• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.11a
• /
• pp.175-176
• /
• 2011

Applying previous studies performed in the moisture transportation characteristics and shrinkage of lightweight concrete application of shrinkage reduction is to discuss. Applicability of shrinkage reduction effect of lightweight concrete applies for the analysis of PSC girder bridge beam placed on the construction site. Stress of the concrete bridge deck, rebar quantity is calculated by effective elastic modulus method and crack risk is assessed by moisture transport and differential shrinkage analysis. After approximately 10 days maximum tensile stress occurs 6MPa, similar to the case of normal concrete, a maximum tensile stress occurs 3MPa in lightweight concrete and comparing to normal concrete stress was reduced to approximately 50%. Normal and lightweight concrete crack index, respectively, is reduced 1.6 to 1.2, 1.2 to 0.9 in surface and boundary region. Therefore, reduction in shrinkage of concrete were able to confirm reduction of crack risk.

• 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.

• Journal of Environmental Health Sciences
• /
• v.30 no.1
• /
• pp.1-6
• /
• 2004

This study was performed to estimate the effects of washing of food wastes on temperature, pH, weight and volume reduction and salinity in aerobic composting of food wastes. Weight ratios of food wastes to water in washing were 1:0(Control), 1:1 (W-1), 1:2(W-2), 1:3(W-3) and :4(W-4), respectively. Ratios of food wastes to wood chips in reactor of Control, W-1, W-2, W-3 and W-4 were 5 kg:5 1, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours aeration per day. The increase in the ratio of food wastes to water used in washing resulted in the decrease of the highest reaction temperature and the elongation of the high temperature reaction period. The lowering of the ratio of food wastes to water used in washing resulted in faster pH increase and the steady state in the weight reduction rate and the volume reduction rate of composts. The final salinities of Control, W-1, W-2, W-3 and W-4 were 0.95%, 0.73％, 0.65%, 0.57％ and 0.41％, respectively.

• Textile Coloration and Finishing
• /
• v.3 no.3
• /
• pp.6-14
• /
• 1991

To develop an one-bath process for weight-reduction and mercerization of polyester/cotton fabric, concentrated NaOH solution was padded and steam-treated at high temperature. Following results which can be used commercially are obtained. (1) Steaming temperature of 110-12$0^{\circ}C$ is most efficient. (2) Optimum concentration of NaOH solution is 15-20%. (3) Most favorable weight-reduction is 20% in the aspect of fabric handle, and under this treating condition, dye exhaustion onto the mercerized cotton fiber is also increased to 40% or more. From above results, we believe that the economical and concurrent weight-reduction and mercerzation of polyester/cotton fabric can be realized. Moreover, with continuous treatment by pad-steam procedure, it is expected that this is, also, advantageous for the improvement of fabric quality and productivity.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.9 s.186
• /
• pp.149-155
• /
• 2006

This paper is concerned with the weight reduction of front side member of a vehicle considering the application of high strength steel sheet. The influence of steel sheet grade and thickness on the energy absorption, impact load and deformed shape of front side member is investigated by using reverse engineering and FE-analysis. The reverse engineering is applied to obtain 3D model of front side member from B.I.W for the FE simulation. FE analysis is carried out with commercial crash analysis SW PAM-CRASH. The crashworthiness of front side member is considerably improved with steel sheet strength and thickness increase. From the result of this study the weight reduction in automotive parts for the improvement of the fuel efficiency can be easily achieved with replacing high strength steel without deterioration of crashworthiness.

• Textile Coloration and Finishing
• /
• v.11 no.1
• /
• pp.1-8
• /
• 1999

This study surveys the mechanical properties such as surface properties(MIU, MMD, SMD) to the weight reduction rate of PET fabrics. For this purpose, 12 kinds of satin and 18 kinds of plain weave fabrics are prepared with change of the physical properties of weft yarn(T.P.M., density, and denier). The weight reduction rate was 0%, 12%, 25%, and 30%. Coefficient of friction(MIU), mean deviation of friction(MMD), and geometrical roughness(SMD) of the fabrics were measured and discussed with wed twist, yarn linear density, weft fabric density and weave structures.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.04b
• /
• pp.7-7
• /
• 2002

Recently social demand to achieve low fuel consumption and clean emission requires the development of new generation vehicle beyond the conventional vehicle concept. In this point, new generation vehicle is newly designed as electric vehicle, hybrid electric vehicle, fuel cell electric vehicle or 3 liter car etc. In order to develop new generation vehicle, it is very important to develop new materials and process technologies now. In this paper these new technologies are presented focusing on weight reduction specially. Steel body can be achieved 20-25% weight reduction by adoption of high strength steel and new process technologies, i.e tailored blank and hydroforming. Aluminium body can be achieved 40-50% weigt down by use of all aluminium monocoque body or aluminium space frame with aluminium panel. Plasitic composite body can be achieved 30% weight reduction comparing with conventional steel body.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.159-163
• /
• 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 analyses were performed. Structural analyses were performed with a finite element analysis. Analyses were done for several cases suggested in various safety regulations of FMVSS(Federal Motor Vehicle Safety Standards). Each result 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. Substitution of the material resulted in a weight reduction effect with equivalent strength, fatigue and impact characteristics. Furthermore, several effects from the replacement of the material besides weight reduction were also examined.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.1071-1082
• /
• 2005

In this paper is studied a theoretical approach to predict structural performances and weight reduction rates of a carbody with shell type sections in case that its materials have to be substituted. For the material substitution design of a carbody, bending, axial and twisting deformations are considered under constant stiffness and strength conditions, which utilizes some new indices derived from a structural point of view. The developed indices to measure the weight reduction by the material substitution give good guidelines on conceptual design of carbodies.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.18-30
• /
• 2006

In this paper is studied a theoretical approach to predict structural performances and weight reduction rates of a car-body with shell type sections in case that its materials have to be substituted. For the material substitution design of a car-body, bending, axial and twisting deformations are considered under constant stiffness and strength conditions, which utilize some new indices derived from a structural performance point of view. The developed indices to measure the weight reduction by the material substitution give good guidelines on conceptual design of car-bodies.