• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.5
• /
• pp.126-133
• /
• 2017

This report investigates the stress distribution according to the location and shape change of the circular hole for the lightweight design of the cross beam of a railway passenger car and studies the lightweight design. To design a lightweight cross beam with a circular hole, we selected the non-circular crossbeam as a basic model, examined the stress distribution and displacement by position and determined the location, shape, size and quantity of the hole for light weight. We analyzed the effects of the position and shape of the hole on the maximum equivalent stress and displacement. The influencing factors were set as the design parameters, and the stress value was examined according to the variation of each variable. By considering the stress value according to the change of each variable and selecting the design parameter with the narrowest scattering value of the stress at each position of the hollow cross beam with various hole positions and shapes, we studied a cross beam with a circle hole under identical load condition to have an equal stress distribution to that of a non-circular cross beam.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.9
• /
• pp.9-17
• /
• 1999

This investigation is the result of the structural analysis by finite element method for optimal design of the cross beam with circular holes of the electric car-body. in order to install the air pipe and electric wire pipe that correspond signal between electric machines for the control system and to reduce the weight of the electric car-body, several circular areas from a cross beam should be taken off. What we want to perform is the optimal design of a cross beam with circular holes to posses equal stress in comparison with no hole cross beam. first, no hole cross beam as basic modal be chosen, executing the analysis, reviewing the distribution of stress and displacement at each location. several parameter should be adopted from the cross beam geometry like the location and shape of the hole to affect the maximum stress and displacement. So the analysis was executed by finite element analysis for finding optimal design parameter to the change of the location and shape of the circular hole. finally, the optimal design of the cross beam with circular holes was obtained and the maximum equivalent stress was compared with no hole cross beam at each location.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.2
• /
• pp.296-303
• /
• 1987

The composite gear which is composed of involute curve and circular arc has been studied. In the vicinity of pitch point, its profile is an involute curve, and in the dedenum, a circular arc. The curve in the dedendum is generated by the circular arc of the mating gear. Though the available range between minimum and maximum radius of circular arc can be given by existing tooth profile equation, there was no formulation which relates design parameters to the desired radius. It is attempted to get the formula for the radius of circular arc as a function of design parameters, such as unwounded angle, number of teeth, module, and pressure angle. The radius of circular arc, the chordal tooth thickness at working root circle, nominal bending stress, Hertz stress and contact ratio obtained from derived formula are compared with those of the existing design criteria. And these are compared with those of involute gear.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.5
• /
• pp.684-689
• /
• 1990

We design a circular microstrip array antenna using the admittance of circular resonator. We can design the array antenna, considering equivalent radius of circular microstdrip consistant with conductances which are obtained from excitation coefficeients of the array elements. The antenna with 10 array elements are made on teflon substrate from Tshebyscheff method. It's perfermence are the gain 8.9dB, half power beam width 11.3dge, max, side lobe level -19dB, and they are almost in agreement with the theoretical results.

• Fashion & Textile Research Journal
• /
• v.18 no.6
• /
• pp.776-786
• /
• 2016

This study intends to suggest production process of circular knitted jackets and dimensional change data of finished clothes after washing. the study provides pattern design method of circular knitted jackets by applying dimensional change. By doing so, the purpose of this study is to increase production efficiency through accurate order in consideration of loss amount of the fabrics in production. With the three fabric materials selected, this study investigated dimensional change of circular knitted jackets after sewing and washing by varying the parts to be attached to padding cloth and with or without inner lining. As for the fabric F-C (including the spandex, thicker and weightier than the other two fabrics), front width shrunk by 4.6%, which showed the biggest shrinkage among the jackets made of test fabrics. Then it suggested design methods of circular knitted jacket patterns to which dimensional change is applied according to materials, and analyzed the amount of fabric required for production by comparison of the materials. When using the fabric F-C without inner lining, there is big dimensional change and more than double amount of fabric is required. It is expected that the research results will be a basic data for pattern design and production process of circular knitted clothing.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.46 no.6
• /
• pp.1039-1057
• /
• 2022

