• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.251-256
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• 2010

By legislating safety regulations for design, manufacturing and operation of rolling stock through rolling stock safety law, diverse of safety requirements have been established. On the other hands, differences of technical level in practical circumstances between domestic and overseas are pointed out that not be able to be overcome in short period. About collision safety requirements for rolling stock, European countries have been applying TSI requirement to all of rolling stock and domestic collision safety requirements in rolling stock safety law are based on TSI. In following thesis, it is showing an analysis simulation for current rubber cushion and hydraulic buffer system to verify if they are fit to collision safety requirements and result of the simulation program for prior verification. This also suggests a method to prove the performances of coupler system for future.

• Elastomers and Composites
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• v.51 no.1
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• pp.24-30
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• 2016

Sole in the footwear usually modified with foaming agent on the polymer resin to improve the lightweightness and crush-cushion effect. In this study, we investigated rheological properties for polymer resin filled with the different type and concentration of foaming agent, capsule type foaming agent and organo-chemical foaming agent, under the time sweep test. Curing times of each polymer resin with different kind of foaming agent are delayed than reference material (epoxy resin with curing agent). In case of adding capsule type foaming agent, however, there is appropriate concentration to reduce the curing time, relatively. When foaming agent is activated, foaming force inflates the sample in contrast to condensation force of curing and then axial normal force develop to the (+) direction. Interestingly, by increase concentration of foaming agent, there is a specific point to break down the axial normal force development. The reason for this phenomenon is that coalescence of foams induce the blocking of axial normal force development.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.581-591
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• 2011

This paper describes the air compressibility effect in the CFD simulation of water impact load prediction. In order to consider the air compressibility effect, two sets of governing equations are employed, namely the incompressible Navier-stokes equations and compressible Navier-Stokes equations that describe general compressible gas flow. In order to describe violent motion of free surface, volume-of-fluid method is utilized. The role of air compressibility is presented by the comparative study of water impact load obtained from two different air models, i.e. the compressible and incompressible air. For both cases, water is considered as incompressible media. Compressible air model shows oscillatory behavior of pressure on the solid surface that may attribute to the air-cushion effect. Incompressible air model showed no such oscillatory behavior in the pressure history. This study also showed that the CFD simulation can capture the formation of air pockets enclosed by water and solid surface, which may be the location where the air compressibility effect is dominant.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.45-51
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• 2003

This study was undertaken to investigate behavior characteristics of soil-cement piles in composite foundations through computer analysis. The soil-cement piles with cushion subjected to the vertical central loading only were analyzed using the program - “ABAQUS”. The investigation was conducted for various conditions including soil property, pile dimension, replacement ratio, pile/soil modular ratio, and load intensity. The results of analysis provided not only the load transfer and settlement behaviors but also the effective pile length and load distribution between a pile and soil. It was concluded that in the design of composite foundations, the modular ratio and replacement ratio are two design parameters.

• Journal of the Society of Disaster Information
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• v.12 no.3
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• pp.279-285
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• 2016

Road sides safety barrier system is the last safety during traffic accident. The structural performance of a roadside safety barrier should be kept above expectations. It is possible to protect the passenger's life. End treatment part is installed in the end of the barrier it prevents a phenomenon in which for the vehicle for the guardrail during a vehicle collision it is facility of the absorbing of car crashed impact. By repeated analysis through computer simulation for improving the vehicle crash it will be able to develop crash barriers to respond appropriately to various parameters.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.171-175
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• 2005

Automotive parts manufacturers are doing their best to strengthen the competitiveness. They are developing a large variety of new manufacturing technologies to reduce the manufacturing cost. Combined One Body Stamping(C.O.B.S) is one of the remarkable technologies to reduce production cost. C.O.B.S makes possible to form several parts together in a process using only one die set while conventional stamping demands the same number of die sets to the number of parts. But the deformation mechanism in C.O.B.S is more complicated because the interactions between blanks. So the interaction effects should be considered in the stage of initial blank shape design. In the study, a blank design method to consider the interactions between blanks was proposed and verified through the simulations and experiments. A commercial incremental FE code, LS-Dyna, was used to simulate the C.O.B.S Process. And a reverse one step FE code, Hyper Form, was used to predict initial blank shape. The boundary conditions of the reverse one step FE analysis were determined by the proposed method.

