Fabric Sound Depends on Fiber and Stitch Types in Weft Knitted Fabrics

Cho, Soomin,Cho, Gilsoo,Kim, Chunjeong SAGE Publications 2009 Textile Research Journal Vol.79 No.8

<P>The purpose of this study is to analyze the characteristic fast Fourier transform (FFT) spectra of weft-knitted fabrics, to investigate the relationship between sound parameters and the mechanical properties of the weft knits, and to determine the effects of fiber type and stitch type on the frictional sound and mechanical properties. The specimens included 12 weft-knitted fabrics made from a combination of 3 fiber types (100% wool, 100% cotton and 49%/51% wool/ cotton) and 4 stitch types (plain, rib, half cardigan and half milano stitch). The rustling sounds of each specimen were recorded and analyzed using FFT analysis including sound parameters such as LPT (level pressure of total sound), Δ<I>L</I> (level difference) and Δ<I>f</I> (frequency difference). We also used Zwicker's psychoacoustic model to calculate the loudness (<I>Z</I>), sharpness (<I>Z</I>), roughness (<I>Z</I>) and fluctuation strength (<I>Z</I>). In addition, the mechanical properties of the specimens were measured using the Kawabata Evaluation System (KES). The FFT spectra for the weft-knitted fabrics showed different shapes according to the fiber and stitch types. Mechanical properties such as the thickness and weight were correlated with several sound parameters. Fiber type was affected by Δ<I> f</I> and stitch type was affected by Δ<I>L</I>, roughness (<I>Z</I>), fluctuation strength (<I>Z</I>) and weight. Both fiber type and stitch type were affected by tensile properties. It is possible, by changing fiber and stitch types of weft-knitted fabrics, to obtain various kinds of knitted fabrics with different frictional sounds.</P>

Physiological Signal Analyses of Frictional Sound by Structural Parameters of Warp Knitted Fabrics

Cho Gilsoo,Kim Chunjeong,Cho Jayoung,Ha Jiyoung The Korean Fiber Society 2005 Fibers and polymers Vol.6 No.1

The purpose of this study is to offer acoustical database of warp knitted fabrics by investigating frictional sound properties and physiological responses according to structural parameters such as construction, lap form, and direction of mutual guide bar movement. Fabric sounds of seven warp knitted fabrics are recorded, and Zwicker's psychoacoustic param­eters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) - are calculated. Also, physiological responses evoked by frictional sounds of warp knitted fabrics are measured such as electroencephalogram (EEG), the ratio of high fre­quency to low frequency (HF/LF), respiration rate (RESP), skin conductance level (SCL), and photoplethysmograph (PPG). In case of constructions, frictional sound of sharkskin having higher loudness(Z) and fluctuation strength(Z) increases RESP. By lap form, open lap has louder and larger fluctuating sound than closed lap, but there aren't significant difference of physi­ological responses between open lap and closed lap. In direction of mutual guide bar movement, parallel direction evokes bigger changes of beta wave than counter direction because of its loud, rough, and fluctuating sound. Fluctuation strength(Z) and roughness(Z) are defined as important factors for predicting physiological responses in construction and mutual guide bar movement, respectively.

Effect of Fabric Sound and Touch on Human Subjective Sensation

Cho, Gilsoo,Casali, John G.,Yi, Eunjou The Korean Fiber Society 2001 Fibers and polymers Vol.2 No.4

In order to investigate the relationship between subjective sensation for fabric sound and touch and the objective measurements, eight different apparel fabrics were selected as specimens. Sound parameters of fabrics including level pressure of total sound (LPT), level range (ΔL), and frequency differences (Δf) and mechanical properties by Kawabata Evaluation System (KES) were obtained. For subjective evaluation, seven aspects of the sound (softness, loudness, pleasantness, sharpness, clearness, roughness, and highness) and eight of the tough (hardness, smoothness, fineness, coolness, pliability, crispness, heaviness, and thickness) were rated using semantic differential scale. Polyester ultrasuede was evaluated to sound softer and more pleasant while polyester taffeta to sound louder and rougher than any other fabrics. Wool fabric such as worsted and woolen showed similar sensation for sound but differed in some touch sensation in that woolen was coarseast, heaviest, and thickest in touch. In the prediction model for sound sensation, LPT affected positively subjective roughness and highness as well as loudness, while ΔL was found as a parameter related positively with softness and pleasantness. Touch sensation was explained by some of mechanical properties such as surface, compressional, shear, and bending properties implying that a touch sensation could be expressed by a variety of properties.

[Textile and Clothing for Future Generations] Future Textiles for Next Generation

Gilsoo Cho 가정과삶의질학회 2011 한국가정관리학회 학술발표대회 자료집 Vol.2011 No.5

Performance Evaluation of Textile-Based Electrodes and Motion Sensors for Smart Clothing

Gilsoo Cho,Keesam Jeong,Min Joo Paik,Youngeun Kwun,Moonsoo Sung IEEE 2011 IEEE SENSORS JOURNAL Vol.11 No.12

