturated soft clay after impact loading is suggested. In this model,the conditions of partial drainage and stages of impact are taken into account. The calculation results by the proposed model are in good accordance with test data. Besides,the effect of disturbance consolidation on the undrained shear strength by this model is discussed.

  2. Impact of Blending on Strength Distribution of Ambient Cured Metakaolin and Palm Oil Fuel Ash Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Taliat Ola Yusuf

    2014-01-01

    Full Text Available This paper investigates the influence of blending of metakaolin with silica rich palm oil fuel ash (POFA on the strength distribution of geopolymer mortar. The broadness of strength distribution of quasi-brittle to brittle materials depends strongly on the existence of flaws such as voids, microcracks, and impurities in the material. Blending of materials containing alumina and silica with the objective of improving the performance of geopolymer makes comprehensive characterization necessary. The Weibull distribution is used to study the strength distribution and the reliability of geopolymer mortar specimens prepared from 100% metakaolin, 50% and 70% palm and cured under ambient condition. Mortar prisms and cubes were used to test the materials in flexure and compression, respectively, at 28 days and the results were analyzed using Weibull distribution. In flexure, Weibull modulus increased with POFA replacement, indicating reduced broadness of strength distribution from an increased homogeneity of the material. Modulus, however, decreased with increase in replacement of POFA in the specimens tested under compression. It is concluded that Weibull distribution is suitable for analyses of the blended geopolymer system. While porous microstructure is mainly responsible for flexural failure, heterogeneity of reaction relics is responsible for the compression failure.

  3. A Computational Investigation of the Multi-Hit Ballistic-Protection Performance of Laminated Transparent-armor Systems

    Science.gov (United States)

    Grujicic, Mica; Pandurangan, B.; Coutris, N.

    2012-06-01

    Multi-hit ballistic-protection performance of a prototypical laminated glass/polycarbonate transparent armor is investigated using a series of transient nonlinear dynamics analyses of armor impact with a sequence of four M2AP full metal jacket (FMJ) armor-piercing bullets. All calculations were carried out using ABAQUS/Explicit commercial finite element program (ABAQUS Version 6.7, User Documentation, Dessault Systems, 2007), and the computational results obtained were compared to their experimental counterparts obtained by Dolan (Ballistic Transparent-armor Testing Using a Multi-hit Rifle Pattern, Bachelors, Thesis, Kettering University, December 2007). The comparison revealed that (a) The proposed computational procedure can reasonably well account for the observed multi-hit ballistic-protection performance of the laminated transparent armor; (b) The role of prior bullet hits in reducing armor's ballistic-protection performance is clearly revealed; (c) The role of polycarbonate lamina in preventing glass fragments from entering the vehicle interior is clearly demonstrated; and (d) Experimentally observed inability of the transparent armor to defeat 0.50-caliber Fragment Simulating Projectiles (FSPs) is confirmed.

  4. The ballistic Mars hopper: An alternative Mars mobility concept

    OpenAIRE

    1987-01-01

    The ballistic Mars hopper is proposed as an alternative mobility concept for unmanned exploration of the martian surface. In the ballistic Mars hopper concept, oxygen and carbon monoxide produced from the martian atmosphere are used as propellants in a rocket propulsion system for an unmanned vehicle on suborbital trajectories between landing sights separated by distances of up to 1000 km. This mobility concept is seen as uniquely capable of allowing both intensive and extensive exploration o...

  5. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Sudhakar

    2015-03-01

    Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  6. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Institute of Scientific and Technical Information of China (English)

    I. SUDHAKAR; V. MADHU; G. MADHUSUDHAN REDDY; K. SRINIVASA RAO

    2015-01-01

    Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  7. The potentials of porous concrete for ballistic protection

    NARCIS (Netherlands)

    Weerheijm, J.; Roebroeks, G.; Krabbenborg, D.; Agar Ozbek, A.S.

    2015-01-01

    A special porous concrete has been developed by the Delft University in collaboration with TNO. The concrete has a static compressive strength of 45 MPa. It fragments at impact into small size debris relative to reference concrete. The porous concrete was developed at laboratory scale and tested at

  8. Ballistic analysis during multiscale explosive eruption at Vesuvius and hazard implications

    Science.gov (United States)

    De Novellis, Vincenzo

    2016-04-01

    Ballistic Projectiles (BP) are rock-basement or magma fragments of variable size and density that are ejected from vents during explosive eruptions and follow almost parabolic trajectories that are influenced by gravity and drag forces before they reach their impact point on the surface. During the past century, numerous observers have described the violent ejection of large blocks and bombs from volcanoes during volcanic explosions. Starting from '40 years of last century, several authors developed a mathematical expression relating initial velocity and trajectory angle of ejected blocks to the range, taking into account air drag and assuming a constant drag coefficient; but only in the last 30 years was developed the first mathematical algorithm for ballistic trajectories in the volcanological literature that considered variations in drag coefficient with Reynolds number. Finally, with 21st century computer power, ballistic computation should be available to anyone as a back-of-the-envelope indicator of explosive power by a user-friendly computer program. At Mt. Vesuvius a series of explosion events accompanied eruptive mechanism stages during its history. In particular the explosive eruptive events at Vesuvius was affected by 3 types of energy activity: i) a normal strombolian activity that consists of rhythmic, mild to moderate explosions lasting a few seconds that eject scoriaceous lapilli and bombs, ash and lithic blocks; ii) a vulcanian or violent explosions characterized by short-lived events involving more than one vent, defined as strombolian paroxysms; iii) from sublinian to plinian activity, that have been the most powerful events observed at Mt. Vesuvius; on the other hand plinian was indicated as the energetic term to define the most famous eruption of 79 AD. In this study, an eruptive model appropriate for exanimated eruptions, is used to estimate initial conditions (ejection height, take-off angle, velocity) for BP, assuming a broad range of gas

  9. Impact toughness improvement of high strength aluminium alloy by intrinsic and extrinsic fracture mechanisms via hot roll bonding

    OpenAIRE

    Cepeda-Jiménez, C.M.; García-Infanta, J.M.; Pozuelo, M.; Ruano, Oscar Antonio; Carreño, Fernando

    2009-01-01

    A multilayer aluminium laminate comprising ten layers of Al-Zn-Mg-Cu alloy (82 vol.%) and nine layers of pure aluminium (18 vol.%) has been processed by hot rolling. The rolled laminate was characterized by electron backscattering diffraction, Charpy impact and shear tests. The multilayer laminate showed an outstanding Charpy impact toughness, being eighteen times higher than that for the as-received Al-Zn-Mg-Cu alloy. Damage tolerance improvement was due to the high volume fra...

  10. Dynamics and thermal sensitivity of ballistic and non-ballistic feeding in salamanders.

    Science.gov (United States)

    Deban, Stephen M; Scales, Jeffrey A

    2016-02-01

    Low temperature reduces the performance of muscle-powered movements, but in movements powered by elastic recoil mechanisms, this effect can be mitigated and performance can be increased. To better understand the morphological basis of high performance and thermal robustness of elastically powered movements, we compared feeding dynamics at a range of temperatures (5-25°C) in two species of terrestrial plethodontid salamanders, Plethodon metcalfi and Ensatina eschscholtzii, which differ in tongue muscle architecture and the mechanism of tongue projection. We found that Ensatina is capable of ballistic projection with a mean muscle mass-specific power of 2100 W kg(-1), revealing an elastic mechanism. Plethodon, in contrast, projected its tongue non-ballistically with a mean power of only 18 W kg(-1), indicating it is muscle powered. Ensatina projected its tongue significantly farther than Plethodon and with dynamics that had significantly lower thermal sensitivity at temperatures below 15°C. These performance differences were correlated with morphological differences, namely elongated collagenous aponeuroses in the projector muscle of Ensatina as compared with Plethodon, which are likely the site of energy storage, and the absence in Ensatina of projector muscle fibers attaching to the tongue skeleton that allows projection to be truly ballistic. These findings demonstrate that, in these otherwise similar species, the presence in one species of elaborated connective tissue in series with myofibers confers not only 10-fold greater absolute performance but also greater thermal robustness of performance. We conclude that changes in muscle and connective tissue architecture are sufficient to alter significantly the mechanics, performance and thermal robustness of musculoskeletal systems.

  11. The impact of a repeated bout of eccentric exercise on muscular strength, muscle soreness and creatine kinase.

    Science.gov (United States)

    Smith, L L; Fulmer, M G; Holbert, D; McCammon, M R; Houmard, J A; Frazer, D D; Nsien, E; Israel, R G

    1994-01-01

    The purpose of this study was to determine if there were any beneficial or detrimental effects regarding delayed onset muscle soreness (DOMS), serum creatine kinase (CK), and maximum concentric strength at 80% of 1-RMconc, if a bout of eccentric exercise was repeated at 48 h after an initial bout. A secondary purpose was to determine whether unaccustomed eccentrics might affect plasma cholesterol (TC). Twenty-six men were randomly assigned to a control (Group 1) or experimental group (Group 2). Both groups performed three sets (12 repetitions per set) of the eccentric phase of a chest press, at 80% of one repetition maximum (1-RMconc); Group 2 repeated this exercise 48 h later. DOMS and CK were measured before, and every 24 h for 8 days after; TC was measured before, and every 24 h for 4 days. Maximum strength during the concentric phase of a chest press (1-RMconc) was measured before and at 48-h intervals after. A repeated measures analysis of variance revealed a significant time effect (P < 0.05) for DOMS, CK and strength, but no significant difference between groups (P < 0.05). An interesting finding was the significant (P < 0.05) reduction in TC at 24, 48 and 72 h, after exercise in both groups, which we hypothesized was associated with cellular repair. From these results we concluded that when a bout of eccentrics is repeated 48 h after an initial bout, there is no change in the characteristic time-course and/or intensity of DOMS, CK or 1-RMconc. PMID:7894959

  12. Estimating the shooting distance of a 9-mm Parabellum bullet via ballistic experiment.

    Science.gov (United States)

    Bresson, F; Franck, O

    2009-11-20

    We demonstrate here how the shooting distance of a 9-mm Parabellum FMJ bullet (115gr) has been estimated via shooting experiments. Such a bullet was found by investigators near a concrete wall, fairly distorted at its tip. The bullet carries no evidence of multiple impact and no evidence of ballistic impact on the wall has been reported. We estimated the impact velocity by comparing the questioned bullet with a set of comparison bullets hitting a wall (rigid target) with different velocities. The shooting distance was recovered from the impact velocity by studying the typical behavior of a manufactured 9 mm bullet weighting 115g (7.45g), shot in pistol or a sub-machine gun. The results demonstrated that the questioned bullet was a lost bullet. The shooting distance also helped the investigators, narrowing the range of the estimated positions of the shooter.

  13. Effect of Welding Speed and Tool Pin Geometry on Impact Strength in Friction Stir Welding of Aluminium 6101 T6 Alloy

    Directory of Open Access Journals (Sweden)

    Singh Rajbir

    2016-01-01

    Full Text Available Friction stir welding (FSW process is a solid state joining method in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters play a major role in deciding the joint characteristics. In this investigation the effect of welding speed and tool pin geometry in friction stir welds of Aluminium alloy was studied. The welded joints were made of Aluminium alloy AA 6101 T6 strips of 6mm thickness with different tool pin profile (Cylindrical, Taper cylindrical, Square and Taper Square. All the welding operations were done at the room temperature. Charpy tests were carried out to find the impact strength. From this investigation it is found that strength is superior with taper square tool pin profile than cylindrical, taper cylindrical and square tool pin profile. The pieces weld at rotational speed of 1200 r.p.m and welding speed of 70mm/min using taper square tool have higher strength.

  14. Resistencia al Impacto y a la Tracción de Materiales Compuestos Plástico-Madera Impact and Tensile Strength of Wood-Plastic Composites

    Directory of Open Access Journals (Sweden)

    M. E Solís

    2005-01-01

    Full Text Available Se describe el efecto de harina de madera de dos especies, Pinus radiata D. Don (pino y Nothofagus alpina (raulí, sobre las propiedades mecánicas de materiales compuestos plástico-madera, cuando se incorpora en porcentajes de 10 y 20% en la matriz polimérica. Los materiales termoplásticos utilizados fueron polietileno de alta densidad (HDPE y polipropileno (PP, ambos de origen comercial. Las mezclas se realizaron en un equipo extrusor de laboratorio de tornillo simple y se fabricaron probetas de ensayo para medir la resistencia al impacto Izod y la resistencia a la tracción, con el incremento de madera. El efecto de la incorporación de 10% de madera de raulí aumenta la resistencia a la tracción de los materiales compuestos a base de HDPE y de PP. En este mismo porcentaje, la madera de pino produce también un incremento de la resistencia a la tracción un poco menor. Materiales compuestos con mayor contenido de madera (20% presentan valores menores de resistencia a la tracción. La resistencia al impacto de los materiales compuestos con 10 y 20% de madera de las dos especies disminuye en un alto porcentaje con respecto del polímero puro.This article describes the effect of addition of wood flour from two different species, Pinus radiata D.Don (pino and Nothofagus alpina (raulí on the mechanical properties of wood-plastic composites, using 10 and 20% wood content in the polymer matrix. The thermoplastic materials employed included high density polyethylene (HDPE and polypropylene (PP, both of commercial origin. The mixtures were prepared using a laboratory single-screw extruder, and samples were prepared to determine Izod impact strength and tensile strength as a function of wood content. The tensile strength of HDPE and PP composites increased with 10% raulí wood content. This resistance was somewhat less in samples having the same pine content. Composites with greater wood content (20% present lower tensile strength values. The

  15. Shot noise effect on noise source and noise parameter of 10-nm-scale quasi-ballistic n-/p-type MOS devices

    Science.gov (United States)

    Jeon, Jongwook; Kang, Myounggon

    2016-05-01

    In this work, we investigated the noise source and noise parameters of a quasi-ballistic MOSFET at the high-frequency regime. We presented the shot noise properties in the measured drain current noise and its impact on the induced gate noise and the noise parameters of 10-nm-scale n-/p-type MOS (N/PMOS) devices for the first time. The measured noise sources and noise parameters were carefully analyzed with the shot and thermal noise models in all operation regions. On the basis of the results, new noise parameter models are proposed and the noise performance improvement in the quasi-ballistic regime is shown.

  16. Superconducting Graphene Nanodevices in Ballistic Transport Regime

    Science.gov (United States)

    Chen, Yu-An; Wang, Joel I.-Jan; Watanabe, Kenji; Taniguchi, Takashi; Jarillo-Herrero, Pablo; Pablo Jarillo-Herrero's Group Team

    2013-03-01

    Superconductivity carried by Dirac fermions can be realized through induced superconductivity in grapheme. Observation of novel phenomena anticipated by theories requires graphene devices with low disorder whereas the carrier transport is ballistic. Current fabrication procedures to make graphene devices with low disorder like suspension or ultra-flat substrates all call for certain kinds of annealing to remove organic residues derived from the fabrication process. Applying these methods to superconducting devices can be challenging since the transparency at the graphene/superconductor interface will be destroyed. Here we present a method to do dry transfer of patterned hexagonal Boron Nitride (hBN) flakes onto graphene. The ultra flatness and lack of dangling bond in the boron nitride substrate reduces the disorder in graphene, and the top layer hBN can protect the graphene from contamination in the nanofabrication procedures and yield the geometry desired for different experimental exploration. National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan

  17. Allegany Ballistics Lab: sensor test target system

    Science.gov (United States)

    Eaton, Deran S.

    2011-06-01

    Leveraging the Naval Surface Warfare Center, Indian Head Division's historical experience in weapon simulation, Naval Sea Systems Command commissioned development of a remote-controlled, digitally programmable Sensor Test Target as part of a modern, outdoor hardware-in-the-loop test system for ordnance-related guidance, navigation and control systems. The overall Target system design invokes a sciences-based, "design of automated experiments" approach meant to close the logistical distance between sensor engineering and developmental T&E in outdoor conditions over useful real world distances. This enables operating modes that employ broad spectrum electromagnetic energy in many a desired combination, variably generated using a Jet Engine Simulator, a multispectral infrared emitter array, optically enhanced incandescent Flare Simulators, Emitter/Detector mounts, and an RF corner reflector kit. As assembled, the recently tested Sensor Test Target prototype being presented can capably provide a full array of useful RF and infrared target source simulations for RDT&E use with developmental and existing sensors. Certain Target technologies are patent pending, with potential spinoffs in aviation, metallurgy and biofuels processing, while others are variations on well-established technology. The Sensor Test Target System is planned for extended installation at Allegany Ballistics Laboratory (Rocket Center, WV).

  18. Ballistic spin transport in exciton gases

    Science.gov (United States)

    Kavokin, A. V.; Vladimirova, M.; Jouault, B.; Liew, T. C. H.; Leonard, J. R.; Butov, L. V.

    2013-11-01

    Traditional spintronics relies on spin transport by charge carriers, such as electrons in semiconductor crystals. The challenges for the realization of long-range electron spin transport include rapid spin relaxation due to electron scattering. Scattering and, in turn, spin relaxation can be effectively suppressed in excitonic devices where the spin currents are carried by electrically neutral bosonic quasiparticles: excitons or exciton-polaritons. They can form coherent quantum liquids that carry spins over macroscopic distances. The price to pay is a finite lifetime of the bosonic spin carriers. We present the theory of exciton ballistic spin transport which may be applied to a range of systems supporting bosonic spin transport, in particular to indirect excitons in coupled quantum wells. We describe the effect of spin-orbit interaction for the electron and the hole on the exciton spin, account for the Zeeman effect induced by external magnetic fields and long-range and short-range exchange splittings of the exciton resonances. We also consider exciton transport in the nonlinear regime and discuss the definitions of the exciton spin current, polarization current, and spin conductivity.

  19. An investigation into the behaviour of air rifle pellets in ballistic gel and their interaction with bone.

    Science.gov (United States)

    Wightman, G; Beard, J; Allison, R

    2010-07-15

    Although air weapons are considerably lower in power than other firearms, there is increasing concern that serious injuries can result from their misuse. The present study was therefore carried out to improve understanding of the terminal ballistic behaviour of air rifle pellets. Pellets were fired into ballistic gel under a variety of conditions. The pellets penetrated further than anticipated from their low cross-sectional density, and Bloom number was not necessarily a good guide to gel behaviour. Pellet penetration into the gel decreased with increasing gel concentration, and appeared to be linear at higher concentrations. Pointed pellets penetrated up to 50% further than rounded pellets. Power and range affect penetration, but other factors are also important, and power alone is not a simple guide to potential penetration. Test firings were also carried out firing pellets into ballistic gel that contained sections of animal bone. Computed tomography (CT) and visual observation were employed to record the interactions. CT scanning showed potential as a tool for examining pellet damage. The bone appeared to be undamaged, but the pellets were severely deformed on impact. If the pellet strikes the bone at an angle, less energy is absorbed by the impact and the pellet fragments may ricochet and cause further damage in the gel. A tentative model is proposed for estimating the energy absorbed by the impact.

