• Structural Engineering and Mechanics
• /
• v.58 no.3
• /
• pp.555-576
• /
• 2016

In this paper an efficient approach is introduced for design and analysis of double-layer grids including both geometrical and material nonlinearities, while the results are compared with those considering material nonlinearity. Optimum design procedure based on Enhanced Colliding Bodies Optimization method (ECBO) is applied to optimal design of two commonly used configurations of double-layer grids. Two ranges of spans as small and big sizes with certain bays of equal length in two directions are considered for each type of square grids. ECBO algorithm obtains minimum weight grid through appropriate selection of tube sections available in AISC Load and Resistance Factor Design (LRFD). Strength constraints of AISC-LRFD specifications and displacement constraints are imposed on these grids.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.5
• /
• pp.83-89
• /
• 1999

A seat frame structure in automotive vehicles made of polymer matrix composite to achieve weight reduction at low cost was developed. In order to design and manufacture the actual product studies on material selection and structural analysis were performed. Structural analysis was performed with a finite element method. The analysis was done for several cases suggested in various safety regulations. Each results was utilized to modify the actual shape to obtain a lighter, safer and more stable design. The final design was used to produce a sample bottom plate of the seat structure with reinforced by X-shape frame. Substitution of the material resulted in a weight reduction effect with equivalent strength fatigue and impact characteristics.

• Corrosion Science and Technology
• /
• v.9 no.3
• /
• pp.116-121
• /
• 2010

For over a decade, research and development on submerged hardware in continuous galvanizing pots has been carried out at Teck's Product Technology Centre. The outcome of numerous laboratory tests and field trials has demonstrated that dissimilar materials with comparable surface hardness are most suitable for the manufacture of roll bearings. Wear debris can be easily retained in bearings made of the same material, thereby negatively affecting bearing performance and service life. Bearings made of the same materials are also vulnerable to catastrophic failures. The dissolution of iron from the coated strip creates an iron-rich zone associated with a high concentration gradient in the vicinity of the sink roll. Consequently, the sink roll becomes a preferential site for dross pick-up. In operations involving extremely high temperatures, such as in Galvalume production, the material selection for pot hardware is immaterial to the final corrosion product of the hardware and the pick-up on the hardware.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.660-663
• /
• 2004

Recently in the automotive industries, light and high quality material is strongly required because of emissions regulation issues. In the electromagnetic stirring process, it has many merits that are the exact control ability about material processing and a good point of the protection of environment. In this paper, the morphology of the change of primary Al phase in A356 alloy by electro magnetic stirrer was investigated to obtain the globular structure. The parameters are the current, stirring time, pouring temperature and cooling rate of different wall thickness; 5mm, 15mm, 25mm respectively. By proper selection of the processing parameters, globular primary particles can be obtained by electromagnetic stirrer.

• Korean Institute of Interior Design Journal
• /
• v.14 no.2 s.49
• /
• pp.55-62
• /
• 2005

In modern days when architectural materials have grave impacts on overall design expression, materials for architecture, modern architecture into the service facility for business, education, religion, cultural assembly and residence, and evaluates each finishing material mainly used in exterior, lobbies and entrances of the building since the 1970's. When being applied social images into firstly selected materials, the scopes for material selection will be more narrowed down in more practical way. High tensity materials are suitable for public and active space and low tensity are for private and static area. This principle enables us to use architectural materials as one of the important elements which express the whole characteristics of the area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.809-812
• /
• 2001

We were fabricated of NiCr thin film resistors on A1$_2$O$_3$and SiO$_2$/Si substrates by dc magnetron sputtering system. The AC characteristics of resistors were studied. The cut-off frequency were found >10 MHz for the resistors with 39 ohm value of Alumina substrates, but the cut-off frequency were found 400 kHz for the resistors with 168 ohm value of SiO$_2$/Si substrates. In high frequency applications, the substrate selection is the most important factor.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.12 no.20
• /
• pp.33-38
• /
• 1989

In order to achieve the most suitable designing of shoemaking, the structure of shoemaking is described in this study by inquiring into structural and functional effects given by shoes to human feet. Also, the role of insole that is an essential portion in view of function in shoemaking is described and. for the improvement of quality the fact that selection of material of insole has an effect to quality is substantiated through experiments of adhesive tensile and absorption percentage. Though identification of the qualify of insole with the naked eyes is impossible because it is inserted between the internal layers of a shoe. It is not only an essential portion for the improvement of the quality of shoemaking but it gives an essential effect to the sanitation and health of human body(feet) when insole of lower qualify is used. In view of these the improvement and enhancement of the quality of home-made material of insole are earnestly required.

• Journal of KIBIM
• /
• v.2 no.2
• /
• pp.17-26
• /
• 2012

This paper presents the results of a theoretical energy analysis of a research test bed called the Zero Net Energy Test House (ZNETH) in Omaha, Nebraska in U.S.A. The ZNETH project is being designed and built with the goal of consuming a negligible amount of energy by offsetting remaining usage after energy conservation. The theoretically consumed and generated energy levels were analyzed using energy modeling software programs. By integrating a highly graphical and intuitive analysis with a Building Information Model(BIM) of the house, this investigation introduces strategies to include sustainable materials and systems to predict energy generation with a case study of ZNETH. In addition, this paper introduces parametric analyses for better envelope design and construction material selection by analyzing simulated energy consumption with various parametric inputs, e.g., material types, location, and size. It was found that the current design of ZNETH does not meet its goal of zero net energy. Sugeestions are presented to assist ZHETH in meeting its net zero energy goal.

• Journal of the Korean Institute of Educational Facilities
• /
• v.5 no.3
• /
• pp.107-115
• /
• 1998

Open education is more relevant to the current educational reality which requires the liberalization, individualization and creativeness, and the effectiveness of open education will be maximized with the full utilization of instructional media. As well known, there are many different types of instructional media to promote open education such as print material, audio material, still picture, movie, computer, and multimedia. The main criteria to choose effective instructional media for open education depend upon easiness of supply and retrieval of information, and promotion of more frequent interaction among participants. In addition, utilization method, cost, curriculum contents, as well as school culture are also elements to consider in the selection of right instructional media.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.53-56
• /
• 2004

This paper presents the improved burn-in method for the reliability of SRAM in MCP Semiconductor reliability is commonly improved through the burn-in process. Reliability problem is more significant in the Multi Chip Package, because of including over two devices in a package. In the SRAM-based Multi Chip Package, the failure of SRAM has a large effect on the yield and quality of the other chips - Flash Memory, DRAM, etc. So, the quality of SRAM must be guaranteed. To improve the quality of SRAM, we applied the improved wafer level burn-in process using multi cell selection method in addition to the current used methods. That method is effective in detecting special failure. Finally, with the composition of some kinds of methods, we could achieve the high qualify of SRAM in Multi Chip Package.