• Biomaterials and Biomechanics in Bioengineering
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• 제3권1호
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• pp.47-57
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• 2016

Results from multiple high profile experiments on the parameters influencing the impacts that cause skull fractures to the frontal, temporal, and parietal bones were gathered and analyzed. The location of the impact as a binary function of frontal or lateral strike, the velocity, the striking area of the impactor, and the force needed to cause skull fracture in each experiment were subjected to statistical analysis using the JMP statistical software pack. A novel neural network model predicting skull fracture threshold was developed with a high statistical correlation ($R^2=0.978$) and presented in this text. Despite variation within individual studies, the equation herein proposes a 3 kN greater resistance to fracture for the frontal bone when compared to the temporoparietal bones. Additionally, impacts with low velocities (<4.1 m/s) were more prone to cause fracture in the lateral regions of the skull when compared to similar velocity frontal impacts. Conversely, higher velocity impacts (>4.1 m/s) showed a greater frontal sensitivity.

• 물과 미래
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• 제29권1호
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• pp.141-150
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• 1996

상수관망에서의 압력과 유량의 정상상태 해석은 수공학에 있어서 매우 중요한 문제이다. 이 경우의 기본방정식은 유량을 미지값으로 하는 연속 방정식과 에너지 방정식으로 구성되는 비선형 연립방정식이다. 이 연립방정식을 풀기 위하여 선형화 기법을 도입하여 반복적으로 해석하였고 그 결과로 나타나는 선형 연립방정식의 효율적인 해석을 위해서 frontal기법을 사용하여 계산하였다. 이 기법은 계수 메트릭스의 '0'이 아닌 요소만을 모아 계산하므로 효과적으로 분산 메트릭스를 해석할 수 있었고, 기존의 band 해석기법보다 적은 앙의 계산 기억용량으로 계산시간을 크게 단축시켜 해석할 수 있었다. 본 연구에서 제시한 상수관망의 해석모형은 기존의 해석방법보다 정확하고 효율적인 계산기법으로서 제시하였다.

• 대한치과보철학회지
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• 제32권4호
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• pp.553-564
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• 1994

Using Sirognathograph Analyzing System, the patterns of chewing movement were analyzed into opening phase and closing phase, each phase to frontal plane, horizontal plane, and sagittal plane by maruyama's classification. In opening phase, the chewing patterns of frontal plane were classifed into Chopping Opening, Grinding Opening, Concave Opening, Lateral Shift Opening, Vertical Guide Opening, Convergence Opening. Those of horizontal plane were classified into Chopping Opening, Grinding Opening, Concave Opening, Protrusive Shift Opening, Posterior Guide Opening, Convergence Opening. Those of sagittal plane were classified into Normal Opening, Protrusive Shift Opening, Vertical Guide Opening, Convergence Opening. In closing phase, the chewing patterns of frontal plane were classified into Normal Closure, Concave Closure, Lateral Shift Closure, Lateral Guide Closure, Vertical Guide Closure, Convergence Closure, Those of horzontal plane were classified into Normal Closure, Concave Closure, Lateral Shift Closure, Protrusive Shift Closure, Lateral Guide closure, Posterior Guide Closure, Convergence Closure. Those of sagittal plane were classified into Normal Closure, Protrusive Shift Closure, Vertical Guide. Closure, Convergence Closure. Results were summarized as follows : 1. Opening phase in chewing movement The Normal Openings in 3 planes(frontal, horizontal, sagittal), the Concave Openings in frontal plane and horizontal plane, the Vertical Guide Opening in frontal plane and the Posterior Guide Opening in horizontal plane were many observed. 2. Closing phase in chewing movement The Concave Closure in frontal and horizontal plane, the Normal Closure in 3 planes (frontal, horizontal, sagittal), the Concave Closure in horizontal plane were many observed.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.583-590
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• 2015

Automobile crash optimization is nonlinear dynamic response structural optimization that uses highly nonlinear crash analysis in the time domain. The equivalent static loads (ESLs) method has been proposed to solve such problems. The ESLs are the static load sets generating the same displacement field as that of nonlinear dynamic analysis. Linear static response structural optimization is employed with the ESLs as multiple loading conditions. Nonlinear dynamic analysis and linear static structural optimization are repeated until the convergence criteria are satisfied. Nonlinear dynamic crash analysis for frontal analysis may not have boundary conditions, but boundary conditions are required in linear static response optimization. This study proposes a method to use the inertia relief method to overcome the mismatch. An optimization problem is formulated for the design of an automobile frontal structure and solved by the proposed method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1156-1161
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• 2008

Nonlinear dynamic analysis is generally used in automobile crash analysis and structural optimization considering crashworthiness uses the results of nonlinear dynamic analysis. Automobile crash optimization has high nonlinearity and difficulty in calculating sensitivity. Recently the equivalent static load (ESL) method has been proposed in order to overcome these difficulties. The ESL is the static load set generating the same displacement field as the nonlinear dynamic displacement field at each time step in dynamic analysis. From various researches regarding the ESL method, it has been proved that the ESL method is fairly useful. The ESL method can mathematically optimize a crash optimization problem through nonlinear analysis and well developed static optimization. The ESL is applied to nonlinear dynamic structural optimization of the automobile frontal impact problem. An automobile bumper is optimized. The mass of the structure is minimized while some constraints are satisfied.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.489-494
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• 2001

This paper develops a finite element model for frontal crash analysis of a large-sized truck. It is composed of 220 parts, 70,041 nodes and 69,073 elements. This paper explains only major parts' models in detail such as frame, cab, floor, and bumper which affect on crash analysis a lot. In order to prevent penetration not only at a part itself but also between parts, all contact areas are defined using type-36, self-impact type. The developed model's reliability is validated by comparing simulation and crash test results. The results used for model validation are vehicle pulses at B-pillar, and frame and deformation of frame and cab. The frontal crash simulation is performed with the same conditions as crash test. And, it is performed using PAM-CRASH installed in super-computer SP2. The developed model whose reliability is verified may be used as a base to develop a finite element model for occupant behavior and injury coefficient analysis.

