EVALUATION OF THE SIGNIFICANCE OF TRANSVERSAL SKILLS IN EDUCATION FOR TEXTILES AND LEATHER SECTOR

Beside engineering skills related to textile, clothing, leather and footwear (TCLF) technology all recent reports from European organizations highlight the importance of introduction of transversal skills into educational programs. This research comprises the opinions of 66 Croatian employers from TCLF sector related to ranking of importance of transversal skills. Social and civic skills, cultural awareness and creative expression, ability to respect diversity and communication skills are more sought after in design related jobs. Psychomotor skills, reaction time, precision of machine and equipment control are highly rated for engineering jobs. Engineers also need skills in the field of human resources management, empathy, analytical and organizational skills, resource management; customer needs targeting and focus on results

Textile Composites for Seat Upholstery

Textile for seat upholstery is a part of wide field of Mobiltech. It is very important segment of the visual identity of a vehicle, so its design, along with other high set requirements, is of the utmost importance. Textiles for seat upholstery are subject to many challenges; therefore, some of the required properties are resistance to stress, abrasion, UV radiation, external temperature and humidity, static electricity and peeling, as well as offering safety and comfort. For cladding car seat construction with textile, individual cutting parts of the fabric are joined by seam, and this part usually has the lowest mechanical properties. Therefore, in designing seat upholstery, the focus needs to be on these material segments. The function of the seam is to provide uniform transmission of loads between two joined materials and keep their integrity, which is not completely possible with stitched seam. Therefore, the material behaviour in places of sewn seam, the impact of the needlepoint and needle type on the strength, the appearance and seam quality will be discussed. Since the textile composites for seat upholstery are exposed to the multi-cyclical stress on certain areas, a part of this chapter will be focused precisely on that field

Analiza i optimizacija uvučenih krajeva u tkanju

U ovom su radu dani temeljni uvjeti za pravilnu tvorbu uvučenih krajeva u tkanini. Optimirani su vezovi, gustoća i finoća pređe u krajevima u odnosu na temeljnu tkaninu. Prema dobivenim rezultatima može se utvrditi da je optimiranje krajeva vrlo kompleksan problem koji ovisi o mnogim parametrima pređe, tkanine i uvjetima tkanja. Labavi ili zategnuti krajevi stvaraju probleme u procesu tkanja te imaju za posljedicu nemogućnost daljnje obrade tkanine i narušavanje kvalitete tkanine

WOVEN FABRIC DEFORMATION AS A FUNCTION OF ANISOTROPY

U ovom doktorskom radu definirani su parametri tkanina različitih konstrukcijskih karakteristika koji utječu na njihovu anizotropnost. Na različitim uzorcima tkanina istražena je anizotropnost njihovih mehaničkih svojstava kao rezultat sinergije prethodno definiranih strukturnih karakteristika te mogućnost predikcije smjera i količine deformacije nastale kao posljedice različitih količina i smjerova naprezanja u tkanini. Definirani prediktori anizotropije praktično su potvrđeni usporedbom rezultata analize s teorijskim materijalnim modelom. Cilj ovog rada je i istraživanje naprezanja pri vlačnom istezanju, Poissonova omjera, modula elastičnosti i smičnog modula na različitim vrstama tkanina. Vrijednosti ovih veličina odredile su se empirijski, standardnim i nestandardnim metodama. Ova istraživanja provela su se na inovativnom, novo razvijenom uređaju koji je dogradni dio dinamometra za mjerenje prekidnih sila plošnih materijala. Time su istražene bočne sile tkanina za vrijeme vlačnog naprezanja. Istražen je utjecaj anizotropije na deformabilnost tkanina u različitim smjerovima i područjima naprezanja (cijela krivulja naprezanja) do samog prekida. Na temelju toga, rezultati ovog istraživanja daju nove spoznaje o ponašanju tkanina prilikom vlačnog i smičnog naprezanja pri (Poissonov omjer, modul elastičnosti, modul smičnosti) čime je dan određeni doprinos dosadašnjim znanstvenim istraživanjima. U ovoj doktorskoj disertaciji istražena su anizotropna svojstva tkanina pri čemu je utvrđena neortotropna karakteristika dijagonalno strukturiranih tkanina. Utvrđen je utjecaj napetosti i utkanja osnove i potke na deformacijska svojstva tkanine. Izrađen je mehanički model za opis vlačnog testa s bočnom restrikcijom te utvrđen Poissonov omjer, Youngov modul elastičnosti i smični modul po čitavom rasponu krivulje naprezanja.In this thesis dissertation, the parameters of the fabric of different structural characteristics that affect their anisotropy are defined. The anisotropy of mechanical properties was investigated on different fabric samples as a result of the synergy of previously defined structural characteristics and the possibility of predicting the direction and amount of deformation caused by different amounts and strain directions in the fabric. Defined predictors of anisotropy are confirmed by comparing the results of the analysis with the theoretical material model. The aim of this thesis is to investigate the stresses in terms of tensile stretching, Poisson ratio, elastic modulus and shear module on different types of fabric. The values were determined by empirical, standard and non-standard methods. The research has been carried out on an innovative, newly developed device that is an integral part of the dynamometer for measuring the breaking forces of the flat material. Thus, the lateral forces of the fabric were investigated during tensile stress. The influence of anisotropy on fabric deformability in different directions and areas of stress (full stress curve) was investigated until the break. Based on this, the results of this research provided new insights on the behavior of the fabric during tensile and shear stress (Poisson's ratio, modulus of elasticity, shear module), thus giving a certain contribution to previous scientific research. In this doctoral dissertation, anisotropic properties of the fabric were investigated and the deviation of orthotropic behaviour of diagonal structured fabrics was defined. The influence of the tension and crimp on the deformation properties of the fabric was determined. A mechanical model for the description of the tensile test with the side restriction was established and the Poisson ratio, the Youngov modul of elasticity and the shear module were determined throughout the range of stress curves

