Tkaniny se zvýšenou odolností proti prořezání
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Tato práce je zaměřena konstrukci a hodnocení vlastností vrstvených textilních struktur s zvýšenou odolností proti pronikání nožů. Každá vrstva je tkaná textilie vyrobená z para-aramidového vlákna Twaron? se stejnou dostavou ve směru osnovy a útku. Je analyzována anizotropie odporu proti pronikání nože jedné i vice vrstev tkaniny. Orientace odporu proti pronikání je charakterizována úhlem penetrace nože (KPA) mezi osou řezání nožem a směrem osnovy tkaniny. Tento úhel byl měněn v pěti směrech řezu, tedy 0°; 22,5°; 45°; 67,5° a 90°. Byla zkoumána kvazi-statická odolnost proti pronikání nože (QSKPR) a dynamická odolnost proti pronikání nože (DSR) tkaninou. Základním cílem této práce je úprava povrchu vláken tak, aby se změnily jejich třecí vlastnosti. Výběr a aplikaci těchto úprav je třeba provést tak, aby nebyly negativně ovlivněny vlastnosti charakterizující komfort. Ze tří předběžně vytipovaných technik modifikace povrchu byly vybrány dvě, které byly detailně zkoumány. Jedná se o depozici oxidu křemičitého (SiO2) na povrch textilie, dále vystavení textilie působení ozónu spolu s depozicí SiO2 a depozici oxidu titaničitého (TiO2) na povrch textilie. Byly sledovány jednak mechanické vlastnosti upravené tkaniny, dále komfortní vlastnosti, odolnost proti bodání nožem a změny povrchu vláken.Byla vyvinuta nová metoda pro aplikaci SiO2 na povrch textilie s použitím vodního skla (WG) jako prekurzoru. Depozice SiO2 byla analyzována a potvrzená pomocí skenovací elektronové mikroskopie (SEM), infračervené spektroskopie s Fourierovou transformací (FTIR) a spektroskopie rentgenového spektra (EDX). Koncentrace Byla nalezena významná souvislost mezi koncentrací WG a růstem QSKPR. Při koncentrací 40% WG ke zvýšení QSKPR o více než 200%. Navíc se ukázalo, že pro neupravené tkaniny vykazuje QSKPR specifický průběh pro různá KPA. Depozice SiO2 na tkaninu zvýšila koeficient tření vláken v tkanině. Ukázalo se, že u upraveného vzorku je třeba vyšší síly k rozestoupení přízí v tkanině než u vzorku neupraveného. Zvýšení koeficientu tření vláken ve tkanině s deponovaným SiO2 bylo srovnatelné s tkaninou vystavenou působení ozónu s naneseným SiO2. Nicméně u tkanin s naneseným SiO2 byla zjištěna relativně vyšší ohybová tuhost.Bylo zjištěno, že kvazi-statické pronikání nože je silně ovlivněno interakcí osnovních a útkových nití, což bylo popsáno modelem na bázi Fourierovy funkce. Tento model se dobře hodí pro hodnocení kvazi-statického pronikání nože pro různé tkaniny. Bylo také ověřeno, že kvazi-statické pronikání nože je přímo úměrné součiniteli tření tkaniny a nepřímo úměrné vzdálenosti mezi nitěmi.Rozdíly v chování upravené a neupravené tkaniny při pronikání nože byly analyzovány pomocí CCD kamery během QSKPR měření. Bylo pozorováno, že klíčovou roli hraje profil nože. Tupá hrana nože zvyšuje odpor a na křivce tlakové síly způsobuje výrazný pík. Naopak po úplném proniknutí tupého kraje nože jsou jednotlivé nitě přeříznuty jedna za druhou. Lze konstatovat, že depozice částic SiO2 zvyšuje tření mezi vlákny uvnitř příze, a proto se vlákna v upravené přízi chovají jako jednolitá masa proti ostré hraně nože. Byl měřen odpor příze proti prokluzu, chování příze při řezání a síla nutná pro vytažení příze z tkaniny ve směru osnovy i útku v upravené a neupravené tkanině. Vyšší odolnost proti kvazi-statickému pronikání nože vykazuje osnova ve srovnání s útkem v obou textiliích (upravené i neupravené).QSKPR byla měřena také na dvou vrstvách orientovaných vzájemně pod různým úhlem kladení (SA) tj. 0°, 45° a 90°. Bylo zjištěno, že SA 45° vykazuje relativně lepší odolnost proti kvazi-statickému pronikání nože do tkaniny. Stejné vrstvy případ byly vyhodnoceny pomocí testu podle modifikované normy NIJ-0115.00. Bylo zjištěno, že 45° SA vykazuje izotropní odolnost proti kvazi-statickému pronikání nože ve všech KPA. Upravené textilní struktury vykazují dvakrát vyšší odolnost proti kvazi-statickému pronikání nože než neupravené.
