Browsing by Author "Neckář Bohuslav"
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- Item21st International Conference Strutex - Structure and Structural Mechanics of Textiles(2016) Neckář Bohuslav; Kolčavová Brigita; Mertová Iva; Drašarová Jana
- Item22nd International Conference Strutex - Structure and Structural Mechanics of Textiles(2018) Neckář Bohuslav; Kolčavová Sirková Brigita; Mertová Iva; Drašarová Jana
- ItemCOMPUTATIONAL METHODOLOGY FOR DETERMINATION OF YARN TWIST AND DIAMETER(Technical University of Liberec, Faculty of Textile Engineering, 2018) Neckář Bohuslav; Das Dipayan
- ItemEffect of fiber orientation on tensile behavior of biocomposites prepared from nettle and poly(lactic acid) fibers: Modeling & experiment(Elsevier Ltd, 2018) Neckář Bohuslav; Das Dipayan; Kumar NavdeepIn this work, a micromechanical model of tensile behavior of fibrous composites was formulated by taking into account of the stress-strain behavior of fiber and matrix, the directional arrangement of fibers in the composites, and the relative space occupied by the constituent fibers and matrix in the composites. A simple and easy-to-use expression was obtained for predicting the tensile stress of composites as a function of tensile stresses of fiber and matrix, fiber and matrix volume fractions, and fiber orientation factor. The model was validated with a set of biocomposites prepared by using nettle and poly(lactic acid) fibers and employing compression moudling technology. The model was also compared with the well-known "rule of mixtures" equation using the experimental results. While the "rule of mixtures" equation was found to highly overestimate the tensile stress, the model predicted the experimental results satisfactorily.
- ItemEXPERIMENTAL AND PREDICTED SPECIFIC STRESS STRAIN CURVES OF WORSTED STAPLE YARNS(Technical University of Liberec, 2016) Zubair Muhammad; Neckář Bohuslav; Maqsood Hafiz Shahzad
- ItemHairiness of staple fiber yarns part I: mathematical modeling(TAYLOR & FRANCIS LTD, 2016) Neckář Bohuslav; Das Dipayan; Krupincová Gabriela
- ItemHairiness of staple fiber yarns Part II: model validation(Taylor and Francis Ltd., 2016) Krupincová Gabriela; Neckář Bohuslav; Das Dipayan
- ItemINFLUENCE OF TWIST ON SELECTED PROPERTIES OF MULTIFILAMENT YARN(AUTEX, Technical University of Lodz,, 2018) Mertová Iva; Moučková Eva; Neckář Bohuslav; Vyšanská MonikaOwing to twisting of filament fiber bundle, the structure and consequently various parameters and properties of a fiber bundle are changed. The aim of the work is to verify the effect of multifilament yarn twist (or twist coefficient) on selected mechanical properties such as multifilament tenacity, breaking elongation, and coefficient of fiber stress utilization in the yarn. Furthermore, the influence of twist on structural parameters such as the angle of peripheral fibers, the packing density, and the substance cross-sectional area of fiber bundle is observed. Two multifilament yarns with different filament cross-section shape and material were used for the experiment. Experimentally obtained data was compared with the known model dependencies derived decades ago based on the helical model. It can be stated that multifilament yarn retraction can be predicted based on the angle of peripheral fibers using the Braschler’s model. The coefficient of fiber stress utilization in the multifilament yarn determined experimentally corresponds with a theoretical curve, constructed according to Gégauff and Neckář, in the area of Koechlin’s twist coefficient α > 54 ktex1/2 m−1. Results as well as possible causes of deviations of experimental data from the theoretical one are discussed in this work.
- ItemLinen Fiber and Yarn Stress Strain Curves(Technical University of Liberec, 2015) Zubair Muhammad; Neckář Bohuslav
- ItemMeasuring of yarn crimp in woven fabric(Slovak University of Technology in Bratislava, 2015) Mertová Iva; Neckář Bohuslav
- ItemNew method to measure yarn crimp in woven fabric(SAGE PUBLICATIONS LTD, 2016) Mertová Iva; Neckář Bohuslav; Ishtiaque Sayed Muzaffar
- ItemOn the Evaluation of the Yarn’s Packing Density(Technical University of Liberec, 2015) Eldessouki Mohamed; Ibrahim Sayed; Neckář Bohuslav
- ItemPredicting Specific Stress of Cotton Staple Ring Spun Yarns: Experimental and Theoretical results(Institute of Biopolymers and Chemical Fibres, 2017) Zubair Muhammad; Neckář Bohuslav; Malik Zulfiqar Ali
- ItemPrediction of spun yarn strength at different gage lengths(TAYLOR & FRANCIS LTD, 2017) El Deeb Moaz Ahmed Samy Moustafa; Neckář BohuslavIn this article, the influence of tensile tester gage length on ring, rotor and air-jet spun yarns tenacity and its coefficient of variation have been investigated. A statistical model has been presented that correlates yarn tenacity and coefficient of variation of yarn tenacity to gage length. The model is based on Peirce model and assuming the three-parameter Weibull distribution of yarn strength values. A reasonable agreement has been shown between the experimental and predicted values. The model successfully captured the change in yarn strength and its coefficient of variation at different gage lengths. Results showed that at longer gage lengths, yarn strength decreases and its coefficient of variation decreases as well.
- ItemSpecific Stress Strain Curves of Viscose yarn: Experimental Verification(Technical university of Liberec, 2016) Zubair Muhammad; Neckář Bohuslav
- ItemTensile behavior of staple fiber yarns part I: theoretical models(TAYLOR & FRANCIS LTD, 2017) Neckář Bohuslav; Das Dipayan
- ItemTensile behavior of staple fiber yarns part II: model validation(Taylor and Francis Ltd., 2017) Zubair Muhammad; Neckář Bohuslav; Das Dipayan
- ItemTensile behavior of staple fiber yarns part III: comparison of mathematical models(Taylor and Francis, Ltd., 2017) Zubair Muhammad; El Deeb Moaz Ahmed Samy Moustafa; Neckář Bohuslav
- ItemTensile behavior of staple fiber yarns, part IV: experimental verification of predicted stress–strain curves(Taylor and Francis Ltd., 2017) Zubair Muhammad; Neckář Bohuslav; El Deeb Moaz Ahmed Samy Moustafa; Baig Gulzar
- ItemTheoretical Models of Tensile Behavior of Staple Fiber Yarns(Technical University of Liberec, 2016) Neckář Bohuslav