WOVEN FABRIC DEFORMATION AS A FUNCTION OF ANISOTROPY

U ovom doktorskom radu definirani su parametri tkanina različitih konstrukcijskih karakteristika koji utječu na njihovu anizotropnost. Na različitim uzorcima tkanina istražena je anizotropnost njihovih mehaničkih svojstava kao rezultat sinergije prethodno definiranih strukturnih karakteristika te mogućnost predikcije smjera i količine deformacije nastale kao posljedice različitih količina i smjerova naprezanja u tkanini. Definirani prediktori anizotropije praktično su potvrđeni usporedbom rezultata analize s teorijskim materijalnim modelom. Cilj ovog rada je i istraživanje naprezanja pri vlačnom istezanju, Poissonova omjera, modula elastičnosti i smičnog modula na različitim vrstama tkanina. Vrijednosti ovih veličina odredile su se empirijski, standardnim i nestandardnim metodama. Ova istraživanja provela su se na inovativnom, novo razvijenom uređaju koji je dogradni dio dinamometra za mjerenje prekidnih sila plošnih materijala. Time su istražene bočne sile tkanina za vrijeme vlačnog naprezanja. Istražen je utjecaj anizotropije na deformabilnost tkanina u različitim smjerovima i područjima naprezanja (cijela krivulja naprezanja) do samog prekida. Na temelju toga, rezultati ovog istraživanja daju nove spoznaje o ponašanju tkanina prilikom vlačnog i smičnog naprezanja pri (Poissonov omjer, modul elastičnosti, modul smičnosti) čime je dan određeni doprinos dosadašnjim znanstvenim istraživanjima. U ovoj doktorskoj disertaciji istražena su anizotropna svojstva tkanina pri čemu je utvrđena neortotropna karakteristika dijagonalno strukturiranih tkanina. Utvrđen je utjecaj napetosti i utkanja osnove i potke na deformacijska svojstva tkanine. Izrađen je mehanički model za opis vlačnog testa s bočnom restrikcijom te utvrđen Poissonov omjer, Youngov modul elastičnosti i smični modul po čitavom rasponu krivulje naprezanja.In this thesis dissertation, the parameters of the fabric of different structural characteristics that affect their anisotropy are defined. The anisotropy of mechanical properties was investigated on different fabric samples as a result of the synergy of previously defined structural characteristics and the possibility of predicting the direction and amount of deformation caused by different amounts and strain directions in the fabric. Defined predictors of anisotropy are confirmed by comparing the results of the analysis with the theoretical material model. The aim of this thesis is to investigate the stresses in terms of tensile stretching, Poisson ratio, elastic modulus and shear module on different types of fabric. The values were determined by empirical, standard and non-standard methods. The research has been carried out on an innovative, newly developed device that is an integral part of the dynamometer for measuring the breaking forces of the flat material. Thus, the lateral forces of the fabric were investigated during tensile stress. The influence of anisotropy on fabric deformability in different directions and areas of stress (full stress curve) was investigated until the break. Based on this, the results of this research provided new insights on the behavior of the fabric during tensile and shear stress (Poisson's ratio, modulus of elasticity, shear module), thus giving a certain contribution to previous scientific research. In this doctoral dissertation, anisotropic properties of the fabric were investigated and the deviation of orthotropic behaviour of diagonal structured fabrics was defined. The influence of the tension and crimp on the deformation properties of the fabric was determined. A mechanical model for the description of the tensile test with the side restriction was established and the Poisson ratio, the Youngov modul of elasticity and the shear module were determined throughout the range of stress curves

