• 한국방사선학회논문지
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• 제12권1호
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• pp.115-122
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• 2018

본 연구에서는 CT영상기반 3차원 고관절모델을 이용한 컴퓨터시뮬레이션을 통해서 고관절의 운동범위(Range of Motion)를 측정하는 방법을 제시하였다. 본 연구에서는 그 측정방법에 대한 기술적인 사항을 제시하고, 그 기술이 재현성 있게 실현할 수 있도록 대퇴골두 중심점의 결절, 대퇴골 외전(Abduction)/내전(adduction)회전축, 굽힙(flexion)/신전(extension) 회전축을 정의하고 측정하는 명확한 방법을 제시하였다. 외전각은 해부학적인 시상면(Sagittal plane)상의 Anterior-Posterior축에 대해 아래쪽(Inferior)면으로부터 Lateral 쪽으로의 회전각으로 정의된다. 최대외전각은 대퇴골두가 엉덩이뼈(Pelvis)의 절구(Acetabulum)의 테두리와 겹치지 않고 Anterior-Posterior축을 중심으로 회전할 수 있는 최대 외전각으로 결정된다. 굴곡각은 해부학적인 관상면(Coronal plane)상의 Medial-Lateral축에 대해 아래쪽(Inferior)면으로부터 회전각으로 정의된다. 최대굴곡각은 대퇴골이 Medial-Lateral축을 중심으로 엉덩이뼈(Pelvis)의 절구(Acetabulum)의 테두리와 겹치지 않고 회전할 수 있는 최대 굴곡각으로 결정된다. 정상고관절에 비해 인공고관절술을 받은 해당 환자의 경우, 외전에서는 60도 정도, 굽힘에서는 4도 정도 운동범위가 줄어들 수 있다는 예측이 나왔다. 본 연구에서 행한 시뮬레이션을 해보고 외전의 경우 운동범위의 감소가 예측되므로, 대퇴골두를 조금 큰 것을 고르거나 대퇴골목부의 길이 (femoral neck offset)를 길게 시술해야 할 필요가 있음을 의미한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.667-672
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• 2004

A modeling method for the modal analysis of cantilever plates undergoing in-plane translational acceleration is presented in this paper. Cartesian deformation variables are employed to derive the equations of motion and the resulting equations are transformed into dimensionless forms. To obtain the modal equation from the equations of motion, the in-plane equilibrium strain measures are substituted into the strain energy expression based on Von Karman strain measures. The effects of two dimensionless parameters (related to acceleration and aspect ratio) on the modal characteristics of accelerated plates are investigated through numerical studies.

• 대한기계학회논문집A
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• 제29권6호
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• pp.889-894
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• 2005

A modeling method for the modal analysis of cantilever plates undergoing in-plane translational acceleration is presented in this paper. Cartesian deformation variables are employed to derive the equations of motion and the resulting equations are transformed into dimensionless forms. To obtain the modal equation from the equations of motion, the in-plane equilibrium strain measures are substituted into the strain energy expression based on Von Karman strain measures. The effects of two dimensionless parameters (related to acceleration and aspect ratio) on the modal characteristics of accelerated plates are investigated through numerical studies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.623-628
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• 2000

Since the influence coefficients method in balancing of rotors is developed with the basement of not the principle of rotor system dynamics, but the linear relationshop of between the measuring quantities and the unbalance quantities, field engineers can apply the method without additional understanding on the rotor dynamics. But the influence coefficients method is not robust to the measurement error. This paper proposes a new method for the two plane balancing of rigid rotor, based on the principle of rotor dynamics. And the kit for experiment is made by ourselves, and in order to measure in the same condition with it, we do a experiment three times. And then with the Response of gap sensor, the SNR(Signal and Noise) is compared and analyzed about measuring error between the influence coefficient method, and the new method, and it is proved that the new method is less robust than the influence coefficient method.