This research focused on the stabbing response of woven fabrics. Woven fabric investigated in this work had an equal set of warp and weft Twaron? para-Aramid filament yarns. In this work, isotropy of single sheet and multiple-sheets stacked together was analyzed at different orientations of knife stabbing. During knife stabbing a knife penetration angle (KPA) is formed between the knife cutting axis and warp yarn of the fabric. The study was conducted at five different cutting angles i.e. 0°, 22.5°, 45°, 67.5°, and 90°. Quasi-static knife penetration resistance (QSKPR) and dynamic stab resistance (DSR) of the woven fabrics were studied in this work.The main objective of this research was to study the behavior of dry woven fabrics whose surface was modified to change their friction. The selection and application of these modifications were made in such a way to keep the comfort and flexibility characteristics minimally affected. We adopted three surface modification techniques; 1) SiO2 deposition, 2) Ozone treatment along with SiO2 deposition and 3) TiO2 deposition. Furthermore, the effect of treatment was characterized against surface topology, anti-stabbing behavior, mechanical, comfort and friction properties of developed fabrics. This research discovered a new method of SiO2 deposition, using Water Glass (WG) as a precursor. The deposition of SiO2 was investigated and confirmed using Scanning Electron Microscopy (SEM), Fourier Transfer Infra-Red (FTIR) spectroscopy, and Energy-Dispersive X-ray (EDX) spectroscopy. The concentration of WG showed the direct relation for an increase in QSKPR. At 40% solution of WG the QSKPR was observed about 200%. The QSKPR measured at 67.5° KPA for untreated fabric was found statistically significantly higher than the mean QSKPR measured for all KPAs. Moreover, the QSKPR seems to follow a specific pattern for different KPAs, irrespective of fabric treatment. The coefficient of friction of fabric surface was well improved by the deposition layer of SiO2. Hence, the yarn pull-out force was increased for treated fabrics as compared to untreated. It was also observed that, treatment with Ozone before depositing SiO2, reduces the adverse effect on comfort and flexibility characteristics of fabric. The quasi-static stabbing was found to be the complementary response to warp and weft yarns, due to their orthogonal orientation. This response was modelled with the Fourier function, that fits well to the quasi-static stab of different fabrics. It was also observed that the behaviour of this response is directly proportional to fabric's coefficient of friction and inversely proportional to the gap between yarns. The interaction of the knife and the fabric was recorded on CCD camera, during QSKPR measurements. It was observed that the shape of the knife profile plays a major role. The blunt edge of the knife finds maximum resistance and causes the major peak in the force-displacement curve. While after the complete penetration of blunt edge, individual yarns cut one by one. It is proposed that SiO2 deposition increases inter-fiber friction, as a result the filaments of the yarn behave as single assembly rather as individual filament against the sharp edge of the knife. Yarn sliding resistance, individual yarn cutting behaviour and yarn pull out force was measured for warp and weft directions of treated and untreated fabrics. It was found that the major response of stabbing resistance depends upon inter yarn friction, while intra-yarn friction accounts for penetration energy of individual yarn. QSKPR was measured for two sheets, oriented at three stacking angles (SA). The 45° SA was found to exhibit better isotropic response of QSKPR than 0°and 90° SA. A modified version of NIJ standard-0115.00 was followed to verify the dynamic stab resistance at 45° SA. It was found that 45° SA exhibits isotropic stab resistance in all KPAs. Furthermore, treated fabrics showed 200% higher stab resistance than