  20. Enhancing the ballistic thermal transport of silicene through smooth interface coupling

    Science.gov (United States)

    Chen, Chao-Yu; She, Yanchao; Xiao, Huaping; Ding, Jianwen; Cao, Juexian; Guo, Zhi-Xin

    2016-04-01

    We have performed nonequilibrium molecular dynamics calculations on the length (L ) dependence of thermal conductivity (K ) of silicene both supported on and sandwiched between the smooth surfaces, i.e. h-BN, at room temperature. We find that K of silicene follows a power law K\\propto {{L}β} , with β increasing from about 0.3-0.4 under the effect of interface coupling, showing an enhancement of the ballistic thermal transport of silicene. We also find that β can be further increased to about 0.6 by increasing the interface coupling strength for the silicene sandwiched between h-BN. The increase of β for the supported case is found to come from the variation of the flexural acoustic (ZA) phonon mode and the first optical phonon mode induced by the substrate, whereas the unusual increase of β for the sandwiched case is attributed to the increment of velocities of all three acoustic phonon modes. These findings provide an interesting route for manipulating the ballistic energy flow in nanomaterials.

  1. Improvement of Interior Ballistic Performance Utilizing Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Hazem El Sadek

    2014-01-01

    Full Text Available This paper investigates the interior ballistic propelling charge design using the optimization methods to select the optimum charge design and to improve the interior ballistic performance. The propelling charge consists of a mixture propellant of seven-perforated granular propellant and one-hole tubular propellant. The genetic algorithms and some other evolutionary algorithms have complex evolution operators such as crossover, mutation, encoding, and decoding. These evolution operators have a bad performance represented in convergence speed and accuracy of the solution. Hence, the particle swarm optimization technique is developed. It is carried out in conjunction with interior ballistic lumped-parameter model with the mixture propellant. This technique is applied to both single-objective and multiobjective problems. In the single-objective problem, the optimization results are compared with genetic algorithm and the experimental results. The particle swarm optimization introduces a better performance of solution quality and convergence speed. In the multiobjective problem, the feasible region provides a set of available choices to the charge’s designer. Hence, a linear analysis method is adopted to give an appropriate set of the weight coefficients for the objective functions. The results of particle swarm optimization improved the interior ballistic performance and provided a modern direction for interior ballistic propelling charge design of guided projectile.

  2. Transition to ballistic regime for heat transport in helium II

    Energy Technology Data Exchange (ETDEWEB)

    Sciacca, Michele, E-mail: michele.sciacca@unipa.it [Dipartimento Scienze Agrarie e Forestali, Università degli studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Sellitto, Antonio, E-mail: ant.sellitto@gmail.com [Dipartimento di Matematica, Informatica ed Economia, Università della Basilicata, Campus Macchia Romana, 85100 Potenza (Italy); Jou, David, E-mail: david.jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2014-07-04

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R{sup 2} (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime.

  3. Effect of Welding Processes and Consumables on Tensile and Impact Properties of High Strength Quenched and Tempered Steel Joints

    Institute of Scientific and Technical Information of China (English)

    G Magudeeswaran; V Balasubramanian; G Madhusudhan Reddy; T S Balasubramanian

    2008-01-01

    Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected gone after welding.The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase.In this investigation,an attempt was made to determine a suitable consumable to replace expensive austenitic consumables.Two different consumables,namely,austenitic stainless steel and lOW hydrogen ferritic steel,were used to fabricate the joints by shielded metal arc welding(SMAW)and flux cored arc welding(FCAW)processes.The joints fabricated by using low hydrogen ferritic steel consumables showed superior transverse tensile properties,whereas joints fabricated by using austenitic stainless steel consumables exhibited better impact toughness,irrespective of the welding process used.The SMAW joints exhibited superior mechanical and impact properties,irrespective of the consumables used,than their FCAW counterparts.

  4. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    OpenAIRE

    Maria J. Gerschutz, PhD; Michael L. Haynes, MS; Derek M. Nixon, BS; James M. Colvin, MS

    2011-01-01

    Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn...

  5. Establishing a Ballistic Test Methodology for Documenting the Containment Capability of Small Gas Turbine Engine Compressors

    Science.gov (United States)

    Heady, Joel; Pereira, J. Michael; Ruggeri, Charles R.; Bobula, George A.

    2009-01-01

    A test methodology currently employed for large engines was extended to quantify the ballistic containment capability of a small turboshaft engine compressor case. The approach involved impacting the inside of a compressor case with a compressor blade. A gas gun propelled the blade into the case at energy levels representative of failed compressor blades. The test target was a full compressor case. The aft flange was rigidly attached to a test stand and the forward flange was attached to a main frame to provide accurate boundary conditions. A window machined in the case allowed the projectile to pass through and impact the case wall from the inside with the orientation, direction and speed that would occur in a blade-out event. High-peed, digital-video cameras provided accurate velocity and orientation data. Calibrated cameras and digital image correlation software generated full field displacement and strain information at the back side of the impact point.

  6. The usage of optical fibers for damage detection in ballistic protection composite laminates

    Directory of Open Access Journals (Sweden)

    Živković Irena D.

    2006-01-01

    Full Text Available This paper describes the procedure of embedding fiber optic sensors in laminar thermoplastic composite material, as well as damage investigation after ballistic loading. Thermoplastic-reinforced composite materials were made for increased material damage resistance during ballistic loading. Damage inside the composite material was detected by observing the intensity drop of the light signal transmitted through the optical fibers. Experimental testing was carried out in order to observe and analyze the response of the material under various load conditions. Different types of Kevlar reinforced composite materials (thermoplastic, thermo reactive and thermoplastic with ceramic plate as the impact face were made. Material damage resistance during ballistic loading was investigated and compared. Specimens were tested under multiple load conditions. The opto-electronic part of the measurement system consists of two light-emitting diodes as light sources for the optical fibers, and two photo detectors for the light intensity measurement. The output signal was acquired from photo detectors by means of a data acquisition board and personal computer. The measurements showed an intensity drop of the transmitted light signal as a result of the applied loading on composite structure for all the optical fibers. All the diagrams show similar behavior of the light signal intensity. In fact, all of them may be divided into three zones: the zone of penetration of the first composite layer, the bullet traveling zone through the composite material till its final stop, and the material relaxation zone. The attenuation of the light signal intensity during impact is caused by the influence of the applied dynamic stress on the embedded optical fibers. The applied stress caused micro bending of the optical fiber, changes in the shape of the cross-section and the unequal changes of the indices of refraction of the core and cladding due to the stress-optic effect. The

  7. Irradiation damage in Gd2Ti2O7 single crystals: Ballistic versus ionization processes

    Science.gov (United States)

    Moll, S.; Sattonnay, G.; Thomé, L.; Jagielski, J.; Decorse, C.; Simon, P.; Monnet, I.; Weber, W. J.

    2011-08-01

    The structural transformations induced in Gd2Ti2O7 single crystals irradiated at high energies (870-MeV Xe), where ionization processes (electronic stopping) dominate, and at low energies (4-MeV Au), where ballistic processes (nuclear stopping) dominate, have been studied via the combination of Rutherford backscattering spectrometry and channeling (RBS/C), Raman spectroscopy, and transmission electron microscopy (TEM) experiments. At high energy, amorphization occurs directly in individual ion tracks from the extreme electronic-energy deposition, and full amorphization results from the overlapping of these tracks as described by a direct impact model. The track diameters lie in the range 6-9 nm. At low energy, amorphization occurs via indirect processes, driven by ballistic nuclear energy deposition from the ions, that is accounted for in the framework of both direct-impact/defect-stimulated and multi-step damage accumulation models. The ion fluence for total amorphization of the irradiated layer is much higher at low energy (0.5 ion nm-2) than at high energy (0.05 ion nm-2), consistent with the nuclear stopping at low energy (5.2 keV/nm) compared to the electronic stopping at high energy (29 keV/nm).

  8. Irradiation Damage in Gd2Ti2O7 Single Crystals: Ballistic vs Ionization Processes

    Energy Technology Data Exchange (ETDEWEB)

    Moll, Sandra [Pacific Northwest National Laboratory (PNNL); Sattonnay, Gael [Universite Paris Sud, Orsay, France; Thome, Lionel [Universite Paris Sud, Orsay, France; Jagielski, Jacek [Institute for Electronic Materials Technology; Decorse, C [Universite Paris Sud, Orsay, France; Simon, Patrick [CEMHTI-CNRS, Universite d' Orleans; Monnet, Isabelle [Grand Accelerateur National d' Ions Lourds (GANIL); Weber, William J [ORNL

    2011-01-01

    The structural transformations induced in Gd2Ti2O7 single crystals irradiated at high energies (870 MeV Xe), where ionization processes (electronic stopping) dominate, and at low energies (4 MeV Au), where ballistic processes (nuclear stopping) dominate, have been studied via the combination of Rutherford backscattering spectrometry and channeling, Raman spectroscopy and transmission electron microscopy experiments. At high energy, amorphization occurs directly in individual ion tracks from the extreme electronic energy deposition from ionization, and full amorphization results from the overlapping of these tracks as described by a direct impact model. The track diameters determined from RBS/C and TEM data lie in the range 6-8 nm. At low energy, amorphization occurs via indirect processes, driven by ballistic nuclear energy deposition from the ions, that is accounted for in the framework of both the direct-impact/defect stimulated and multi-step damage accumulation models. The ion fluence for total amorphization of the irradiated layer is much higher (0.5 ion nm-2) at low energy than at high energy (0.05 ion nm-2), consistent with the nuclear stopping at low energy (5.2 keV/nm) compared to the electronic stopping at high energy (29 keV/nm).

  9. Noteworthy impacts of polyurethane-urea ionomers as the efficient polar coatings on adhesion strength of plasma treated polypropylene

    Science.gov (United States)

    Chashmejahanbin, Mohammad. R.; Daemi, Hamed; Barikani, Mehdi; Salimi, Ali

    2014-10-01

    In present research, polypropylene (PP) was selected as a model nonpolar substrate for chemical modification using plasma. In the first step, the PP samples were treated using oxygen and argon atmospheres, individually. The prepared samples were analyzed using both FTIR and AFM techniques. The output of these techniques revealed that the carbonyl, carboxylic acid and its derivatives have been formed on the surface of PP. Afterward, a series of aqueous polyurethane-urea dispersions were synthesized as the novel polar coating for modified nonpolar polymers and characterized by different techniques including FTIR, DSC, TGA, mechanical properties and contact angle. Finally, the plasma treated samples were coated by prepared polyurethane ionomer. The results of pull-off analysis confirmed the significant role of the polyurethane as an extremely polar coating to create hydrogen bonding with functional groups on the surface of treated PP. The adhesion strength of polypropylenes increased from 0.04 MPa to 0.61 MPa for neat and oxygen-based plasma treated samples, respectively.

  10. Perturbed lignification impacts tree growth in hybrid poplar--a function of sink strength, vascular integrity, and photosynthetic assimilation.

    Science.gov (United States)

    Coleman, Heather D; Samuels, A Lacey; Guy, Robert D; Mansfield, Shawn D

    2008-11-01

    The effects of reductions in cell wall lignin content, manifested by RNA interference suppression of coumaroyl 3'-hydroxylase, on plant growth, water transport, gas exchange, and photosynthesis were evaluated in hybrid poplar trees (Populus alba x grandidentata). The growth characteristics of the reduced lignin trees were significantly impaired, resulting in smaller stems and reduced root biomass when compared to wild-type trees, as well as altered leaf morphology and architecture. The severe inhibition of cell wall lignification produced trees with a collapsed xylem phenotype, resulting in compromised vascular integrity, and displayed reduced hydraulic conductivity and a greater susceptibility to wall failure and cavitation. In the reduced lignin trees, photosynthetic carbon assimilation and stomatal conductance were also greatly reduced, however, shoot xylem pressure potential and carbon isotope discrimination were higher and water-use efficiency was lower, inconsistent with water stress. Reductions in assimilation rate could not be ascribed to increased stomatal limitation. Starch and soluble sugars analysis of leaves revealed that photosynthate was accumulating to high levels, suggesting that the trees with substantially reduced cell wall lignin were not carbon limited and that reductions in sink strength were, instead, limiting photosynthesis.

  11. Novel formulations of ballistic gelatin. 1. Rheological properties.

    Science.gov (United States)

    Zecheru, Teodora; Său, Ciprian; Lăzăroaie, Claudiu; Zaharia, Cătălin; Rotariu, Traian; Stănescu, Paul-Octavian

    2016-06-01

    Ballistic gelatin is the simulant of the human body during field tests in forensics and other related fields, due to its physical and mechanical similarities to human trunk and organs. Since the ballistic gelatin used in present has important issues to overcome, an alternative approach is the use of gelatin-polymer composites, where a key factor is the insertion of biocompatible materials, which replicate accurately the human tissues. In order to be able to obtain an improved material in terms of mechanical performances by an easy industrial-scale technology, before the verification of the ballistic parameters by shooting in agreement with military standards, one of the best and cheapest solutions is to perform a thorough check of their rheological properties, in standard conditions.

  12. ["Piggyback" shot: ballistic parameters of two simultaneously discharged airgun pellets].

    Science.gov (United States)

    Frank, Matthias; Schönekess, Holger C; Grossjohann, Rico; Ekkernkamp, Axel; Bockholdt, Britta

    2014-01-01

    Green and Good reported an uncommon case of homicide committed with an air rifle in 1982 (Am. J. Forensic Med. Pathol. 3: 361-365). The fatal wound was unusual in that two airgun pellets were loaded in so-called "piggyback" fashion into a single shot air rifle. Lack of further information on the ballistic characteristics of two airgun pellets as opposed to one conventionally loaded projectile led to this investigation. The mean kinetic energy (E) of the two pellets discharged in "piggyback" fashion was E = 3.6 J and E = 3.4 J, respectively. In comparison, average kinetic energy values of E = 12.5 J were calculated for conventionally discharged single diabolo pellets. Test shots into ballistic soap confirmed the findings of a single entrance wound as reported by Green and Good. While the ballistic background of pellets discharged in "piggyback" fashion could be clarified, the reason behind this mode of shooting remains unclear.

  13. Ballistic spin filtering across the ferromagnetic-semiconductor interface

    Directory of Open Access Journals (Sweden)

    Y.H. Li

    2012-03-01

    Full Text Available The ballistic spin-filter effect from a ferromagnetic metal into a semiconductor has theoretically been studied with an intention of detecting the spin polarizability of density of states in FM layer at a higher energy level. The physical model for the ballistic spin filtering across the interface between ferromagnetic metals and semiconductor superlattice is developed by exciting the spin polarized electrons into n-type AlAs/GaAs superlattice layer at a much higher energy level and then ballistically tunneling through the barrier into the ferromagnetic film. Since both the helicity-modulated and static photocurrent responses are experimentally measurable quantities, the physical quantity of interest, the relative asymmetry of spin-polarized tunneling conductance, could be extracted experimentally in a more straightforward way, as compared with previous models. The present physical model serves guidance for studying spin detection with advanced performance in the future.

  14. Using modified ballistic limit equations in spacecraft risk assessments

    Science.gov (United States)

    Schonberg, William P.

    2016-09-01

    The fundamental components of any meteoroid/orbital debris (MOD) risk assessment calculation are environment models, damage response predictor equations, and failure criteria. In the case of a spacecraft operating in low earth orbit, the response predictor equation typically takes the form of a ballistic limit equation (BLE) that defines the threshold particle sizes that cause failure of a spacecraft wall or component. Spacecraft risk assessments often call for BLEs for spacecraft components that do not exist. In such cases, it is a common procedure to use an existing BLE after first equivalencing the actual materials and/or wall thicknesses to the materials that were used in the development of the existing BLE. The question naturally arises regarding how close are the predictions of such an 'adapted BLE' to the response characteristics of the actual materials/wall configurations under high speed projectile impacts. This paper presents the results of a study that compared the predictions of a commonly used BLE when adapted to the Soyuz OM wall configuration against those of a new BLE that was developed specifically for that Soyuz wall configuration. It was found that the critical projectile diameters predicted by the new Soyuz OM wall BLE can exceed those predicted by the adapted use of the existing BLE by as much as 50% of the existing BLE values. Thus, using the adapted version of the existing BLE in this particular case would contribute to a more conservative value of assessed risk. If the same trends were to hold true for other spacecraft wall configurations, then it is also possible that using existing BLEs, even after they have been adjusted for differences in materials, etc., may result in predictions of smaller critical diameters (i.e., increased assessed risk) than would using BLEs purposely developed for actual spacecraft configurations of interest.

  15. Dynamic Strength and Fracturing Behavior of Single-Flawed Prismatic Marble Specimens Under Impact Loading with a Split-Hopkinson Pressure Bar

    Science.gov (United States)

    Li, Xibing; Zhou, Tao; Li, Diyuan

    2017-01-01

    Dynamic impact tests are performed on prismatic marble specimens containing a single flaw using a modified split-Hopkinson pressure bar device. The effects of pre-existing flaws with different flaw angles and lengths on the dynamic mechanical properties are analyzed. The results demonstrate that the dynamic strength of marble is influenced by the flaw geometry. The dynamic fracturing process of flawed specimens is monitored and characterized with the aid of a high-speed camera. Cracking of marble specimens with a single pre-existing flaw under impact loading is analyzed based on experimental investigations. Cracking involves two major stages: formation of white patches and development of macrocracks. Six typical crack types are identified on the basis of their trajectories and initiation mechanisms. The presence of an artificial flaw may change the failure mode of marble from splitting-dominated for an intact specimen to shear-dominated for a flawed specimen under dynamic loading. Nevertheless, the geometry of the flaws appears to have a slight influence on the failure modes of flawed specimens under impact loading.

  16. Terminal Performance of Lead-Free Pistol Bullets in Ballistic Gelatin Using Retarding Force Analysis from High Speed Video

    CERN Document Server

    Courtney, Elijah; Andrusiv, Lubov; Courtney, Michael

    2016-01-01

    Due to concerns about environmental and industrial hazards of lead, a number of military, law enforcement, and wildlife management agencies are giving careful consideration to lead-free ammunition. The goal of lead-free bullets is to gain the advantages of reduced lead use in the environment while maintaining equal or better terminal performance. Accepting reduced terminal performance would foolishly risk the lives of military and law enforcement personnel. This paper uses the established technique of studying bullet impacts in ballistic gelatin to characterize the terminal performance of eight commercial off-the- shelf lead-free handgun bullets for comparison with earlier analysis of jacketed lead bullets. Peak retarding force and energy deposit in calibrated ballistic gelatin are quantified using high speed video. The temporary stretch cavities and permanent wound cavities are also characterized. Two factors tend to reduce the terminal performance of these lead-free projectiles compared to similar jacketed ...