<P>Development of textile-based electrodes and motion sensors is one of the main issues of recent smart textile research utilizing electronic textiles. Electrocardiogram (ECG) electrodes have been developed by various textile technologies such as sputtering or electroless-plating on the fabric surfaces, and embroidering or knitting with stainless steel yarns. In addition, two types of motion sensors have also been developed using piezo-resistive textiles. They were fabricated by knitting and braiding. To examine the usability of the ECG electrode, waveforms of the conventional AgCl electrode, and the new electrodes developed in our lab were compared. It was found that electrodes using metallic embroidering are more efficient when its substrate was a metal blended fabric. The electrolessly Cu/Ni plated fabrics obtained the best conductivity in textile-based electrodes. The first motion-measuring textile-based sensor was used to predict and measure the changes in electric resistances that accompany the angle changes in the elbow joint. An advanced piezo-resistive textile by braiding showed more accurate resistance changes and also better durability. Changes in its electrical resistance were mapped to changes in its length extension. From the relationship between the extension and the electrical resistance, movement or posture of human body was detected.</P>

Sensory Evaluation of Fabric Touch by Free Modulus Magnitude Estimation

Cho, Gilsoo,Kim, Chunjeong,Casali, John G. The Korean Fiber Society 2002 Fibers and polymers Vol.3 No.4

Fabric touch was evaluated psychophysically in order to determine the relationship between mechanical properties and subjective sensation. For subjective touch sensation, eight aspects such as hardness, smoothness, coarseness, coolness, pliability, crispness, heaviness and thickness were evaluated using free modulus magnitude estimation (FEME) technique. KES-FB was used to measure the mechanical properties of fabrics. Woolen fabric with the highest values of WC and weight was evaluated as the coarsest, heaviest and thickest. While silk crepe do chine with the lowest LT, G, 2HG, thickness and weight was rated as smoother and more pliable than any other fabrics. And flax with the highest values of LT and SMD was evaluated as hard, cool and crisp. Fabric touch and satisfaction were predicted well from the mechanical properties, especially from SMD, by regression analysis. Satisfaction for touch increased as smoothness increased.

Dyeability of Heat Treated Synthetic Fibers (1) : On the Basis of Polyester Filament Yarns 폴리에스터 필라멘트사를 중심으로

Cho, Gilsoo 한국의류학회 1986 한국의류학회지 Vol.10 No.1

본 연구에서는 연신정도가 다른 완전배향사(FDY)와 부분배향사(POY)를 열처리시켜 내부구조변화를 유도한 후 염색성을 연구하였고, 염색성과의 관련성을 위해 결정화도 및 복굴절률을 조사하였다. 열처리는 silicone oil속에서 정장상태로 실시하였으며, 시료의 염색은 Disperse Yellow 42를 이용해 무한염욕상태에서 실시하였다. 그리고, DMF를 이용해 염료를 추출시킨후 spectrophotometer로 염료흡착량을 측정하였다. 결정화도는 밀도-결정화도 관계식으로 구하였으며, 복굴절률은 편광현미경으로 시료의 두께와 retardation을 측정한 후 계산하였다. FDY와 POY필라멘트사의 염색성은 열처리시 감소하였으며 POY의 염색성이 FDY보다 우수했다. 결정화도는 열처리시 증가하였으며 열처리되지 않은 POY가 열처리되지 않은 FDY에 비해 낮은 값을 나타냈다. 복굴절률은 열처리시 증가하였으며 열처리되지 않은 POY가 열처리되지 않은 FDY에 비해 낮은 값을 나타냈다. 열처리후에도 POY가 FDY보다 낮은 복굴절률을 나타낸 반면 결정화도는 열처리된 POY가 열처리된 FDY와 비슷한 값을 나타냈다. 염색성은 결정화도와 배향도에 부적인 상관관계 즉 결정화도와 배향도가 증가함에 따라 염색성은 감소하는 관계를 시사했다.

직물의 소리가 주관적 감각에 미치는 영향

조길수 ( Gilsoo Cho ),( John G. Casali ) 한국감성과학회 1999 춘계학술대회 Vol.1999 No.-

This study was carried out to evaluate human subjective sensation for fabric rustling sounds and predict the sensation with quantified sound color measurements and mechanical properties of fabrics. Thirty subjects at Virginia Tech were asked to evaluate seven sound sensation descriptors by semantic differential scale after hearing eight different fabric sounds. Sound measurements were quantified by calculating total sound pressure(LPT), level range(ΔL), and frequency difference (Δf). Mechanical properties of fabrics were measured by KES-FB. Subjective sensation for fabric sound showed significant differences among fabrics except clearness sensation. Subjective sensation predicted by sound measurements showed well fitted regression equation with ΔL and LPT> Sharpness, clearness, and highness were significantly released with mechanical properties of fabrics. All sensation was found to be predicted with sound measurements LPT and Δf and mechanical properties such as LT, 2HG5, WC, T, and W.

슈트용 직물의 스치는 소리와 물성간의 관계

조길수 ( Gilsoo Cho ),이은주 ( Eunjou Yi ) 한국감성과학회 1999 춘계학술대회 Vol.1999 No.-

This study was carried out to investigate the relationship between sound color and physical propertiessuiting fabrics. Rustling sounds of 23 suiting fabrics by sound generator developed for this study were recorded and analysed through FFT analysis. Three sound color factor(ΔL Δf. LPT) were obtained. Physical properties of specimens were measured by KES-FB. Level range(L) showed significant correlation with tensile resilience(RT) and thickness (T). Frequency difference(Δf) showed significant correlation with tensile linearity(LT), shear properties(G, 2HG, 2HG5), compressional energy(WC), and weight(W). Total sound pressure (LPT) showed significant correlation with elongation at maximum load (EM), tensile linearity(LY), and tesile energy(WT). By stepwise regression LPT was found to be explained by EM, MIU, RC, LT significantly.

감성의류 연구의 현황과 방법론

조길수(Gilsoo Cho) 한국생활환경학회 2002 한국생활환경학회지 Vol.9 No.3