• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.90-93
• /
• 1999

In this paper a local remeshing technique assisted by user-interface capabiities is presented for precise forging simulation. The rigid-plastic finite element formulation is introduced and the basic approach to the new local remeshing technique is presented. A piercing process in cold forging is simulated by the presented technique and the results are compared in detail.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.163-168
• /
• 2000

In this paper, a 3-D computer-aided die design process was developed for automobile rear frame with drawing, trimming, flanging, cam-piercing and piercing for tool design. The tool design has been done using Pro/Engineer on a personal computer. It is composed of four stations. The goal of this research is to apply each of stations for the standard tool specification to each station.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2003.08a
• /
• pp.276-282
• /
• 2003

The breakwater of surface-piercing type has been developed mainly for application within bays or estuaries that are semi-protected from the direct impact of targe waves. Most of bays have soft foundation which is too weak to bear the weight of gravity type breakwater. (omitted)

• 건강소식
• /
• v.30 no.3 s.328
• /
• pp.14-15
• /
• 2006

• Journal of the Korean Society of Safety
• /
• v.30 no.4
• /
• pp.1-7
• /
• 2015

Self-piercing riveting (SPR) process is gaining popularity due to its many advantages. The SPR does not require a pre-drilled hole and has capability to join a wide range of similar or dissimilar materials and combinations of materials. This study investigated the fatigue strength of self-piercing rivet joint with aluminum alloy (Al-5052) and steel (SPCC) sheets. Static and fatigue tests on tensile-shear specimens were conducted. From the static strength aspect, the optimal punching force for the specimen with upper SPCC (U.S) sheet and lower aluminum alloy(L.A) sheets was 34 kN. During static test the specimens fractured in pull-out fracture mode due to influence of plastic deformation of joining area. There was a relationship between applied load amplitude $P_{amp}$ and number of cycles N ; $P_{amp}=19588N_f^{-0.211}$ and $P_{amp}=4885N_f^{-0.083}$ for U.S-L.A and U.A-L.S specimens, respectively. U.A-L.S fatigue specimens failed due to fretting crack initiation around the rivet neck between upper and lower sheets.

• International Journal of Oral Biology
• /
• v.32 no.3
• /
• pp.109-112
• /
• 2007

Somatic cells nuclear transfer (SCNT) is a useful tool in studies of developmental biology and animal cloning. However, SCNT experiments only are allowed to skilled technical experts. In this experiment, laser-assisted zona pellucida piercing tool (LASER) was applied in murine SCNT. LASER minimized the use of piezo-driven micromanipulator (PIEZO), reducing chances of problems caused by PIEZO pulses. LASER reduced time that took to pierce zona pellucida in removal of nucleus from oocyte and somatic cell injection, which might have taken longer time with PIEZO. Time and difficulties that took researcher of equivalent skilled for their experiments were decreased with LASER, and this might affect the improvement of embryonic development. (LASER, 6.2% versus PIEZO, 2.9%; P<0.05). Thus, these data support that the use of LASER can be used for zona pellucida piercing in murine SCNT program as an alternative to PIEZO.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.12 no.1
• /
• pp.88-92
• /
• 2009

Although transfusion of blood and plasma products are accepted as the principle means of transmission of HCV, other parenteral methods, such as acupuncture, tattooing needles, piercing, and surgery are possible methods of transmission of HCV. We managed a case of chronic hepatitis C acquired through ear piercing and acupuncture. A 10-year old girl presented with nausea, abdominal pain, and anorexia for 1 month. Her laboratory finding showed the following: AST/ALT, 865/1,290 IU/L; positive anti-HCV Ab; and HCV RNA. One year previously, she was treated with acupuncture for an ankle sprain and 2 years previously, she had her ears pierced. Laboratory findings of family members showed AST/ALT in the normal ranges, and negative anti-HCV Ab and HCV RNA. The pathologic findings of a liver biopsy revealed chronic hepatitis with mild lobular activity, moderate porto-periportal activity, and portal fibrosis. She was treated with pegylated interferon ${\alpha}$-2a and oral ribavirin for 6 months, after which the clinical symptoms and laboratory findings improved.

• Fashion & Textile Research Journal
• /
• v.8 no.5
• /
• pp.537-544
• /
• 2006

The purpose of this study is as well as Body decoration is a means to identify self-expression from the original nature of an individual freedom and originality, so there remains a race has not a cloth on, but there is no race does not pierce, it has been done with the beginning of a mankind. Subjects for this study were 202 persons, who experienced body piercing with twenties as the central figure. Statistical analysis was done by using SPSS 10.0 version and included AVOVA, Cronbach ${\alpha}$ realbility, Multiple Regression Analysis, Duncan's multiple range test, and Cross tabulation analysis. The result are as follow, The difference of self-conception classified by body piercer's sex distinction did not show significantly. Of the body piercer's feeling of depression to a sex role, neuter gender's feeling of depression showed highly in case of the physical self and the moral self and in case of the social self neuter's feeling and feminine gender's feeling to a sex role showed high. For the reason why he/she did body piercing, neuter gender's feeling showed high in case of influenced by the fashion and masculine gender's and feminine gender's feeling showed high in case of influenced by the curiosity. The body decoration classified by self-conception of body piercer did not show a significant difference.

• Transactions of Materials Processing
• /
• v.29 no.5
• /
• pp.257-264
• /
• 2020

This paper is concerned with the influence of the plastic property of the rivet on the numerical prediction of the Self-Piercing Rivet (SPR) Joining. In order to predict the plastic property of the rivet, a ring compression specimen was directly fabricated from the rivet used for the mechanical joining of dissimilar materials, and the FE analysis together with the ring compression test was iteratively carried out by changing the plastic property of the rivet. For reliable FE analysis, a friction coefficient was estimated based on a friction calibration curve, measuring the reductions in inner diameter and height of the ring specimen after the compression test. From each simulation result, the force-displacement curves were then compared from each other so as to obtain the rivet plastic property that shows good agreement with the experimental result. The SPR joining between GA590 1.0t and Al5052 2.0t was conducted, and the numerical prediction was performed with the use of the plastic property evaluated based on the inverse analysis and the one referred from Mori et al. [11]. Comparison of the experiment and the numerical predictions in terms of the interlock and bottom thickness revealed that the reliable evaluation of the plastic property of the rivet is necessary for the trustworthy numerical prediction of the SPR joining.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.6
• /
• pp.22-32
• /
• 1998

This paper describes a research work of developing a computer-aided design of irregularly shaped-sheet metal product with bending and piercing operation for progressive working. An approach to the CAD system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of five main modules, which are input and shape treatment, flat pattern-layout, production feasibility check, blank-layout, and strip-layout module. Based on knowledge-based rules, the system is designed by considering several factors, such as radius and angle of bend, material and thickness of product, complexities of blank geometry and punch profile, and availability of press. This system is capable of unfolding a formed sheet metal part to give flat pattern and automatically account for the adjustment of bend allowances to match tooling requirements by checking dimensions and the best utilization ratio of blank-layout within bending production feasibility area which is beyond ${\pm}30^{\circ}$ degrees intersecting angle between grain flow and bending edge line and which is suitable to progressive bending operation. Also the strip-layout drawing generated by a bending and a piercing operation according to punch profiles divided into automatically for external area of irregularly shaped-sheet metal product is displayed in graphic forms.