• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.89-93
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• 1991

A new kind of a non-contact torque sensor which uses the difference of the maximum magnetic inductions as measurand was constructed. The torque sensor utilizes the tensile and compressive stress of two cores which are attached on the rotating shaft. This sensor shows that the linearity was better than 1 %, and the transient torque can be measured at the sampling rate of 10 kHz which is the same as magnetizing frequency of the core.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.295-299
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• 1996

Intrinsic Fabry-Perot Optical fiber sensors were embedded to tensile side of the 20cm$\times$20cm$\times$150cm cement concrete structures. The sensors were attached to the reinforcing steels and then, the cement concretes were applied. It took 30 days for curing the specimens. After that, the specimens were tested with 4-point bending method by universal testing machine. Strains were measured and recorded by the strain gauges embedded near optical fiber sensors. Output data of fiber sensor showed good linearity to the strain data from the strain gauges up 2000microstrain. The optical fiber sensors showed good response after yielding of structure while embedded metal film strain gauges did not show any response. We also specimens were broken down. In conclusion, the optical fiber sensors can be used as elements of health monitoring systems for cement concrete infra-structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.12
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• pp.1153-1160
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• 2008

In this paper, the algorithm of Abaqus UMAT is introduced to analyze the shape memory alloy. The SMA has two main effects which show non-linearity. Due to this, it is hard to analyze SMA using analysis tools and to describe all of two effects. Therefore, in this study, the program using Abaqus UMAT based on Modified Brinson model is used to analyze SMA. The martensite fraction, the most important factor which defines SMA motion, is also calculated by Fortran program in UMAT. In addition, the tensile test of SMA specimen is conducted. The availability of algorithm is proved by comparing analysis to experimental result.

• Structural Engineering and Mechanics
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• v.22 no.1
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• pp.107-130
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• 2006

The paper deals with the numerical solution of the dynamic problem of masonry structures. Masonry is modelled as a non-linear elastic material with zero tensile strength and infinite compressive strength. Due to the non-linearity of the adopted constitutive equation, the equations of the motion must be integrated directly. In particular, we apply the Newmark or the Hilber-Hughes-Taylor methods implemented in code NOSA to perform the time integration of the system of ordinary differential equations obtained from discretising the structure into finite elements. Moreover, with the aim of evaluating the effectiveness of these two methods, some dynamic problems, whose explicit solutions are known, have been solved numerically. Comparisons between the exact solutions and the corresponding approximate solutions obtained via the Newmark and Hilber-Hughes-Taylor methods show that in the cases under consideration both numerical methods yield satisfactory results.

• The Korean Journal of Community Living Science
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• v.23 no.3
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• pp.317-328
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• 2012

In this study, printing was introduced to the common dip-dyeing method of persimmon juice dyeing so as to develop two different colored persimmon juice dyed fabrics with printings of 'jorangmal' patterns (a national monument) instead of producing a plain textile. Following are the results of a comparative study between the persimmon dyed fabric and undyed fabric, both with printings, in terms of its properties, and hand values. Cotton and rayon were chosen as samples and were compared separately. Firstly, the samples showed differences in terms of clarity and visual sensation depending on the presence of persimmon dye, even if the same pattern and color was used. Secondly, the air permeability of two samples improved after persimmon dyeing even though their thickness increased, and their moisture regain increased as well in all humidity conditions. Thirdly, protectiveness against UV increased in dyed samples, and sweat, sunlight, and compound colorfastness improved in printed dye-fabrics compared to plain dyed ones. Therefore, printing proved to be effective in preventing discoloration. Fourthly, tensile linearity and resilience, bending rigidity, compressive linearity and resilience, and shearing stiffness increased more in the dyed samples compared to undyed ones. However, shearing recovery decreased in both dyed fabrics. Fifthly, the result of its hand value showed that Koshi value increased in all samples than undyed ones, whereas Fukurami, Numeri, and Softosa values decreased. Incorporating printing in persimmon dyeing process could expect creative outcomes not only in today's diverse fashion but in areas of arts or crafts as well.

• Textile Coloration and Finishing
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• v.8 no.3
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• pp.52-58
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• 1996

In order to study an applicable level for the graft finish of silk filaments and the characteristics of silk fabric, some sample fabrics were woven with grafted weft and the characteristics of sample fabrics were analyzed to evaluate the mechanical properites and the handle values according to the graft yield(%) of MMA and HEMA monomers on silk filaments. 1. The tensile properties were detected in the increase of linearity(LT) and the recovery in time of the increasing resilience(RT). 2. The bending properties were detected to have a lot of effect on the balance of bending rigidity(B) to hysteresis(2HB) according to the elastic relaxation of warp tension and the interlacing stress. 3. The shearing properities were detected to show the softness and the elastics in a case of the decrease in shearing rigidity(G) and hysteresis(2HG, 2HG5) according to the graft yields. 4. The compression properties were detected in the decrease of linearity(LC) and the uniformity of resilience(RC). It explains that the tendancies of compressible variation is not accepted. 5. The surface properities were detected to be affected by the surface forms of grafted silk filaments and the variation in the morphologies of interlacing sections. Considering the interlacing eveness, MMA grafted fabrics were accepted within the level of WOMEN'S THIN DRESS(KN-201-LDY) but HEMA grafted fabrics were not accepted. 6. The variation of handles were detected in the increase of total hand(TAV) within the levels of 65% of KOSHI and 82% of HARI on the average. 7. The handle fashions were detected in the nature of Habuta and Dechine from MAA graft but the nature of Fugi were shaped from HEMA graft in proportion to the graft yields.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.91-99
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• 2017

