The compression properties of welded seams depending on welding parameters using the hot wedge and hot air welding technique, ultrasonic welding technique, and high-frequency welding technique were ...studied. The compression properties, expressed by parameters such as compressional energy WC, compressional resilience RC, linearity LC, and compressibility C, are important information about the welded seam quality in terms of touch, voluminosity, stiffness, and flexibility of the welded seam. KES-FB and FAST measurement systems were used to test the compression properties of the welded seams. Based on the analysis of the results obtained, the influence of the welding parameters on the compression properties of the welded seam was determined. The results of the investigation showed that improperly selected welding parameters, such as the supply or introduction of too much heat into the material to be welded or too long exposure of the material in the weld zone to heat, result in welded seams with expressive extrusion edges, which affects the quality of the welded seams. These welded seams have very low values of compressional resilience RC and very high values of compressional energy WC and compressibility C.
The thermal properties of most clothing products are still not designed according to engineering science due to the lack of simple and acceptable measuring equipment and methods; the type of thermal ...insulation material, the number of layers of clothing and their thickness are thus chosen empirically. The novelty of this study was the development of a new measuring device and method for simultaneous measurements in the determination of the thermal resistance in one or more textile material layers, such as in multilayer composite clothing. Temperature gradients of textile material layers are presented, as well as the theoretical principles of operation and practical results. Four materials for the production of protective jackets were selected, from which different combinations of composite clothing were constructed and the thermal parameters were measured with a new method and a new device, both individually for the built-in materials and for the composites. Subsequently, five test jackets with the same arrangement of textile material layers as the previously tested composites were produced, and measurements of important thermal parameters were recorded with a thermal mannequin. The determined temperature gradients and measurement results are presented, and based on these it was determined that the total thermal resistance was not equal to the algebraic sum of the resistances of the individual textile material layers in the horizontal position; it was, however, higher, increasing from 30% to 94% due to small air layers caused by crimping and protruding fibres of yarn in the textile fabrics. The same textile material layers built into clothing in the vertical position allowed the formation of significantly wider air layers that increased the thermal resistance by between 2.5 and 9 times.
High frequency (HF) welding of polymer materials is increasingly used in modern manufacturing processes. The literature on HF welding process parameters was reviewed and it was found that 3-5 basic ...welding parameters were considered, which is insufficient for the scientific study of HF welding of polymeric materials. This article presents the mathematical expressions for the evaluation combining 17 influential parameters. For the first time, the specific and latent heat of the welded polymer material were used. The breaking forces of welds made by RF welding are investigated by varying the anode current, the coupling capacitor, and the exposure time of the HF electromagnetic fields. It was found that the amount of HF energy supplied depends on the breaking forces of the weld. A characteristic inflection point was also observed in the graph of the dependence of the breaking forces on the percentage of the coupling capacitor and the anode current. During elongation, it was observed that the weld is separated by peeling before the inflection point and breaks after the inflection point by tearing at the extruded edges of the weld. If the HF energy is applied to the weld for too long, there will be excessive melting of the material in the weld, thinning of the weld, unfavourable appearance of the extruded edges and electrical breakdown, and a drastic drop in the breaking force.
This paper presents the measurement results of the thermal insulation of the outer shell, thermal inserts, and clothing systems, as well as a comparative analysis of the thermal insulation of ...multi-layer thermal inserts in a thermal jacket intended for professional services in cold weather. Detachable thermal inserts are made of double-faced, diamond-shaped quilted lining with different masses per unit area, and together with the jacket, they form clothing systems with different thermal properties. Tests of the thermal properties of clothing were performed on a thermal manikin. They showed that an increase in the mass of thermal insulation textile materials contributes to an increase in the thermal insulation properties of clothing and are insufficient for a complete analysis of the thermal properties of clothing. Therefore, for the first time, three new parameters of integration efficiency of the thermal insert, thermal insulation efficiency parameters, and efficiency parameters of the integration of the textile material integrated into the clothing system were introduced. Based on these parameters, it is possible to perform an effective and accurate comparative analysis of the thermal insulation of multi-layer thermal inserts in clothing. This makes it possible to apply exact scientific methods largely in the technical design of the thermal properties of integrated textile materials, instead of experience-based methods as in the past.
