Wydział Technologii Materiałowych i Wzornictwa Tekstyliów / Faculty of Material Technologies and Textile Design / W4
Stały URI zbioruhttp://hdl.handle.net/11652/4
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Pozycja Analysis of pressure parameters in orthopedic footwear for people suffering from diabetic foot syndrome(Wydawnictwo Politechniki Łódzkiej, 2022) Mikołajczyk, Zbigniew; Nowak, Iwona; Kuchyts, Yvan; Mikołajczyk-Solińska, MelaniaThe paper examines the anthropotechnical design of orthopedic footwear for patients with diabetic foot syndrome. A 3D distance knitted fabric is used for the shoe insert. For the purpose of the research, a 7 mm thick knitted fabric with transverse elasticity of 76 kPa was designed and produced on a doublebar warp knitting machine. With the use of the FreeMed Professional strain gauge mat, the pressures exerted by the foot on a „bare” walking surface and on the surface equipped with the distance knitted fabric were measured and compared, proving that in the latter case the unit pressure on the patient's foot decreased by 25%. The obtained measurements provide a good starting point for further research on the optimization of loads on the human foot, in case of various lower limbs diseases, including anatomical changes, as well as and in relation to people who are physically overloaded due to working in standing position or being in constant motion.Pozycja Spatial structure`s analysis of 3D knitted spacer fabric(Wydawnictwo Politechniki Łódzkiej, 2022) Walkowska, Aleksandra; Mikołajczyk, ZbigniewThe subject of this paper concerns an identification of a spatial structure of a warp-knitted spacer fabric, paying particular attention to the structure of the inner layer. The transverse elasticity of the knitted fabric, both in static and dynamic terms, will depend on the properties of the monofilament, its shape and Young's modulus. The environments of OptaView and Inventor programs were used in the research. Analytical activities were selected that enabled the creation of theoretical models. The empirical verification showed the compliance of the model objects with the actual shape of the threads. It has been proved that the developed methodology can be used in the description of the spatial structure of the spacer knitted fabric as an indispensable element in the numerical experiment of the mechanical properties of the knitted fabric.Pozycja Knitted shields against electromagnetic waves(Wydawnictwo Politechniki Łódzkiej, 2022) Mikołajczyk, Zbigniew; Nowak, Iwona; Szewczyk, Monika; Januszkiewicz, Łukasz; Junak, JoannaThe purpose of the research is to counteract the negative impact of electromagnetic waves on the human body by using knitted textile barriers. Four variants of knitted fabrics with plain weft stitches were designed and manufactured from electrically conductive yarns with resistance of 490 ohms. The variants of the knitted fabrics differed significantly in structural parameters, including loop density – varying from 15 to 0.9 thousand loops and fabric cover from 64 to 33%. The barrier properties against reflected waves at frequencies from 2 to 7 GHz ranged from 10 to 64 dB. It has been proven that shielding effectiveness SE depends on stitch geometry and structural parameters of the knitted fabric. It is a good starting point for further research on the optimization of the performance of knitted barriers against electromagnetic waves.Pozycja Numerical analysis of the dynamic thread stretching process(Wydawnictwo Politechniki Łódzkiej, 2022) Prążyńska, Aleksandra; Mikołajczyk, Zbigniew; Kuchar, MaciejThe subject of the paper is the analysis of the dynamic thread stretching process under extreme conditions of the excitation speed with the physical phenomena described in terms of rheological models. The analysis was carried out using three basic models relating to viscoelastic bodies, i.e. the Maxwell, Kelvin-Voigt and Standard 2 models. The relationships between the reaction forces of the stretched threads and the input parameters of the process were included both in an analytical form and in a numerical model. The theoretical analysis was related to the experimental tests carried out on polyester threads with a linear mass of 84, 110 and 334 dtex, assuming the tensile speed ranging from 0.6 to 1.5 m / s. The experiment was carried out on a custom designed test stand. In the conclusion of the obtained research, it can be stated that the most appropriate model for the description of the analysed thread stretching process is the Standard model 2 and it should be emphasized that the traditional analysis based on analytical relationships coincides with the results of numerical analysis. This proves the correctness of the adopted numerical model with specific boundary conditions.Pozycja Identification of wearing comfort of the textile uppers of commercial footwear(Wydawnictwo Politechniki Łódzkiej, 2022) Kaziur, Patrycja; Mikołajczyk, Zbigniew; Matusiak, MałgorzataKnitting technologies have contributed to the production of textile footwear not only to reduce waste, but also to increase their physiological comfort. In this study, the functional properties of twelve commercially available knitted uppers and two footwear leathers were identified. For each of the tested variants, the following parameters were determined: thickness, mass per square meter, air and water vapor permeability, and selected parameters related to the thermal insulation and moisture sorption. On the basis of conducted research, it was shown that the best parameters were characteristic for knitted fabrics with jacquard weaves produced on cylindrical crocheting machines of large diameters.