The purpose of this paper is to evaluate the flexural performance of reinforced concrete (RC) beams repaired with polymer mortar. The repaired and non-repaired 13th beams which was fabricated by considering repair position, repair depth, and curing age of polymer mortar as test variables were tested under three point loading. All specimens repaired in compressive and tensile zone did not fail due to interfacial failure between polymer mortar and concrete but failed when the strain of repaired mortar exceeded the ultimate tensile strain of polymer mortar. Maximum load of specimens repaired in compressive zone was similar to that of non-repaired specimen, reference specimen. Additionally, their ductility index was higher than that of reference specimen. On the other hand, specimens repaired in tensile zone failed very brittlely and have a lower ductility index than reference specimen. Nonlinear analysis by using OpenSees was performed to predict the behavior of RC beam repaired with polymer mortar. Two dimension frame element was used to simplify an analysis model and fiber model was applied to consider the material non-linearity. It was confirmed from the analysis results that nonlinear analysis properly predicts the behavior of specimens repaired in compressive zone and overestimates the behavior of specimens repaired in tensile zone.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.123-128
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• 2015

The iron is an element having a high yield strength, mechanical hardness, good electrical conductivity, and also it has been used in various fields because of ease machining. In bridges have been used tendon made of a steel wire for large loads and light weight. Tension measurement of tendon employed in PreStressed Concrete (PSC) bridge is very important for the bridge safety check. NDT (Non-Destructive Testing) is essential for the safety check, however, magnetic NDT is difficult to apply due to the non-linear magnetization curve and hysteresis loop in the magnetic properties. In this work, for basic study of magnetic NDT application, we have constructed a B-H loop measuring system for 7-strand tendon of which diameter is 15.5 mm, and which can apply tensile stress up to 2.0 GPa. We have measured hysteresis loops of two kinds of tendons under different tensile stress. Amplitude permeability and maximum magnetic induction near knee show the most sensitive and high linearity depends on tensile stress. Relative amplitude permeability was decreased from 500 to 200 and maximum magnetic flux density changed 0.6 T.

• Fashion & Textile Research Journal
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• v.15 no.4
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• pp.620-629
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• 2013

This study examines the rustling sound characteristics of electrospun nanofiber web laminates according to layer structures. This study assesses mechanical properties and frictional sounds (such as SPL); in addition, Zwicker's psychoacoustic parameters (such as Loudness (Z), Sharpness (Z), Roughness (Z), and Fluctuation strength (Z)) were calculated using the Sound Quality Program (ver.3.2, B&K, Denmark). The result determined how to control these characteristics and minimize rustling sounds. A total of 3 specimens' frictional sound (generated at 0.63 m/s) was recorded using a Simulator for Frictional Sound of Fabrics (Korea Patent No. 10-2008-0105524) and SPLs were analyzed with a Fast Fourier Transformation (FFT). The mechanical properties of fabrics were measured with a KES-FB system. The SPL value of the sound spectrum showed 6.84~58.47dB at 0~17,500Hz. The SPL value was 61.2dB for the 2-layer PU nanofiber web laminates layered on densely woven PET(C1) and was the highest at 65.1dB for the 3-layer PU nanofiber web laminates (C3). Based on SPSS 18.0, it was shown that there is a correlation between mechanical properties and psychoacoustic characteristics. Tensile properties (LT), weight (T), and bending properties (2HB) showed a high correlation with psychoacoustic characteristics. Tensile linearity (LT) with Loudness (Z) showed a negative correlation coefficient; however, weight (T) with Sharpness (Z) and Roughness (Z), and bending hysteresis (2HB) with Roughness (Z) indicated positive correlation coefficients, respectively.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.3
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• pp.173-180
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• 2008

Cotton, wool, cotton/wool blended (80:20) and tencel fabrics were treated with low temperature oxygen plasma, enzymes (cellulase or protease), or oxygen plasma-enzyme and they were examined for dyeing and handling properties for environment friendly finishing. The appropriate conditions for cellulase treatment were enzyme concentration of 3g/l, pH of 5, and $60^{\circ}C$ for one hour, and for protease treatment were enzyme concentration of 4g/l, pH of 8, and $60^{\circ}C$ for one hour. The equilibrium uptake of a direct dye on cotton changed with plasma treatment and plasma-cellulase treatment, and the rate of dyeing slightly decreased. When wool was dyed with acid dye, the equilibrium dye uptake did not change with plasma, protease treatment nor plasma-protease treatment, however, the rate of dyeing had increased with plasma-protease treatment. From these results, it is assumed that plasma attacks the surface of the fiber, and enzyme mainly affects the inner part of the fiber. Plasma treatment did not affect mechanical properties related to the handling of fabrics. The handling test showed increased extension at maxmum load(EM), tensile energy(WT) with decreased tensile resilience (RT), and the fabrics became softer but resilience decreased slightly with enzyme treatment. The bending recidity(B), hysteresis of bending moment(2HB), and hysteresis of shear force at five degrees(2HG5) decreased, however, shear stiffness(G) increased. I knew the plasma pre-treatment made fabrics softer with lower koshi(stiffness). The handling of plasma pre-treated fabrics was better than that of enzyme-treated fabrics. When we pre-treated fabrics, the handling test showed decreased coefficient of friction(MIU), geometrical roughness(SMD), while the surface of fabrics became smoother and numeri increased. Even though compression resilience(RC) increased, fukurami(bulky property) and compressive elasticity, decreased due to the linearity of compression-thickness curve(LC) and compression energy(WC).