• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.242-249
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• 2017

In this study, the relationship between the shape of a passenger airbag and the possibility of injury is analyzed using the Taguchi method. The optimal shape combination is proposed for a design guideline that can reduce the possibility of injury to the dummy. The airbag FE model for analysis is obtained using a CAD system that can change the shape through several independent variables. The widths of the left / right, top / bottom, and back / forth direction of the airbag shape are set as the design factors, and the effect of the combination injury probability according to the shape is analyzed. The minimum geometric combinations are obtained using the orthogonal array method. The signal to noise ratio is calculated and the optimal shape combination is obtained through sensitivity analysis. The obtained optimal shape combination is compared with the possibility of injury of the initial airbag shape to confirm improved airbag performance.

• Structural Engineering and Mechanics
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• v.22 no.4
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• pp.419-432
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• 2006

Experimental studies on the behaviors of box-shape steel reinforced concrete (SRC) composite beams were conducted. Seven 1:3 scale model composite beams were tested to failure. Each of the beams was simply supported at the ends and two concentrated loads were applied at the one-third span and two-thirds span respectively. Experimental results indicate that the flexural strength can be enhanced when the ratio of flexural reinforcements and flange thickness of the shape steel are increased; the shear strength is enhanced with increase of web thickness of the shape steel. Insignificant effects of concrete in the box-shape steel are found on improving the flexural strength and shear strength of the box-shape SRC composite beams, thus concrete inside the box-shape steel can be saved, and the weight of the SRC beams can be decreased. Shear studs can strengthen the connection and co-work effects between the shape steel and the concrete and enhance the shear strength, but stud design for the composite beams should be further improved. Formulas for flexural and shear strength of the composite beams are proposed, and the calculated results are in good agreement with the experimental results. In general, the box-shape SRC composite beam is a kind of ductile member, and suitable for extensive engineering application.

• The Journal of the Korean dental association
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• v.22 no.5 s.180
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• pp.423-427
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• 1984

A total of 114 extracted human mandibular first molars were used to study the configuration of the floor of the chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 58.8% of the teeth were square, 34.2% were triangle and 7.0% were ovoid shape. 2. 58.8% of the specimens have 4 root canal orifices, 34.2% have 3 root canal orifices, 7.0% have 2 root canal orifices. 3. 41.2% of the specimens show 'H' shape, 17.6% show 'Square' shape, 31.6% show 'T' shape, 2.0% show 'reverse-T' shape and 7.0% show 'I' shape.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.93-98
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• 2012

In this study, we introduced image processing technic to measure shape variations of general bodies and applied it to the flexible yacht sail. Shape measurements of simple bodies sails were carried out and results showed that technic can be a reliable method to measure shape variations of the flexible yacht sail. The sail shape variation of 30ft sloop type yacht sail is measured on different sailing conditions. As velocity and direction of wind are increased, trailing edges in the upper part of the sail become more open than the lower part of the sail which are not changed. So it is confirmed that the shape measurement of a sail shape depending on a sailing condition is possible to use image processing scheme.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.151-160
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• 2004

Genetic algorithm is the theory of grafting the principle of survival of the fittest in genetics on to the computer algorithm and it is used to solve the optimization problems, especially the shape and size optimization of the structure in Architectural problems. In the size optimization problem discrete variables are used, but series variables have to be used in the shape optimization problem because of the incongruenty. The purpose of this study is to obtain the optimum shape of cable domes by using the real coding genetic algorithm. Generally, the structural performance of the cable domes is influenced very sensitively by pre-stress, geometry and length of the mast because of its flexible characteristic. So, it is very important to decide the optimum shape to get maximum stiffness of cable domes. We use the model to verify the usefulness of this algorithm for shape optimization and analyze the roof system of Seoul Olympic Gymnastic Arena as analytical model of a practical structures. It is confirmed lastly that the optimum shape domes have more stiffness than initial shape ones.

• Structural Engineering and Mechanics
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• v.53 no.4
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• pp.725-744
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• 2015

In this paper, a new damage indicator based on mode shape data is introduced to identify damage in beam structures. In order to construct the indicator proposed, the mode shape, mode shape slope and mode shape curvature of a beam before and after damage are utilized. Mode shape data of the beam are first obtained here using a finite element modeling and then the slope and curvature of mode shape are evaluated via the central finite difference method. In order to assess the robustness of the proposed indicator, two test examples including a simply supported beam and a two-span beam are considered. Numerical results demonstrate that using the proposed indicator, the location of single and multiple damage cases having different characteristics can be accurately determined. Moreover, the indicator shows a better performance when compared with a well-known indicator found in the literature.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.306-314
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• 2004

This paper explains the qualitative shape representation scheme and general shape analysis procedure based on shape feature categories. It takes two different groups of architectural drawings as examples and comparer them so as to confirm that the procedure is capable of comparing one group with another. In order to verify the validity of qualitative shape representation scheme, we used statistical methods as well as symbolic representation and analysis techniques. This paper concludes that two different groups of architectural drawings of similar kind are analyzed to be distinguished and specifically characterized. 11 drawings of Kahn and 13 drawings of Aalto are taken into considerations. Linear regressions are used in characterizing the shape featural relationships.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.275-280
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• 2004

Shape optimization was performed to obtain the precise shape of cutouts including the internal shape of cutouts in laminated composite plates by three dimensional modeling using solid element. The volume control of the growth-strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. The volume control of the growth-strain method makes Tsai-Hill failure index at each element uniform in laminated composites under the initial volume. Then shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study. (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminate composite, (2) The optimal shapes of the various load conditions and cutouts were obtained, (3) The maximum Tsal-Hill failure index was reduced up to 67% when shape optimization was peformed under the initial volume by volume control of growth-strain method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.343-347
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• 2008

Design of shape for visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is frequently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs. ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape. where density of either 0 or 1 for finite elements is used for physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure will be presented for a mount of an air-conditioner compressor system and the effectiveness will be discussed.

• Transactions of Materials Processing
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• v.18 no.7
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• pp.550-555
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• 2009

In the multi-pass shape drawing process, the pass schedule that includes the determination of reduction ratio and intermediate die shape is very important. This study used the equal reduction, equal load, and electric field analysis method for pass schedule of the multi-pass shape drawing. The reduction ratio was calculated by the equal reduction and equal load method. And the intermediate die shape was determined by the result of the electric field analysis and the calculated reduction ratio. The proposed pass schedule method was applied to a shape drawing for producing cross roller guide. Finally, FE-analysis and shape drawing experiment were performed to verify the effectiveness of the proposed method.