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Dulgheriu I.,Technical University Gheorghe Asachi | Avadanei M.,Technical University Gheorghe Asachi | Badea S.,Scientific Research Center for Defense and Ecology | Safta I.,Scientific Research Center for Defense and Ecology
Industria Textila | Year: 2012

A great potential direction of development is the structures design for ballistic protection. Significant progress achieved by scientists, designers and manufacturers of advanced materials, used for individual ballistic protection, allowed, at this level, the competition revival, between projectile and armor. The paper presents the way of achieving and testing 6 variants of ballistic packages made of Kevlar laminate fabric, Kevlar XP and metallic fabric, within the Testing Laboratory for Ballistic and Pyrotechnic Protection of the Scientific Research Center for CBRN Defense and Ecology.

Yan Q.-L.,Tel Aviv University | Trzcinski W.A.,Military University of Technology | Cudzilo S.,Military University of Technology | Paszula J.,Military University of Technology | And 4 more authors.
Combustion and Flame | Year: 2016

Conceptually new cylindrical charges enveloped by Al foils have been designed and their thermobaric effects, due to simultaneous fragmentation and combustion of the foils, have been experimentally determined. The fragmentation processes of Al foil was supported by numerical simulations. It has been shown that the quasistatic pressures (QSP) for phlegmatized RDX (RDXph) enveloped with Al-coated plastic foils are higher than that of the pure RDXph, due to combustion of these foil fragments in a thermobaric explosion. The QSP generated by Al-Ni foils enveloping RDXph was found to be much lower than performance of other foils, possibly due to relatively inert nature of Ni. In a small detonation chamber, the charges of RDXph/Al foil (RDXph/Alf) produced even higher experimental maximum peak pressure (δpmax) than the charges that contained Al powder (Alp). In a closed bunker, the impulse amplitudes of RDXph enveloped by aluminized polyethylene (Al-PE) foils and RDXph enveloped by 100μm Alf (Alf100) charges are much lower than those of the other charges. It was found that the charges enveloped by Al foils have even larger δpmax than that of RDXph/Alp charges, indicating that the Alf could generate better blast performances than the Alp. The simulations indicate that the observed blast enhancement is dependent not on the thickness, but on the size of surrounding space. The thermobaric fire-ball generated by 40g RDX/Alf charge could sustain combustion up to 40ms, reaching a maximum radius of about 2.4m. © 2016 The Combustion Institute.

Pirvu C.,Tncas Bucharest | Georgescu C.,University of Galati | Badea S.,Scientific Research Center for Defense and Ecology | Deleanu L.,University of Galati
IOP Conference Series: Materials Science and Engineering | Year: 2016

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. © Published under licence by IOP Publishing Ltd.

Pirvu C.,University of Galati | Badea S.,Scientific Research Center for Defense and Ecology | Deleanu L.,University of Galati
Applied Mechanics and Materials | Year: 2014

This paper presents a simulation of a bullet impact on a plate, all materials being assigned to a bilinear isotropic hardening model. The developed model takes into account the yield and fracture limits of both involved materials for the bullet and the plate one. The model was developed with the help of Ansys 14.5 and could be used to establish a theoretical value of the plate thickness that will offer protection to the bullet penetration in order to minimize the number of laboratory tests for evaluating the plate resistance. The authors presented the influence of impact velocity of the bullet. The bullet velocity just reaching the plate is an essential parameter influencing the plate integrity. Also, the authors established a correlation between the evolution of the theoretical maximum von Mises stresses and the stages taking place during the impact. © (2014) Trans Tech Publications, Switzerland.

Pirvu C.,Incas Bucharest | Deleanu L.,Incas Bucharest | Lazaroaie C.,Scientific Research Center for Defense and Ecology
IOP Conference Series: Materials Science and Engineering | Year: 2016

Ballistic experiments are fundamental for body armor new products and help to identify key factors influencing the damage processes of sophisticated materials these armors are made of. Tests made on packs made of LFT SB1 according to Ballistic Resistance of Body Armor NIJ Standard-0101.06-2008 gave good results for the packs made of 24 layers of this fabric and the backface signature (BFS - the depth of the deformation generated in the support material - ballistic clay) was measured. The average value of 23.11 mm recommends this system for protection level of II and IIA, according to the above-mentioned standard. Macro photography investigations pointed out the penetration process in both slim pack (with total penetration) and thick packs (with partial penetration). © Published under licence by IOP Publishing Ltd.