This research focused on the stabbing response of woven fabrics. Woven fabric investigated in this work had an equal set of warp and weft Twaron? para-Aramid filament yarns. In this work, isotropy of single sheet and multiple-sheets stacked together was analyzed at different orientations of knife stabbing. During knife stabbing a knife penetration angle (KPA) is formed between the knife cutting axis and warp yarn of the fabric. The study was conducted at five different cutting angles i.e. 0°, 22.5°, 45°, 67.5°, and 90°. Quasi-static knife penetration resistance (QSKPR) and dynamic stab resistance (DSR) of the woven fabrics were studied in this work.The main objective of this research was to study the behavior of dry woven fabrics whose surface was modified to change their friction. The selection and application of these modifications were made in such a way to keep the comfort and flexibility characteristics minimally affected. We adopted three surface modification techniques; 1) SiO2 deposition, 2) Ozone treatment along with SiO2 deposition and 3) TiO2 deposition. Furthermore, the effect of treatment was characterized against surface topology, anti-stabbing behavior, mechanical, comfort and friction properties of developed fabrics. This research discovered a new method of SiO2 deposition, using Water Glass (WG) as a precursor. The deposition of SiO2 was investigated and confirmed using Scanning Electron Microscopy (SEM), Fourier Transfer Infra-Red (FTIR) spectroscopy, and Energy-Dispersive X-ray (EDX) spectroscopy. The concentration of WG showed the direct relation for an increase in QSKPR. At 40% solution of WG the QSKPR was observed about 200%. The QSKPR measured at 67.5° KPA for untreated fabric was found statistically significantly higher than the mean QSKPR measured for all KPAs. Moreover, the QSKPR seems to follow a specific pattern for different KPAs, irrespective of fabric treatment. The coefficient of friction of fabric surface was well improved by the deposition layer of SiO2. Hence, the yarn pull-out force was increased for treated fabrics as compared to untreated. It was also observed that, treatment with Ozone before depositing SiO2, reduces the adverse effect on comfort and flexibility characteristics of fabric. The quasi-static stabbing was found to be the complementary response to warp and weft yarns, due to their orthogonal orientation. This response was modelled with the Fourier function, that fits well to the quasi-static stab of different fabrics. It was also observed that the behaviour of this response is directly proportional to fabric's coefficient of friction and inversely proportional to the gap between yarns. The interaction of the knife and the fabric was recorded on CCD camera, during QSKPR measurements. It was observed that the shape of the knife profile plays a major role. The blunt edge of the knife finds maximum resistance and causes the major peak in the force-displacement curve. While after the complete penetration of blunt edge, individual yarns cut one by one. It is proposed that SiO2 deposition increases inter-fiber friction, as a result the filaments of the yarn behave as single assembly rather as individual filament against the sharp edge of the knife. Yarn sliding resistance, individual yarn cutting behaviour and yarn pull out force was measured for warp and weft directions of treated and untreated fabrics. It was found that the major response of stabbing resistance depends upon inter yarn friction, while intra-yarn friction accounts for penetration energy of individual yarn. QSKPR was measured for two sheets, oriented at three stacking angles (SA). The 45° SA was found to exhibit better isotropic response of QSKPR than 0°and 90° SA. A modified version of NIJ standard-0115.00 was followed to verify the dynamic stab resistance at 45° SA. It was found that 45° SA exhibits isotropic stab resistance in all KPAs. Furthermore, treated fabrics showed 200% higher stab resistance than
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Subject(s)
odpor proti prořezání; Oxid křemičitý; Oxid titaničitý; Ozón; Aramidy; vrstvené textilní struktury; vodní sklo, Stab Resistance; Silicon dioxide; Titanium dioxide; Ozone; Aramid; Woven; Sodium Silicate; Water Glass