Comparison of GA-Optimized Viscoelastic Models for the Characterization of Compression Behavior of Warp-Knitted Spacer Fabrics
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2017-0027
Nowadays, Warp-Knitted Spacer Fabrics (WKSF) have been widely used for many technical applications. Compressional behavior of WKSF is one of their important properties. Physical modeling is one of the solutions to predict these properties for engineered designing of WKSF. In this study, four common physical models are introduced and compared in order to simulate compressional behavior of polyester WKSF. Genetic Algorithm (GA) was applied to optimize each model parameter. The results showed that the Burger model has the highest adoption with 0.2 percent Mean Absolut Error (MAE). The effect of thickness, outer fabric structure and spacer monofilament density on viscoelastic properties of the samples were also studied.
Analysis of Woven Fabric at the Place of the Sewn Seam
Key importance and the role of sewn seam in the woven fabric are presented. Fabric properties in the places joined with the sewn seam on which garment durability, applicability, appearance and quality depend are highlighted. Seam location is usually the weakest spot on the garment, especially when the great loads are present at these places. Mechanical properties of the sewn fabrics were investigated in different test conditions. The influence of the load on the sewn seam is analyzed in time intervals. Sample with seam have approximately 70% lower breaking properties (breaking force and elongation at break) than the sample without seam. By preloading the seam fabrics with 30%, 50% and 70% of elongation at break, for a 3-h period, the effect on mechanical properties were tested and the differences in pre-stretching intensity were observed. By conducting such test, it is expected that the fabric experience further degradation and that breaking properties further reduce, but the exact opposite occurred (breaking properties, by increasing the preload, increase even more), because of various material properties (structural fabric properties, raw material characteristics, seam characteristics).
Determination of Regional Presence of Male Body Types as a Prerequisite for Improving Garment Manufacture
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2017-0023
Garment manufacture and garment fit to physique is a never-ending research subject. The human body is subject to changes that are reflected in its shape and body measurements, and appear in all periods of life. Monitoring the changes and gaining insight into the actual amounts of physical dimensions of an individual population unfold numerous opportunities to affect clothing design and manufacturing. In accordance with the issues mentioned above, a research was carried out to determine male body types of the Croatian male population. Male body types for a specific clothing size determine waist and hip girth, which completes the information on main body measurement amounts. Furthermore, the types of bodies are prescribed by the European Standard 14302-3 and, accordingly, in the observed sample, the presence of a particular type is determined with respect to regional affiliation and age. This study was conducted on a sample of 4090 test subjects divided into five regions, ages 20 to 85 years, divided into seven age groups. By statistical analysis of the results, that is, by the methods of descriptive statistics, the values of physical dimensions necessary for this research were determined.
Properties and Structure of Cellulosic Membranes Obtained from Solutions in Ionic Liquids Coagulated in Primary Alcohols
This paper presents the results of studies on the preparation of cellulosic membranes, from a solution in 1-ethyl-3- methylimidazolium acetate (EMIMAc), using the phase inversion method. Initially, the membranes were obtained by coagulation of the polymer film in water and primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol), 1-hexanol, 1-octanol) resulting in membranes with significantly differing morphologies. Subsequently, composite membranes were produced, with the support layer being a membrane with the largest pores, and the skin layer a membrane with smaller pores. The resulting membranes were tested for physicochemical and transport properties. The morphology of the membrane surfaces and their cross-sections were investigated by using a scanning electron microscope (SEM). The structure of the membranes, on the other hand, was investigated by FTIR spectroscopy and WAXS structural analysis.
3-D Simulation of Double-Bar Plush Fabrics with Jacquard Patterns
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2017-0029
A realistic computerized simulation of double-bar plush fabrics can result in a time-saving development process with high quality. Based on basic analysis of jacquard principles, a fast 3-D simulation method of warp-knitted plush fabrics is proposed by using a geometry shader on GPU. Firstly, pile areas and non-pile areas are identified according to the jacquard design graphs and chain notations. According to the directions of observation and raised pile, two layered chips are formed in the geometry shader with an approach of multi-layered textures. To ensure that the simulated piles resemble the real ones, the directions of the piles are randomized with the Perlin noise method. One pile is generated along its length with numerous layers in the plush fabric model. Simulation results of piles on both the technical face and technical back are obtained via the model built above, which is confirmed with practicability and efficiency. This 3D simulation approach improves the visualization appearance of piles just as they are actually raised.