  17. Ballistic Missile Defense Final Programmatic Environmental Impact Statement

    Science.gov (United States)

    2008-02-15

    The main type of batteries to be considered would be reserve lithium thionyl chloride (Li/SOCl2 ), and reserve lithium /iron disulfide (Li/FeS 2... Lithium Thionyl Chloride Electric power supply to Lithium /Iron Disulfide onboard missile guidance Zinc/Silver Oxide systems Pyrotechnic Material Lithium ...production. Power sources are needed for GBIs and space-based elements. GBI would utilize a battery power source to power internal systems. However

  18. Physical Mechanisms of Soft Tissue Injury from Penetrating Ballistic Impact

    Science.gov (United States)

    2012-11-30

    2008; 64(6):1420-1426. 18. Gryth D, Rocksen D, Persson JK, Arborelius UP, Drobin D, Bursell J, Olsson LG, Kjellstrom BT. Severe lung contusion and...elastic tissues such as lungs and muscle, where the tissue tends to spring back into place with little damage from temporary stretch, most tissue...in a study comparing penetrating thoracic wounds caused by stab injuries to those caused by gunshot injuries, the occurrence of lung

  19. Environment Impact Analysis Process. Small Intercontinental Ballistic Missile Program

    Science.gov (United States)

    1986-03-01

    OF INVESTIGATION: Regional Growth, and Associated Demands on Housing, Public Services, and Public Finance DISCUSSION: The potential deployment areas...AREAS OF INVESTIGATION: Regional Growth, and Associated Demands on Housing,a Public Services, and Public Finance DISCUSSION: The potential deployment...Housing, Public Services, and Public Finance DISCUSSION: The potential deployment areas for southern Nevada are dispersed over a four-county region

  20. Ballistic Missile Defense System (BMDS) Programmatic Environmental Impact Statement

    Science.gov (United States)

    2007-01-01

    for decommissioning the BMDS to prot(lct the Uruted ~tatoo lU.~.J . ns depbyed forces . friends. and aUlas hom b~Uistic missile throats. The...intcr~contincmal balh:. tic 7) The President would, m reaffirm the entire L’l’- de\\’cl<I•Pmcn:, human rigl:ts ~;caic. leader the ratitlcatlon...aspi."Ct’< oft he Balli~ tic Miss1k DetCnsc (BMD) pwgrarn. Acid rain; The MDA ihcl:·noti..’S i:1 the ?EIS the pn:.sibility cfa..:id rain cuuseC

  1. Legislative Environmental Impact Statement: Small Intercontinental Ballistic Missile Program.

    Science.gov (United States)

    1986-11-01

    east from San Luis , Arizona to about Dos Cabezas, Arizona (Figure 3.9.3-1). Quaternary faulting in extreme southeast Arizona is dominated by north...Orr, and R. Gary Roybal 1981 Water Resources of the Rincon and Mesilla Valleys and Adjacent Areas, New Mexico. New Mexico State Engineer Office

  2. Impact of intraprosthetic drilling on the strength of the femoral stem in periprosthetic fractures: A finite element investigation.

    Science.gov (United States)

    Brand, Stephan; Bauer, Michael; Petri, Maximilian; Schrader, Julian; Maier, Hans J; Krettek, Christian; Hassel, Thomas

    2016-07-01

    Treatment of periprosthetic femur fractures after total hip arthroplasty remains a major challenge in orthopedic surgery. Recently, a novel surgical technique using intraprosthetic screw fixation has been suggested. The purpose of this study was to evaluate the influence of drilling the femoral hip stem on integrity and strength of the implant. The hypothesis was that intraprosthetic drilling and screw fixation would not cause the load limit of the prosthesis to be exceeded and that deformation would remain within the elastic limit. A sawbone model with a conventional straight hip stem was used and a Vancouver C periprosthetic fracture was created. The fracture was fixed with a nine-hole less invasive stabilization system plate with two screws drilled and inserted through the femoral hip stem. Three different finite element models were created using ANSYS software. The models increased in complexity including joint forces and stress risers from three different dimensions. A variation of drilling positions was analyzed. Due to the complexity of the physiological conditions in the human femur, the most complex finite element model provided the most realistic results. Overall, significant changes in the stresses to the prosthesis caused by the drilling procedure were observed. While the stresses at the site of the bore hole decreased, the load increased in the surrounding stem material. This effect is more pronounced and further the holes were apart, and it was found that increasing the number of holes could counteract this. The maximum load was still found to be in the area of the prosthesis neck. No stresses above the load limit of titanium alloy were detected. All deformations of the prosthesis stem remained in the elastic range. These results may indicate a potential role for intraprosthetic screw fixation in the future treatment of periprosthetic femur fractures.

  3. Internal Ballistics of High Velocity Special Purpose Guns

    Directory of Open Access Journals (Sweden)

    V. K. Gupta

    1976-07-01

    Full Text Available More and more conventional guns are being utilized as special purpose guns to achieve very high velocity by using unconventionally high C/W ratios. The existing methods of internal ballistics give satisfactory results only for low (less than one C/W ratios. In the present paper the basic internal ballistic equations have been modified to cater for non-linear rate of burning, cubical form function and a realistic pressure gradient between breech face and the projectile base. The equations have been numerically solved. The results for low and high C/W ratios have been compared with those obtained by using conventional methods.

  4. Geometrical optimization of a local ballistic magnetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, Yuhsuke; Hara, Masahiro [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Nomura, Tatsuya [Advanced Electronics Research Division, INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Kimura, Takashi [Advanced Electronics Research Division, INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan)

    2014-04-07

    We have developed a highly sensitive local magnetic sensor by using a ballistic transport property in a two-dimensional conductor. A semiclassical simulation reveals that the sensitivity increases when the geometry of the sensor and the spatial distribution of the local field are optimized. We have also experimentally demonstrated a clear observation of a magnetization process in a permalloy dot whose size is much smaller than the size of an optimized ballistic magnetic sensor fabricated from a GaAs/AlGaAs two-dimensional electron gas.

  5. Advanced Computer Science on Internal Ballistics of Solid Rocket Motors

    Science.gov (United States)

    Shimada, Toru; Kato, Kazushige; Sekino, Nobuhiro; Tsuboi, Nobuyuki; Seike, Yoshio; Fukunaga, Mihoko; Daimon, Yu; Hasegawa, Hiroshi; Asakawa, Hiroya

    In this paper, described is the development of a numerical simulation system, what we call “Advanced Computer Science on SRM Internal Ballistics (ACSSIB)”, for the purpose of improvement of performance and reliability of solid rocket motors (SRM). The ACSSIB system is consisting of a casting simulation code of solid propellant slurry, correlation database of local burning-rate of cured propellant in terms of local slurry flow characteristics, and a numerical code for the internal ballistics of SRM, as well as relevant hardware. This paper describes mainly the objectives, the contents of this R&D, and the output of the fiscal year of 2008.

  6. Low-Energy Ballistic Transfers to Lunar Halo Orbits

    Science.gov (United States)

    Parker, Jeffrey S.

    2009-01-01

    Recent lunar missions have begun to take advantage of the benefits of low-energy ballistic transfers between the Earth and the Moon rather than implementing conventional Hohmann-like lunar transfers. Both Artemis and GRAIL plan to implement low-energy lunar transfers in the next few years. This paper explores the characteristics and potential applications of many different families of low-energy ballistic lunar transfers. The transfers presented here begin from a wide variety of different orbits at the Earth and follow several different distinct pathways to the Moon. This paper characterizes these pathways to identify desirable low-energy lunar transfers for future lunar missions.

  7. Layer by layer H-bonded assembly of P4VP with various hydroxylated PPFS: impact of the donor strength on growth mechanism and surface features.

    Science.gov (United States)

    Chen, Jing; Duchet, Jannick; Portinha, Daniel; Charlot, Aurélia

    2014-09-01

    Hydrogen bond mediated films made by step by step deposition of poly(4-vinylpyridine) (P4VP) and hydroxylated poly(2,3,4,5,6-pentafluorostyrene) (PPFS) copolymers prepared by thiol para-fluoro coupling, bearing either one (PPFSME) or two (PPFSMPD) hydrogenated hydroxyl groups or a (poly)fluorinated hydroxyl (PPFSOH), respectively, were successfully constructed. The influence of the structural parameters, such as the hydroxyl environment (which dictates the H-bond strength) was in-depth investigated in terms of their impact on (i) growth mechanism, (ii) internal organization, and (iii) surface features. The use of the weaker H-bond donor partner (PPFSME) leads to low quality films composed of irregularly distributed aggregates. While [PPFSMPD/P4VP] multilayer films are comparatively thick and composed of stratified layers with smooth topology, the use of PPFSOH with P4VP yields thin films made of mixed and interpenetrated polymer layers. Playing on the interaction strength appears as a powerful tool to elaborate tailored multilayer films with molecularly tunable properties.

  8. Fracture mechanisms assessment of a multilayer material with high strength and excellent impact toughness based on the aerospace Al 7075 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cepeda-Jimenez, C. M.; Ruano, O. A.; Carreno, F.

    2012-11-01

    An aluminium multilayer laminate has been processed by hot rolling. It is constituted by 19 alternated layers of high-strength aluminium alloy (Al 7075-T6, 82 % vol) and thinner pure aluminium layers (Al 1050-H24, 18 % vol). The microstructure of the constituent alloys and the composition gradient across the interfaces has been characterized. The multilayer laminate and the as-received aluminium alloys have been tested at room temperature by Vickers microhardness, three-point bend test and impact Charpy test. The outstanding improvement in damage tolerance, which is 18 times higher than that for the as-received Al 7075 alloy, is due to both intrinsic and extrinsic fracture mechanisms operating in the multilayer laminate during mechanical testing. (Author) 19 refs.

  9. Overcoming the Fundamental Challenges in Improving the Impact Strength and Crystallinity of PLA Biocomposites: Influence of Nucleating Agent and Mold Temperature.

    Science.gov (United States)

    Nagarajan, Vidhya; Zhang, Kunyu; Misra, Manjusri; Mohanty, Amar K

    2015-06-03

    Poly(lactic acid) (PLA), one of the widely studied renewable resource based biopolymers, has yet to gain a strong commercial standpoint because of certain property limitations. This work is a successful attempt in achieving PLA biocomposites that showed concurrent improvements in impact strength and heat deflection temperature (HDT). Biocomposites were fabricated from a super toughened ternary blend of PLA, poly(ether-b-amide) elastomeric copolymer and ethylene-methyl acrylate-glycidyl methacrylate and miscanthus fibers. The effects of varying the processing parameters and addition of various nucleating agents were investigated. Crystallinity was controlled by optimizing the mold temperature and cycle time of the injection process. With the addition of 1 wt % aromatic sulfonate derivative (Lak-301) as a nucleating agent at a mold temperature of 110 °C, PLA biocomposites exhibited dramatic reduction in crystallization half time to 1.3 min with crystallinity content of 42%. Mechanical and thermal properties assessment for these biocomposites revealed a 4-fold increase in impact strength compared to neat PLA. The HDT of PLA biocomposites increased to 85 °C from 55 °C compared to neat PLA. Crystallization behavior was studied in detail using differential scanning calorimetry and was supported with observations from wide-angle X-ray diffraction profiles and polarized optical microscopy. The presence of a nucleating agent did not alter the crystal structure of PLA; however, a significant difference in spherulite size, crystallization rate and content was observed. Fracture surface morphology and distribution of nucleating agent in the PLA biocomposites were investigated through scanning electron microscopy.

  10. Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life

    Science.gov (United States)

    Trombetti, A.; Reid, K. F.; Hars, M.; Herrmann, F. R.; Pasha, E.; Phillips, E. M.; Fielding, R. A.

    2016-01-01

    Summary This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age. Introduction The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking. Methods Twenty-six healthy older subjects (age, 74.1±3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2±4.4; SPPB score ≥9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively. Results At 3-year follow-up, muscle cross-sectional area (CSA) (p<0.013) and power decreased (p<0.001), while intermuscular fat infiltration increased (p<0.001). These decrements were accompanied with a longer time to complete 400 m by 22±46 s (p<0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p<0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p<0.020), muscle CSA (p<0.046), and increased 400 m walk time (p<0.003). Conclusions In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical performance contribute

  11. Comportamento balístico de compósito de polietileno de altíssimo peso molecular: efeito da radiação gama Ballistic behaviour of ultra-high molecular weight polyethylene: effect of gamma radiation

    Directory of Open Access Journals (Sweden)

    Andreia L. S. Alves

    2004-06-01

    Full Text Available Os materiais compósitos de matriz polimérica (PMCs reforçados por fibras são considerados excelentes materiais de engenharia. Em aplicações estruturais, quando uma elevada relação resistência peso é fundamental para o projeto, os PMCs vêm substituindo com sucesso diversos materiais convencionais. Materiais têxteis são utilizados, desde a 2ª Guerra Mundial, como blindagens balísticas. Materiais fabricados com fibra do polietileno de altíssimo peso molecular (UHMWPE são empregados na produção de blindagens, para proteção pessoal e em carros de combate. Todavia, em virtude de terem sido desenvolvidos e comercializados mais recentemente, não existem informações suficientes sobre o desempenho balístico desses materiais após a sua exposição aos agentes ambientais. No presente trabalho foi estudado o comportamento balístico de placas compósitas fabricadas com fibra de polietileno de altíssimo peso molecular (UHMWPE, após sua exposição à radiação gama. Os resultados dos testes balísticos foram relacionados com as alterações macromoleculares induzidas pela irradiação por meio de ensaios mecânicos (dureza, impacto e flexão e físico-químicos (espectroscopia no infravermelho, calorimetria diferencial de varredura e análise termogravimétrica. Foi verificado que a irradiação gama provoca modificações nas cadeias macromoleculares do polímero, que alteram as propriedades mecânicas do compósito de UHMWPE, reduzindo, nas doses de radiação mais elevadas, o seu desempenho balístico. Estes resultados são apresentados e discutidos.The fiber reinforced polymer matrix composites (PMCs are considered excellent engineering materials. In structural applications, when a high strength-to-weight ratio is fundamental for the design, PMCs are successfully replacing many conventional materials. Since World War II textile materials have been used as ballistic armor. Materials manufactured with ultrahigh molecular weight

  12. CHARACTERIZATION OF 6061 T651 ALUMINUM PLATES SUBJECTED TO HIGH-VELOCITY IMPACT LOADS

    Directory of Open Access Journals (Sweden)

    Evren ÖZŞAHİN

    2011-06-01

    Full Text Available Ballistic response of single or multi-layered metal armor systems subjected to kinetic energy pro-jectiles was investigated in many experimental, theoretical and numerical studies.In this study, 6061 T651 aluminum plates impacted by 9 mm bullets were investigated. Microstructural investigations have been carried out using optical microscopy. Microhardness values were used to determine the strength behavior of the plates. Influence of the plate thickness and impact velocity on the microstructure has been evaluated. It was concluded from the study that thinner plates are more prone to deformation hardening with high penetration depth values even at low impact velocities while thick plates are more susceptible to thermal softening with less penetration depths. Maximum hardness values were obtained just below the impact zone in both plate thicknesses.

  13. Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Nikolay, E-mail: n.n.belov@mail.ru; Kopanitsa, Dmitry, E-mail: kopanitsa@mail.ru; Yugov, Alexey, E-mail: yugalex@mail.ru; Kaparulin, Sergey, E-mail: kaparulin@mail.ru; Plyaskin, Andrey, E-mail: plyaskinandrei@mail.ru; Kalichkina, Anna, E-mail: aniotka@mail.ru; Ustinov, Artyom, E-mail: artemustinov@bk.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq. Tomsk, 634003 (Russian Federation); Yugov, Nikolay, E-mail: n.t.yugov@mail.ru [Tomsk State University for Radio Electronics and Control Systems, 40, Lenin Av. Tomsk, 634050 (Russian Federation); Kopanitsa, Georgy, E-mail: kopanitsa@mail.ru [National Research Tomsk Polytechnic University, 30, Lenin Av. Tomsk, 634050 (Russian Federation)

    2016-01-15

    When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

  14. Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

    Science.gov (United States)

    Belov, Nikolay; Yugov, Nikolay; Kopanitsa, Dmitry; Kopanitsa, Georgy; Yugov, Alexey; Kaparulin, Sergey; Plyaskin, Andrey; Kalichkina, Anna; Ustinov, Artyom

    2016-01-01

    When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

  15. Strength Training

    Science.gov (United States)

    ... en español Entrenamiento de la fuerza muscular Strength training is a vital part of a balanced exercise routine that includes aerobic activity and flexibility exercises. Regular aerobic exercise, such as running or ...

  16. Strength Training

    Science.gov (United States)

    ... strengthens your heart and lungs. When you strength train with weights, you're using your muscles to ... see there are lots of different ways to train with weights. Try a few good basic routines ...

  17. Models of Ballistic Propagation of Heat at Low Temperatures

    Science.gov (United States)

    Kovács, R.; Ván, P.

    2016-09-01

    Heat conduction at low temperatures shows several effects that cannot be described by the Fourier law. In this paper, the performance of various theories is compared in case of wave-like and ballistic propagation of heat pulses in NaF.

  18. On the Trajectories of Projectiles Depicted in Early Ballistic Woodcuts

    Science.gov (United States)

    Stewart, Sean M.

    2012-01-01

    Motivated by quaint woodcut depictions often found in many late 16th and 17th century ballistic manuals of cannonballs fired in air, a comparison of their shapes with those calculated for the classic case of a projectile moving in a linear resisting medium is made. In considering the asymmetrical nature of such trajectories, the initial launch…

  19. The application of computed tomography in wound ballistics research

    Science.gov (United States)

    Tsiatis, Nick; Moraitis, Konstantinos; Papadodima, Stavroula; Spiliopoulou, Chara; Kelekis, Alexis; Kelesis, Christos; Efstathopoulos, Efstathios; Kordolaimi, Sofia; Ploussi, Agapi

    2015-09-01

    In wound ballistics research there is a relationship between the data that characterize a bullet and the injury resulted after shooting when it perforates the human body. The bullet path in the human body following skin perforation as well as the damaging effect cannot always be predictable as they depend on various factors such as the bullet's characteristics (velocity, distance, type of firearm and so on) and the tissue types that the bullet passes through. The purpose of this presentation is to highlight the contribution of Computed Tomography (CT) in wound ballistics research. Using CT technology and studying virtual “slices” of specific areas on scanned human bodies, allows the evaluation of density and thickness of the skin, the subcutaneous tissue, the muscles, the vital organs and the bones. Density data taken from Hounsfield units can be converted in g/ml by using the appropriate software. By evaluating the results of this study, the anatomy of the human body utilizing ballistic gel will be reproduced in order to simulate the path that a bullet follows. The biophysical analysis in wound ballistics provides another application of CT technology, which is commonly used for diagnostic and therapeutic purposes in various medical disciplines.

  20. Optimal control of the ballistic motion of Airy beams.

    Science.gov (United States)

    Hu, Yi; Zhang, Peng; Lou, Cibo; Huang, Simon; Xu, Jingjun; Chen, Zhigang

    2010-07-01

    We demonstrate the projectile motion of two-dimensional truncated Airy beams in a general ballistic trajectory with controllable range and height. We show that the peak beam intensity can be delivered to any desired location along the trajectory as well as repositioned to a given target after displacement due to propagation through disordered or turbulent media.

  1. Study on ballistic penetration resistance of titanium alloy TC4, Part Ⅱ: Numerical analysis

    Institute of Scientific and Technical Information of China (English)

    Zhang Tao; Chen Wei; Guan Yupu; Gao Deping; Li Shuguang

    2013-01-01

    Enhancing containment capability and reducing weight are always great concerns in the design of casings.Ballistic tests can help to mitigate a catastrophic event after a blade out,yet taking time and costing money.A wise way is to hunt for a validated numerical simulation technology,through which the material dynamic behavior over the strain rate range in the ballistic tests should be represented and reasonable failure strain should be defined.The simulation results show that the validation of the numerical simulation technology based on the test data can accurately estimate the absorption energy,describe the physical process and failure mode during the penetration,as well as the failure mechanism.It is found that energy dissipation of projectiles is in manner of compression stage,energy conversion stage,and interactive scrap stage.An effect indicator is proposed,where the factors of critical velocity including impact orientation and mass of projectiles and thickness of casings are considered.The critical velocity presents a linear relation with the effect indicator,which implies the critical velocity obtained by the flat casing could underestimate the capability of the real casing.