This paper describes methods for evaluating the thermal properties of textile materials, clothing composites, and clothing using an integrated measurement system that includes a hot plate, a ...multi-purpose differential conductometer, a thermal manikin, a temperature gradient measurement device, and a device for measuring the physiological parameters of the human body during the exact evaluation of garment thermal comfort. In practice, measurements were taken on four types of materials widely used in the production of conventional and protective clothing. The measurements were carried out using a hot plate and a multi-purpose differential conductometer, determining the thermal resistance of the material both in its uncompressed form and when a force was applied that was ten times greater than that needed to determine its thickness. Using a hot plate and a multi-purpose differential conductometer, thermal resistances of textile materials were assessed at different levels of material compression. On hot plates, both conduction and convection had an impact on thermal resistance, but in the multi-purpose differential conductometer, only conduction did. Moreover, a reduction in thermal resistance was observed as a result of compressing textile materials.
The paper presents the investigation of thermal properties of thermal insulation chambers as an actuator in intelligent clothing, having the property of automatically adjusting the thermal protection ...level. The chambers are designed to vary their thickness based on the pressure of the inflated air in them. The pressure value measured in the thermal insulation chamber gives the microcomputer information on the thickness of the chamber. The paper presents the investigation of the functional dependencies of changes in the thickness of the chambers on the air pressure in them and the thermal resistance depending on the thickness of the thermal insulation chamber. Experimental thermal insulation chambers were made and integrated into an intelligent article of clothing and filled with air of 0–50 mbar, whereby chamber thicknesses of 0–25 mm were measured. Next, thermal resistance of 0.1876–0.5022 m2 k/W was measured on the thermal manikin. It was found that the ratio of thermal insulation of non-activated to maximally activated chambers was 1:2.7. Research has shown good results for the area where intelligent clothing can automatically adjust its thermal insulation properties. The technical systems described represent a suitable basis for experiments and scientific research during the introduction of intelligent clothing with active thermal protection into human life. The third-generation prototype shows very good properties from the aspect of automatic control of thermal protection in intelligent clothing. This forms the basis for further research. Cold protection has always been carried out by wearing garments with higher or lower thermal protection as well as wearing multiple layers of clothing. The conceptual starting point of the development of intelligent clothing is the development of an adaptive insulation layer with changeable thickness in the form of thermal insulation chambers filled with air. In this way, layered clothing as well as the use of several clothing layers can be avoided. Thus, one intelligent article of clothing regulating its thermal insulation properties can be used in a wide range of cold weather in the environment of the wearer.
Evaluating mechanical and thermal characteristics of garment systems or their segments is important in an attempt to provide optimal or at least satisfying levels of comfort and safety, especially in ...the cold environment. The target groups of users may be athletes engaged in typical sports that are trained in the cold, as well as football players that play matches and train outdoors during the winter season. Previous studies indicated an option to substitute the inner layers of an intelligent garment with polyurethane inflated chambers (PIC) to increase and regulate thermal insulation. In this paper, the authors investigate the mechanical properties of polyurethane material with and without ultrasonic joints. Furthermore, they investigate the potential of designed PICs in terms of efficiency and interdependence of air pressure and heat resistance. The results indicated that an inflated PIC with four diagonal ultrasonic joints has the highest ability to maintain the optimal thermal properties of an intelligent clothing system. The influence of direction and number of ultrasonic joints on the mechanical properties of polyurethane material is confirmed, especially in terms of compression resilience and tensile energy.
Former studies done by other authors investigated the first- and second-layered air gaps beneath the clothing garments. None of the previous studies reported multidisciplinary clothing design testing ...approach linking both the objective measuring methods and subjective responses, while testing the thermal properties linked to a microclimatic volume formed between the layers of garments forming the ensemble. Neither was determined the limiting value of the microclimatic volume for outerwear garments, after which the thermal insulation will start to decrease due to convection. By taking the advantage of the precise three-dimensional (3D) body scanning technology and reverse engineering 3D CAD tool, the volume of the microclimatic air layers formed under outerwear garments was determined to study the impact of the ensemble’s microclimatic volume on the overall insulation value, measured by means of the thermal manikin. The jacket with the smaller microclimatic volume provided 5.2–13.5% less insulation than wider jackets, while the ensembles with tighter jackets showed 0.74–1.9% less insulation in static and 0.9–2.7% more insulation in dynamic conditions, thus proving that the limiting value of the microclimatic volume is greater than previously reported for three-layered ensembles. The effective thermal insulation value was reduced in average by 20.98–25.34% between standing and moving manikins. The thermal manikins are designed for steady-state measurements and do not work well under transient conditions, so three human subjects were employed as evaluators of the clothing thermal quality. In cooler climatic conditions, the measured physiological parameters and subjects’ grades pointed to discomfort while wearing ensembles with tighter jackets.
Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of ...the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.
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