• Archives of Plastic Surgery
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• 제38권5호
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• pp.594-601
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• 2011

Purpose: The frontal sinuses are a pair of triangularly shaped, air-filled chambers lined by mucoperiosteum and located between the inner and outer tables of the frontal bone. Until recently, our understanding of gender variations in craniofacial anatomy has been chiefly built upon anthropometric studies, which typically employ facial surface measurements or plain film radiography. The aim of this study i to determine the sizes of the frontal sinus in both sexes in Koreans. Methods: 95 Korean subjects who underwent maxillofacial 3-Dimensional computed tomography (CT) between January 2009 and December 2009 were enrolled. Frontal sinus dimensions and forehead measurements were taken at midline and at 10, 20, and 30 mm to the left and right of midline using sagittal, coronal, and axial images. The data was analyzed for significant differences between measurements made at the selected points in the frontal sinus, for left to right variations, for gender variations, and for racial differences. Results: The mean thickness of the anterior table ranged from 2.31 to 3.23 mm. Mean anteroposterior depth of the frontal sinus ranged from 7.38 to 9.45 mm and did not vary significantly at any distance from midline. Frontal sinus height was greatest at midline (mean=29.24 mm) and progressively lessened at lateral distances. Mean total width at the level of the supraorbital ridge was 53.66 mm. For all measurements, no significant left to right variation was noted. Comparing the sexes, males were found to have greater dimensions in most frontal sinus measurements, though these differences were only found to be significant at or close to midline. The male forehead was marked by more acute nasofrontal angle ($133.3^{\circ}$ versus $141.6^{\circ}$) and a steeper posterior forehead inclination ($14.9^{\circ}$ versus $7.7^{\circ}$). Conclusion: Using CT imaging, forehead and frontal sinus dimensions have been described. Generally, males had larger overall frontal sinus dimensions. And Korean had similar sized frontal sinus to Caucasian in height and width. But in AP distance Korean had lesser measurement. The result of this study may be helpful in the comprehension of normal size of frontal sinus in Korean.

• 공업화학
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• 제10권5호
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• pp.672-676
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• 1999

흡착을 이용한 분리공정에서 가장 기본적인 것은 흡착평형식이다. 본 연구에서는 용출곡선법과 frontal analysis(FA)을 사용하여 용출곡선에서 직접 흡착평형식을 구하였다. 역상 액체 크로마토그래피(RP-HPLC)에서 시료는 5'-GMP이고 buffer로서 sodium phosphate를 물에 첨가하여 이동상으로 사용하였다. 이 실험조건에서는 시료의 양이 증가함에 따라서 체류시간이 감소하고 피크의 앞부분이 매우 경사가 심한 Langmuir 흡착평형식이 되었다. 용출곡선을 이용한 방법을 이용하여 Langmuir 흡착평형식의 매개변수를 최적화하여 구하였고 FA 방법을 이용하여 고정상의 농도를 용출곡선으로부터 측정하고 회귀분석에 의하여 흡착평형식을 측정하였다. FA 방법에 비해서 용출곡선법은 시료의 양이 적게 소모되고 실험 횟수도 1-2번 정도로 간편하였다. 이동상에 포함된 sodium phosphate의 농도에 따라서 Langmuir 흡착평형식의 매개변수에 미치는 영향을 고찰하였다.

• 자동차안전학회지
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• 제9권2호
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• pp.20-25
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• 2017

KNCAP is a program to evaluate the automobile safety, providing consumer vehicle safety assessment results. The safety evaluation tests are Frontal Impact, Offset Frontal Crash, Side Crash, Side Pole Crash, Rear Impact. This is the study of the offset frontal impact safety evaluation. Currently, IIHS is performing a small overlap test. NHTSA plans to implement the oblique moving deformable barrier test. Euro-NCAP plans to implement a mobile frontal impact test. Simulation is used to compare occupant behavior and injury. We have investigated whether the introduction of the test at KNCAP is necessary. The dummy model used in the simulation was the 50th percentile male Hybrid III dummy.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.234-241
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• 2002

In this study, the car crash analysis that simulates the crushing behavior of car forestructure during a frontal impact is carried out. The analysis model for front impact of a car consists of the lumped mass and the spring model. The characteristics value of masses and springs is obtained from the static analysis of a target car. The deceleration-time curve obtained from the simulation are compared with NCAP test data from the NHTSA. They show a good agreement with frontal crash test data. The deceleration-time curve of passenger compartment is classified into 3 stages; beginning stage, middle stage, and last stage. And the behavior of masses at each stage is explained. The effect of stiffness variation on deceleration of passenger compartment is resolved. The maximum loaded peak-time of torque box and dash is the main factor to control the passenger compartment's maximum deceleration.