  2. Ballistic tongue projection in chameleons maintains high performance at low temperature.

    Science.gov (United States)

    Anderson, Christopher V; Deban, Stephen M

    2010-03-23

    Environmental temperature impacts the physical activity and ecology of ectothermic animals through its effects on muscle contractile physiology. Sprinting, swimming, and jumping performance of ectotherms decreases by at least 33% over a 10 degrees C drop, accompanied by a similar decline in muscle power. We propose that ballistic movements that are powered by recoil of elastic tissues are less thermally dependent than movements that rely on direct muscular power. We found that an elastically powered movement, ballistic tongue projection in chameleons, maintains high performance over a 20 degrees C range. Peak velocity and power decline by only 10%-19% with a 10 degrees C drop, compared to >42% for nonelastic, muscle-powered tongue retraction. These results indicate that the elastic recoil mechanism circumvents the constraints that low temperature imposes on muscle rate properties and thereby reduces the thermal dependence of tongue projection. We propose that organisms that use elastic recoil mechanisms for ecologically important movements such as feeding and locomotion may benefit from an expanded thermal niche.

  3. Ballistic parameters and trauma potential of pistol crossbows.

    Science.gov (United States)

    Frank, Matthias; Schikorr, Wolfgang; Tesch, Ralf; Werner, Ronald; Hanisch, Steffen; Peters, Dieter; Ekkernkamp, Axel; Bockholdt, Britta; Seifert, Julia

    2013-07-01

    Hand-held pistol crossbows, which are smaller versions of conventional crossbows, have recently increased in popularity. Similar to conventional crossbows, life threatening injuries due to bolts discharged from pistol crossbows are reported in forensic and traumatological literature. While the ballistic background of conventional crossbows is comprehensively investigated, there are no investigations on the characteristic ballistic parameters (draw force, potential energy, recurve factor, kinetic energy, and efficiency) of pistol crossbows. Two hand-held pistol crossbows (Barnett Commando and Mini Cross Bow, rated draw force 362.9 N or 80 lbs) were tested. The maximum draw force was investigated using a dynamic tensile testing machine (TIRAtest 2705, TIRA GmbH). The potential energy was determined graphically by polynomial regression as area under the force-draw curve. External ballistic parameters of the bolts discharged from pistol crossbows were measured using a redundant ballistic speed measurement system (Dual-BMC 21a and Dual-LS 1000, Werner Mehl Kurzzeitmesstechnik). The average maximum draw force was 190.3 and 175.6 N for the Barnett and Mini Cross Bow, respectively. The corresponding total energy expended was 10.7 and 11 J, respectively. The recurve factor was calculated to be 0.705 and 1.044, respectively. Average bolt velocity was measured 43 up to 52 m/s. The efficiency was calculated up to 0.94. To conclude, this work provides the pending ballistic data on this special subgroup of crossbows which operate on a remarkable low kinetic energy level. Furthermore, it demonstrates that the nominal draw force pretended in the sales brochure is grossly exaggerated.

  4. Signs of muscle thixotropy during human ballistic wrist joint movements.

    Science.gov (United States)

    Axelson, H W

    2005-11-01

    A study was conducted on healthy subjects to determine whether voluntary ballistic wrist flexion movements are influenced by immediately preceding conditioning of the forearm muscles. Single rapid wrist flexion movements were made in response to an auditory "Go" signal. Rectified surface EMG was recorded from wrist flexors and extensors, and joint position was measured by a goniometer. The movements were preceded (2-3 s) by four different conditioning routines: 40-s rest (Rest), 10-s voluntary alternating wrist joint flexion and extension movements (Osc), and 10 s of 25 degrees weak isometric wrist extensor (Ext) or flexor contractions (Flex). When subjects made ballistic movements after Osc compared with Rest, peak velocity was higher (P = 0.02) and movement time shorter (P = 0.06), but there was no difference (P = 0.83) in motor reaction time (time between the onset of the first agonist burst and movement onset). If the movements were preceded by Ext compared with Flex, motor reaction time was longer (P = 0.01), indicating a longer electromechanical delay. There were no indications that postconditioning differences in agonist or antagonist muscle activity could explain the results. It was also demonstrated that, after Rest, peak velocity was lower (P < 0.01) for the first than for the second of a series of repetitive ballistic movements. The observations corresponded to results from passive experiments in which the median nerve was electrically stimulated. In conclusion, history-dependent (thixotropic) changes in skeletal muscle resistance seem to have implications for voluntary ballistic wrist movements. The study also provided evidence that muscle conditioning influences the central nervous reaction time preceding ballistic contractions.

  5. A comparison of finite element analysis to smooth particle hydrodynamics for application to projectile impact on cementitious material

    Science.gov (United States)

    Nordendale, Nikolas A.; Heard, William F.; Sherburn, Jesse A.; Basu, Prodyot K.

    2016-03-01

    The response of structural components of high-strength cementitious (HSC) materials to projectile impact is characterized by high-rate fragmentation resulting from strong compressive shock waves coupled with reflected tensile waves. Accurate modeling of armor panels of such brittle materials under high-velocity projectile impact is a complex problem requiring meticulous experimental characterization of material properties. In a recent paper by the authors, an approach to handle such problems based on a modified Advanced Fundamental Concrete (AFC) constitutive model was developed. In the HSC panels considered in this study, an analogous approach is applied, and the predictions are verified with ballistic impact test data. Traditional Lagrangian finite element analysis (FEA) of these problems tends to introduce errors and suffers from convergence issues resulting from large deformations at free surfaces. Also, FEA cannot properly account for the issues of secondary impact of spalled fragments when multiple armor panels are used. Smoothed particle hydrodynamics (SPH) is considered to be an attractive alternative to resolve these and other issues. However, SPH-based quantitative results have been found to be less accurate than the FEA-based ones when the deformations are not sufficiently large. This paper primarily focuses on a comparison of FEA and SPH models to predict high-velocity projectile impact on single and stacked HSC panels. Results are compared to recent ballistic experiments performed as a part of this research, and conclusions are drawn based on the findings.

  6. New Diagnostic, Launch and Model Control Techniques in the NASA Ames HFFAF Ballistic Range

    Science.gov (United States)

    Bogdanoff, David W.

    2012-01-01

    This report presents new diagnostic, launch and model control techniques used in the NASA Ames HFFAF ballistic range. High speed movies were used to view the sabot separation process and the passage of the model through the model splap paper. Cavities in the rear of the sabot, to catch the muzzle blast of the gun, were used to control sabot finger separation angles and distances. Inserts were installed in the powder chamber to greatly reduce the ullage volume (empty space) in the chamber. This resulted in much more complete and repeatable combustion of the powder and hence, in much more repeatable muzzle velocities. Sheets of paper or cardstock, impacting one half of the model, were used to control the amplitudes of the model pitch oscillations.

  7. Possible influences on bullet trajectory deflection in ballistic gelatine.

    Science.gov (United States)

    Riva, Fabiano; Kerkhoff, Wim; Bolck, Annabel; Mattijssen, Erwin J A T

    2017-02-01

    The influence of the distance to the top and bottom of a gelatine block and to bullet tracks from previously fired shots on a bullet's trajectory, when passing through ballistic gelatine, was studied. No significant difference in deflection was found when trajectories of 9mm Luger bullets, fired at a 3.5cm distance to the top and bottom of a gelatine block and to bullet tracks from previously fired shots, were compared to trajectories of bullets fired 7cm or more away from any of the aforementioned aspects. A surprisingly consistent 6.5° absolute deflection angle was found when these bullets passed through 22.5 to 23.5cm of ballistic gelatine. The projection angle, determined by the direction of the deflection, appeared to be random. The consistent absolute angle, in combination with the random projection angle, resulted in a cone-like deflection pattern.

  8. The Ballistic Pressure Wave Theory of Handgun Bullet Incapacitation

    CERN Document Server

    Courtney, Michael

    2008-01-01

    This paper presents a summary of seven distinct chains of evidence, which, taken together, provide compelling support for the theory that a ballistic pressure wave radiating outward from the penetrating projectile can contribute to wounding and incapacitating effects of handgun bullets. These chains of evidence include the fluid percussion model of traumatic brain injury, observations of remote ballistic pressure wave injury in animal models, observations of rapid incapacitation highly correlated with pressure magnitude in animal models, epidemiological data from human shootings showing that the probability of incapacitation increases with peak pressure magnitude, case studies in humans showing remote pressure wave damage in the brain and spinal cord, and observations of blast waves causing remote brain injury.

  9. Ballistic Missile Warhead Recognition based on Micro-Doppler Frequency

    Directory of Open Access Journals (Sweden)

    Sun Hui-Xia

    2008-11-01

    Full Text Available To elucidate the spinning-precession signatures of ballistic warhead, the model of spinning precessionfor ballistic missile warhead is established and the mathematics of micro-Doppler signatures caused by spinning-precession is derived. Then the micro-Doppler features are analysed using high-resolution time-frequencytransform, and the model predictions match the experimental data well. Based on  different mass of warheadsand decoys, the feature, which can reflect the mass of the targets, is extracted from the time-frequency plane,proving a new method for recognising warheads and discriminating these from decoys. Finally the validityof the feature extracted in this study is verified by computer simulations even with low signal-to-noise ratio.Defence Science Journal, 2008, 58(6, pp.705-709, DOI:http://dx.doi.org/10.14429/dsj.58.1697

  10. A ballistic gate-tunable contact junction in graphene

    Science.gov (United States)

    Wilmart, Quentin; Rosticher, Michael; Boukhicha, Mohamed; Inhofer, Andreas; Morfin, Pascal; Feve, Gwendal; Berroir, Jean-Marc; Placais, Bernard; Equipe de Physique Mésoscopique Team

    2015-03-01

    Field-effect control of carrier is very efficient in graphene and allows controlling the doping profile with a great accuracy and high spatial resolution. This is needed if one wants to implement Dirac fermion optics experiments or simply to improve the performance of graphene devices. In this work we realize graphene transistors equipped with a set of local back-gates that provide control of local electric fields in the 108 V / m range at the 10 nanometer scale. In particular we demonstrate ballistic contact junctions using transistors with independent channel and contact back-gates. We shall discuss the possibilities offered by this technology for ballistic electronic and opto-electronic applications.

  11. Learning without knowing: subliminal visual feedback facilitates ballistic motor learning

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo

    During daily life we are constantly bombarded by sensory input providing information on the state of our body and the surrounding world. Although we do not consciously perceive all sensory inputs, these may nevertheless have consequences for our future behavior (e.g. Goodale and Milner...... was on the screen during learning. Despite of this, there was a significantly larger learning effect in the subliminal 13-26 ms group compared to the subliminal 0 ms group. In conclusion, the results demonstrate that in addition to supraliminal feedback, subliminal feedback, which was not consciously perceived...... by the learner, indeed facilitated ballistic motor learning. This effect likely relates to multiple (conscious versus unconscious) processing of visual feedback and to the specific neural circuitries involved in optimization of ballistic motor performance....

  12. Effect of Ballistic-Type Hot Atom Adsorption Mechanism on the Phase Diagram of Monomer-Dimer CO-O2 Surface Catalytic Reaction:A Monte Carlo Simulation

    Institute of Scientific and Technical Information of China (English)

    M. Khalid; K. M. Khan; A. U. Qaisrani; Q. N. Malik

    2004-01-01

    @@ We investigate the effect of the ballistic mechanism on the phase diagram using a square surface. While using this mechanism whenever an O2 molecule hits a randomly vacant selected site, the molecule breaks up into atomic form and then executes a ballistic flight. The paths of the two oxygen atoms are taken exactly to be opposite to each other, i.e. anti-parallel, and the ranges of the atoms are taken to be equal, i.e. they may fly up to 1 or 1.414 or 2 of the atomic spacing from the site of impact. Four cases have been studied on the basis of the range of hot atoms. The range of the hot oxygen atoms executing a ballistic flight might be up to the first nearest neighbourhood (1 atomic spacing from the site of impact), the second nearest neighbourhood (1.414 atomic spacing from the site of impact), the third nearest neighbourhood (2 atomic spacing from the site of impact),known as cases a, b, and c, respectively, while for case d the range of the oxygen atoms executing the ballistic flight might be up to 1 atomic spacing or 1.414 atomic spacing or 2 atomic spacing from the site of impact. The steady reactive window is observed and the continuous transition disappears. As soon as the CO partial pressure departs from zero, the production of CO2 is observed, which clearly verifies the experimental observation.

  13. Quadrennial Defense Review and Ballistic Missile Defense Review

    Science.gov (United States)

    2010-03-11

    global defense posture 3 BMDR Highlights • Outlines a strategy and policy framework to – Defend the homeland against limited ballistic missile attack...abroad – Collaborate closely with allies and partners – Pursue a cooperative and tailored global defense posture – Strengthen US civilian capacity...reviews in 2010 – QDR and BMDR released February 1, 2010 – Nuclear Posture Review to be released this spring – Space Posture Review, with Director of

  14. Ballistic Thermal Transistor of Dielectric Four-terminal Nanostructures

    OpenAIRE

    Yang, Ping; Hu, Bambi

    2009-01-01

    We report a theoretical model for a thermal transistor in dielectric four-terminal nanostructures based on mesoscopic ballistic phonon transport, in which a steady thermal flow condition of system is obtained to set up the temperature field effect of gate. In the environment, thermal flow shows the transisting behaviors at low temperatures: saturation, asymmetry, and rectification. The phenomena can be explained reasonably by the nonlinear variation of the temperature dependence of propagatin...

  15. Pseudomagnetic fields and ballistic transport in a suspended graphene sheet.

    Science.gov (United States)

    Fogler, M M; Guinea, F; Katsnelson, M I

    2008-11-28

    We study a suspended graphene sheet subject to the electric field of a gate underneath. We compute the elastic deformation of the sheet and the corresponding effective gauge field, which modifies the electronic transport. In a clean system the two-terminal conductance of the sample is reduced below the ballistic limit and is almost totally suppressed at low carrier concentrations in samples under tension. Residual disorder restores a small finite conductivity.

  16. Development of a Two-Dimensional Implicit Interior Ballistics Code

    Science.gov (United States)

    1980-01-01

    the universal gas constant, W is the gas molecular weight, u m and n is the covolume factor, which is composition dependent . Following Gough (Ref...c is dependent on the gas composition but not temperature. v The static enthalpy is then h = p e + p The specific heat at constant pressure is...Gun Interior Ballistics Transient Combustion Time- dependent Adaptive Grid 20, ABST’RACT (Cazrt&au:e _. .. ._._ lliO 11 ~ llltld ldenllly by block

  17. Model of risk assessment under ballistic statistical tests

    Science.gov (United States)

    Gabrovski, Ivan; Karakaneva, Juliana

    The material presents the application of a mathematical method for risk assessment under statistical determination of the ballistic limits of the protection equipment. The authors have implemented a mathematical model based on Pierson's criteria. The software accomplishment of the model allows to evaluate the V50 indicator and to assess the statistical hypothesis' reliability. The results supply the specialists with information about the interval valuations of the probability determined during the testing process.

  18. Ballistics Modeling for Non-Axisymmetric Hypervelocity Smart Bullets

    Science.gov (United States)

    2014-06-03

    rapidly spinning rifle bullet [2]. However, the Magnus moment can be important in terms of stability. The Magnus moment is the one effect we consider...is the result when the magnus moment is neglected. Although the magnus effect is small, the effect of neglecting it is discernable. The solution 19...11 2. Spin and Pitch Damping 11 3. Magnus Moment 12 IV. CFD Simulations and Ballistic Trajectories 12 A. CFD Modeling of a Standard Bullet 12 B

  19. Ballistic anomalies in solid rocket motors due to migration effects

    Science.gov (United States)

    Pröbster, M.; Schmucker, R. H.

    Double base and composite propellants are generally used for rocket motors, whereby double base propellants basically consist of nitrocellulose plasticized with an explosive plasticizer, mostly nitroglycerine, and in some cases with an additional inert plasticizer and ballistic additives. Composite propellants consist of an oxidizer like ammonium perchlorate and of aluminum, binder and plasticizer and often contain liquid or solid burning rate catalysts. A common feature of both propellants is that they contain smaller or larger amounts of chemically unbonded liquid species which tend to migrate. If these propellants loose part of the plasticizer by migration into the insulation layer, not only will there be a change in mechanical propellant properties but also the bond between propellant and insulation may degrade. However, depending on the severity of these effects, the change in the ballistic properties of the propellant grain caused by plasticizer migration may be of even more importance. In the past, most emphasis was placed on the behaviour of end-burning configurations. However, more recent theoretical and experimental studies revealed that not only for end-burning grain configurations but also for internal burning configurations there is a common effect which is responsible for ballistic anomalies: migration of liquid species from the propellant into the insulation. By using a plasticizer equilibrated insulation in an internal burning configuration the liquid species migration and thus the previously observed ballistic anomalies are avoided. Using this approach for end-burning configurations provides similar positive results. The various factors affecting plasticizer migration are studied and discussed, and several methods to prevent liquid species migration are described as well as methods to obtain plasticizer resistant insulations.

  20. Ballistic Evaluation of Magnesium Alloy AZ31B

    Science.gov (United States)

    2007-04-01

    S. Burkins, and William A. Gooch Weapons and Materials Research Directorate, ARL Richard D. DeLorme Magnesium Elektron North America, Inc...ballistic properties. In order to fill this gap, the U.S. Army Research Laboratory (ARL) and Magnesium Elektron North America (MENA), Inc., conducted a...plate (H24 condition). The magnesium plate was alloyed, cast, rolled, thermally treated and tensile tested by Magnesium Elektron North America (MENA

  1. System Architecture for Anti-Ship Ballistic Missile Defense (ASBMD)

    OpenAIRE

    Hobgood, Jean; Madison, Kimberly; Pawlowski, Geoffrey; Nedd, Steven.; Roberts, Michael; Rumberg, Paige

    2009-01-01

    Approved for public release; distribution is unlimited. Recent studies suggest that China is developing a new class of ballistic missiles that can be used against moving targets, such as ships. One such technology is anticipated to cover a range of 2,000 kilometers and operate at a speed of Mach 10. The threat is also capable of maneuvering both during the midcourse and terminal flight phases for the purposes of guidance, target acquisition, and countermeasures. This threat could greatl...

  2. Long-Range Ballistic Missile Defense in Europe

    Science.gov (United States)

    2010-04-26

    Standard Missile 3) missile defenses. Czech President Vaclav Klaus pronounced himself unsurprised by the announcement, and assured that he was “100...was holding the six-month revolving European Union (EU) presidency. On May 15, President Vaclav Klaus announced the installation of an interim...September 17, 2009. 5 Withdrawal From Radar No Cooling of Czech-U.S. Relations – Klaus . CTK Daily News. September 17, 2009. . Long-Range Ballistic Missile

  3. Going ballistic:dealing with guns, gangs and knives

    OpenAIRE

    2008-01-01

    Murders involving knives and firearms never fail to grab the headlines, yet they are relatively rare. Gun crime represents only 0.4% of all recorded crime in England and Wales. The public are often sceptical, however, when they read figures such as this – and they have reason to be so. Going Ballistic's findings support four primary arguments: that official crime figures do not reflect the experiences of many communities in England and Wales; that information and intelligence sharing between ...

