• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.125-132
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• 2002

Bumpers are structural components to reduce physical damage to the front and rear ends of a passenger motor vehicle from low speed collisions. Damage assessment and the protectiveness are the commonly used designing criteria but in this study, relative displacements of the bumper are examined. To absorb the crash energy without significant damage to the bumper itself, foam material is installed between fascia and beam. However, it is not easy to predict the exact displacements generated in bumper structures through FEM because the compressive stress-strain curve of a foam material depends on strain rates that deviates significantly on each trial. Under this uncertain condition, a range of displacements is calculated and the optimum design is performed using the design of experiments. The result will be used to find the design that minimizes the weight within displacement constraints. The orthogonal array of L9 is introduced to find the optimum of the design variables that considers the thickness of inner beam, outer beam and stay, This study will suggest the design procedure of a front bumper using the uncertain stress-strain curve of a foam material.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.157-161
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• 2005

In the FY 2003, the number of registered vehicles in Korea reached 14 million, which is 7.7% increase from the previous year. The increase of number of vehicles has caused a lot of social problem with enormous costs. The social costs related to the vehicles includes environmental costs resulting from pollution and scraping of vehicles, those resulting from life-saving and repairing from car accidents and so on. There have been m any efforts to reduce the social costs in m any areas. As a part of the efforts, there are recent grow ing interests on the damageability & repairability in related industries. In this study, we investigated the cases of two different types of bum per stay. Futhermore, we analyzed their effects on damageability & repairability and reduction of repair cost. So we found that if the manufacturers design new cars with good damageability & repairability, then the total repair cost in crash will be reduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.1-9
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• 2010

The purpose of this study is to analyze the bumper mounting structure of passenger vehicles at low speed collision. In order to improve the repairability and damageability of the vehicle, the low speed crash tests of RCAR(Research Council for Automobile Repairs) standard(front & rear 15km/h 40% offset crash test) were carried out for analysis of 3 different types of bumper mounting structures. The results of experiments show that the impact energy absorbing ability of bumper stay with rectangular crash box type vehicle which is inserted into the bumper rail was superior to another two different bumper mounting structures that are applied to many passenger vehicles. In this thesis, well designed bumper mounting structure such as rectangular crash box type can enhance the safety of occupants as well as contribute to reduce repair cost at low collision accident by improving repairability and damageability of vehicle.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.6
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• pp.546-554
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• 2021

Purpose: Malnutrition is a significant issue for pediatric patients with cancer. We sought to evaluate the effectiveness and complication rate of percutaneous endoscopic gastrostomy (PEG) placement in pediatric oncology patients. Methods: A retrospective chart review was performed on 49 pediatric oncology patients undergoing PEG placement at Johns Hopkins All Children's Hospital between 2000 and 2016. Demographic and clinical characteristics, complications, absolute neutrophil count at time of PEG placement and at time of complications, length of stay, and mortality were identified. Weight-for-age Z-scores were evaluated at time of- and six months post-PEG placement. Results: The overall mean weight-for-age Z-score improved by 0.73 (p<0.0001) from pre- (-1.11) to post- (-0.38) PEG placement. Improvement in Z-score was seen in patients who were malnourished at time of PEG placement (1.14, p<0.0001), but not in those who were not malnourished (0.32, p=0.197). Site infections were seen in 12 (24%), buried bumper syndrome in five (10%), and tube dislodgement in one (2%) patient. One patient (2%) with fever was treated for possible peritonitis. There were no cases of other major complications, including gastric perforation, gastrocolic fistula, clinically significant bleeding, or PEG-related death documented. Conclusion: Consistent with previous studies, our data suggests a relationship between site complications (superficial wound infection, buried bumper syndrome) and neutropenia. Additionally, PEG placement appears to be an effective modality for improving nutritional status in malnourished pediatric oncology patients. However, larger prospective studies with appropriate controls and adjustment for potential confounders are warranted to confirm these findings.