• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.252-259
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• 1999

One of the most important factors for a proper design of a slender compression member may be the exact determination of the elastic critical load of that member. In the cases of non-prismatic compression member, however, there are times when the exact critical load becomes impossible to determinate if one relies on the neutral equilibrium method or energy principle. Here in this paper, the approximate critical loads of symmetrically or non-symmetrically tapered members are computed by finite element method. The two parameters considered in this numerical analysis are the taper parameter, $\alpha$ and the sectional property parameters, m. The computed results for each sectional property parameter, m are presented in an algebraic equation which agrees with those by F.E.M The algebraic equation can be easily used by structural engineers, who are engaged in structural analysis and design of non-prismatic compression member.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.311-318
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• 2000

In constructions of dams and ports structure, gravels are used as principle structural materials. Gravels have different material property compared with other materials like soil and concretes, etc. For example, material properties of gravels obtained from normal triaxial compression test are usually overestimated due to scale and penetration effects. Also, material properties of gravels under dynamic loads are the main interest when structural behavior of rockfill dam under earthquake loads is analyzed. The development of large triaxial compression apparatus is needed for the better estimation of material property of gravel. This paper reports work in progress to development of large triaxial compression apparatus.

• Textile Coloration and Finishing
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• v.24 no.1
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• pp.54-61
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• 2012

This study surveyed the preparation of 8oz coated fabric and the physical property of the coated fabric according to the treated condition for the sail yacht. And the coated fabrics were compared with the performance of overseas products for verification. Physical properties of the coated fabric treated with non-yellowing functional polyurethane resin were examined according to the treatment condition such as compression and ageing treatments. Finally, yellowing fastness to light for 60 hours was assessed. Considering the compression condition after coating, good physical property was obtained at $6kgf/cm^2$. Also, the performance of yellowing fastness was similar to performance of overseas goods.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.52-59
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• 2006

Graphite is well known as a material which has high-temperature thermostable property, chemical resistance against acid and alkaline state also is very easy to environment. Nowadays the need of graphite product is increasing rapidly because of its advantages. In this paper, the mechanical property of newly developed graphite products with high density is investigated with especially in compression test. I introduced the graphite specimens for this study by NGF method with two expandable graphite and compared to the specimens of commercial graphite sheet from expanded graphite which made by the rolling process. I investigated the characteristics of these materials by measuring specific weight, hardness, compressive strength and investigating structures by SEM, It is verified that the graphite products with NGF method has superior properties for using gasket materials than that of commercial graphite sheet.

• Fibers and Polymers
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• v.4 no.4
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• pp.151-155
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• 2003

The abrasion behavior of three kinds of warp knitted fabrics, which are normally used for upper sole of footwear, was evaluated. We measured the changes of mechanical and structural properties of each sample as abrasion cycle increased. Each sample showed similar trends in compression and surface properties but there were significant differences in abrasion rate among the samples. The mechanical properties showed remarkable differences with directions. The frictional coefficient (MIU) of fabric surface increased at the beginning of abrasion and decreased as abrasion cycles increased. The weight and thickness of the fabric linearly decreased with abrasion cycles. The surface roughness (SMD) and the compressional resilience (RC) decreased as abrasion cycles increased while compressional energy (WC) increased.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.329-332
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• 1999

Currently, the most important technology is compression methods in the multimedia society. In audio compression, the method using human auditory nervous property is used. This method using psychoacoustical model is applied to perceptual audio coding, because human's audibility is limited. MPEG-II AAC(Advanced Audio Coding) is the most advanced coding scheme that is of benefit to high quality audio coding. The compression ratio is 1.4 times compared with MPEG-I layer-III. In this paper, the vector processor for MDCT/IMDCT(Modified Discrete Cosine Transform /Inverse Modified Discrete Cosine Transform) of MPEG-II AAC is designed.

