• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.269-272
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• 2006

The hydroforming processing is a relatively new technology in comparison with conventional stamping process. The hydroforming processing makes torsion beam in rear suspension of automobile. The durability of torsion beam is very important characteristic that operate in an automobile. In order to optimize the hydroforming process and satisfy the durability, the hydroforming simulation which could control an axial compression and high internal pressure with computer simulation has to be operated. This paper is about an optimum design to improve the kinematic and compliance characteristics of a torsion-beam of suspension system. The result from finite element analysis shows that the forming and the durability are optimized. If there is effect of First pressure in hydroforming processing that gap is in the die tool, the prototype of tube is not satisfied on the durability test.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.466-471
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• 2004

Efficient numerical finite element analysis of creeping concrete structures requires the use Kelvin or Maxwell chain model, which is most conveniently identified from a continuous retardation or relaxation spectrum, the spectrum in turn being determined from the given compliance or relaxation function. The method of doing that within the context of solidification theory for creep with aging was previously worked out by Bazant and Xi, but only for the case of a continuous retardation spectrum based on Kelvin chain. The present paper is motivated by the need to incorporate concrete creep into the recently published microplane model M4 for nonlinear triaxial behavior of concrete, including tensile fracturing and behavior under compression. In that context. the Maxwell chain is more effective than Kelvin chain. because of the kinematic constraint of the microplanes used in M4. Determination of the continuous relaxation spectrum for Maxwell chain. based on the solidification theory, is outlined and numerical examples are presented.

• 한국소음진동공학회논문집
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• 제17권10호
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• pp.958-966
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• 2007

This study presents full vehicle dynamics model for the dynamic characteristic analysis of chassis parts which are suspension and brake system. This vehicle dynamics model is appled to kinematics and quasi-static analysis for each chassis part. In order to develop the vehicle dynamics model, the parameters of each chassis element part which are bush, spring and damper are measured by experiment. Also the wheel forces and moments of 6 DOF are measured at each wheel center. These data are applied to input parameter for vehicle dynamics model. And the verification of the developed model is achieved to comparison with the experimental force data of spring, trailing arm and assist arm by using the load response by strain gauge. These experimental force data are acquired by road test at event surfaces of P/G which are belgian and chuck holes roads.

• 한국정밀공학회지
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• 제30권9호
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• pp.961-968
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• 2013

In this paper, we propose an optimal design for starfish capturing manipulator module with four-bar linkage mechanism. A tool link with compliance is attached on the four-bar linkage, and the tool repeats detaching starfish from the ground and putting it into the storage box. Since the tool is not rigid and the manipulator is operating underwater, the trajectory of the tool tip is determined by its dynamics as well as kinematics. We analyzed the trajectory of the manipulator tool tip by quasi-static analysis considering both kinematics and dynamics. In optimization, the lengths of each link and the tool stiffness are considered as control variables. To maximize the capturing ability, capturing stroke of the four-bar manipulator trajectory is maximized. Reaction force and reaction moment, and other kinematic constraints were considered as inequality constraints.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.409-414
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• 2007

Nowadays, with the advancement of computational mechanics, and vehicle dynamics simulation linked up with virtual testing laboratory(VTL) and virtual proving ground(VPG) technologies has become a useful method for analyzing numerous driving performances and diverse noise/vibration characteristics. In this paper, the analytical vehicle model based on multi-body dynamics theory was developed to investigate the vibration characteristics according to various road conditions. For the purpose, the whole vehicle parameters, each vehicle's part parameter, and part connecting elements such as spring, damper, and bush were measured by an experiment. Also, the vehicle dynamics model, which includes the front suspension, rear suspension, steering, front wheel, rear wheel, and body subsystems has been constructed for computer simulation. With the developed vehicle dynamics model, three forces and three moments measured at each wheel center were applied to evaluate and analyze dynamics and vibration characteristics for miscellaneous road conditions.

• 한국지반공학회논문집
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• 제36권12호
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• pp.125-132
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• 2020

암반내의 절리는 암반의 전체적인 역학적 거동에 중요한 역할을 한다. 암반에 대한 수치해석은 절리면의 역학적 물성, 방향성, 간격 그리고 연속성을 정교하게 모델링할수 있어야 한다. 본 논문의 내재적 절리-연속체 접근법은 절리군을 포함한 암반의 역학적 모델을 제시한다. 암반에 대한 강성 텐서는 온전한 암석과 절리군의 역학적 특성으로부터 산정하였다. 이는 온전한 암석과 절리군에 대한 연속적 강성 시스템의 컴플라이언스 텐서 합으로부터 산정할 수 있다. 암반사면의 평면파괴에 대한 수치해석은 기존의 daylight envelope과 측면한계를 적용하는 경험적인 방법과 상당히 일치함을 확인하였다. 개발된 내재적 절리-연속체 모델은 연속체 기반으로 수식화되어 기존의 절리에 대한 열-수리-화학적 실험적 결과들을 실제 수치해석에 적용할수 있을 것이다.

• 대한정형외과스포츠의학회지
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• 제8권2호
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• pp.76-82
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• 2009

목적: 아킬레스 동종건을 이용한 관절경적 후방십자인대 재건술을 시행한 환자군에 대해 임상적 결과를 평가하고 보행분석을 시행하고자 하였다. 대상 및 방법: 2004년 3월에서 2005년 3월 까지 후방십자인대 손상에 대해 신선 동결 아킬레스 동종건을 이용한 관절경적 재건술을 시행 받은 환자들 중, 저자들이 지시한 재활 프로그램에 순응한 12명의 환자를 대상으로 하였다. 모든 환자에서 수술후 추시 36개월에 임상적 결과 평가와 보행분석을 시행하였다. 임상적 결과는 관절 운동 범위, Lysholm knee score, Tegner Activity Score, IKDC score, 후방 전위 검사, Telos stress arthrometer를 이용한 후방 전위를 측정하여 평가하였고 보행검사는 3차원적 보행분석기를 이용하여 분석하였다. 결과: 모든 임상적 결과 평가 항목에 있어서 술 전과 비교하여 후방십자인대 재건술 후 통계학적으로 유의한 만족할 만한 결과를 보였다. 보행분석 결과 환측과 건측 슬관절에 굴곡각 및 내반각의 약간의 차이를 보였지만 통계적으로 유의성을 보이지 않았으며, 전반적으로 양쪽 슬관절의 유의한 보행의 차이는 관찰되지 않았다. 결론: 후방십자인대 손상 슬관절에서 관절경적 재건술을 시행한 환자 중 재활프로그램에 순응한 환자를 대상으로 평가한 결과 술 전과 비교하여 의미있게 증가된 임상적 결과와 건측과 비교하여 차이를 보이지 않는 보행분석 결과를 얻은바 후방십자인대 재건시 체계적이고 엄격한 재활치료가 중요할 것으로 사료된다.