• Transactions of Materials Processing
• /
• v.14 no.3 s.75
• /
• pp.257-262
• /
• 2005

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.11a
• /
• pp.33-38
• /
• 2004

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Journal of the Korean Society for Heat Treatment
• /
• v.30 no.5
• /
• pp.207-214
• /
• 2017

In this study, failure behavior of piercing plug for seamless tube manufacturing process was studied. Three different kinds of passed piercing plugs (10, 90, 215 times) were prepared. The shape deformation of the passed piercing plugs was observed by 3D coordinate measuring machine, and the oxidized layer on the surface of piercing plug was observed by optical microscopy. The length reduction of piercing plug presented at 215 times passed plug. It was found that the oxidized layer consisted of outer scale, inner scale and internal oxidation layers, and the inner scale layer had vertical cracks, and interfaces had horizontal cracks. We proposed the failure mechanism of piercing plug during seamless tube manufacturing process based on the formation of vertical and horizontal crack.

• International Journal of Advanced Culture Technology
• /
• v.9 no.4
• /
• pp.126-134
• /
• 2021

This study was a cross-sectional reaserch that analyzed the effect of emotional expression type on happiness level with structured questionnaires. A total of 186 participants in the study were in their 20s to 60s. Data collection was received from those who voluntarily agreed to the study from September 1 to 15, 2021. The collected data were frequency analysis, t-test, and regression analysis with spss 18.0. As a result of the analysis, it was found that people who perform superficial acts disguised as emotions were less satisfied with their current life (t=-10.482, p<0.01). People who do inner behavior showed high levels of happiness. These results suggest the following: It can be seen that in order to improve effective happiness, it is required to actively and truthfully act in a physical environment.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.25 no.4
• /
• pp.773-782
• /
• 2001

This study was to investigate the value changes in Korean women by analyzing the ads of womens magazines. The contents of ads were classified into two types of values: general and consumption values. The general values, composed of inner-directedness and outer-directrdness, might predict consumer behavior in general. The consumption values, utilitarians and hedonic, were expected to affect the consumer purchasing attitude to a specific product. Factors affecting the cultural values were per capita income and womens social status. Total 2969 illustrated ads with verbal theme from 32 Korean womens magazines were used. The content analysis, chi-square test, logistic regression were done for the analysis. The results showed that inner-directedness was dominant general value in Korean womens culture and increased over time. Younger consumers were more inner-directed than older ones were, and inner-directed values increased with income growth. For the consumption values, utilitarian values were higher than hedonic ones and went up over time. For the product types, utilitarian ads were frequent in cosmetics while hedonic ads were high for apparels. Those results implied that Korean womens culture became more inner-directed with increased income. Also consumption values were likely to differ between product groups. Per capita income was shown to increase inner-directedness while womens social status was to increase outer-directedness.

• Advances in concrete construction
• /
• v.14 no.3
• /
• pp.195-204
• /
• 2022

As a brittle failure mode, punching-shear failure can be widely found in traditional RC slab-column connections, which may lead to the entire collapse of a flat plate structure. In this paper, a novel RC slab-column connection with inner steel truss was proposed to enhance the punching strength. In the proposed connection, steel trusses, each of which was composed of four steel angles and a series of steel strips, were pre-assembled at the periphery of the column capital and behaved as transverse reinforcements. With the aim of exploring the punching behavior of this novel RC slab-column connection, a static punching test was conducted on two full-scaled RC slab specimens, and the crack patterns, failure modes, load-deflection and load-strain responses were thoroughly analyzed to explore the contribution of the applied inner steel trusses to the overall punching behavior. The test results indicated that all the test specimens suffered the typical punching-shear failure, and the higher punching strength and initial stiffness could be found in the specimen with inner steel trusses. The numerical models of tested specimens were analyzed in ABAQUS. These models were verified by comparing the results of the tests with the results of the analyzes, and subsequently the sensitivity of the punching capacity to different parameters was studied. Based on the test results, a modified critical shear crack theory, which could take the contribution of the steel trusses into account, was put forward to predict the punching strength of this novel RC slab-column connection, and the calculated results agreed well with the test results.