The fashion system has been criticized for relying on a linear economy to reduce short-term costs and increase profits. Meanwhile, the circular economy strives to expand the value chain through a closed loop for companies, society, and the environment by separating consumption from resources. This study aims to elucidate the strategic characteristics of the technological measures that fashion companies and brands are trying to innovate into a sustainable fashion system on the basis of the circular economy concept. Thus, we conducted case studies by dividing the value chain of the fashion system into design, production, and consumption to identify the technological development of the circular fashion system from a technologization perspective that incorporates technological values. First, design appeared to strengthen emotional durability, design and process with circulation in mind, and fashion product digitalization. Second, production manifested itself as material development for the new fiber economy, improvement of non-environmental processes, and customization of demand-driven, responsive production. Third, consumption was the spread of the environmental consumption culture through the sharing economy platform, the realization of a virtual wearing experience to prevent rapid disposal, and the provision of information on sustainable consumption.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.905-909
• /
• 2002

Characteristics of reflective LCDs, which have gained a lot of notice in recent years, rely largely on optical design of circular polarizers and the quarter-wave plates, as a component. Important design includes wavelength dispersion, viewing angle, uniformity of display and matching of refractive index. Our work has contributed to improving performance of reflective LCDs by enhancing the characteristics of polymer film using stretching and optical lamination technologies. To design that offers higher contrast and wider viewing angle, we have discovered that it is necessary to control viewing angle variation of the polarizing axis in order to compensate for the viewing angle of the polarizing film as well as the optical anisotropic properties of liquid crystal. Applying this technology to circular polarizers used for reflective LCDs enables design of wide viewing angle circular polarizers. In order to realize higher contrast for reflective LCDs, it is also necessary to design other optical materials including polarizing films. For design of hybrid optical film, it is particularly necessary to reduce surface reflection and interface reflection. This paper also reports our findings concerning this topic.

• Steel and Composite Structures
• /
• v.6 no.4
• /
• pp.285-302
• /
• 2006

This paper describes the design and behaviour of cold-formed stainless steel slender circular hollow section columns. The columns were compressed between fixed ends at different column lengths. The investigation focused on large diameter-to-plate thickness (D/t) ratio ranged from 100 to 200. An accurate finite element model has been developed. The initial local and overall geometric imperfections have been included in the finite element model. The material nonlinearity of the cold-formed stainless steel sections was incorporated in the model. The column strengths, load-shortening curves as well as failure modes were predicted using the finite element model. The nonlinear finite element model was verified against test results. An extensive parametric study was carried out to study the effects of cross-section geometries on the strength and behaviour of stainless steel slender circular hollow section columns with large D/t ratio. The column strengths predicted from the parametric study were compared with the design strengths calculated using the American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. It is shown that the design strengths obtained using the Australian/New Zealand and European specifications are generally unconservative for the cold-formed stainless steel slender circular hollow section columns, while the American Specification is generally quite conservative. Therefore, design equation was proposed in this study.

• 한국금형공학회:학술대회논문집
• /
• 2008.06a
• /
• pp.23-26
• /
• 2008

In order to examine the deformation characteristics of Al circular pipe underthe biaxial compression, the horizontal biaxial compression die for the experiment was manufactured. From this, in the various compressive strain rate (1 mm/min. ${\sim}$ 400 mm/min.)conditions, the circular pipes, which were made by Al materials, were investigated based on the properties change of cross section area, punch load and deformation behavior. The tensile and compressive strains were evaluated from micro Vickers hardness tester. From these results, the punch load and deformation characteristic of Al circular pipes were highly changed in the compressive strain rate about 200 mm/min. The Al circular pipes had the tendency that the punch load decreased with increasing the compressive strain rate. In addition, following as the change of the shape and position of neutral axis due to the deformation proceeding of the circular pipe, the special point of the internal circular pipe at maximum load showed the maximum deformation strain and the maximum measured hardness value. The CAE (computer aided engineering) simulation using Deform-2D program was performed on the circular pipe in order to know and verify the exact compressive deformation behavior. From these results, the experimentally measured results were reasonably in good agreement with the simulation results.

• Journal of Satellite, Information and Communications
• /
• v.12 no.1
• /
• pp.72-75
• /
• 2017

In this paper, we design the circular slits in the parch antenna for size reduction and high gain working at 900 MHz. Modifying the rectangular type patch, we decrease the antenna real-estate, leading to antenna miniaturization with added circular slits in itself. The antenna is tuned for under -30 dB return loss by adjusting the number of circular slits and their radii, and its design is performed for the maxim bean pattern of 4 dBi gain. Compared with the antenna without circular slits, the designed antenna shows 20 MHz downward shift of frequency, proving that the size reduction is achieved with this antenna design.