  4. Theory of vortices in hybridized ballistic/diffusive-band superconductors

    Science.gov (United States)

    Tanaka, K.; Eschrig, M.; Agterberg, D. F.

    2007-06-01

    We study the electronic structure in the vicinity of a vortex in a two-band superconductor in which the quasiparticle motion is ballistic in one band and diffusive in the other. This study is based on a model appropriate for such a case, that we have introduced recently [Tanaka , Phys. Rev. B 73, 220501(R) (2006)]. We argue that in the two-band superconductor MgB2 , such a case is realized. Motivated by the experimental findings on MgB2 , we assume that superconductivity in the diffusive band is “weak,” i.e., mostly induced. We examine intriguing features of the order parameter, the current density, and the vortex core spectrum in the “strong” ballistic band under the influence of hybridization with the “weak” diffusive band. Although the order parameter in the diffusive band is induced, the characteristic length scales in the two bands differ due to Coulomb interactions. The current density in the vortex core is dominated by the contribution from the ballistic band, while outside the core the contribution from the diffusive band can be substantial, or even dominating. The current density in the diffusive band has strong temperature dependence, exhibiting the Kramer-Pesch effect when hybridization is strong. A particularly interesting feature of our model is the possibility of additional bound states near the gap edge in the ballistic band, that are prominent in the vortex center spectra. This contrasts with the single band case, where there is no gap-edge bound state in the vortex center. We find the above-mentioned unique features for parameter values relevant for MgB2 .

  5. Chaotic and ballistic dynamics in time-driven quasiperiodic lattices.

    Science.gov (United States)

    Wulf, Thomas; Schmelcher, Peter

    2016-04-01

    We investigate the nonequilibrium dynamics of classical particles in a driven quasiperiodic lattice based on the Fibonacci sequence. An intricate transient dynamics of extraordinarily long ballistic flights at distinct velocities is found. We argue how these transients are caused and can be understood by a hierarchy of block decompositions of the quasiperiodic lattice. A comparison to the cases of periodic and fully randomized lattices is performed.

  6. Chaotic and ballistic dynamics in time-driven quasiperiodic lattices

    CERN Document Server

    Wulf, Thomas

    2016-01-01

    We investigate the nonequilibrium dynamics of classical particles in a driven quasiperiodic lattice based on the Fibonacci sequence. An intricate transient dynamics of extraordinarily long ballistic flights at distinct velocities is found. We argue how these transients are caused and can be under- stood by a hierarchy of block decompositions of the quasiperiodic lattice. A comparison to the cases of periodic and fully randomized lattices is performed.

  7. Chaotic and ballistic dynamics in time-driven quasiperiodic lattices

    Science.gov (United States)

    Wulf, Thomas; Schmelcher, Peter

    2016-04-01

    We investigate the nonequilibrium dynamics of classical particles in a driven quasiperiodic lattice based on the Fibonacci sequence. An intricate transient dynamics of extraordinarily long ballistic flights at distinct velocities is found. We argue how these transients are caused and can be understood by a hierarchy of block decompositions of the quasiperiodic lattice. A comparison to the cases of periodic and fully randomized lattices is performed.

  8. Pneumatic capillary gun for ballistic delivery of microparticles

    CERN Document Server

    Rinberg, D; Groisman, A; Rinberg, Dmitry; Simonnet, Claire; Groisman, Alex

    2005-01-01

    A pneumatic gun for ballistic delivery of microparticles to soft targets is proposed and demonstrated. The particles are accelerated by a high speed flow of Helium in a capillary tube. Vacuum suction applied to a concentric, larger diameter tube is used to completely divert the flow of Helium from the gun nozzle and prevent it from hitting the target. Depths of penetration of micron-sized gold particles into agarose gels and their speeds of ejection from the gun nozzle are measured.

  9. Experimental techniques for design of impact-resistant material (poster)

    NARCIS (Netherlands)

    Fan, J.; Weerheijm, J.; Sluys, L.J.

    2013-01-01

    Some polymers are not only transparent and lightweight, but also impact and ballistic resistant. Designing and preparing such polymeric materials with a high impact‐resistant performance is of importance to e.g. aviation, military and windscreen applications.

  10. Long-term strength training for community-dwelling people over 75: impact on muscle function, functional ability and life style.

    Science.gov (United States)

    Capodaglio, Paolo; Capodaglio Edda, Maria; Facioli, Marco; Saibene, Francesco

    2007-07-01

    The objective was to determine the impact of a 1-year mixed strength-training programme on muscle function, functional ability, physical activity and life style. Twice-a-week hospital-based exercise classes and a once-a-week home session were conducted. Nineteen healthy community-dwelling training (T) men (76.6 +/- 3.1 years), 19 women (77.5 +/- 4.0 years) and 20 matched controls (C) participated in this study. Training was given with a two multi-gym machines for the lower limbs (Sitting calf and Leg press, TECHNOGYM, Italy) at 60% of the repetition maximum (1 RM) and at home it was with elastic bands. The following were the measurements made: muscle function-maximum isometric strength of the knee extensors (KE) and ankle plantar flexors (PF) measured with a Cybex Norm dynamometer, leg extensor power (LEP) with the Nottingham Power Rig; functional abilities-functional reach, chair rise, bed rise, 6-min walking test, stair climbing, get up and go, one-leg standing; physical activity-aerobic activities over 3 MET intensity (AA3), intensity classes; life-style-mean daily energy expenditure (MDEE). Significant gains in muscle function and functional abilities in both training females and males were observed, but females improved significantly more than males. Males (T + C) showed higher AA3 times than females (T + C) (P = 0.02), with females significantly more involved in light-intensity activities. We observed a 60% increase (t = 2.45) in AA3 time in T, but no increase in C. Trained males increased Class 2 physical activity time by 146% (t = 2.82) and trained females by 16% (t = 2.23). MDEE increased by 10% (t=2.62) in trained males. Our long-term mixed programme can improve muscle function and functional abilities in elderly females and functional abilities in males. It can positively affect the amount of habitual physical activity and the life-style of males and females over 75.

  11. Comparing Terminal Performance of .357 SIG and 9mm Bullets in Ballistic Gelatin Using Retarding Force Analysis from High Speed Video

    CERN Document Server

    Keys, Elizabeth; Courtney, Michael

    2015-01-01

    High-speed video has emerged as an valuable tool for quantifying bullet performance in ballistic gelatin. This paper presents the results of testing four .357 SIG bullets using high-speed video of bullet impacts in ballistic gelatin to determine retarding force curves, permanent cavities, temporary cavities, and energy deposit vs. penetration depth. Since the methods are identical, results are meaningfully compared with four 9mm NATO bullets studied in an earlier project. Though .357 SIG bullets perform slightly better due to higher impact energy, the principal finding is that there is a much bigger difference in performance between the best and worst performing bullets in each cartridge than there is between bullets of similar design in the two cartridges. In each cartridge, higher performing expanding bullets (jacketed hollow points) outperform non-expanding bullets (full metal jacket) by a wide margin, showing a much higher probability of rapid incapacitation according to an Army Research Laboratory model ...

  12. Pivotal role of ballistic and quasi-ballistic electrons on LED efficiency

    Science.gov (United States)

    Ni, X.; Li, X.; Lee, J.; Liu, S.; Avrutin, V.; Matulionis, A.; Özgür, Ü.; Morkoç, H.

    2010-08-01

    Significant progress in the power conversion efficiency and brightness of InGaN-based light emitting diodes (LEDs) has paved the way for these devices to be considered for LED lighting. In this realm, however, the efficiency must be retained at high injection levels in order to generate the lumens required. Unfortunately, LEDs undergo a monotonic efficiency degradation starting at current densities even lower than 50 A/cm 2 which would hinder LED insertion into the general lighting market. The physical origins for the loss of efficiency retention are at present a topic of intense debate given its enormous implications. This paper reviews the current status of the field regarding the mechanisms that have been put forward as being responsible for the loss of efficiency, such as Auger recombination, electron overflow (spillover), current crowding, asymmetric injection of electrons and holes, and poor transport of holes through the active region, the last one being applicable to multiple quantum well designs. While the Auger recombination received early attention, increasing number of researchers seem to think otherwise at the moment in that it alone (if any) cannot explain the progressively worsening loss of efficiency reduction as the InN mole fraction is increased. Increasing number of reports seems to suggest that the electron overflow is one of the major causes of efficiency degradation. The physical driving force for this is likely to be the relatively poor hole concentration and transport, and skewed injection favoring electrons owing to their relatively high concentration. Most intriguingly there is recent experimental convincing evidence to suggest that quasi-ballistic electrons in the active region, which are not able to thermalize within the residence time and possibly longitudinal optical phonon lifetime, contribute to the carrier overflow which would require an entirely new thought process in the realm of LEDs.

  13. Evaluation of bone surrogates for indirect and direct ballistic fractures.

    Science.gov (United States)

    Bir, Cynthia; Andrecovich, Chris; DeMaio, Marlene; Dougherty, Paul J

    2016-04-01

    The mechanism of injury for fractures to long bones has been studied for both direct ballistic loading as well as indirect. However, the majority of these studies have been conducted on both post-mortem human subjects (PMHS) and animal surrogates which have constraints in terms of storage, preparation and testing. The identification of a validated bone surrogate for use in forensic, medical and engineering testing would provide the ability to investigate ballistic loading without these constraints. Two specific bone surrogates, Sawbones and Synbone, were evaluated in comparison to PMHS for both direct and indirect ballistic loading. For the direct loading, the mean velocity to produce fracture was 121 ± 19 m/s for the PMHS, which was statistically different from the Sawbones (140 ± 7 m/s) and Synbone (146 ± 3 m/s). The average distance to fracture in the indirect loading was .70 cm for the PMHS. The Synbone had a statistically similar average distance to fracture (.61 cm, p=0.54) however the Sawbones average distance to fracture was statistically different (.41 cm, pballistic testing was not identified and future work is warranted.

  14. The Second National Ballistics Imaging Comparison (NBIC-2)

    Science.gov (United States)

    Vorburger, TV; Yen, J; Song, JF; Thompson, RM; Renegar, TB; Zheng, A; Tong, M; Ols, M

    2014-01-01

    In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to establish a national traceability and quality system for ballistics identifications in crime laboratories utilizing ATF’s National Integrated Ballistics Information Network (NIBIN). The original NBIC was completed in 2010. In the second NBIC, NIST Standard Reference Material (SRM) 2461 Cartridge Cases were used as reference standards, and 14 experts from 11 U.S. crime laboratories each performed 17 image acquisitions and correlations of the SRM cartridge cases over the course of about half a year. Resulting correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed quality system and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard. PMID:26601051

  15. Experimental model for civilian ballistic brain injury biomechanics quantification.

    Science.gov (United States)

    Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A; Guan, Yabo; Gennarelli, Thomas A

    2007-01-01

    Biomechanical quantification of projectile penetration using experimental head models can enhance the understanding of civilian ballistic brain injury and advance treatment. Two of the most commonly used handgun projectiles (25-cal, 275 m/s and 9 mm, 395 m/s) were discharged to spherical head models with gelatin and Sylgard simulants. Four ballistic pressure transducers recorded temporal pressure distributions at 308kHz, and temporal cavity dynamics were captured at 20,000 frames/second (fps) using high-speed digital video images. Pressures ranged from 644.6 to -92.8 kPa. Entry pressures in gelatin models were higher than exit pressures, whereas in Sylgard models entry pressures were lower or equivalent to exit pressures. Gelatin responded with brittle-type failure, while Sylgard demonstrated a ductile pattern through formation of micro-bubbles along projectile path. Temporary cavities in Sylgard models were 1.5-2x larger than gelatin models. Pressures in Sylgard models were more sensitive to projectile velocity and diameter increase, indicating Sylgard was more rate sensitive than gelatin. Based on failure patterns and brain tissue rate-sensitive characteristics, Sylgard was found to be an appropriate simulant. Compared with spherical projectile data, full-metal jacket (FMJ) projectiles produced different temporary cavity and pressures, demonstrating shape effects. Models using Sylgard gel and FMJ projectiles are appropriate to enhance understanding and mechanisms of ballistic brain injury.

  16. Quantum ballistic evolution in quantum mechanics application to quantum computers

    CERN Document Server

    Benioff, P

    1996-01-01

    Quantum computers are important examples of processes whose evolution can be described in terms of iterations of single step operators or their adjoints. Based on this, Hamiltonian evolution of processes with associated step operators T is investigated here. The main limitation of this paper is to processes which evolve quantum ballistically, i.e. motion restricted to a collection of nonintersecting or distinct paths on an arbitrary basis. The main goal of this paper is proof of a theorem which gives necessary and sufficient conditions that T must satisfy so that there exists a Hamiltonian description of quantum ballistic evolution for the process, namely, that T is a partial isometry and is orthogonality preserving and stable on some basis. Simple examples of quantum ballistic evolution for quantum Turing machines with one and with more than one type of elementary step are discussed. It is seen that for nondeterministic machines the basis set can be quite complex with much entanglement present. It is also pr...

  17. Converting Between PLY and Ballistic Research Laboratory-Computer-Aided Design (BRL-CAD) File Formats

    Science.gov (United States)

    2015-02-01

    Converting Between PLY and Ballistic Research Laboratory–Computer-Aided Design (BRL- CAD ) File Formats by Rishub Jain ARL-CR-0760...0760 February 2015 Converting Between PLY and Ballistic Research Laboratory–Computer-Aided Design (BRL- CAD ) File Formats Rishub Jain US...and Ballistic Research Laboratory–Computer-Aided Design (BRL- CAD ) File Formats 5a. CONTRACT NUMBER W911NF-10-2-0076 5b. GRANT NUMBER 5c. PROGRAM

  18. Development of Mortar Simulator with Shell-In-Shell System – Problem of External Ballistics

    Directory of Open Access Journals (Sweden)

    A. Fedaravicius

    2007-01-01

    Full Text Available The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed.

  19. Engineering Polymer Blends for Impact Damage Mitigation

    Science.gov (United States)

    Gordon, Keith L.; Smith, Russell W.; Working, Dennis C.; Siochi, Emilie J.

    2016-01-01

    Structures containing polymers such as DuPont's Surlyn® 8940, demonstrate puncture healing when impacted by a 9 millimeter projectile traveling from speeds near 300 meters per second (1,100 feet per second) to hypervelocity impacts in the micrometeoroid velocity range of 5 kilometers per second (16,000 feet per second). Surlyn® 8940 puncture heals over a temperature range of minus 30 degrees Centigrade to plus 70 degrees Centigrade and shows potential for use in pressurized vessels subject to impact damage. However, such polymers are difficult to process and limited in applicability due to their low thermal stability, poor chemical resistance and overall poor mechanical properties. In this work, several puncture healing engineered melt formulations were developed. Moldings of melt blend formulations were impacted with a 5.56 millimeter projectile with a nominal velocity of 945 meters per second (3,100 feet per second) at about 25 degrees Centigrade, 50 degrees Centigrade and 100 degrees Centigrade, depending upon the specific blend being investigated. Self-healing tendencies were determined using surface vacuum pressure tests and tensile tests after penetration using tensile dog-bone specimens (ASTM D 638-10). For the characterization of tensile properties both pristine and impacted specimens were tested to obtain tensile modulus, yield stress and tensile strength, where possible. Experimental results demonstrate a range of new puncture healing blends which mitigate damage in the ballistic velocity regime.

  20. Rigorous model-based uncertainty quantification with application to terminal ballistics, part I: Systems with controllable inputs and small scatter

    Science.gov (United States)

    Kidane, A.; Lashgari, A.; Li, B.; McKerns, M.; Ortiz, M.; Owhadi, H.; Ravichandran, G.; Stalzer, M.; Sullivan, T. J.

    2012-05-01

    This work is concerned with establishing the feasibility of a data-on-demand (DoD) uncertainty quantification (UQ) protocol based on concentration-of-measure inequalities. Specific aims are to establish the feasibility of the protocol and its basic properties, including the tightness of the predictions afforded by the protocol. The assessment is based on an application to terminal ballistics and a specific system configuration consisting of 6061-T6 aluminum plates struck by spherical S-2 tool steel projectiles at ballistic impact speeds. The system's inputs are the plate thickness and impact velocity and the perforation area is chosen as the sole performance measure of the system. The objective of the UQ analysis is to certify the lethality of the projectile, i.e., that the projectile perforates the plate with high probability over a prespecified range of impact velocities and plate thicknesses. The net outcome of the UQ analysis is an M/U ratio, or confidence factor, of 2.93, indicative of a small probability of no perforation of the plate over its entire operating range. The high-confidence (>99.9%) in the successful operation of the system afforded the analysis and the small number of tests (40) required for the determination of the modeling-error diameter, establishes the feasibility of the DoD UQ protocol as a rigorous yet practical approach for model-based certification of complex systems.

  1. 24th International Symposium on Ballistics

    Science.gov (United States)

    2008-09-26

    launch dynamics Chaired by Don Carlucci & ken kuo 1:30 pm IB098 Numerical Simulation of Projectile Acceleration Process Using Solid/Gas Two-Phase...analysis Wilber related the size and shape of fracture damage To the radius of curvature of the impacting weapon. intersecting chord theorem 0 2...4 6 8 10 100 1000 Radius of curvature (mm) F o r c e ( K n ) Wilber helmet shells 50 cal helmet 1 50 cal concept 50 cal helmet 2 30 cal concept Log

  2. Results of a Round Robin ballistic load sensing headform test series

    NARCIS (Netherlands)

    Philippens, M.A.G.; Anctil, B.; Markwardt, K.C.

    2014-01-01

    The majority of methods to assess the behind armour blunt trauma (BABT) risk for ballistic helmets is based on plastic deformable headforms. An alternative, the Ballistic Load Sensing Headform (BLSH) can record the dynamic contact force between helmet back face and the skull. Helmet BABT methods are

  3. Multiple-Sensor Discrimination of Closely-Spaced Objects on a Ballistic Trajectory

    Science.gov (United States)

    2015-05-18

    aim_point; Determine Interceptor Trajectory This segment of code calculates the trajectory necessary for the interceptor to converge on the target ...identifying and tracking an object of interest within closely-spaced objects traveling on a ballistic trajectory. The algorithms utilize a target object map...ballistic objects, dissimilar sensor correlation, target object map, Dempster-Shafer discrimination algorithms, simulation environment for various

  4. Scaling of ballistic deposition from a Langevin equation.

    Science.gov (United States)

    Haselwandter, Christoph A; Vvedensky, Dimitri D

    2006-04-01

    An exact lattice Langevin equation is derived for the ballistic deposition model of surface growth. The continuum limit of this equation is dominated by the Kardar-Parisi-Zhang (KPZ) equation at all length and time scales. For a one-dimensional substrate the solution of the exact lattice Langevin equation yields the KPZ scaling exponents without any extrapolation. For a two-dimensional substrate the scaling exponents are different from those found from computer simulations. This discrepancy is discussed in relation to analytic approaches to the KPZ equation in higher dimensions.