• Composites Research
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• v.31 no.6
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• pp.421-428
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• 2018

In order to optimize the prepreg compression molding (PCM) process, the forming simulation is required to cope with any problems that may be raised during the process. For the improvement of simulation accuracy, the input data of material property should be measured accurately. However, most studies assume that the compressive properties of the prepreg are identical to the tensile properties without quantifying them separately. Therefore, in this study, the in - plane compressive properties of the prepreg are presented to improve the accuracy of the forming simulation. As a result, the compressive modulus of the fibers was measured to be about $10^{-2}$ times lower than the tensile modulus. Also we designed a square-cup mold with a tilting angle of $110^{\circ}$ to simulate the prepreg formability during the high temperature compression mold process. Shear angles were measured at each corner, which were compared with the simulation results. It was observed that the simulation results using the accurate compressive properties of the prepreg showed a similar trend with the experimental results. It was confirmed that the measured data of the in-plane compression property improved the accuracy of the forming simulation results.

• Korean Journal of Materials Research
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• v.24 no.11
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• pp.625-631
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• 2014

To investigate the deformation properties of TiC-(5-20) mol% Mo solid solution single crystals at high temperature by compression testing, single crystals of various compositions were grown by the radio frequency floating zone technique and were deformed by compression at temperature from 1250K to 2270K at strain rates from $5.1{\times}10^{-5}$ to $5.9{\times}10^{-3}/s$. The plastic flow property of solid solution single crystals was found to be clearly different among a three-temperature range (low, intermediate and high temperature ranges) whose boundaries were dependent on the strain rate. From the observed property, we conclude that the deformation in the low temperature range is controlled by the Peierls mechanism, in the intermediate temperature range by the dynamic strain aging and in the high temperature range by the solute atmosphere dragging mechanism. The work softening tends to become less evident with an increasing experimental temperature and with a decreasing strain rate. The temperature and strain rate dependence of the critical resolved shear stress is the strongest in the high temperature range. The curves are divided into three parts with different slopes by a transition temperature. The critical resolved shear stress (${\tau}_{0.2}$) at the high temperature range showed that Mo content dependence of ${\tau}_{0.2}$ with temperature and the dependence is very marked at lower temperature. In the higher temperature range, ${\tau}_{0.2}$ increases monotonously with an increasing Mo content.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.1
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• pp.106-122
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• 2021

This study confirmed the mechanical properties of an auxetic re-entrant pattern prepared using 3D printing technology and its composite fabric with neoprene for the production of functional auxetic patterns/textiles for safety shoes. Samples were prepared by the tilt angle of a re-entrant pattern of 0°, 30°, 45°, 60° and 90°, and then analyzed using Poisson's ratio, bending, compression, and tensile properties. A 3D printed auxetic re-entrant pattern (3DP-RE) and its composite fabric (3DP-RE/NP) showed a negative Poisson's ratio in all tilting angles that indicated auxetic properties. The results of the bending property shown that strength of 3DP-RE/NP was 1.5 times lower than NP, but the strain improved 2.0 times. It was confirmed that the deformation of 3DP-RE/NP is possible with a low load. Each sample type of compression behavior indicated similar regardless of the tilting angles; in addition, the compression toughness of 3DP-RE/NP increased 1.2 times compared with NP. In the case of tensile properties, 3DP-RE and 3DP-RE/NP were affected by the tilting angle, samples with 90° (the opposite of load direction) showed best tensile property and toughness. 3DP-RE/NP indicated improved bending, compression, and tensile properties.

• Fashion & Textile Research Journal
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• v.19 no.2
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• pp.240-248
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• 2017

This study compares general jacquard fabrics and jacquard fabrics with optical fiber on mechanical properties, sensibility and preference evaluation of fabric for the blind. The analysis also assesses the effect of optical fiber in the evaluation and identifies those best suited for consumers. The mechanical properties of jacquard fabrics were measured by the KES-FB system. Sensibility and the preference of the jacquard fabric for the blind were rated on tactile sensation by women experts in their 20's and 30's. It was found that the optical fiber in jacquard fabric affected the change of mechanical properties as well as sensibility and preference. Jacquard fabric with optical fiber were softer and more transformable, while the fabrics had lower recover property by shear force and compression as well as more violent unevenness. Jacquard fabrics were also classified into three hand factors of surface property, resilience and weightiness. There were significant differences on surface property perceptions and weightiness, hand and blind preferences by optical fiber. Jacquard fabrics that contained optical fiber were not preferred by the blind because they were perceived to be uneven and heavy. Those, that were smooth and light, were preferred for jacquard fabric; in addition, fabrics preferred by the blind had good compression.