Novel Weaving Technology for the Manufacture of 2D Net Shape Fabrics for Cost Effective Textile Reinforced Composites
Despite significant weight and performance advantages over metal parts, today’s demand for fiber-reinforced polymer composites (FRPC) has been limited mainly by their huge manufacturing cost. The combination of dry textile preforms and low-cost consolidation processes such as resin transfer molding (RTM) has been appointed as a promising approach to low-cost FRPC manufacture. This paper presents an advanced weaving technique developed with the aim to establish a more cost-effective system for the manufacture of dry textile preforms for FRPC. 2D woven fabrics with integrated net shape selvedge can be obtained using the open reed weave (ORW) technology, enabling the manufacture of 2D cut patterns with firm edge, so that oversize cutting and hand trimming after molding are no longer required. The introduction of 2D woven fabrics with net shape selvedge helps to reduce material waste, cycle time and preform manufacturing cost significantly. Furthermore, higher grade of automation in preform fabrication can be achieved.
Glycolide/L-Lactide Copolymer (PGLA) Fibers Formed by Wet Spinning from Solution and Modified with Ceramic Nanoadditives
The paper presents the results of research into glycolide/L-lactide copolymer (PGLA) fiber formation by wet spinning from solution. The selected process conditions led to fibers with a specific tensile strength of more than 35 cN/tex. Furthermore, ceramic nanoadditives such as hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) were used to obtain fibers with osteoconductive properties. It was found that the ceramic nanoadditives reduced the specific strength of fibers (to 24 cN/tex for β-TCP and to 27 cN/tex for HAp). The paper also presents wide-angle X-ray scattering (WAXS) evaluation of the supramolecular structure of the fibers as well as their porosity parameters and microscopic structure. The obtained fibers were woven into a textile fabric with potential applications in biomedical engineering.
The Use of Fabrics to Improve the Acoustic Absorption: Influence of the Woven Fabric Thread Density Over a Nonwoven
Noise is frequently unnoticed, but it is one of the causes of unhealth for human beings reducing people’s quality of life. There are many materials that can be considered as acoustic absorbents. Textiles can be used to both improve the acoustic quality of and to decorate the room where they have been placed. In this study, we used some fabrics with 15, 20 and 30 ends/cm and 15, 20 and 30 picks/cm. The acoustic absorption coefficient was measured when the fabric was added as a resistive layer on top of a nonwoven made of polyester fiber. Results evidence that these fabrics can be efficiently used to modify the acoustic absorption of the nonwoven. Sound absorption coefficients measured via the impedance tube method show that these modifications occur. The results show how it is possible to improve the acoustic characteristics of a simple nonwoven to obtain sound absorption coefficients close to values of 1 at different frequencies by choosing a fabric with the appropriate combination of warp and weft count.
Virtual Reconstruction of Historical Men’s Suit
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2018-0001
Nowadays, the virtual technology is being widely applied in the area of clothing design and try-on. However, the possibilities of these technologies cover only the contemporary marketable clothes, while the insight in the aspect of historical costume is very limited. In this research, we developed the method that allows to reconstruct and do the virtual try-on of historical men’s suit consisting from four different garments—trousers, shirts, vest, and coat. The method includes, on one hand, the analysis of pattern drafting systems, patterns construction, special means of bespoke tailoring that were popular in the history and, on the other hand, the way of its adapting and preparing to contemporary technologies of 2D and 3D design. The exploration was done with men’s suit and the patterns from the nineteenth century. We studied how the tailors took all measurements, the content of size charts including divisional, direct measurements, and its combination. To parameterize the historical patterns of men’s clothes, we created the schedule of special indexes. We developed the method how to identify the means of garment shaping by steam pressing, which are hiding in the patterns, and how to perform ones by darts. The preparation of historical patterns to virtual try-on was done by CAD. As example, the reconstruction of full-dress suite painted on the Prince Albert of Saxe-Coburg and Gotha’ portrait (1840) was done, and high adequacy between the historical prototype and the virtual suit has been proved.