  5. Ballistic Reconstruction of a Migrating Bullet in the Parapharyngeal Space

    Directory of Open Access Journals (Sweden)

    David Bächinger

    2015-01-01

    Full Text Available A 21-year-old male suffering from severe throat pain after being hit by a bullet in Syria claimed that he was shot through his eye and that the bullet subsequently descended behind his throat. Even though the first medical report stated that this course is implausible, meticulous workup provided evidence that the bullet might have entered the parapharyngeal space in a more cranial position than the one it was found eight months later. Our case highlights that bullets are able to move within the body, rendering ballistic reconstruction difficult. However, after removal of the bullet the patient’s symptoms completely resolved.

  6. Aerodynamic heating of ballistic missile including the effects of gravity

    Indian Academy of Sciences (India)

    S N Maitra

    2000-10-01

    The aerodynamic heating of a ballistic missile due to only convection is analysed taking into consideration the effects of gravity. The amount of heat transferred to the wetted area and to the nose region has been separately determined, unlike A Miele's treatise without consideration of gravity. The peak heating ratesto the wetted area and to the nose of the missile are also investigated. Finally four numerical examples are cited to estimate the errors, in heat transfers and heating ratesto both wetted area and nose region of the missile, arising out of neglecting the gravitational forces.

  7. Two-wavelength phase shift interferometry to characterize ballistic features

    Science.gov (United States)

    Pagano, Glenn W.; Mann, Christopher J.

    2014-05-01

    We apply two-wavelength phase shifting interferometry to generate 3D surface profile maps of spent bullet cartridge cases. From the captured interferograms, an optimized algorithm was used to calculate a phase profile from which a precise digital surface map of the cartridge casing may be produced. This 3D surface profile is used to enhance a firearms examiner's ability to uniquely identify distinct features or toolmarks imprinted on the casing when the weapon is fired. These features play a key role in the matching process of ballistic forensic examination.

  8. Probing magnetic microstructures with quasi-ballistic Hall crosses

    Science.gov (United States)

    Fasbender, S.; Schluck, J.; Cerchez, M.; Heinzel, T.; Sievers, S.; Pierz, K.; Schumacher, H. W.

    2016-03-01

    Hall sensing is performed on a localized magnetic field pattern using a quasi-ballistic Hall cross device. The Hall resistance shows a pronounced peak as a function of the magnetic field amplitude which is absent in the magnetization hysteresis loop. This non-monotonic response exemplifies qualitatively the failure of conventional Hall sensing. It is demonstrated how, by using a numerical simulation based on the Landauer-Büttiker model, the amplitude of the magnetic field profile can be determined from such measurements.

  9. Ballistic electron propagation through periodic few-layer graphene nanostructures

    Science.gov (United States)

    Dragoman, Daniela; Mihalache, Iulia

    2016-10-01

    We have studied electron propagation in periodic structures containing mono- and few-layer graphene regions and/or semiconducting stripes. The calculation of the transmission coefficient in all cases has been performed using transfer matrices inside regions with the same material/potential energy, as well as interface matrices between regions in which the evolution laws of charge carriers differ. Numerical simulations of the transmission coefficient, as well as of the low-temperature conductance, suggest that different periodic structures modulate differently the electrical current. The obtained results can be used to model ballistic transport in all-graphene devices, in particular in few-layer graphene structures.

  10. Persistent currents for interacting electrons in ballistic/chaotic billiards

    Science.gov (United States)

    Zelyak, Oleksandr; Murthy, Ganpathy

    2005-03-01

    We study persistent currents in a quantum billiard enclosing a magnetic flux φ by analytical and numerical methods. We concentrate on the family of Robnik-Berry billiards generated by conformal maps of the unit disk. We study the persistent current as a function of magnetic flux and parameters of the billiard in the chaotic regime. We include Fermi-liquid interactions in a mean-field approach, justified by the recent large-N approach[1] for ballistic/chaotic quantum dots. [1] G. Murthy, R. Shankar, D. Herman, and H. Mathur, Phys. Rev. B 69, 075321 (2004); G. Murthy, R. Shankar, and H. Mathur, cond-mat/0411280.

  11. Computer Aided Ballistic Orbit Classification Around Small Bodies

    Science.gov (United States)

    Villac, Benjamin F.; Anderson, Rodney L.; Pini, Alex J.

    2016-09-01

    Orbital dynamics around small bodies are as varied as the shapes and dynamical states of these bodies. While various classes of orbits have been analyzed in detail, the global overview of relevant ballistic orbits at particular bodies is not easily computed or organized. Yet, correctly categorizing these orbits will ease their future use in the overall trajectory design process. This paper overviews methods that have been used to organize orbits, focusing on periodic orbits in particular, and introduces new methods based on clustering approaches.

  12. Minimum Ballistic Factor Problem of Slender Axial Symmetric Missiles

    Directory of Open Access Journals (Sweden)

    V. B. Tawakley

    1979-01-01

    Full Text Available The problem of determining the geometry of slender, axisymmetric missiles of minimum ballistic factor in hypersonic flow has been solved via the calculus of variations under the assumptions that the flow is Newtonian and the surface averaged skin-friction coefficient is constant. The study has been made for conditions of given length and diameter, given diameter and surfacearea, and given surface area and length. The earlier investigations/sup 8/ where only regular shapes were determined has been extended to cover those class of bodies which consist of regular shapes followed or preceded by zero slope shapes.

  13. Development of ballistics identification—from image comparison to topography measurement in surface metrology

    Science.gov (United States)

    Song, J.; Chu, W.; Vorburger, T. V.; Thompson, R.; Renegar, T. B.; Zheng, A.; Yen, J.; Silver, R.; Ols, M.

    2012-05-01

    Fired bullets and ejected cartridge cases have unique ballistics signatures left by the firearm. By analyzing the ballistics signatures, forensic examiners can trace these bullets and cartridge cases to the firearm used in a crime scene. Current automated ballistics identification systems are primarily based on image comparisons using optical microscopy. The correlation accuracy depends on image quality which is largely affected by lighting conditions. Because ballistics signatures are geometrical micro-topographies by nature, direct measurement and correlation of the surface topography is being investigated for ballistics identification. A Two-dimensional and Three-dimensional Topography Measurement and Correlation System was developed at the National Institute of Standards and Technology for certification of Standard Reference Material 2460/2461 bullets and cartridge cases. Based on this system, a prototype system for bullet signature measurement and correlation has been developed for bullet signature identifications, and has demonstrated superior correlation results.

  14. The 25 September 2007 eruption of Mount Ruapehu, New Zealand: Directed ballistics, surtseyan jets, and ice-slurry lahars

    Science.gov (United States)

    Kilgour, G.; Manville, V.; Della Pasqua, F.; Graettinger, A.; Hodgson, K. A.; Jolly, G. E.

    2010-03-01

    At 20:26 (NZDT) on 25 September 2007 a moderate gas-driven eruption beneath the summit Crater Lake of Mt. Ruapehu, New Zealand generated a directed ballistic fallout apron and surtseyan jet that impacted an area of c. 2.5 km 2 to the north of the vent. Two climbers were caught in the blast at a hut 600 m from the vent. Primary, ice-slurry lahars were generated in two catchments draining the summit region, including a flow that entered a commercial ski field. The ejecta consists of blocks of andesitic lava and scoria erupted during previous volcanic episodes, a variety of mineral-cemented lake-floor sediments, vent-fill debris and rare glassy material interpreted to be derived from a fresh batch of magma. A minority of clasts contain formerly molten elemental sulphur, indicating that vent temperatures at the base of the lake were in excess of 119 °C. The ballistic deposit is confined to a c. 40° wide swath directed northwards that extends up to 2 km from the inferred vent location beneath Crater Lake. The strong directionality of the jetted deposits and ballistic-free 'shadow-zones' sheltered by intervening topography all point to a relatively low-angle directed blast. Previous similar eruptions at Ruapehu also show preferred deposit orientations that are here correlated with an inclined and off-centre vent beneath Crater Lake. The 25 September 2007 eruption appears to have resulted from failure of a relatively shallow hydrothermal seal composed of elemental sulphur and other mineral precipitates developed in the vent breccia, which breached following overpressurization by a pulse of magmatic gases released from deeper in the conduit. This event highlights the potential hazard from relatively minor gas-driven eruptions at Ruapehu that can occur with little or no warning. Improved understanding of the eruption mechanism for this style of eruption will inform future risk assessments for Ruapehu and other similar volcanoes worldwide.

  15. IMPACT OF PHYSIOTHERAPIST-DESIGNED SUPERVISED EXERCISE PROTOCOL ON MUSCLE STRENGTH, AND AUTONOMIC PARAMETERS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS: A CLINICAL TRIAL

    Directory of Open Access Journals (Sweden)

    Renu B. Pattanshetty

    2015-04-01

    Full Text Available Background and Objectives: Type 2 diabetes mellitus is a heterogeneous group of disorders characterized by variable degree of insulin resistance, impaired insulin secretion, and increased glucose production. Physical activity is central to the management type 2 diabetes. There is less evidence to suggest the efficacy of combined effect of physiotherapist- designed supervised exercise protocol on muscle strength and autonomic parameters in such subjects. Hence, the present study was designed to evaluate effect of physiotherapist designed supervised exercise protocol of muscle strength and autonomic parameters in this subject population. Material and Methods: This clinical trial was conducted in thirty (30 adult subjects with type 2 diabetes mellitus including both males and females in the age group of 18 to 65 years. All subjects received physiotherapist designed supervised exercise training protocol consisting of aerobic, resistance & flexibility training. Pre-exercise and post-exercise outcome measurements were taken at baseline, 7th & 14th day in the form of 1-RM for muscle strength and autonomic parameters. Results: Statistical analysis of outcomes at baseline, 7th day and 14th day showed statistically significant difference in strength (p=0.0001, and reduction in autonomic parameters (p=0.0001 Conclusion: The therapist designed exercise protocol has shown to improve muscle strength , mean systolic blood pressure, diastolic blood pressure, pulse rate, pulse pressure, mean arterial pressure, rate pressure product. The protocol has also proved to be safe since no adverse event was noted post exercise.

  16. Ballistic Spin Hall Transistor Using a Heterostructure Channel and Its Application to Logic Devices

    Science.gov (United States)

    Choi, Won Young; Kim, Hyung-Jun; Chang, Joonyeon; Han, Suk Hee; Koo, Hyun Cheol

    2016-09-01

    In a ballistic spin transport channel, spin Hall and Rashba effects are utilized to provide a gate-controlled spin Hall transistor. A ferromagnetic electrode and a spin Hall probe are employed for spin injection and detection, respectively, in a two-dimensional Rashba system. We utilize the spin current of which polarization direction is controlled by the gate electric field which determines the strength of the Rashba effective field. By observing the spin Hall voltage, spin injection and coherent spin precession are electrically monitored. From the original Datta-Das technique, we measure the channel conductance oscillation as the gate voltage is varied. When the magnetization orientation of the injector is reversed by 180°, the phase of the Datta-Das oscillation shifts by 180° as expected. Depending on the magnetization direction, the spin Hall transistor behaves as an n- or p-type transistor. Thus, we can implement the complementary transistors which are analogous to the conventional complementary metal oxide semiconductor transistors. Using the experimental data extracted from the spin Hall transistor, the logic operation is also presented.

  17. Superluminal non-ballistic jet swing in the quasar NRAO 150 revealed by mm-VLBI

    CERN Document Server

    Agudo, I; Krichbaum, T P; Marscher, A P; Gonidakis, I; Diamond, P J; Perucho, M; Alef, W; Graham, D A; Witzel, A; Zensus, J A; Bremer, M; Acosta-Pulido, J A; Barrena, R

    2007-01-01

    NRAO 150 -a compact and bright radio to mm source showing core/jet structure- has been recently identified as a quasar at redshift z=1.52 through a near-IR spectral observation. To study the jet kinematics on the smallest accessible scales and to compute the first estimates of its basic physical properties, we have analysed the ultra-high-resolution images from a new monitoring program at 86 GHz and 43 GHz with the GMVA and the VLBA, respectively. An additional archival and calibration VLBA data set, covering from 1997 to 2007, has been used. Our data shows an extreme projected counter-clock-wise jet position angle swing at an angular rate of up to ~11 deg./yr within the inner ~31 pc of the jet, which is associated with a non-ballistic superluminal motion of the jet within this region. The results suggest that the magnetic field could play an important role in the dynamics of the jet in NRAO 150, which is supported by the large values of the magnetic field strength obtained from our first estimates. The extre...

  18. Theory of ballistic quantum transport in the presence of localized defects

    Science.gov (United States)

    Kolasiński, K.; Mreńca-Kolasińska, A.; Szafran, B.

    2016-09-01

    We present an efficient numerical approach for treating ballistic quantum transport across devices described by tight-binding (TB) Hamiltonians designated to systems with localized potential defects. The method is based on the wave function matching approach, Lippmann-Schwinger equation (LEQ), and the scattering matrix formalism. We show that the number of matrix elements of the Green's function to be evaluated for the unperturbed system can be essentially reduced by projection of the time reversed scattering wave functions on LEQ which radically improves the speed and lowers the memory consumption of the calculations. Our approach can be applied to quantum devices of an arbitrary geometry and any number of degrees of freedom or leads attached. We provide a couple of examples of possible applications of the theory, including current equilibration at the p -n junction in graphene and scanning gate microscopy mapping of electron trajectories in the magnetic focusing experiment on a graphene ribbon. Additionally, we provide a simple toy example of electron transport through 1D wire with added onsite perturbation and obtain a simple formula for conductance showing that Green's function of the device can be obtained from the conductance versus impurity strength characteristics.

  19. Robust Hybrid Control for Ballistic Missile Longitudinal Autopilot

    Institute of Scientific and Technical Information of China (English)

    WAEL Mohsen Ahmed; QUAN Quana

    2011-01-01

    This paper investigates the boost phase's longitudinal autopilot of a ballistic missile equipped with thrust vector control.The existing longitudinal autopilot employs time-invariant passive resistor-inductor-capacitor (RLC) network compensator as a control strategy,which does not take into account the time-varying missile dynamics.This may cause the closed-loop system instability in the presence of large disturbance and dynamics uncertainty.Therefore,the existing controller should be redesigned to achieve more stable vehicle response.In this paper,based on gain-scheduling adaptive control strategy,two different types of optimal controllers are proposed.The first controller is gain-scheduled optimal tuning-proportional-integral-derivative (PID) with actuator constraints,which supplies better response but requires a priori knowledge of the system dynamics.Moreover,the controller has oscillatory response in the presence of dynamic uncertainty.Taking this into account,gain-scheduled optimal linear quadratic (LQ) in conjunction with optimal tuning-compensator offers the greatest scope for controller improvement in the presence of dynamic uncertainty and large disturbance.The latter controller is tested through various scenarios for the validated nonlinear dynamic flight model of the real ballistic missile system with autopilot exposed to external disturbances.

  20. Four-terminal resistance of a ballistic quantum wire.

    Science.gov (United States)

    de Picciotto, R; Stormer, H L; Pfeiffer, L N; Baldwin, K W; West, K W

    2001-05-03

    The electrical resistance of a conductor is intimately related to the relaxation of the momentum of charge carriers. In a simple model, the accelerating force exerted on electrons by an applied electric field is balanced by a frictional force arising from their frequent collisions with obstacles such as impurities, grain boundaries or other deviations from a perfect crystalline order. Thus, in the absence of any scattering, the electrical resistance should vanish altogether. Here, we observe such vanishing four-terminal resistance in a single-mode ballistic quantum wire. This result contrasts the value of the standard two-probe resistance measurements of h/2e2 approximately 13 kOmega. The measurements are conducted in the highly controlled geometry afforded by epitaxial growth onto the cleaved edge of a high-quality GaAs/AlGaAs heterostructure. Two weakly invasive voltage probes are attached to the central section of a ballistic quantum wire to measure the inherent resistance of this clean one-dimensional conductor.

  1. Graphene ballistic nano-rectifier with very high responsivity

    Science.gov (United States)

    Auton, Gregory; Zhang, Jiawei; Kumar, Roshan Krishna; Wang, Hanbin; Zhang, Xijian; Wang, Qingpu; Hill, Ernie; Song, Aimin

    2016-05-01

    Although graphene has the longest mean free path of carriers of any known electronic material, very few novel devices have been reported to harness this extraordinary property. Here we demonstrate a ballistic nano-rectifier fabricated by creating an asymmetric cross-junction in single-layer graphene sandwiched between boron nitride flakes. A mobility ~200,000 cm2 V-1 s-1 is achieved at room temperature, well beyond that required for ballistic transport. This enables a voltage responsivity as high as 23,000 mV mW-1 with a low-frequency input signal. Taking advantage of the output channels being orthogonal to the input terminals, the noise is found to be not strongly influenced by the input. Hence, the corresponding noise-equivalent power is as low as 0.64 pW Hz-1/2. Such performance is even comparable to superconducting bolometers, which however need to operate at cryogenic temperatures. Furthermore, output oscillations are observed at low temperatures, the period of which agrees with the lateral size quantization.

  2. Ballistic modeling of InAs nanowire transistors

    Science.gov (United States)

    Jansson, Kristofer; Lind, Erik; Wernersson, Lars-Erik

    2016-01-01

    In this work, the intrinsic performance of InAs nanowire transistors is evaluated in the ballistic limit. A self-consistent Schrödinger-Poisson solver is utilized in the cylindrical geometry, while accounting for conduction band non-parabolicity. The transistor characteristics are derived from simulations of ballistic transport within the nanowire. Using this approach, the performance is calculated for a continuous range of nanowire diameters and the transport properties are mapped. A transconductance exceeding 4S /mm is predicted at a gate overdrive of 0.5V and it is shown that the performance is improved with scaling. Furthermore, the influence from including self-consistency and non-parabolicity in the band structure simulations is quantified. It is demonstrated that the effective mass approximation underestimates the transistor performance due to the highly non-parabolic conduction band in InAs. Neglecting self-consistency severely overestimates the device performance, especially for thick nanowires. The error introduced by both of these approximations gets increasingly worse under high bias conditions.

  3. Quasi-ballistic Electronic Thermal Conduction in Metal Inverse Opals.

    Science.gov (United States)

    Barako, Michael T; Sood, Aditya; Zhang, Chi; Wang, Junjie; Kodama, Takashi; Asheghi, Mehdi; Zheng, Xiaolin; Braun, Paul V; Goodson, Kenneth E

    2016-04-13

    Porous metals are used in interfacial transport applications that leverage the combination of electrical and/or thermal conductivity and the large available surface area. As nanomaterials push toward smaller pore sizes to increase the total surface area and reduce diffusion length scales, electron conduction within the metal scaffold becomes suppressed due to increased surface scattering. Here we observe the transition from diffusive to quasi-ballistic thermal conduction using metal inverse opals (IOs), which are metal films that contain a periodic arrangement of interconnected spherical pores. As the material dimensions are reduced from ∼230 nm to ∼23 nm, the thermal conductivity of copper IOs is reduced by more than 57% due to the increase in surface scattering. In contrast, nickel IOs exhibit diffusive-like conduction and have a constant thermal conductivity over this size regime. The quasi-ballistic nature of electron transport at these length scales is modeled considering the inverse opal geometry, surface scattering, and grain boundaries. Understanding the characteristics of electron conduction at the nanoscale is essential to minimizing the total resistance of porous metals for interfacial transport applications, such as the total electrical resistance of battery electrodes and the total thermal resistance of microscale heat exchangers.