Rotariu A.-N.,Military Technical Academy | Lixandru P.,PILOTARM Ltd. | Matache L.-C.,Scientific Research Center for Defense and Ecology | Enache C.,Military Technical Academy | Zecheru T.,Scientific Research Center for Defense and Ecology
Journal of Materials Processing Technology | Year: 2014

In order to test and evaluate the drawing efficiency of 6082 0 temper aluminium alloy for cartridge tubes, both experimental and numerical analyses were conducted. The theoretical assessment validation was performed by overlapping the graph of stress triaxiality ratio vs. plastic strain and the graph of 6082 0 temper aluminium alloy fracture envelope for a zero Lode parameter. The numerical simulation in Ls-Dyna® gave the stress triaxiality ratio vs. plastic strain correlation. With the view to defining the constitutive material model and fracture envelope, both experimental determinations and numerical simulations for plane stress and plane strain specimens were performed (tensile, shear and compression tests for various samples). The simulation results were compared with the experimental observations. The possibility of using the concept of triaxiality for a constant Lode parameter and an isotropic elastic/plastic material model in the field of drawing was also considered. © 2014 Elsevier B.V. All rights reserved.

Iordache P.Z.,Scientific Research Center for Defense and Ecology | Lungu R.M.,Scientific Research Center for Defense and Ecology | Safta I.,Scientific Research Center for Defense and Ecology
RSC Advances | Year: 2012

This work reports the fabrication of a novel functionalized nanocomposite material capable of reticulation, degradation and the efficient encapsulation of very toxic organic compounds and their degradation by-products. The degradation and encapsulation efficiency was investigated by testing our material on (RS)-O-isopropyl methylphosphonofluoridate (GB), 2,2′-dichlorodiethyl sulfide (HD) and dimethyl methylphosphonate (DMMP). The morphological and morphochemical structure was investigated by means of TEM, SEM and EDX spectrometry. Likewise, the functional structure of the material and the degradation and encapsulation efficiency of toxic compounds and their degradation by-products were elucidated by means of IR spectrometry and gas chromatography coupled with mass spectrometry (GC-MS). It has been found that our fabricated nanocomposite shows a highly structural and functional stability, without counting residual traces of toxic compounds, degradation by-products or molecular fragments coming from degradation samples or from the internal structure of nanocomposite framework. Moreover, experimental evidence proves that our nanocomposite is able to degrade and encapsulate all toxic compounds and all their degradation by-products in less than 16, 5.35, 1 min (in the case of HD, GB and DMMP, respectively), both by catalytic and reticulation processes. We also formulated mechanisms for the degradation and encapsulation of tested toxic compounds and their intermediary by-products in the presence of functionalized substrate. We found that chemically active molecular clusters and Brønsted-Lewis sites coming from the composite framework catalyze the degradation processes. Moreover, we found that grafted functionalities, uncoordinated and unbound metal atoms and metal ion sites play a significant role in reticulation and encapsulation processes. © The Royal Society of Chemistry 2012.

Petre R.,Scientific Research Center for Defense and Ecology | Hubca G.,Polytechnic University of Bucharest
UPB Scientific Bulletin, Series B: Chemistry and Materials Science | Year: 2013

The main results of the present study reside in the development of an original laboratory technology for the luminol synthesis and its intermediaries: α-nitronaphthalene, 3-nitrophthalic acid, and 3-nitrophthalhydrazide. The total chromatograms and the mass spectra have been compared with a Merck reference luminol. The advantages of this technology are: the synthesized luminol presents a higher purity against the standard and is costly available.

Zecheru T.,Scientific Research Center for Defense and Ecology | Zecheru T.,Military Technical Academy | Lungu A.,Polytechnic University of Bucharest | Iordache P.-Z.,Scientific Research Center for Defense and Ecology | Rotariu T.,Military Technical Academy
Combustion, Explosion and Shock Waves | Year: 2013

Studies on specific thermochemical processes contribute to the understanding of combustion processes and, meanwhile, to the calculus of the safety characteristics and the systems design parameters. In this paper, five different compositions have been studied through TGA and DTA. The reaction rate constants and the activation energies have been determined. Also, the solid combustion products obtained have been evaluated through SEM, EDX, and XPS. Nonisothermal kinetic analyses performed yield results that prove an important difference among the first fire compositions, where the activation energies are considerable, up to 400 kJ/mol, in comparison with the activation energies of the flare compositions, which are lower, 150-250 kJ/mol. © 2013 Pleiades Publishing, Ltd.

PubMed | Scientific Research Center for Defense and Ecology, Military Technical Academy and Polytechnic University of Bucharest
Type: | Journal: Forensic science international | Year: 2016

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.

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