Kinetyka formowania struktur tkanych na krośnie rotacyjnym
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Referat stanowi streszczenie rozprawy doktorskiej pt. Kinetyka formowania struktur tkanych na krośnie rotacyjnym. W rozprawie postawiono tezę, iż rotacyjne formowanie struktur tkanych znacząco zmienia warunki tkania, w tym obciążenia dynamiczne nitek osnowy. Celem pracy było poszerzenie wiedzy teoretycznej i praktycznej na temat zjawisk, możliwości oraz ograniczeń tkania na krośnie rotacyjnym. W pracy można wyróżnić trzy kluczowe części. Są to: teoretyczna analiza formowania przesmyku, bezpośrednie porównanie warunków tkania na krośnie rotacyjnym i klasycznym oraz określenie wpływu parametrów nastawczych krosna na zmienność podziałki wątku. Praca oraz prowadzone badania miały charakter pionierski, gdyż dostępna wiedza i występujące zjawiska są nieznane lub znane w niewielkim stopniu. Mimo to udało się zrealizować postawiony cel. Ponadto odkryto wiele ciekawych zjawisk, z których najistotniejsze jest podwójne dobicie wątku, występujące jedynie na krośnie rotacyjnym. Udowodniono, iż formowanie struktur tkanych na krośnie rotacyjnym znacząco zmienia warunki tkania, w tym obciążenia dynamiczne nitek osnowy. Dzięki tej pracy odkryto ciekawy, nowy i bardzo szeroki obszar badawczy.PhD thesis "Kinetics of woven structures formation on a rotational loom" concerns weaving technology which was not previously investigated. This new method of fabric forming gives completely new, unknown conditions for the warp and weft threads. Hereafter summary of thesis. In the present study author tries to define and characterize the phenomena that occur during rotational weaving. It is necessary to improve theoretical and practical knowledge about the possibilities and limitations of rotational loom. Knowledge and experience in this area are unknown or little known, therefore the research done is pioneering. The dissertation can be divided into two main parts, theoretical and practical. The theoretical part presents analysis of the weaving process. The practical part includes a description of the experiments done, together with the results analysis. A literature review includes discussion of classical weaving methods and a number of technologies alternative to the classic loom. There are presented are examples of looms, which were obtained in different weaving conditions by using rotating components for sheading and beating. Special attention was paid to the laboratory model of rotational loom and the prototype of an industrial rotational loom (used in experiments), which was established in 2004. The importance of individual elements of the loom was explained. The next stage of work was to develop, build and mount fully electronically controlled warp pay-off mechanism in the industry prototype of rotational loom. Because of planned experiment, possibility of electronic warp pay-off mechanism control was very important. Theoretical analysis of the kinetics of rotational weaving was divided into two sections. The first concerns formation of the shed and weft beating with detail discussion about the fabric formation zone. There was examined and described the situation when weaving starts and first six wefts are inserted into the fabric. It has been demonstrated how sheds geometry changes with each introduced weft. The summary of this analysis is anew trajectory of the weft thread in the rotational loom. Double weft beating phenomenon was discovered during this analysis. The nature of this unique phenomenon has been described. For more comprehensive description of the phenomena, shedding formation analysis was performed separately (second section). For clarity of the drawings only the shed geometry change during weaving beam move was considered. During analyzing of forming a new shed process, it was observed that there were increases in the length of the warp threads between weaving beam and back rest. Length analysis was carried out, but author considered only extreme case without threads slippage on the weaving beam, friction and elasticity of the warp. In the next part of the thesis conditions on the classic weaving loom and a rotational loom were compared. The following was discussed: used yarns, fabric design and looms setup parameters. Warp was examined for changes in breaking load after weaving. The breaking load was chosen as the parameter which can describe the degree of degradation of the warp threads after weaving process. Obtained results were evaluated statistically. During trials also measurements of the dynamic tension of warp on both looms were taken. The presented analysis significantly explained the theoretical kinetics of formation of the fabric on a rotational loom. This generated next experiment designed to investigate the influence of loom setting parameters on fabric structure. According to the experiment plan 31 cases were selected to carry out on the rotational loom. Used in the experiment yarns and loom parameters were described in the thesis. As an output parameter, the coefficient of weft pitch variation was selected. This coefficient reflects the structure of the fabric. To determine which loom setting parameters have a significant influence on the coefficient of weft pitch variation, stepwise multiple regression was used. There has been no ability to detect statistically significant relationships between the independent variables (loom setting parameters) and coefficient of weft pitch variation. For a better understanding of the situation the experiment was extended for an additional nine cases in which varied only one parameter. The obtained results were evaluated and selected groups of cases were compared. Such evaluation of coefficient of weft pitch variation allowed creating final conclusions for the experiment. The results show that phenomena which accompany the formation of fabric on a rotational loom are more complex than expected. It seems that in future experiments rotational loom should be considered as a control system composed not only of the weaving beam, warp and weft, but cooperating with the warp payoff and fabric take-up mechanisms. hi this thesis the author managed to significantly improve theoretical and practical knowledge about the weaving on a rotational loom. The author discovered many interesting phenomena, the most important of which is a double weft beating, occurring only on the rotational loom. It has been proved that the formation of woven structures on a rotational loom significantly changes the conditions of the weaving and the warp dynamic loads. The author discovered an interesting, new and very extensive research area, which is beyond the scope of this work.