Wyniki wyszukiwania - BazTech

1

Study on Low-Velocity Impact Behavior of Twaron® Fabric Subjected to Double-Impactor Impact from a Numerical Analysis Perspective

Huang Canyi, Cui Lina, Qiu Yiping, Liu Yajun

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 1

38--51

EN

In the present study, a finite element impact model was developed and analyzed using commercial FEM code ANSYS® and then validated via a drop-weight impact experiment. Moreover, double-impactor impact models were designed and developed with different impact distribution and locations of two impactors to compare impact properties. A total of 18 impact scenarios comprised of asymmetric and symmetric types were performed. The effect of impact location on the impact resistance force and duration time was investigated: the closer the impact point is to the fabric center, the longer the impact duration time. In addition, the effect of impact location on impactor failure deflection was also investigated and it was concluded that regardless of the symmetric or asymmetric impact scenario, the smaller the average distance between the impact location of the two impactors from the fixed boundary, the smaller the overall average failure deflection that occurs. The relevance of impact location and fabric energy absorption capacity was also identified. Furthermore, the effect of impact location on fabric stress distribution and transverse deformation and of the variation of the impact velocity on fabric impact behaviors were investigated. These findings will provide important guidance for engineering soft body armor and composite materials.

2

Low-velocity impact performance of UHMWPE composites consolidated with carbide particles

Gürgen Selim

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 2

112--123

EN

Ultra-high molecular weight polyethylene (UHMWPE) is one of important materials utilized against impacting threats. In this work, bulk UHMWPE specimens were fabricated in a compression molding chamber, and molding parameters such as pressure and temperature were varied in the specimen preparation stage to investigate the effect of molding parameters on the impact performance. In addition, silicon carbide fillers were included in the UHMWPE matrix to enhance the anti-impact properties of the specimens. From the results, high molding pressure provides enhanced impact resistance due to improved microstructural consolidation. On the other hand, molding temperature just above the melting point of polymer is much beneficial to the anti-impact behavior of the structures. Carbide fillers lead to an increase in the frictional interaction between the impactor and composites and thereby enhancing the impact resistance of the structures. However, the gain in the protective properties performance is restricted up to a certain amount of carbide loading because at higher filler ratios, the composites change from ductile to brittle characteristics. For this reason, crack growth susceptibility develops in the composites at excessive carbide loadings.

3

Experimental analysis of puncture resistance of aramid laminates on styrene-butadiene-styrene and epoxy resin matrix for ballistic applications

Pach Joanna, Mayer Paulina, Jamroziak Krzysztof, Polak Sławomir, Pyka Dariusz

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1327--1337

EN

The work aimed to evaluate the influence of the type of matrix and the number of reinforcement layers on the puncture of aramid laminates. The samples were examined under laboratory conditions and in ballistic tests. Two series of aramid laminates were produced with different types of the polymer matrix. The epoxy resin (EP) and the styrene-butadiene-styrene (SBS) copolymer were used as the matrix. For comparison, a puncture test was performed for the fabric with the same number of layers in contrast to the laminates. Laboratory tests were carried out using the InstronDynatup 9250 HV drop hammer. The results obtained during the laboratory and ballistic examinations were compared. The samples were fired with a 9 - 19 mm Parabellum projectile. Research into the low-velocity range have shown that SBS laminates absorb impact energy more effectively than epoxy resin ones, but they are similar to fabrics without a polymer matrix. The results of ballistic tests are divergent and indicate that unbound materials are more efficient at absorbing energy than laminates. The reason for this is the different damage mechanisms.

4

Synthesis and Stab Resistance of Shear Thickening Fluid (STF) Impregnated Glass Fabric Composites

Yu K., Cao H., Qian K., Jiang L., Li H.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 6A (95)

126--128

EN

A shear thickening fluid (STF) was prepared successfully and its rheological behavior was investigated. Glass fabrics were soaked in STF/ethanol solution to prepare STF-glass fabric composites. The morphologies of the STF-glass fabric composites were observed by SEM. Quasi-static stab-resistant tests were carried out on both the neat glass fabrics and STF-glass fabric composites using a knife based on the areal density. The corresponding puncture and strengthen mechanisms were also investigated.

PL

Przygotowano ciecz gęstniejącą pod wpływem ścinania (STF) i zbadano jej właściwości reologiczne. Tkaniny z włókien szklanych były nasycane roztworem STF/etanol dla przygotowania kompozytów. Morfologię kompozytów badano za pomocą skaningowej mikroskopii elektronowej. Prowadzono quasi-statyczne badania na przebicie na tkaninach szklanych nienasączonych oraz na opracowanych kompozytach za pomocą noża o specjalnie zaprojektowanej konstrukcji. Niezależnie od testów porównawczych badano również mechanizm przebicia.

5

Gamma irradiation effect on polystyrene + SBR blends: morphology and microhardness

Brostow W., Castańo V. M., Martinez-Barrera G.

Polimery

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2005

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T. 50, nr 9

657-662

EN

Blends with 0, 5, 10 and 13 weight % of styrene/butadiene (SBR) copolymer embedded in a rigid polystyrene matrix were prepared. Microhardness was determined and morphology evaluated by scanning electron microscopy (SEM) before and after gamma irradiation. We relate the morphology to chemical structure and to composition of the SBRs as well as to irradiation dosages. We also connect the microhardness to the impact strength determined previously.

PL

Praca stanowi kontynuację badań opisanych w [5] i dotyczy takich samych kompozycji zawierających 5, 10 lub 13 % masowych kopolimeru styren/butadien (SBR) w matrycy polistyrenu (PS); stosowany SBR różnił się przy tym składem (57-75 % mas. butadienu) i charakterem struktury (gwiaździsta - S, liniowa - L, multiblokowa - MB - por. tabela 1). Wyniki badań mikrotwardości (rys. l i 2) i wcześniejszych pomiarów udarności [5] powiązano z ocenianą metodą elektronowej mikroskopii skaningowej (SEM) morfologią powierzchni próbek (rys. 3-12). Badano próbki nienapromieniane oraz napromieniane różnymi dawkami promieniowania g (do 250 kGy). Ustalono, że zwiększanie zawartości SBR w kompozycji oraz wzrost udziału butadienu w SBR (co polepszało udarność) na ogół pogarsza mikrotwardość. Interpretacja wyników badania morfologii powierzchni próbek przed i po napromienianiu pozwoliła na wyjaśnienie zaobserwowanego uprzednio wpływu struktury SBR, zawartości w nim butadienu oraz dawki promieniowania na udarność.