  4. Observation of the β-delayed γ-proton decay of (56)Zn and its impact on the Gamow-Teller strength evaluation.

    Science.gov (United States)

    Orrigo, S E A; Rubio, B; Fujita, Y; Blank, B; Gelletly, W; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Cáceres, L; Cakirli, R B; Fujita, H; Ganioğlu, E; Gerbaux, M; Giovinazzo, J; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C

    2014-06-06

    We report the observation of a very exotic decay mode at the proton drip line, the β-delayed γ-proton decay, clearly seen in the β decay of the T_{z}=-2 nucleus ^{56}Zn. Three γ-proton sequences have been observed after the β decay. Here this decay mode, already observed in the sd shell, is seen for the first time in the fp shell. Both γ and proton decays have been taken into account in the estimation of the Fermi and Gamow-Teller strengths. Evidence for fragmentation of the Fermi strength due to strong isospin mixing is found.

  5. Ballistic magnetotransport and spin-orbit interaction in indium antimonide and indium arsenide quantum wells

    Science.gov (United States)

    Peters, John Archibald

    While charge transport in a two-dimensional electron system (2DES) is fairly well understood, many open experimental and theoretical questions related to the spin of electrons remain. The standard 2DES embedded in Alx Ga1-xAs/GaAs heterostructures is most likely not the optimal candidate for such investigations, since spin effects as well as spin-orbit interactions are small perturbations compared to other effects. This has brought InSb- and InAs-based material systems into focus due to the possibility of large spin-orbit interactions. By utilizing elastic scattering off a lithographic barrier, we investigate the consequence of spin on different electron trajectories observed in InSb and InAs quantum wells. We focus on the physical properties of spin-dependent reflection in a 2DES and we present experimental results demonstrating a method to create spin-polarized beams of ballistic electrons in the presence of a lateral potential barrier. Spatial separation of electron spins using cyclotron motion in a weak magnetic is also achieved via transverse magnetic focusing. We also explore electrostatic gating effects in InSb/InAlSb heterostructures and demonstrate the effective use of polymethylglutarimide (PMGI) as a gate dielectric for InSb. The dependence on temperature and on front gate voltage of mobility and density are also examined, revealing a strong dependence of mobility on density. As regards front gate action, there is saturation in the density once it reaches a limiting value. Further, we investigate antidot lattices patterned on InSb/InAlSb and InAs/AlGaSb heterostructures. At higher magnetic fields, ballistic commensurability features are displayed while at smaller magnetic fields localization and quantized oscillatory phenomena appear, with marked differences between InSb and InAs. Interesting localization behavior is exhibited in InSb, with the strength of the localization peak decreasing exponentially with temperature between 0.4 K and 50 K. InAs on the

  6. Impact of Weight Loss on Physical Function with Changes in Strength, Muscle Mass, and Muscle Fat Infiltration in Overweight to Moderately Obese Older Adults: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Adam J. Santanasto

    2011-01-01

    Full Text Available Purpose. Evaluate the effects of weight loss on muscle mass and area, muscle fat infiltration, strength, and their association with physical function. Methods. Thirty-six overweight to moderately obese, sedentary older adults were randomized into either a physical activity plus weight loss (PA+WL or physical activity plus successful aging health education (PA+SA program. Measurements included body composition by dual-energy X-ray absorptiometry, computerized tomography, knee extensor strength, and short physical performance battery (SPPB. Results. At 6 months, PA+WL lost greater thigh fat and muscle area compared to PA+SA. PA+WL lost 12.4% strength; PA+SA lost 1.0%. Muscle fat infiltration decreased significantly in PA+WL and PA+SA. Thigh fat area decreased 6-fold in comparison to lean area in PA+WL. Change in total SPPB score was strongly inversely correlated with change in fat but not with change in lean or strength. Conclusion. Weight loss resulted in additional improvements in function over exercise alone, primarily due to loss of body fat.

  7. Ballistic Studies on TiB2-Ti Functionally Graded Armor Ceramics

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2012-11-01

    Full Text Available The objective of this paper is to discuss the results of the ballistic testing of the spark plasma sintered TiB2-Ti based functionally graded materials (FGMs with an aim to assess their performance in defeating small-calibre armor piercing projectiles. We studied the efficacy of FGM design and compared its ballistic properties with those of TiB2-based composites as well as other competing ceramic armors. The ballistic properties are critically analyzed in terms of depth of penetration, ballistic efficiency, fractographs of fractured surfaces as well as quantification of the shattered ceramic fragments. It was found that all the investigated ceramic compositions exhibit ballistic efficiency (η of 5.1 -5.9. We also found that by increasing the thickness of FGM from 5mm to 7.8 mm, the ballistic property of the composite degraded. On comparing the results with available armor systems, it has been concluded that TiB2 based composites show better ballistic properties except B4C. SEM analysis of the fragments showed that the FGM fractured by mixed mode of failure.Defence Science Journal, 2012, 62(6, pp.382-389, DOI:http://dx.doi.org/10.14429/dsj.62.2666

  8. Scanning electron microscope analysis of gunshot defects to bone: an underutilized source of information on ballistic trauma.

    Science.gov (United States)

    Rickman, John M; Smith, Martin J

    2014-11-01

    Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurus scapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguish SP from FMJ lesions. SEM analysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma.

  9. Effects of relative humidity and ambient temperature on the ballistic delivery of micro-particles to excised porcine skin.

    Science.gov (United States)

    Kendall, Mark; Rishworth, Stephen; Carter, Fiona; Mitchell, Thomas

    2004-03-01

    The effectiveness of ballistic particle delivery to the skin is often dependent upon breaching the stratum corneum (SC) and targeting cells within defined layers of the viable epidermis. This paper experimentally determines the influence of relative humidity (RH) and temperature on the ballistic delivery of particles to the skin. Gold particles of radius 0.9+/-0.6 microm were accelerated by a hand-held supersonic device to impact freshly excised porcine skin at 410-665 m per s. Increasing the RH from 15% to 95% (temperature at 25 degrees C) led to a particle penetration increase by a factor of 1.8. Temperature increases from 20 degrees C to 40 degrees C (RH at 15%) enhanced particle penetration 2-fold. In both cases, these increases were sufficient to move the target layer from the SC to the viable epidermis. Relative trends in particle penetration compared well with predictions from a theoretical model well. Calculated absolute penetration depths are 6-fold greater than the measurements. The inversely calculated dynamic yield stress of the SC is up to a factor of 10 higher than reported quasi-static measurements, due to changes in tissue failure modes over a strain-rate range spanning 10 orders of magnitude. If targeted particle delivery is required, it is recommended that the environmental RH and temperature be monitored.

  10. Modeling of ballistic and trapping effects on the collection efficiency of holes and electrons separately for a planar mercuric iodide detector (HgI2

    Directory of Open Access Journals (Sweden)

    Cedric E. Beogo

    2016-07-01

    Full Text Available For the room temperature nuclear detector application, signal created in the detector depends not only to the energy of the incident photon but also to the position of the interaction. This can bring an incomplete charge collection caused by a deep-trapping or a ballistic deficit of charge carrier. Many scientists used to demonstrate their impact on the global efficiency of the charge collection. Here we show this effect, not globally but separately, according to the position where holes and electrons are created. It permits us to see the contribution of each kind of carrier in the signal formation. An analytical model of charge collection is developed firstly to take into account the deep-trapping only. Secondly, this model is improved adding the ballistic deficit effect. The deep-trapping contributes to reduce the efficiency of hole above all on thicker detector. In the other part, ballistic deficit reduce electron efficiency above all near anode in the negatively polarized detector.

  11. 基于TOPSIS的战区高层反导威胁评估%Threat Assessment of the High Altitude Area Ballistic Missile Defense Based on TOPSIS

    Institute of Scientific and Technical Information of China (English)

    范学渊; 邢清华; 黄沛; 王小光

    2012-01-01

    Firstly, the characteristics of the high altitude area ballistic missile defense' s threat assessment are analyzed. Then the threat assessment's model index system is set up and quantitated, such as launch position of tactical ballistic missile (TBM) , forecasting impact point, range and so on. Finally, the theory of technique for order preference by similarity to idea solution (TOPSIS) based on weight of entropy is used to compute the model. The result shows that the threat assessment' s model and the algorithm is effective and useful for developing the battle manage of the high altitude area ballistic missile defense ' s.%在分析战区高层反导威胁评估特点的基础上,建立了以来袭TBM发射点、预测落点、射程等为核心的战区高层反导威胁评估模型指标体系并进行了相应的量化,然后利用基于熵值权重确定的TOPSIS理论对模型进行求解.通过实例证明所提出的战区高层反导威胁评估模型和算法的有效性,对研究美军的战区高层反导武器系统具有一定的借鉴意义.

  12. Room temperature ballistic transport in InSb quantum well nanodevices.

    Science.gov (United States)

    Gilbertson, A M; Kormányos, A; Buckle, P D; Fearn, M; Ashley, T; Lambert, C J; Solin, S A; Cohen, L F

    2011-12-12

    We report the room temperature observation of significant ballistic electron transport in shallow etched four-terminal mesoscopic devices fabricated on an InSb/AlInSb quantum well (QW) heterostructure with a crucial partitioned growth-buffer scheme. Ballistic electron transport is evidenced by a negative bend resistance signature which is quite clearly observed at 295 K and at current densities in excess of 10(6) A/cm(2). This demonstrates unequivocally that by using effective growth and processing strategies, room temperature ballistic effects can be exploited in InSb/AlInSb QWs at practical device dimensions.

  13. Enhanced Rectification Efficiency In Cascaded Ballistic GaAs/AlGaAs Rectifiers

    Science.gov (United States)

    Wieser, U.; Knop, M.; Koop, P.; Kunze, U.; Reuter, D.; Wieck, A. D.

    2007-04-01

    We report on an enhanced efficiency of inertial-ballistic rectification in a cascade of rectifier stages. Each rectifier stage is composed of a pair of current injecting branches which oppositely merge into a central voltage stem. The voltages obtained at both ends of the stem enable to separate inertial-ballistic and mode-controlled rectification. In a cascade composed of two rectifier stages the total inertial-ballistic signal is enhanced compared to the single contributions while the mode-controlled signal is almost unaffected.

  14. A discussion on the usefulness of a shared European ballistic image database.

    Science.gov (United States)

    De Ceuster, J; Hermsen, R; Mastaglio, M; Nennstiel, R

    2012-12-01

    The introduction of electronic systems into the comparison of weapon marks in the mid 1990s caused a revolution in the discipline of "forensic ballistics". Most European states now use this technology to search their national open case files. Globalisation of crime and the loss of effective border controls have made the idea of a unified European ballistic system seem logical. The article critically considers the requirements and possible outcomes of such a system. Based on the experience of forensic practitioners it seems probable that a shared European electronic ballistic system will be of a very limited value at present. Further improvements of existing systems to reach compatibility are encouraged.

  15. Performance Comparison of EKF/UKF/CKF for the Tracking of Ballistic Target

    Directory of Open Access Journals (Sweden)

    Wu Guang-bin

    2012-11-01

    Full Text Available This paper considers three well know nonlinear Kalman Filters for the tracking of a ballistic target. Extended Kalman Filter (EKF, Unscented Kalman Filter (UKF, and the Cubature Kalman Filter (CKF are applied for estimating the position, velocity and the ballistic coefficient of the ballistic target. The theory formulation and computer simulation has been done for the comparison of the three nonlinear Kalman Filters. Results show that all of them can accomplish the estimation task, but the UKF and CKF both have higher accuracy and less computation cost than the EKF.

  16. Closed vessel technique for assessment of ballistic characteristics in quality control of propellant manufacture

    Directory of Open Access Journals (Sweden)

    G. Siva Ramakrishnan

    1958-07-01

    Full Text Available "In order to assess the ballistic performance of a propellant it is necessary to measure its following characteristics: (aForce constant, (bvivacity, and (cshape. It is possible to determine (aand (bby the closed vessel technique which enables ballistic performance of the propellant in the gun to be estimated. It can be very usefully employed for quality control of propellant manufacture. As more and more experience is gained in the closed vessel technique these tests have several other possible practical applications such as those: (afor inspection of propellants, (bfor assessment of quality, (c to reduce proof in guns, and (dto check ballistics of a lot after long storage."

  17. Application of Extended Kalman Filter to Tactical Ballistic Missile Re-entry Problem

    CERN Document Server

    Bhowmik, Subrata

    2007-01-01

    The objective is to investigate the advantages and performance of Extended Kalman Filter for the estimation of non-linear system where linearization takes place about a trajectory that was continually updated with the state estimates resulting from the measurement. Here tactile ballistic missile Re-entry problem is taken as a nonlinear system model and Extended Kalman Filter technique is used to estimate the positions and velocities at the X and Y direction at different values of ballistic coefficients. The result shows that the method gives better estimation with the increase of ballistic coefficient.

  18. Ballistic Resistance of Armored Passenger Vehicles: Test Protocols and Quality Methods

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey M. Lacy; Robert E. Polk

    2005-07-01

    This guide establishes a test methodology for determining the overall ballistic resistance of the passenger compartment of assembled nontactical armored passenger vehicles (APVs). Because ballistic testing of every piece of every component of an armored vehicle is impractical, if not impossible, this guide describes a testing scheme based on statistical sampling of exposed component surface areas. Results from the test of the sampled points are combined to form a test score that reflects the probability of ballistic penetration into the passenger compartment of the vehicle.

  19. General-Service Ballistic Computer Programming Based on B-Method

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu-jun; ZHANG Zi-qiu; WANG Jin-quan; XUE Jin-yun

    2006-01-01

    Formal methods offer the promise of significant improvement on quality and reliability of critical embedded software. B-Method is employed to develop general-service ballistic computer programs in the paper, each of which can be adapted to a family of service/weapon-specific ballistic computers. Based on the structuring mechanisms of B-method, a unified approach is proposed to systematically control the complexity of ballistic parameters in the process of type and operation refinement, and ultimately a series of high reliable, reusable, and scalable programs are produced. Experiences with the application of the method and tools are also discussed.

  20. Comparison of magnetoresistances of triangular and rectangular ballistic graphene npn junctions

    Science.gov (United States)

    Morikawa, Sei; Masubuchi, Satroru; Watanabe, Kenji; Taniguchi, Takashi; Machida, Tomoki

    2016-10-01

    We compared the magnetotransport properties of ballistic graphene npn junctions with two different geometries. We found that a rectangular npn junction shows a positive magnetoresistance around zero magnetic field; this finding can be explained by the suppression of Klein tunneling in a finite magnetic field. In contrast, a triangular npn junction shows a negative magnetoresistance because the transmission is enhanced in a commensurability magnetic field where the ballistic carriers in a cyclotron motion are injected perpendicularly to both the np and pn interfaces. These results suggest possibilities for manipulating ballistic carrier trajectories through the designs of local-gate geometries.

  1. Comparison of Residual Strength Characteristics for Double and Single Hull Submarine Subjected to Impact Loading%单/双壳体潜艇结构耐撞剩余强度特性研究

    Institute of Scientific and Technical Information of China (English)

    梅志远; 李卓; 吕岩松

    2011-01-01

    单/双圆柱壳体结构是潜艇的两种典型结构形式.以单/双壳体潜艇典型结构为研究对象,分别设计初始深水静压强度相当的典型单/双耐压环肋圆柱壳体结构模型,基于MSC/Dytran罚函数接触算法,开展相同撞击强度载荷作用下结构模型耐撞动态响应特性分析,提取撞击后结构模型中耐压壳体结构的稳定变形位移场,作为MSC/Marc静强度求解的初始位移边界条件输入,通过有限元数值方法,对撞击后典型单/双结构耐压壳体结构的剩余强度特性进行比较分析.分析结果表明,当撞击载倚强度较低时,双壳模型的耐压壳体结构剩余强度较大,随着撞击载荷强度的不断增大,单/双壳结构耐压壳体结构的剩余强度将趋于一致,进一步提高撞击载荷强度,单壳体结构的剩余强度将高于双壳体结构.%The single and double hull are main types of submarine structure. In order to compare the residual strength characteristic of two type structures after impacted, the two type structure modes have been designed and used with same initial static strength. First, the dynamical response of this two structure modes under the same impact load was calculated based on FE eode-MSC/Dytran, then the residual displacement field was picked out, the static strength analysis was carried out based on FE code-MSC/Marc. The comparison analysis results show that the double hull structure have higher residual strength, when the collision load is low. However, with the impact load increased, the residual strength of this two types structure will correspond with each other.

  2. The Application of Erosive Burning to Propellant Charge Interior Ballistics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-lin

    2009-01-01

    Erosive burning is a common burning phenomenon of the gunpowder with inner holes. The actual combustion law of the gunpowder with inner holes can be changed by erosive burning. Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning. The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate, heat transfer and erosion of the combustion gas in inner holes on burning rate. The mathematic model of erosive burning of the propellant is established. The effects of the factors such as loading density, inner hole size and grain length on erosive burning and interior ballistic performance are analyzed .The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.

  3. Parametric Studies on Star Port Propellant Grain For Ballistic Evaluation

    Directory of Open Access Journals (Sweden)

    Himanshu Shekhar

    2005-10-01

    Full Text Available Star port propellant grains have been extensively studied for their operating as well as geometrical parameters. It is observed that reduced tail-off and better neutrality cannot be achieved simultaneously in a configuration. Parametric study is conducted to know the effect of various parameters of star-shaped propellant grains for ballistic evaluation motor. For reduced tail-off, higher characteristic velocity, lower outer diameter of the star, and lower value of angular fraction is preferred. Star angle, burning rate, and throat diameter have negligible effects on the tail-off factor. For better neutrality, higher value of angular  fraction, higher star outer diameter, and star angle near to neutrality, is needed. An alternate configuration is suggested using this parametric study to ascertain least tail-off and enhanced neutrality.

  4. Electron optics with p-n junctions in ballistic graphene

    Science.gov (United States)

    Chen, Shaowen; Han, Zheng; Elahi, Mirza M.; Habib, K. M. Masum; Wang, Lei; Wen, Bo; Gao, Yuanda; Taniguchi, Takashi; Watanabe, Kenji; Hone, James; Ghosh, Avik W.; Dean, Cory R.

    2016-09-01

    Electrons transmitted across a ballistic semiconductor junction are expected to undergo refraction, analogous to light rays across an optical boundary. In graphene, the linear dispersion and zero-gap band structure admit highly transparent p-n junctions by simple electrostatic gating. Here, we employ transverse magnetic focusing to probe the propagation of carriers across an electrostatically defined graphene junction. We find agreement with the predicted Snell’s law for electrons, including the observation of both positive and negative refraction. Resonant transmission across the p-n junction provides a direct measurement of the angle-dependent transmission coefficient. Comparing experimental data with simulations reveals the crucial role played by the effective junction width, providing guidance for future device design. Our results pave the way for realizing electron optics based on graphene p-n junctions.

