• 한국화재소방학회논문지
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• 제33권2호
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• pp.139-144
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• 2019

노인인구의 증가로 노인운전자의 손상과 사망자도 증가하였다. 하지만 노인운전자의 손상과 중증도에 대한 연구는 활발히 이루어지지 않아 영향 요인을 파악하지 못하고 있다. 본 연구에서는 정면충돌에서의 노인운전자에 손상과 중증도에 영향을 미치는 요인을 찾아 중증도 분류에 추가적으로 활용하고자 하였다. Collision Deformation Classification Code를 통해 차량 파손 정도를 확인하였으며 간편손상척도(Abbreviated Injury Scale, AIS)로 손상부위와 정도를, 손상중증도점수(Injury Severity Score, ISS)로 환자의 중증도를 확인하였다. 중증외상환자의 발생률은 5이상의 차량 파손 정도를 가진 대상자에서 Odds ratio가 7.381로 나타났으며 선형회귀분석을 통한 중증도 요인 분석에서도 차량 파손 정도의 ${\beta}$값이 0.453으로 나타났다. 따라서 5이상의 차량 파손 정도는 노인운전자에서 중증도 분류에 추가적으로 활용될 수 있는 기준으로 제안될 수 있다.

• 한국지반공학회지:지반
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• 제8권3호
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• pp.37-50
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• 1992

지진으로 인한 액상화현상은 토목구조물에 막대한 피해를 주고 있다. 본 연구에서는 액상화 현상에 대란 대책을 연구할 목적으로 모형 항만구조물을 대상으로 하여 진동대 실험을 실시하였다. 액상화현상으로 항만구조물에 발생하는 과잉변형을 방지하기 위하여 보강구간을 설치하고 그 효과에 대하여 검토하였다. 제방, 이중 널말뚝벽과 앵커 구조물의 진동대 실험을 통하여, 액상화 지반의 유동변형에 대한 특성과 보강범위에 대한 정량적 자료를 얻었다. 항만구조물을 보호하기 위한 보강구간의 범위는 진동가속도의 크기에 따라 다르다. 실험을 통하여 얻어진 구조물의 과잉변형을 보강구간의 범위와 진동가속도의 크기에 따라 나타내었다.

• 한국기계가공학회지
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• 제14권6호
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• pp.69-76
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• 2015

This study investigates the thermal efficiency and the efficiency of heat transfer through thermal analysis when the same heat is applied to a mortar frame by firing with various configurations of mortar. As the inside diameter of the mortar increases, the additional material must be reinforced. In comparison with the extent of getting cold due to models, a mortar with the strut under the gun barrel becomes cooler than one with no strut. The thermal deformation at firing becomes different. According to the configuration of mortar and its inside diameter, the extent of getting cold becomes different. This study result can be effectively applied for improving the efficiency of the heat transfer of mortar.

• 한국정밀공학회지
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• 제20권2호
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• pp.66-75
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• 2003

This paper describes about the estimation method of die lift by wear and plastic deformation in hot forging process. The thermal load and the thermal softening are happened by the high temperature in hot forging process. Tool lift decreases considerably due to the softening of the surface layer of a tool caused by high thermal load and long contact time between tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. Above all, the main factors which affects die accuracy and tool lift are wear and the plastic deformation of a die. The new developed technique for predicting tool life applied to estimate the production quantity for a spindle component and these techniques assist to improve the tool life in hot forging process.

• Structural Engineering and Mechanics
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• 제51권5호
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• pp.867-891
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• 2014

An equivalent single layer trigonometric shear deformation theory taking into account transverse shear deformation effect as well as transverse normal strain effect is presented for static flexure of cross-ply laminated composite and sandwich plates. The inplane displacement field uses sinusoidal function in terms of thickness coordinate to include the transverse shear deformation effect. The cosine function in thickness coordinate is used in transverse displacement to include the effect of transverse normal strain. The kinematics of the present theory is much richer than those of the other higher order shear deformation theories, because if the trigonometric term (involving thickness coordinate z) is expanded in power series, the kinematics of higher order theories (which are usually obtained by power series in thickness coordinate z) are implicitly taken into account to good deal of extent. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. The closed-form solutions of simply supported cross-ply laminated composite and sandwich plates have been obtained. The results of present theory are compared with those of the classical plate theory (CPT), first order shear deformation theory (FSDT), higher order shear deformation theory (HSDT) of Reddy and exact three dimensional elasticity theory wherever applicable. The results predicted by present theory are in good agreement with those of higher order shear deformation theory and the elasticity theory.