Impact of Fabric Construction on Adsorption and Spreading of Liquid Contaminations

A contamination on a textile material is defined as an undesirable, local formation that deviates in appearance from the rest of the material. In this paper the relationship between the shape and surface of liquid contaminations and the firmness factor of woven fabric is investigated. The interdependence of constructional and structural parameters of raw and bleached cotton fabrics were analysed. The results show that selected contaminations are distributed differently, primarily depending on the construction characteristics of the fabric, type of contamination and hydrophilicity of cotton fabric

WOVEN FABRIC DEFORMATION AS A FUNCTION OF ANISOTROPY

U ovom doktorskom radu definirani su parametri tkanina različitih konstrukcijskih karakteristika koji utječu na njihovu anizotropnost. Na različitim uzorcima tkanina istražena je anizotropnost njihovih mehaničkih svojstava kao rezultat sinergije prethodno definiranih strukturnih karakteristika te mogućnost predikcije smjera i količine deformacije nastale kao posljedice različitih količina i smjerova naprezanja u tkanini. Definirani prediktori anizotropije praktično su potvrđeni usporedbom rezultata analize s teorijskim materijalnim modelom. Cilj ovog rada je i istraživanje naprezanja pri vlačnom istezanju, Poissonova omjera, modula elastičnosti i smičnog modula na različitim vrstama tkanina. Vrijednosti ovih veličina odredile su se empirijski, standardnim i nestandardnim metodama. Ova istraživanja provela su se na inovativnom, novo razvijenom uređaju koji je dogradni dio dinamometra za mjerenje prekidnih sila plošnih materijala. Time su istražene bočne sile tkanina za vrijeme vlačnog naprezanja. Istražen je utjecaj anizotropije na deformabilnost tkanina u različitim smjerovima i područjima naprezanja (cijela krivulja naprezanja) do samog prekida. Na temelju toga, rezultati ovog istraživanja daju nove spoznaje o ponašanju tkanina prilikom vlačnog i smičnog naprezanja pri (Poissonov omjer, modul elastičnosti, modul smičnosti) čime je dan određeni doprinos dosadašnjim znanstvenim istraživanjima. U ovoj doktorskoj disertaciji istražena su anizotropna svojstva tkanina pri čemu je utvrđena neortotropna karakteristika dijagonalno strukturiranih tkanina. Utvrđen je utjecaj napetosti i utkanja osnove i potke na deformacijska svojstva tkanine. Izrađen je mehanički model za opis vlačnog testa s bočnom restrikcijom te utvrđen Poissonov omjer, Youngov modul elastičnosti i smični modul po čitavom rasponu krivulje naprezanja.In this thesis dissertation, the parameters of the fabric of different structural characteristics that affect their anisotropy are defined. The anisotropy of mechanical properties was investigated on different fabric samples as a result of the synergy of previously defined structural characteristics and the possibility of predicting the direction and amount of deformation caused by different amounts and strain directions in the fabric. Defined predictors of anisotropy are confirmed by comparing the results of the analysis with the theoretical material model. The aim of this thesis is to investigate the stresses in terms of tensile stretching, Poisson ratio, elastic modulus and shear module on different types of fabric. The values were determined by empirical, standard and non-standard methods. The research has been carried out on an innovative, newly developed device that is an integral part of the dynamometer for measuring the breaking forces of the flat material. Thus, the lateral forces of the fabric were investigated during tensile stress. The influence of anisotropy on fabric deformability in different directions and areas of stress (full stress curve) was investigated until the break. Based on this, the results of this research provided new insights on the behavior of the fabric during tensile and shear stress (Poisson's ratio, modulus of elasticity, shear module), thus giving a certain contribution to previous scientific research. In this doctoral dissertation, anisotropic properties of the fabric were investigated and the deviation of orthotropic behaviour of diagonal structured fabrics was defined. The influence of the tension and crimp on the deformation properties of the fabric was determined. A mechanical model for the description of the tensile test with the side restriction was established and the Poisson ratio, the Youngov modul of elasticity and the shear module were determined throughout the range of stress curves

