• Journal of Ocean Engineering and Technology
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• v.32 no.4
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• pp.253-260
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• 2018

Recently, the application of non-steel materials in ships and offshore plants is increasing because of the development of various nonlinear materials and the improvement of performance. Especially, hyper-elastic materials, which have a nonlinear stress-strain relationship, are used mainly in marine plant structures or ships where impact relaxation, vibration suppression, and elasticity are required, while elasticity must be maintained, even under high strain conditions. In order to simulate and evaluate the behavior of the hyperelastic material, it is very important to select an appropriate material model according to the strain of the material. This study focused on the selection of material models for hyperelastic materials, such as rubber used in the marine and offshore fields. Tension and compression tests and finite element simulations were conducted to compare the accuracy of the nonlinear material models due to variations in the stretch ratio of hyper-elastic material. Material coefficients of nonlinear material models are determined based on the curve fitting of experimental data. The results of this study can be used to improve the reliability of nonlinear material models according to stretch ratio variation.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.622-624
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• 2008

This investigation studies the effects of material properties and corresponding propagation wave types on optimal configurations of sound absorbing porous materials in maximizing the absorption performance by topology optimization. The acoustic behavior of porous materials is characterized by their material properties which determine motions of the frame and the air. When the frame has a motion, two types of compressional wave propagate in the porous material. Because each wave in the material make different influence on the absorption performance, it is important to understand the relative contribution of each wave to the sound absorption. The relative contribution of the propagating waves in a porous material is determined by the material properties, therefore, an optimal configuration of a porous material to maximize the absorption performance is apparently affected by the material properties. In fact, virtually different optimal configurations were obtained for absorption coefficient maximization when the topology optimization method developed by the authors was applied to porous materials having different material properties. In this investigation, some preliminary results to explain the findings are presented. Although several factors should be considered, the present investigation is focused on the effects of the material properties and corresponding propagation waves on the optimized configurations.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.231-234
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• 2008

Each corporation isn't consistent because of offering specific information for publicity. It spends considerable labor force and time surfing of the material information and choosing need material. That's the reason it's different with material information and choice system between production and marketing corporation. Among lots of material information, some of them are used by offering material information simplify. So it is demanded necessity of reasonable material choice system. That system helps it choose a material more easily. So we studied about the information retrieval system of reasonable material choice through the study about assortment system of material information and material choice method. It's the basic study for the suggestion of reasonable material choice system. According to this study, if that system is suggested and realized, we can overcome from the system of typical and repeatable at every course of architecture during several times. It will be helpful to increase about the productivity of architecture as the minimization of time, labor, resource and cost for the material choice.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.842-853
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• 2008

In the construction of dam, the key factor which decides the type of dam is security of materials resource. Because of the large scale earth work, the ability to supply the materials is essential part about economical efficiency. The research is the case study about controlling the plan to secure the material resources in the design of Buhang multipurpose dam. In case of Buhang multipurpose dam, at that time of basic design, it was planned to use a rock fill material. From the detail investigation about the river bed accumulative layer widely spread on the submerged district on the basic design, the research is accomplished to replace rock material with gravel material. After the investigation of whole reserves of gravel material, estimation of conformity as dam construction material from analysis of grain size distribution, the case study of oversea construction, and the material property comparison between rock fill material and gravel fill material, it is verified th possibility of using the gravel fill. Thereafter, the analysis of dam stability using a gravel fill material is accomplished. Finally, A gravel fill material can be used as the main construction material of CFRD, therefore the efficiency of resource recycling in the submerged area is maximized, and the established plan is more advantageous to stability, constructibility, environmentibility than the case of using a rock fill.

• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.90-90
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• 2005

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.10
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• pp.920-927
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• 2013

The requirement of acoustic performance about underwater acoustic material which is used in underwater environment more increases. Underwater acoustic material was made by viscoelastic material such as a rubber and a polyurethane etc. In order to increase an acoustic performance, several kinds of inclusions were added to viscoelastic material. In this paper, acoustic modelling and analysis techniques were introduced and the acoustic characteristics of underwater acoustic material were studied. Echo reduction and transmission loss were calculated with volume fraction of inclusion in the material. Also the characteristic impedance and the input impedance of underwater acoustic material were obtained and effects on the echo reduction and transmission loss of material were discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.107-114
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• 2006

Material selection is one of the important activities in design and manufacturing. A selected material at the conceptual design stage affects functionality of the designed part as well as manufacturability and cost of the final product. Unfortunately there are not many accessible material databases that can be used for design. In this research, a web-based material database was constructed. In order to assist designers to compare different materials, two-dimensional and three-dimensional graphs were provided via the web browser Using these graphical tools, multi-dimensional comparison was available in more intuitive manner. As a case study, this system was applied for material selection of an automotive engine pulley.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.89-94
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• 2011

In this research, among thermoplasticity plastic raw material that recycling is possible polyolefine(TPO) and polyvinyl chloride(PVC) as target recycling plan examine wish to. It is polyolefine(TPO) and polyvinyl chloride(PVC)) is mediocrity material that there are a lot of amount useds among plastic material and it is material that recycling is also activated most. Long term made first new regulation raw material, by-product raw material happened at process of production at second factory and third time to examine recycling plan of this material divides this as raw material that pass through process separation and pelet Tuesday and analyzed each special quality removing each removed waste after is used. Measure tension strength and ext. heightening gradually mixing proportion of refreshing resources on standard Sample manufactured as new raw material and application examined possibility availability to single fly system.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.237-238
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• 2010

The purpose of this research is to develop the method for the beneficial use of dredged material. In this research, authors investigate the material properties of dredged material contained with dredge material of various contents. The compressive strength of cement mortar with 10% dredged material from the Busan harbor is slightly higher than it of conventional mortar, but, it is to need to further research for developing the application technique on the dredged material as the substitutional material of a sand.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.259-264
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• 2003

This paper suggests a material mixing method to mix several materials in a structure. This method is based on ESO(Evolutionary Structural Optimization), which has been used to optimize topology of only one material structure. In this study, two criterions for material transformation and element removal are implemented for mixing several materials in a structure. Optimal topology for a multiple material structure can be obtained through repetitive application of the two criterions at each iteration. Two practical design examples of a short cantilever are presented to illustrate validity of the suggested material mixing method. It is found that the suggested method works very well and a multiple material structure has more stiffness than one material structure has under the same mass.