• Journal of Yeungnam Medical Science
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• v.36 no.2
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• pp.92-98
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• 2019

Forefoot disorders are often seen in clinical practice. Forefoot deformity and pain can deteriorate gait function and decrease quality of life. This review presents common forefoot disorders and conservative treatment using an insole or orthosis. Metatarsalgia is a painful foot condition affecting the metatarsal (MT) region of the foot. A MT pad, MT bar, or forefoot cushion can be used to alleviate MT pain. Hallux valgus is a deformity characterized by medial deviation of the first MT and lateral deviation of the hallux. A toe spreader, valgus splint, and bunion shield are commonly applied to patients with hallux valgus. Hallux limitus and hallux rigidus refer to painful limitations of dorsiflexion of the first metatarsophalangeal joint. A kinetic wedge foot orthosis or rocker sole can help relieve symptoms from hallux limitus or rigidus. Hammer, claw, and mallet toes are sagittal plane deformities of the lesser toes. Toe sleeve or padding can be applied over high-pressure areas in the proximal or distal interphalangeal joints or under the MT heads. An MT off-loading insole can also be used to alleviate symptoms following lesser toe deformities. Morton's neuroma is a benign neuroma of an intermetatarsal plantar nerve that leads to a painful condition affecting the MT area. The MT bar, the plantar pad, or a more cushioned insole would be useful. In addition, patients with any of the above various forefoot disorders should avoid tight-fitting or high-heeled shoes. Applying an insole or orthosis and wearing proper shoes can be beneficial for managing forefoot disorders.

• Journal of Fashion Business
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• v.22 no.5
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• pp.52-63
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• 2018

The purpose of this study was to explore and understand why and how elementary school students do their makeup. An interview with 13 sixth grade female students attending an elementary school in Seoul was conducted to identify the reasons, learning routes, and purchasing patterns related to their makeup purchase and use. The results of this qualitative analysis showed that the girls were influenced to start wearing makeup by friends or family members, such as sisters and mothers. The students thought that their faces were ugly before they did makeup. They thought they became more beautiful and they were pleased after makeup. Elementary school students mostly reported that they used sunscreen, sun cushion with a whitening function, and lip tint. Some students also used a concealer to cover their flaws. They learned the methods of makeup by watching YouTube videos and from friends. They showed different purchasing patterns depending on the type of cosmetics they buy. They reported that their parents often bought their basic cosmetics such as lotions, and creams, while they tend to use their own money to purchase cosmetics for makeup.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.269-282
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• 2019

Due to top-coal and immediate roof as cushion layer connecting with support and overlying strata, it can make significant influence on strata behaviors in fully mechanical top-coal caving working face (TCCWF). Taking Qingdong 828 working face as engineering background, $FLAC^{3D}$ and $UDEC^{2D}$ were adopted to explore the influence of top-coal thickness (TCT), immediate roof thickness (IRT), top-coal elastic modulus (TCEM) and immediate roof elastic modulus (IREM) on the vertical stress and vertical subsidence of roof, caving distance, and support resistance. The results show that the maximum roof subsidence increases with the increase of TCT and IRT as well as the decrease of TCEM and IREM, which is totally opposite to vertical stress in roof-control distance. Moreover, although the increase of TCEM and IREM leading to the increase of peak value of abutment pressure, the position and distribution range have no significant change. Under the condition of initial weighting occurrence, support resistance has negative and positive relationship with physical parameters (e.g., TCT and IRT) and mechanical properties (e.g., TCEM and IREM), respectively.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.5
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• pp.271-280
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• 2021

The code developed using a pressure-based method for unified conservation laws of incompressible/compressible fluids is expanded to handle moving or deforming body boundaries using the hybrid Cartesian/immersed boundary method. An instantaneous pressure field is calculated from a pressure Poisson equation for the whole fluid domain, including the compressible gas region. The polytropic gas is assumed for the compressible fluid so that the energy equation is decoupled. Immersed boundary nodes are identified based on edges crossing body boundaries. The velocity vector is reconstructed at the immersed boundary node using an interpolation along the assigned local normal line. The developed code is validated by comparing the time histories of pressure and wave elevation for sloshing in a rectangular and a membrane-type tank. The validated code is applied to simulate air cushion effects in a rectangular tank under sway motion. Time variations of pressure fields are analyzed in detail as the air pocket pulsates. It is shown that the contraction and expansion of the air pocket dominate the pressure loads on the wall of the tank. The present results are in good agreement with other experimental and computational results for the amplitude and the decay of the pressure oscillations measured at the pressure gauges.