Browsing by Author "KYOSEV, YORDAN"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemMULTI-CRITERIA NUMERICAL OPTIMIZATION OF MECHANICAL PROPERTIES IN ULTRASONIC WELDING PROCESS PARAMETERS OF PVC-COATED HYBRID TEXTILES FOR WEATHER PROTECTION(Technical University of Liberec, ) HUSSEN, MUKTAR SEID; KYOSEV, YORDAN; PIETSCH, KATHRIN; BOLL, JESSICA; KABISH, ABERA KECHI; Technická univerzita v LiberciA series of research was carried out to determine the correlation between ultrasonic welding process parameters and weld seam mechanical properties. However, multi-objective numerical optimization of coated hybrid textiles for weather protection has not been addressed. To ensure a comprehensive evaluation of ultrasonic weld seams, the research investigates the optimal solution of the multi-objective function of ultrasonic welding process parameters and formulates a single criteria objective function. Lapped and superimposed types of seams were applied based on 33 factorial designs of experiments for 6 and 12 mm welding widths. Single-criteria objective functions instead of three independent problems were developed as a generalized utility function. A single-criteria optimization method was introduced through predetermined weight and normalization within the range of acceptable/unacceptable values. Numerical and graphical optimization methods were also applied to determine possible optimal solutions through generalized utility functions. The best optimal value of the generalized utility function (0.670425 and 0.944374) was attained at welding speed (2 and 2.01564 m/min), power (93.756 and 117.973 W), and pressure force (198.803 and 239.756 N) of 6 and 12 mm welding widths, respectively. The acceptable range of satisfactory values was determined for the roof and wall of awnings and camping tents through standard, in which seam performance level indicated. Nonlinear quadratic numerical models were formulated to estimate the generalized utility function, and their results were close to the regressed diagonal line against the actual points. The statistical analysis was shown a statistically significant effect of welding process parameters on the generalized utility function.
- ItemPATTERN RELATED ISSUES IN THE MODELLING OF DEFORMED OVER SURFACE WARP KNITTED STRUCTURES WITH LONGER UNDERLAPS(Technical University of Liberec, ) LIU, HAISANG; KYOSEV, YORDAN; JIANG, GAOMING; Technická univerzita v LiberciThe yarn level modelling of warp knitted structures is a complex process. For structures placed on the plane, it is well investigated and there are a few software solutions and papers reported. This paper considers the simulation of warp knitted structure, deformed in the 3D space. Especially the modelling of the areas of high curvature are detailed observed. Underlaps with longer lengths makes an unreal visualization for simulation results. Different pattern with different length of the underlaps are modelled with original algorithm developed by the authors. Modelling and visualization problems in the areas with long underlaps are discussed and possible solutions are proposed.