• Fisheries and Aquatic Sciences
• /
• v.27 no.1
• /
• pp.1-6
• /
• 2024

In this study, the swimming behavior of a small box jellyfish (Carybdea brevipedalia), which consists of inhaling external seawater and expelling it through its mouth to generate forward thrust, was characterized using particle image velocimetry (PIV). The flow rate and structure during the suction and discharge process were quantitatively analyzed. During swimming, there was a change in the ratio of the internal area during inhalation and expulsion. Specifically, there was a 1.10-fold difference between the maximum area after inhalation and the minimum area after discharge. The maximum distance traveled after discharge was inversely proportional to the size of the inner area, with a 2.48-fold difference in the minimum distance traveled after suction. Depending on the propulsion stage, the inner area decreased and then increased in proportion to the moving distance and speed. The moving distance of the small box jellyfish was measured for each period. The speed for each swimming stage increased and then decreased at intervals of 0.15 to 0.2 seconds, and the suction and discharge cycle period was measured at approximately 0.5 seconds. Collectively, our findings provide a methodological basis for studying the swimming behavior of small and highly active trailing jet jellyfish, as well as the biological mechanisms that determine this behavior.

• Smart Structures and Systems
• /
• v.28 no.6
• /
• pp.761-777
• /
• 2021

This study presents a numerical investigation on the sensitivity of electromechanical (EM) impedance responses to inner damaged concrete of a prestressed anchorage zone. Firstly, the Ottosen yield criterion is selected to simulate the plasticity behavior of the concrete anchorage zone under the compressive loading. Secondly, several overloading cases are selected to analyze inner damage formations in the concrete of the anchorage zone. Using a finite element (FE) model of the anchorage zone, the relationship between applied forces and stresses is analyzed to illustrate inner plasticity regions in concrete induced by the overloading. Thirdly, EM impedance responses of surface-mounted PZT (lead-zirconate-titanate) sensors are numerically acquired before and after concrete damage occurrence in the anchorage zone. The variation of impedance responses is estimated using the RMSD (root-mean-square-deviation) damage metric to quantify the sensitivity of the signals to inner damaged concrete. Lastly, a novel PZT skin, which can measure impedance signatures in predetermined frequency ranges, is designed for the anchorage zone to sensitively monitor the EM impedance signals of the inner damaged concrete. The feasibility of the proposed method is numerically evaluated for a series of damage cases of the anchorage zone. The results reveal that the proposed impedance-based method is promising for monitoring inner damaged concrete in anchorage zones.

• Journal of Korean Association for Spatial Structures
• /
• v.22 no.1
• /
• pp.67-73
• /
• 2022

Middle size of membrane retractable roof is under 25m span which consists of various moving systems. Sliding carriage is the system that leads the membrane to parking place, transferring the load from the membrane to structural cable. When membrane moves roof, thus, structural behavior of sliding carriage, which may contain various shapes with friction coefficients, should be investigated by vertical load as well as horizontal load. Nummerical simulation of sliding carriage prototypes, in this research, were performed by incrementation of vertical load and horizontal load as well. Consequently, this paper evaluated proper shapes of inner holder of Sliding carriage and evaluated the effective contact area of inner hold.

• Journal of the Korea Concrete Institute
• /
• v.13 no.1
• /
• pp.77-85
• /
• 2001

Concrete filled steel tubular (CFT) columns are becoming popular in structural applications. The increased popularity comes from their excellent structural properties such as high strength, high ductility, and large energy absorption capacity. However, the disadvantage feature of CFT column is the difficulty in predicting its time dependant characteristic (i.e., creep and shrinkage) of inner concrete. The time dependent behavior of CFT column can cause serious serviceability problems. Therefore, it is necessary to investigate the long term behavior of CFT column. This paper presents analytical and experimental studies on long-term behavior of CFT-column under a central axial loading. Two loading cases are considered in the research; (1) the load applied only at the inner core concrete of CFT-column and (2) the load applied simultaneously on both concrete and steel tube. Analysis method using the bond strength model is proposed and conclusions on long-term properties of CFT-column can be derived from the results.