A Case Study for the Spine Fracture of a Pedestrian Impacted by SUV / 대한법의학회지

The civilization has given us a great comfort and convenience but also it has been threatening our life at the same time. Among these causes of death the traffic accident is the most dangerous thing to threat our life in recent years. According to the report of traffic accident in 2003, the pedestrian to car accident is almost 50% of all types of traffic accident and this percentage is very high level compare to other countries. So this is why we have to focus on this field of accident. This case is as follows, when a pedestrian was riding a bicycle and crossing the road, a taxi hit the bicycle with left outside mirror. The impact was not so severe, the pedestrian stood up by himself. Unfortunately he was impacted once again by a SUV which was following behind the taxi. The evidence were the SUV, clothing and victim. A complete autopsy was performed on the victim. The skull was slightly fractured with line shape and showed hypodermal bleeding under the head skin. The thoracic vertebrae of No. 11-12 was fractured. The cause of death was apparently head trauma and fracture of thoracic vertebrae. But we could not explain why the thoracic vertebrae was fractured without damage of internal organs in chest and abdomen. To analyze this case, we used a dynamic analysis program Madymo V6.2 and applied the Hybrid-III human model. Finally we could prove that if the pedestrian stand against the SUV, the bending moment in spine was raised suddenly at the beginning of impact. At this moment the leg was started to be move to the backward of pedestrian but the upper part of body could not move because of inertia. This bending moment make the spine hyper-extension and this level of moment can fracture the spine enough in low speed of SUV. In this study we analysis the car to pedestrian accident with engineering view and introduce the detail analysis method to reconstruct the accident involving the human trauma.

A Case Study of Stress Analysis for Compression Tank Using Finite Element Method / 대한법의학회지

A compression tank is normally made like round column shape to the middle part and plate shape in both sides. These kinds of tanks are usually designed to resist inner pressure but if the inner pressure is too high the tank will be exploded and some pieces can severe damage to human. If the shape of corner is about 90 degrees the stress will be very high at corner. So this kind of tank have been manufactured as smooth round corner even though its cost. Although smooth round type of corner, there is always some area of high level of stress and it is very difficult to calculate exactly because of complicate shape of corner. In this case study, here we introduce the FEM method to calculate the exact solution and compare the result with engineering fomula. The edge of tank was modeled like actual edge of tank and the critical inner pressure is 2.5 kg/cm2. This result is proven by engineering formula and we knew that this FEM method would be trustable to calculate a plenty of delicate problem whether the structures have original defect or not.