Bicomponent Carbon Fibre within Woven Fabric for Protective Clothing

For the purpose of this research, six types of woven fabrics with different proportions of bicomponent carbon fibres (CF), differently distributed in the fabric, were woven and tested. Fibre composition in the core and sheath was determined with X-ray spectroscopy (EDS). Two types of bicomponent CF were selected which are characterised by different proportions of carbon and other polymers in the fibre core and sheath and different cross-sections of the fibres formed during chemical spinning. Physical-mechanical properties were investigated, as well as deformations of fabrics after 10,000, 20,000 and 30,000 cycles under biaxial cyclic stress on a patented device. Tests of the surface and vertical electrostatic resistance from fabric front to back side and from the back side to the fabric front were conducted. According to the obtained results and statistical analyses, it was concluded that the proportion of CF affects the fabric’s physical and mechanical properties, the electrostatic resistance as well as the deformations caused by biaxial cyclic stresses. A higher proportion of CF in the fabric and a higher proportion of carbon on the fibre surface, gave lower electrostatic resistance, i.e., better conductivity, especially when CFs are woven in the warp and weft direction. The higher presence of CF on the front of the fabric, as a consequence of the weave, resulted in a lower surface electrostatic resistance

Study of Aramid Yarns Sizing

The process and efficiency of sizing aramid yarns before the weaving process was studied. The sizing was carried out under different conditions, with and without the pre-wetting of the threads before the actual sizing process. Two groups of yarns were tested. The first group consisted of five yarn samples that were blended with 95% meta-aramid and 5% para-aramid in counts of 20 × 2, 17 × 2, 14 × 2 and 12.5 × 2 tex. The second group of yarns consisted of three yarn samples that were blended with 93% meta-aramid, 5% para-aramid and 2% carbon in counts of 20, 20 × 2 and 17 × 2 tex. The inlet moisture of the yarn before sizing was 40% (with pre-wetting) and 4% (without pre-wetting), and the outlet moisture after drying was 4%. In order to carry out such tests to reproduce them, the sizing was carried out on a laboratory-sizing machine with the possibility of adapting to industrial conditions. According to the obtained results related to the properties of yarn before and after sizing, it can be concluded that sizing of aramid yarns is justified. When sizing the yarn without pre-wetting, the mechanical properties improved, especially breaking force, strength and abrasion resistance. Irregularity and hairiness were also reduced, especially when sizing with pre-wetting. Yarn hairiness or the frequency of protruding fibres also decreased with sizing in almost all samples and sizing conditions. The second group of yarns with a carbon fibre content mostly showed better mechanical properties before sizing, which continued after sizing. In general, the aramid yarn sized with pre-wetting showed certain deformations caused by stretching in the wet state and thus reduced the size pick-up, which caused less breaking forces and strength. Sizing with pre-wetting resulted in a slightly better smoothness of the thread and its higher evenness. It can be concluded that the aramid yarn should be sized with a lower size percentage (up to 4.5%), i.e., without pre-wetting in order to minimise the deformation of the yarn during sizing and thus improve the mechanical properties in the weaving process

Biaxial Cyclic Loading of Woven Fabrics

For the purpose of this paper, investigations were carried out on specifically designed fabrics with different structural parameters. The biaxial cyclic loading of fabrics and its consequences were investigated. The weave structures with the smallest weave units (plain weave, basket weave 2/2, rib weave 1/1 (2+2) and rib weave 2/2 (1+1) with the same warp and weft density (24 ends/cm and 24 picks/cm) were selected. Biaxial cyclic loadings of fabrics were performed on a newly developed patented device. The influence of the low level of cyclic loadings of fabrics on the change of tensile properties in warp and weft direction was investigated. The results showed that the low level of biaxial cyclic loading can lead to a permanent linear deformation of fabrics. Despite the fact that the forces that cyclically strain the fabric in two directions amount to 10% of the breaking elongation, after a certain number of cycles there is an irreversible deformation and reduction of breaking forces, but sometimes they can result in an increase in breaking forces. It was found that the tensile elongation of fabrics is affected both by thread crimping and by the structural properties of fabrics resulting from changes in the weave