Designs of Textile Antenna Arrays for Smart Clothing Applications
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2018-0002
In this work, three designs of textile antennas, namely, a rectangular microstrip patch antenna, annular slot antenna, and planar inverted-F antenna (PIFA), operating in the 2.45 GHz WLAN band were developed for smart clothing applications. Conductive textile, a copper-plated polyester fabric, was used for fabricating antenna radiators and grounds. An insulating neoprene fabric with a thickness of 4 mm and a permittivity of 1.5 was used for preparing the substrates. The textile patch antenna achieved a maximum gain of 5.96 dBi and a bandwidth of 4.6%. The annual slot antenna showed a moderate gain and bandwidth of 2.9 dBi and 13.1%, respectively. The PIFA achieved the widest bandwidth of 31% but the smallest gain of 1.2 dBi. Furthermore, the performance deterioration of the proposed antennas under various bending conditions was analyzed to evaluate their suitability for wearable applications. Moreover, two 2 × 2 patch and slot antenna arrays were assembled to increase gain and bandwidth. The measured results proved that the developed antenna designs provide superior performance.
An in Situ Crystal Growth of Metal Organic Frameworks-5 on Electrospun PVA Nanofibers
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2017-0024
In this study, a simple, general and straightforward method for growing metal-organic frameworks (MOFs) crystals directly on nanofibers is presented. A chelating polymer was first blent with metal cation and then electrospun. The obtained nanofibers were immersed in a linker solution. Metal cations were released and the metal-organic frameworks crystals were grown on the fibers’ surface. In this work, this method was tested with polyvinyl alcohol as chelating polymer, Zn2+ as metal cation and Terephthalic acid as linker. The pair cation/linker corresponds to the MOF-5. The latter is a robust metal organic framework formed from Zn4O nodes with 1,4-benzodicarboxylic acid struts between the nodes. SEM images revealed that the MOF-5 nanocrystals have grown along the PVA/Zn2+ nanofibers that served as the crystals’ growth template by providing the Zn2+ ions. This result was also confirmed by infrared spectroscopy, which indicates the presence of characteristic bands of MOF-5 in the modified nanofibers spectrum. Moreover, the X-ray diffraction showed that MOF-5 material was well crystallized on the nanofibers surface according to a cubic symmetry with a space group Fm-3m and a lattice constant a = 25.8849 Å.
Dynamic Measurement of Foam-Sized Yarn Properties from Yarn Sequence Images
First Online: 06 Sep 2018; DOI: https://doi.org/10.1515/aut-2017-0030
Unlike the normal sizing method, the foam sizing had been proven to be a low-add-on technology. To investigate the effect of foam sizing, film thickness, sized-yarn evenness, and size penetration rate were necessary to evaluate the performances of foam-sized yarns. However, the conventional image analysis of sized-yarn cross sections primarily relied on artificial testing with a low efficiency. This paper proposed a novel dynamic method to measure the sized-yarn properties including film thickness, sized-yarn evenness, and size penetration rate based on yarn sequence images captured from a moving yarn. A method of dynamic threshold module was adopted to obtain threshold for segmenting yarns in the sequence images. K-means clustering algorithm was applied to segment pixels of the images into yarn and background. To further remove burrs and noise in the images, two judgment templates were carried out to extract the information of yarn core. The film thickness, sized-yarn evenness, and size penetration rate were measured based on the yarn core of each frame in sequence images. In order to compare with the experimental results of the dynamic method, the yarn properties of the same samples were tested by static and artificial testing. Results revealed that the proposed method could efficiently and accurately detect the film thickness, sized-yarn evenness, and size penetration rate.