• Journal of the Korean Society for Railway
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• v.5 no.3
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• pp.196-200
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• 2002

In this paper, the straightening process of a steel bar straightener is studied. The straightener carries out the bending and reverse bending process repeatedly. Plastic theory is employed for the analysis of roller-supporting-load, and the residual stress and the axial load of a steel bar are calculated by using the bending moment. The Bauschinger effect and plastic moment are calculated by using the residual stress and Swift's method respectively. It is verified from the experiments that the displacement calculated from theory makes it possible to straighten a steel bar.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.806-818
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• 2006

The shear spinning process, where the plastic deformation zone is localized in a very small portion of the workpiece, shows a promise for increasingly broader application to the production of axially symmetric parts. In this paper, the three components of working force are calculated by the newly proposed deformation model in which the spinning process is understood as shearing deformation after uniaxial yielding by bending, and shear stress, $\tau_{rz}$ becomes $\kappa$, yield limit in pure shear, in the deformation zone. The tangential forces are first calculated and the feed forces and the normal forces are obtained by the assumption of uniform distribution of roller pressure on the contact surface. The optimum contact area is obtained by minimizing the bending energy required to get the assumed deformation of the blank. The calculated forces are compared with experimental results. A comparison shows that theoretical prediction is reasonably in good agreement with experimental results.

• Design & Manufacturing
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• v.12 no.3
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• pp.31-35
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• 2018

In this paper, the method of improving the flatness and perpendicularity for a corner fixing bracket of the large display frame is studied through experiments. Three specimens were tested, one specimen not subjected to bending line before bending, and two specimens with a straight groove with 0.2 mm and 0.5 mm depth. Experimental results show that the flatness of bracket becomes worse with deeper depth. When there is no straight groove, the perpendicularity becomes worse. For the flatness correction, a restriking process was added. The twist of bracket was corrected by performing the restriking with a curvature larger than the twist amount in the direction opposite to the deformed direction. We also found that the perpendicularity is maintained regardless of the amount of curvature with the restriking process.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.459-468
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• 2010

Materials are such an important factor in designing furniture. Wood is the biggest part of furniture materials. While wood is soft, eco-friendly and natural material, it is variable because it is characterized by severe expansion and contraction. Thus, if the changeable characteristic of wood is not considered in furniture design, the good design of furniture cannot be produced. As one of the skills dealing with woods, bending is such a useful way for making various forms of furniture. While it has been used in furniture-making for a long time, wood processing techniques like steaming bending, bending with ammonia and high frequency bending has been advanced. As wood is a viscoelastic material and has some plasticity, beautiful curves can be created when force is applied. Therefore this paper studies the types of bending methods for furniture and each characteristic of them. Furthermore, this study classifies wood process according to suitability for mass production or small-scale production and researches the proper wood process by the forms and the way of furniture production. Also this study aims to help furniture designers and cabinet makers with wood bending.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.199-205
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• 2001

This paper describes the design methodology, manufacturing process, rebar tensile and bending properties. Braidtrusion is a direct Composite fabrication technique utilizing an in-line braiding and pultrusion process. The produced Composite rebar exhibits ductile stress-strain behavior similar to that of conventional steel bar. Various rebar diameters ranging from modeling scale(3m) to full-scale prototype of 9.5mm have been produced Glass Fiber Reinforced Plastics(GFRP) rebar were successfully fabricated at $\phi$8.5mm and $\phi$9.5mm nominal diameters of soild and hollow type using a braidtrusion process. Tensile and bending specimens were tested and compared with behavior of stress-strain of GFRP rebar and steel bar.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.402-408
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• 2003

Currently tube hydroforming has many studies and applications in manufacturing industry, especially in automotive industry. But tube hydroforming was applied to the automotive component with simple shape. So the manufacturer and the researcher proposed additional processes to form the automotive component with complex shape. It is prebending and preforming. Prebending is to crush bend or rotary draw bend a tubular blank into a shape that facilitates placement into the next forming tool. Preforming is where the prebent tube is crushed into a shape that facilitates placement into the final forming tool. This paper analyzed and compared to the tube hydroforming process to using of general and preformed bending tube, also explained the importance of tube bending and preforming process. The explicit finite element program PAM-STAMP$\^$TM/ was used to simulate the tube hydroforming operations.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.357-360
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• 2008

In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. In this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal SILL SIDE manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.62-70
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• 2001

As the ship hull is a compound-curved structure, plate bending process is indispensible. The process includes press bending process for forming major 1st curvature and heating process for forming the rest curvature. Especially the heating process that is above 50 percents of entire bending work is carried out exclusively by skillful workers. Many researches have been made to automate the heating process but most of these are about line heating process and researches for triangle heating process are rare. This study is a fundamental study to develop a efficient analysis method for triangle heating and focused on clarifying the deformation characteristics of plate by triangle heating. In this paper, we carried out heating experiments and analysed the deformation characteristics of plate to explain the deformation characteristics of plates rationally by showing the phase transformed high temperature region. Also we investigated the heating effect on the hull material properties by mechanical tests.

• Journal of Fashion Business
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• v.8 no.4
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• pp.22-32
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• 2004

The purpose of this research is to know the pattern of Hanbok Jegory with measuring Jegory and studying manufacturing method of the Jegory used currently. It is a purpose to find constitutional problem caused by the character of the bending somatotype and, to study the standard model of the Jegory for bending somatotyped women in old age, by comparison of this fitness for bending-somatotyped women in old age. The results obtained are as follows; 1. The kinds of measurements considered in manufacturing process are Hwajang Length, Bust girth, and the skirt length. The length of Jegory and width of Neck are also considered. 2. Manufacturers consider somatotype the most important thing when they make Jegory for women in old age. Front length, Back length and Width of the Jegory are considered secondly important. 3. The results of the comparison show that the Standard Hanbok drafting method is not suitable for drafting Jegory for bending somatotyped women in old age. 4. The suitability test for the model designed by the above methods shows that it fits in bending somatotyped women in old age better than standard drafting method. The results show the superiority of the above methods especially in the breast width, the Godae length, and the adaptedness to the body.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1327-1345
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• 2016

$Al_2O_3$/SiC particulate reinforced (Metal Matrix Composites) MMCs which were produced by using stir casting process, bending strength and hardening behaviour were obtained using an analysis of variance (ANOVA) technique that uses full factorial design. Factor variables and their ranges were: particle size $2-60{\mu}m$; the stirring speed 450 rpm, 500 rpm and the stirring temperature $620^{\circ}C$, $650^{\circ}C$. An empirical equation was derived from test results to describe the relationship between the test parameters. This model for the tensile strength of the hybrid composite materials with $R^2$ adj = 80% for the bending strength $R^2$ adj = 89% were generated from the data. The regression coefficients of this model quantify the tensile strength and bending strengths of the effects of each of the factors. The interactions of all three factors do not present significant percentage contributions on the tensile strength and bending strengths of hybrid composite materials. Analysis of the residuals versus was predicted the tensile strength and bending strengths show a normalized distribution and thereby confirms the suitability of this model. Particle size was found to have the strongest influence on the tensile strength and bending strength.