• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.67-75
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• 2011

A new energy absorbing mechanism for car seat was developed to reduce the neck injury in rear impacts. Energy absorbing principle is based on the shear-bolt behavior of thin-walled cast components subjected to static and dynamic loads. Results of shear bolt test using AM60 of Mg alloys showed robust behavior giving an approximately constant mean force during failure processes. Simply designed energy absorbing mechanism was assembled with the recliner between seat backs and seat rails. We have simulated the sled test of seat with dummy under the rear end impact using the finite element method. Results of simulation show that the new seat mechanism reduces thorax acceleration to a considerable extent, but it is not sufficient to mitigate neck injury indices e.g. neck shear force, neck tension force and NIC. With heightened headrest and narrowed backset, the energy absorbing mechanism resulted in good performance of protecting the neck injuries.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1284-1292
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• 2006

Heat treatment is a controlled heating and cooling process to improve the physical and/or mechanical properties of metal products without changing their shapes. Today finite element method is widely used to simulate lots of manufacturing processes including heat treatment and surface hardening processes, which aims to reduce the number of time- and cost-consuming experimental tryouts. In this study we tried, using this method, to simulate the full carburizing process that consists of carburizing, diffusing and quenching, and to predict the distribution of carbon contents, phase fraction and hardness, thermal deformation and other mechanical characteristics as the results. In the finite element analysis deformation, heat transfer, phase transformation and diffusion effects are taken into consideration. The carburizing process of a lock gear, a part of the car seat recliner, that is manufactured by the fine blanking process is adopted as the analysis model. The numerical results are discussed and partly compared with experimental data. And a combination of process parameters that is expected to give the highest surface hardness is proposed on the basis of this discussion.

• Journal of The Korean Dental Society of Anesthesiology
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• v.14 no.1
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• pp.57-62
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• 2014

Background: The aim of this study was to analyze outpatient anesthesia for dental treatment in handicapped patients with behavior disorder in order to use data for carrying out better and safe anesthetic management. Methods: The data were drawn from the 100 patients with behavior disorder who visited CNUDH dental clinic for disabled based on anesthesia record to investigate patient's systemic condition, cooperative level, anesthesia method according to patients cooperation, and side effects after recovery time. Results: Mental retardation (58%) is the most reason to choose general anesthesia. The methods of induction according to cooperative level are intravenous propofol injection in 22 cases and inhalation of sevoflurane in 78 cases. Induction time of anesthesia were within 10 seconds in cases of propofol induction and average $48.8{\pm}18.5$ seconds in cases of inhalation induction. The time spent on dental treatment was average $3.2{\pm}1.1$ hours. After the end of treatment, average time to move from unit chair to recovery bed, to recliner, and to discharge from hospital are $10.4{\pm}5.1$, $36.9{\pm}17.1$ and $72.4{\pm}16.0$ minutes, respectively. During recovery, there are nausea with 9%, vomiting with 4%, dizziness with 2%, finger injury with 1%. Conclusions: This study showed our successful anesthetic outcomes without any severe side effects or complications. Through this study, it will be used for safe anesthetic management as useful reference data.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.155-163
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• 2006

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code(ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool(CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame. Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.