• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.971-978
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• 2016

Recent trends in miniaturization and lightness in portable electronics parts have driven developments in subminiature screws. This study aims to investigate the thread rolling process of a subminiature screw with an outer diameter and pitch of 1.0 and 0.25 mm, respectively. Finite element (FE) analyses were performed for the thread rolling process of symmetric and asymmetric screw threads. Through FE analyses, various process parameters, such as the horizontal and vertical die gap and the rolling stroke, were investigated in terms of the forming accuracy. The material flow characteristics in the thread rolling process of the symmetric and asymmetric screws were also discussed, and the relevant process parameters were determined accordingly. These simulation results were then reflected on real thread rolling processes, from which the symmetric and asymmetric screws could be formed successfully with allowable dimensional accuracy.

• Journal of Fashion Business
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• v.22 no.1
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• pp.100-113
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• 2018

From the late 17th to the early 18th century, Europeans were strongly intrigued by products from the East. Therefore, several countries like England, France, and Netherlands formed the 'East India Company' to pursue trade. First, European markets rapidly responded to this desire for exoticism by importing goods; then, they produced imitation Oriental goods. Finally, they made stylistically advanced exotic merchandise from the perspectives of European. In terms of the textile industry, this trend was expressed in the pattern design of silk, or the so called 'bizarre silk.' In this paper, bizarre silk patterns were scrutinized based on a digital archive of museums, catalogues of museums, portal sites, and the literature. The bizarre silk patterns were analyzed then classified into six categories: pseudo-Oriental plant pattern, pattern mingled with architectural motifs, pattern of juxtaposed with Oriental goods, abstract pattern, exuberant pattern with metal threads, and semi-naturalistic pattern. These patterns were characterized according to the following features: strangely large exotic floral patterns were undulating and asymmetrical; exotic foliage and flowers were sometimes mixed with architectural motifs or Oriental goods to easily show the Oriental influence; motifs of bizarre silk patterns were abstractly stylized; bizarre silk patterns became luxurious once more like the Baroque period; finally, floral patterns became more natural, and still exotic motifs remained in the background to maintain the bizarre silk features. These bizarre silk patterns evolved from the viewpoints of Europeans through acceptance stage, compound stage, and confluent stage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.765-770
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• 2014

This paper describes the study on a method for improving the structural durability of bolted joints applied to a composite bogie frame. In this study, three bolted joints with and without inserts and screw threads were selected for determining the effect of the inserts, using experiment and analysis. The structural performances of the proposed bolted joints were compared and evaluated using the test method prescribed by the ASTM D5961 standard. The results revealed that the bolted joint having an insert shape without the screw thread offered improved durability for application to a composite bogie frame. Furthermore, the structural integrity of the frame comprising the bolted joints was evaluated using finite element analysis according to the JIS E 4207 standard. The Tasi-Wu and Von-Mises failure criteria were used for determining the failure of the composite structure and bolted joints, respectively. A sub-modeling technique was introduced for investigating the performance of the bolted joints in greater detail. The analysis results demonstrated that the Tasi-Wu failure index of the composite structure near the bolted joints was reduced by approximately one-half after applying an insert without the screw thread. This implies that the structural durability of the bolted joints of a composite bogie frame could be improved by using a metal insert without the screw thread.