  5. Steepest descent ballistic deposition of complex shaped particles

    Science.gov (United States)

    Topic, Nikola; Pöschel, Thorsten

    2016-03-01

    We present an efficient event-driven algorithm for sequential ballistic deposition of complex-shaped rigid particles. Each of the particles is constructed from hard spheres (typically 5 … 1000) of variable radii. The sizes and relative positions of the spheres may mutually overlap and can be chosen such that the surface of the resulting particle appears relatively smooth. In the sequential deposition process, by performing steps of rolling and linear motion, the particles move along the steepest descent in a landscape formed by the boundaries and previously deposited particles. The computer time for the simulation of a deposition process depends on the total number of spheres but only weakly on the sizes and shapes of the particles. The proposed algorithm generalizes the Visscher-Bolsterli algorithm [1] which is frequently used for packing of spheres, to non-spherical particles. The proposed event-driven algorithm allows simulations of multi-million particle systems using desktop computers.

  6. Study of surface charges in ballistic deflection transistors

    Science.gov (United States)

    Millithaler, J.-F.; Iñiguez-de-la-Torre, I.; Mateos, J.; GonzáIez, T.; Margala, M.

    2015-12-01

    This paper presents a comprehensive study of the behavior of surface charges in ballistic deflection transistors, at room temperature, where the in-plane geometry associating two drains with two gates in push-pull modes allows the control of electron path. Monte Carlo simulations were performed and compared with experimental data by using different models for accounting for surface charge effects. The simple model which assumes a constant and uniform value of the surface charge provides good results at equilibrium, but it is not able to correctly reproduce the BDT’s complex behavior when biased. We have confirmed that for a correct description of the device operation it is necessary to use a model allowing the surface charge to adapt itself locally to the carrier concentration in its surroundings.

  7. Semiclassical Quantization of Spinning Quasiparticles in Ballistic Josephson Junctions

    Science.gov (United States)

    Konschelle, François; Bergeret, F. Sebastián; Tokatly, Ilya V.

    2016-06-01

    A Josephson junction made of a generic magnetic material sandwiched between two conventional superconductors is studied in the ballistic semiclassic limit. The spectrum of Andreev bound states is obtained from the single valuedness of a particle-hole spinor over closed orbits generated by electron-hole reflections at the interfaces between superconducting and normal materials. The semiclassical quantization condition is shown to depend only on the angle mismatch between initial and final spin directions along such closed trajectories. For the demonstration, an Andreev-Wilson loop in the composite position-particle-hole-spin space is constructed and shown to depend on only two parameters, namely, a magnetic phase shift and a local precession axis for the spin. The details of the Andreev-Wilson loop can be extracted via measuring the spin-resolved density of states. A Josephson junction can thus be viewed as an analog computer of closed-path-ordered exponentials.

  8. Ballistic evaluationof LOVA propellant in high calibre gun

    Directory of Open Access Journals (Sweden)

    A.G.S. Pillai

    2001-04-01

    Full Text Available 'This paper presents the data obrained on dynamic firing of a cellulose acetate binder-based low vulnerability ammunition (LOV A propellant using 120 mm fin-stabilised armour piercing discarding sabot (FSAPDS kinetic energyammunition. An optimised propellant composition formulated ~sing fine RDX as an energetic ingredient and a mixture of cellulose acetate and nitrocellulose as binder was qualified fit for firing in a high calibre gun by its successful static evaluation for absolute ballistics using high pressure closed vessel technique. Dynamic firing of the propellant processed in heptatubular geometry was undertaken to assess the propellant charge mass. This propellant achieved higher muzzle velocity as compared to the standard NQ/M119 triple-base propellant while meeting the non-vulnerability characteristics convincingly.

  9. Interacting electrons in ballistic conformal billiard quantum dots

    Science.gov (United States)

    Murthy, Ganpathy; Mathur, Harsh; Shankar, Ramamurti

    2004-03-01

    Interacting electrons in a ballistic quantum dot present a novel regime of disorder + interactions. An instability of the ground state towards a spontaneous deformation of the Fermi surface (the Pomeranchuk transition) has been found by the present authors[1], by assuming that Random Matrix Theory describes the states in the Thouless shell near the Fermi energy. However, the question of whether the mesoscopic transition occurs before the bulk transition remains open[2]. Here we describe calculations on the conformal billiard[3] and attempt to see how well RMT assumptions hold, and to what extent the physics of the transition is described by our previous work. 1. G. Murthy, R. Shankar, D. Herman, and H. Mathur, cond-mat/0306529. 2. S. Adam, P. W. Brouwer, and P. Sharma, cond-mat/0309074. 3. M. V. Berry and M. Robnik, J. Phys. A19, 669 (1986).

  10. Ballistic gelatin as a putative substrate for EEG phantom devices

    CERN Document Server

    Hairston, W David; Yu, Alfred B

    2016-01-01

    Phantom devices allow the human variable to be controlled for in order to allow clear comparison and validation of biomedical imaging hardware and software. There is currently no standard phantom for electroencephalography (EEG). To be useful, such a device would need to: (a) accurately recreate the real and imaginary components of scalp electrical impedance, (b) contain internal emitters to create electrical dipoles, and (c) be easily replicable across various labs and research groups. Cost-effective materials, which are conductive, repeatable, and easily formed are a missing key enabler for EEG phantoms. Here, we explore the use of ballistics gelatin, an inexpensive, easily-formable and repeatable material, as a putative substrate by examining its electrical properties and physical stability over time. We show that varied concentrations of NaCl salt relative to gelatin powder shifts the phase/frequency response profile, allowing for selective tuning of the material electrical properties.

  11. Great Balls of Fire: A probabilistic approach to quantify the hazard related to ballistics - A case study at La Fossa volcano, Vulcano Island, Italy

    Science.gov (United States)

    Biass, Sébastien; Falcone, Jean-Luc; Bonadonna, Costanza; Di Traglia, Federico; Pistolesi, Marco; Rosi, Mauro; Lestuzzi, Pierino

    2016-10-01

    We present a probabilistic approach to quantify the hazard posed by volcanic ballistic projectiles (VBP) and their potential impact on the built environment. A model named Great Balls of Fire (GBF) is introduced to describe ballistic trajectories of VBPs accounting for a variable drag coefficient and topography. It relies on input parameters easily identifiable in the field and is designed to model large numbers of VBPs stochastically. Associated functions come with the GBF code to post-process model outputs into a comprehensive probabilistic hazard assessment for VBP impacts. Outcomes include probability maps to exceed given thresholds of kinetic energies at impact, hazard curves and probabilistic isoenergy maps. Probabilities are calculated either on equally-sized pixels or zones of interest. The approach is calibrated, validated and applied to La Fossa volcano, Vulcano Island (Italy). We constructed a generic eruption scenario based on stratigraphic studies and numerical inversions of the 1888-1890 long-lasting Vulcanian cycle of La Fossa. Results suggest a ~ 10- 2% probability of occurrence of VBP impacts with kinetic energies ≤ 104 J at the touristic locality of Porto. In parallel, the vulnerability to roof perforation was estimated by combining field observations and published literature, allowing for a first estimate of the potential impact of VBPs during future Vulcanian eruptions. Results indicate a high physical vulnerability to the VBP hazard, and, consequently, half of the building stock having a ≥ 2.5 × 10- 3% probability of roof perforation.

  12. Comparative study of Gamow-Teller strength distributions in the odd-odd nucleus 50V and its impact on electron capture rates in astrophysical environments

    CERN Document Server

    Nabi, Jameel-Un; 10.1103/PhysRevC.76.055803

    2011-01-01

    Gamow-Teller (GT) strength transitions are an ideal probe for testing nuclear structure models. In addition to nuclear structure, GT transitions in nuclei directly affect the early phases of Type Ia and Type-II supernovae core collapse since the electron capture rates are partly determined by these GT transitions. In astrophysics, GT transitions provide an important input for model calculations and element formation during the explosive phase of a massive star at the end of its life-time. Recent nucleosynthesis calculations show that odd-odd and odd-A nuclei cause the largest contribution in the rate of change of lepton-to-baryon ratio. In the present manuscript, we have calculated the GT strength distributions and electron capture rates for odd-odd nucleus 50V by using the pn-QRPA theory. At present 50V is the first experimentally available odd-odd nucleus in fp-shell nuclei. We also compare our GT strength distribution with the recently measured results of a 50V(d,2He)50Ti experiment, with the earlier work ...

  13. Ballistic heat transport in laser generated nano-bubbles

    Science.gov (United States)

    Lombard, Julien; Biben, Thierry; Merabia, Samy

    2016-08-01

    Nanobubbles generated by laser heated plasmonic nanoparticles are of interest for biomedical and energy harvesting applications. Of utmost importance is the maximal size of these transient bubbles. Here, we report hydrodynamic phase field simulations of the dynamics of laser induced nanobubbles, with the aim to understand which physical processes govern their maximal size. We show that the nanobubble maximal size and lifetime are to a large extent controlled by the ballistic thermal flux which is present inside the bubble. Taking into account this thermal flux, we can reproduce the fluence dependence of the maximal nanobubble radius as reported experimentally. We also discuss the influence of the laser pulse duration on the number of nanobubbles generated and their maximal size. These studies represent a significant step toward the optimization of the nanobubble size, which is of crucial importance for photothermal cancer therapy applications.Nanobubbles generated by laser heated plasmonic nanoparticles are of interest for biomedical and energy harvesting applications. Of utmost importance is the maximal size of these transient bubbles. Here, we report hydrodynamic phase field simulations of the dynamics of laser induced nanobubbles, with the aim to understand which physical processes govern their maximal size. We show that the nanobubble maximal size and lifetime are to a large extent controlled by the ballistic thermal flux which is present inside the bubble. Taking into account this thermal flux, we can reproduce the fluence dependence of the maximal nanobubble radius as reported experimentally. We also discuss the influence of the laser pulse duration on the number of nanobubbles generated and their maximal size. These studies represent a significant step toward the optimization of the nanobubble size, which is of crucial importance for photothermal cancer therapy applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/C6NR02144A

  14. Manganese oxalate nanorods as ballistic modifier for composite solid propellants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Supriya [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India); Chawla, Mohit [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Siril, Prem Felix, E-mail: prem@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India)

    2014-12-10

    Highlights: • Manganese oxalate nanorods were prepared using mild thermal precipitation and aging. • The nanorods were found to be efficient ballistic modifier for solid propellants. • The nanorods sensitized the thermolysis of ammonium perchlorate. • Controlled thermal decomposition of nanorods yielded manganese oxide nanoparticles. • MnO nanoparticles formed insitu in the condensed phase enhance the burning rates. - Abstract: Rod-shaped nanostructures of manganese oxalate (MnC{sub 2}O{sub 4}) were synthesized via mild thermal precipitation and aging process. Chemical composition of the MnC{sub 2}O{sub 4} nanorods was confirmed using Fourier transform infra-red (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and selected area electron diffraction (SAED) studies revealed the crystal structure. Field emission scanning electron microscopy (FE-SEM) imaging and high resolution transmission electron microscopy (HR-TEM) were employed to study the structural features of the nanorods. The MnC{sub 2}O{sub 4} nanorods were found to be efficient ballistic modifier for the burning rate enhancement of composite solid propellants (CSPs). Thermal analysis using TGA-DSC showed that MnC{sub 2}O{sub 4} nanorods sensitized the thermal decomposition of ammonium perchlorate (AP) and the CSPs. Controlled thermal decomposition of the MnC{sub 2}O{sub 4} nanorods resulted in the formation of managanese oxide nanoparticles with mesoporosity. A plausible mechanism for the burning rate enhancement using MnC{sub 2}O{sub 4} nanorods was proposed.

  15. Molecular dynamics simulations of ballistic He penetration into W fuzz

    Science.gov (United States)

    Klaver, T. P. C.; Nordlund, K.; Morgan, T. W.; Westerhof, E.; Thijsse, B. J.; van de Sanden, M. C. M.

    2016-12-01

    Results are presented of large-scale Molecular Dynamics simulations of low-energy He bombardment of W nanorods, or so-called ‘fuzz’ structures. The goal of these simulations is to see if ballistic He penetration through W fuzz offers a more realistic scenario for how He moves through fuzz layers than He diffusion through fuzz nanorods. Instead of trying to grow a fuzz layer starting from a flat piece of bulk W, a new approach of creating a fully formed fuzz structure 0.43 µm thick out of ellipsoidal pieces of W is employed. Lack of detailed experimental knowledge of the 3D structure of fuzz is dealt with by simulating He bombardment on five different structures of 15 vol% W and determining the variation in He penetration for each case. The results show that by far the most important factor determining He penetration is the amount of open channels through which He ions can travel unimpeded. For a more or less even W density distribution He penetration into fuzz falls off exponentially with distance and can thus be described by a ‘half depth’. In a 15 vol% fuzz structure, the half depth can reach 0.18 µm. In the far sparser fuzz structures that were recently reported, the half depth might be 1 µm or more. This means that ballistic He penetration offers a more likely scenario than He diffusion through nanorods for how He moves through fuzz and may provide an adequate explanation for how He penetrates through the thickest fuzz layers reported so far. Furthermore, the exponential decrease in penetration with depth would follow a logarithmic dependence on fluence which is compatible with experiments. A comparison of these results and molecular dynamics calculations carried out in the recoil interaction approximation shows that results for W fuzz are qualitatively very different from conventional stopping power calculations on W with a similarly low but homogeneous density distribution.

  16. 芯壳结构竹塑复合材料断口冲击强度的分形表征%Fractal characterization of impact strength fracture of bamboo plastic composites with core-shell structure

    Institute of Scientific and Technical Information of China (English)

    羡瑜; 王翠翠; 王戈; 程海涛

    2015-01-01

    为了定量表征不同壳层材料对芯壳结构竹塑复合材料冲击断口复杂程度的影响,以造纸剩余物竹屑和高密度聚乙烯(high density polyethylene,HDPE)作为芯层材料,以纯HDPE、竹浆纤维/HDPE、纳米碳酸钙/HDPE和白泥/HDPE分别作为壳层材料,采用熔融共挤工艺制备芯壳结构竹塑复合材料。在室温(23℃)环境下,测试了复合材料无缺口冲击强度,采用扫描电镜对4种不同壳层材料断口进行形貌分析,基于分形理论和图像处理技术,运用像素点法计算了复合材料的冲击断口表面分形维数,考察了复合材料断口表面分形维数和冲击强度的关系。结果表明,不同壳层材料的芯壳结构竹塑复合材料冲击断口表面分形维数存在一定差异,壳层为HDPE的复合材料断口表面分形维数最大,为2.2204,壳层为白泥/ HDPE的分形维数最小,为2.2075。不同壳层复合材料冲击断口表面分形维数拟合曲线的决定系数均大于0.98,说明复合材料断口表面分形特征显著。并且,复合材料断口表面分形维数与冲击强度之间拟合曲线的决定系数为0.9857,近似呈指数函数关系。研究结果为进一步深入研究芯壳结构竹塑复合材料的表面微观结构提供参考。%In order to study the rupture mechanism of the bamboo plastic composites (BPCs) with core-shell structure, in this paper bamboo residue fibers and high density polyethylene (HDPE) were used as materials of core layer; HDPE, bamboo pulp fibers/HDPE, nano-CaCO3/HDPE and white mud/HDPE, were respectively used as materials of shell layer to manufacture the BPCs with core-shell structure by coextrusion technology. The ratios of bamboo pulp fibers, nano-CaCO3 and white mud to HDPE in the shell layer structure were to be 10:90 respectively. To present the theoretical relationship between fractal dimensions (D) and the impact strength (δ), and analyze the effects

  17. Compare and Contrast the Strengths and Weaknesses of Task-based Language Teaching Method and Audio Lingual Teaching Method and Study How They Impact Upon Both the Teachers and the Learners

    Institute of Scientific and Technical Information of China (English)

    曹怡之

    2013-01-01

    This essay focused on comparing and contrasts audio lingual method and Task-based language teaching method, demonstrating the strengths and weaknesses of the two methods and discusses how they impact upon both the teachers and the learners. TBLT is the contemporary teaching method with a great number of strong points. It seems that if there is more relatively scientific and effective method, TBLT should give way to it. The ultimate goal is to advocate the comparatively successful teaching method in the field of foreign language education.

  18. Ultrahigh-Strength Magnesium Alloys for the Future Force: A Final Report on the 5-Year Mission Program, 2009-2013

    Science.gov (United States)

    2014-01-01

    microhardness across the diameter of a ZK60 sample produced via HPT...Photos of the ballistic tested samples are given in (b) as received, (c) texture A, and (d) texture C conditions. The top row of photos is the front of... test results indicating the significant increase in bond strength between Mg and UHMWPE following atmospheric plasma treatment (b

  19. LOW-VELOCITY IMPACT CHARACTERISTICS AND COMPRESSIVE STRENGTH AFTER IMPACT OF PLAIN WOVEN CARBON FIBER REINFORCED SILICON CARBIDE COMPOSITES%平纹编织碳纤维增强碳化硅复合材料低速冲击特性及冲击后的压缩强度

    Institute of Scientific and Technical Information of China (English)

    程起有; 童小燕; 陈刘定; 姚磊江; 李斌

    2009-01-01

    采用落锤冲击试验系统对平纹编织碳纤维增强碳化硅复合材料平板试样进行低速冲击,冲击能量为1.5~9J.冲击试验后,采用超声C扫描得到冲击损伤的大小.对含冲击损伤的试样进行压缩试验,通过与未冲击试样的压缩强度比较,得到冲击试样的剩余压缩强度.并对比了编织陶瓷基复合材料和树脂基复合材料的损伤阻抗和损伤容限.结果显示:随着冲击能量的增加,冲击力峰值、复合材料损伤面积和凹坑深度明显增加,到达峰值冲击力的时间减小.冲击能量的增加会导致冲击损伤面积的增加,而损伤面积的增加会导致剩余压缩强度的明显降低.相对于编织纤维增强树脂基复合材料,编织纤维增强陶瓷基复合材料的损伤阻抗较低,但损伤容限较高.%An experimental study was carried out to investigate the low-velocity impact characteristics and the strength after impact of plain woven carbon fiber reinforced silicon carbide composite.The test specimens were impacted using a dropped.weight impact test apparatus with an instrumented spherical tip.Non-destructive test methods were then utilized to characterize and quantify the impact damage.The residual compressive strengths of composites after impact were determined.The impact damage resistance and tolerance of woven fiber-reinforced ceramic.matrix composite were compared with those of woven fiber-reinforced polymer-matrix composite.The resuits show that a circular indentation on the impacted surface of specimens is formed in the impact.The peak load and the diameter and depth of indentation increase with the increase of the impact energy.The time reached to impact the peak load decrease with the increase of impact energy.According to observation of optical photographs and the image characteristics of samples obtained by ultrasonic C-scan after impact,the impact damage areas increase with the increase of impact energy.With the increase of impact

  20. Radar signal analysis of ballistic missile with micro-motion based on time-frequency distribution

    Science.gov (United States)

    Wang, Jianming; Liu, Lihua; Yu, Hua

    2015-12-01

    The micro-motion of ballistic missile targets induces micro-Doppler modulation on the radar return signal, which is a unique feature for the warhead discrimination during flight. In order to extract the micro-Doppler feature of ballistic missile targets, time-frequency analysis is employed to process the micro-Doppler modulated time-varying radar signal. The images of time-frequency distribution (TFD) reveal the micro-Doppler modulation characteristic very well. However, there are many existing time-frequency analysis methods to generate the time-frequency distribution images, including the short-time Fourier transform (STFT), Wigner distribution (WD) and Cohen class distribution, etc. Under the background of ballistic missile defence, the paper aims at working out an effective time-frequency analysis method for ballistic missile warhead discrimination from the decoys.