• Korean Journal of Geomatics
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• 제3권1호
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• pp.1-6
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• 2003

The purpose of this study is to make out a history of the coastline deformation with annual aerial photos of the target area and to suggest an efficient method for interpreting the coastline deformation. First, there were difficulties in obtaining annual aerial photos of an identical area as well as collecting periodical datum because of too much change of the real area during more than 27 years. Besides the past aerial photo is inferior to the latest one in quality. So there is nothing but to exclude an accuracy evaluation of the ortho photo. Taken into account the extent of the coastline change for 27 years is more than 10M and the all errors of the ortho image is included in this extent, both an accuracy and an error are ignored. The result of this study show that the coastline in the sea area of Namhangjin maintain advanced forward the ocean and keeps on moving with maintaining fairly wider shape of balance beach. Also The coastline deformation off l㎞ from the estuary is greatly irregular, which means the erosion of the sea in this area is in progress. The latest data being the aerial photo in 1996, it is difficult to find out the current conditions of a coastal erosion. However, considered the construction of a breakwater in Anmok Harbor is going on, the beach erosion becomes more accelerative recently. The aerial photos of the present Namhangjin's situation will make it possible to understand the history of the coastline change more accurately.

• 한국세라믹학회지
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• 제23권5호
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• pp.75-80
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• 1986

The mechanical properties were measured for magnesium phosphate glasses containing small amounts of water. The decrease in hardness with increasing water content was resulted from a looser chain structure caused by water. The fracture of these glasses was changed from brittle fracture to plastic deformation as a results of the increased viscous flow with increasing water contents. The extent of any viscous flow or deformation initiating from the crack tips in these glasses could be considered as quite small.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.163-168
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• 2002

Hot forging is widely used in the manufacturing of industry machine component. The mechanical, thermal load and thermal softening which are happened by the high temperature in hot forging process. Tool life decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load and long contact time between the tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. These are one of the main factors affecting die accuracy and tool life. That is because hot forging process has many factors influencing tool life, and there was not accurate in-process data. In this research, life prediction of hot forging tool by wear and plastic deformation analysis considering tempering parameter has been carried out for automobile component. The new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

• Journal of Welding and Joining
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• 제22권1호
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• pp.43-49
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• 2004

Contact tip is located so near to welding arc that it is heated to high temperature during long time welding. In such a situation, tip changes in its microstructure and in turn its mechanical properties. This study was intended to investigate those changes by using simulated heat treatment. As a result of this study, it was confirmed that tip of Cu-P alloy hardened with severe cold deformation lose its initial hardness to a large extent within 60 min due to the occurrence of rapid recrystallization while that of Cu-Cr composition hardened by proper aging treatment can preserve its intial hardness for about 1,000 min or longer. Based on these results, suggested was a guideline that can classify contact tips into two different grades: deformation-hardened type and precipitation-hardened type. Following a guideline, a tip with Cu-Cr composition can be classified into the deformation-hardened type if it is in the over-aged condition. Such a guideline is well described.

• Steel and Composite Structures
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• 제25권1호
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• pp.19-34
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• 2017

The widespread damage to steel Moment Resisting Frames (MRFs) in past major earthquakes have underscored the need to understand the nonlinear inelastic behaviour of such systems. To assess the seismic performance of steel MRF, it is essential to model the nonlinear force-deformation behaviour of beam to column joints. To determine the extent of inelasticity in a beam to column joint, nonlinear finite element analysis is generally carried out, which is computationally involved and demanding. In order to obviate the need of such elaborate analyses, a simplistic method to predict the force-deformation behaviour is required. In this study, a simple, mechanics driven, hand calculation method is proposed to obtain the forcedeformation behaviour of strong axis beam to column moment joints. The force-deformation behaviour for twenty-five interior and exterior beam to column joints, having column to beam strength ratios ranging from 1.2 to 10.99 and 2.4 to 22, respectively, have been obtained. The force-deformation behaviour predicted using the proposed method is compared with the results of finite element analyses. The results show that the proposed method predicts the force-deformation behaviour fairly accurately, with much lesser computational effort. Further the proposed method has been used to conduct Nonlinear Dynamic Time History Analyses of two benchmark frames; close correspondence of results obtained with published results establishes the usefulness and computational accuracy of the method.