• 소음진동
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• 제10권5호
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• pp.849-858
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• 2000

In this paper the chaotic out-of-plane vibrations of the uniformly curved pipe with pulsating flow are theoretically investigated. The derived equations of motion contain the effects of nonlinear curvature and torsional coupling. The corresponding nonlinear ordinary differential equation is a type of nonhomogenous Hill's equation . this is transformed into the averaged equation by averaging theorem. Bifurcation curves of chaotic motion are obtained by Melnikov's method and plotted in several cases of frequency ratios. The theoretically obtained results are demonstrated by numerical simulation. And strange attractors are shown.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.188-189
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• 2013

The purpose of this research is to comprehend experimentally the characteristic of human dynamic load and provide the result as basic data to suggest a valid impact-resistance evaluation method. Human motions exerting dynamic load are classified to 3 types. Selecting 3 ranks of motion strength, 3 ranks of load plane stiffness (A:20kN/cm, B:4.7kN/cm, C:2.2kN/cm), and 30 male grownup inspectors in their twenties, load was measured when they applied force on load plane. Result of this research is as follows: (1) Human dynamic load has different nature from object collision in the highest load ratio depending on the load plane stiffness and action time (2) The highest load ratio for each motion was 10.06 for kicking, 4.44 for hitting with shoulder, and 5.58 for fist blow.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1379-1388
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• 2008

In this paper, we present the equations of motion by which the natural vibration of a rotating annular disk can be accurately analyzed. These equations are derived from the theory of finite deformation and the principle of virtual work. The radial displacements of annular disk which is rotating at constant angular velocity are determined by non-linear equations formulated using 1-dimensional finite elements in radial direction. The equations of the in-plane vibrations at disturbed state are also formulated using 1-dimensional finite elements in radial direction along the number of nodal diameters. They are expressed as in functions of the radial displacements at the steady state and the disturbed displacements about the steady state. In-plane static deformation modes of the annular disk are used as the interpolation functions of 1-dimensional finite elements in radial direction. The natural vibrations of an annular disk with different boundary conditions are analyzed by using the presented model and the 3-dimensional finite element model to verify accuracy of the presented equations of motion. Its results are compared and discussed.

• Clinics in Shoulder and Elbow
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• 제1권2호
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• pp.221-229
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• 1998

평균 나이 23세.의 건강한 남자 31명을 대상으로 하여 측각도계즐 이용한 견관절운동역을 측정한 결과 Dominant arm과 Non-dominant arm 모두에서 능동운동역에 비해 수동운동역이 증가되었고, 능동운동시 견갑외전, 중립신전, 수평신전, 수평굴곡, 그리고 중립 및 수평내회전에서, 수동운동의 격우에는 견갑외전, 수평굴곡, 그리고 중립 및 수평내회전에서 Non-dominant arm의 운동증가를 보였고, 수평외회전의 경우 Dominant arm의 운동증가소견을 보였다(p〈0.05) .또한 방사선투시기를 이용하여 관절와상완각과 견갑흉곽각의 비(θGH/θST)를 측정해 본 결과 첫째로 Dominant arm과 Non-dominant arm에서 모두 완전거상시 관절와상완각과 견값흥곽각의 비(θGH/θST)는 1.6이었으며 60도이상 150도 거상때까지 지속적으로 견값흉곽운동 분율이 커지는 양상이었다. 둘째천 30도에서 완전거상시까지 운동분율(θGH/θST)은 Dominant arm과 Non-domlnant arm에서 각각 1.2 및 1.3으로 나타났다. 견갑사위는 중립위에서 약 42도였고 거상에 따라 점차 작아졌으며 완전거상시에는 약 20도로 측정되었다. 이렇게 해서 얻어진 방사선조사 각도는 단순방사선 촬영에 적용하여, 견관절 질환 치료 후 운동범위의 회복의 경과를 판정하는데 도움을 줄 수 있을 것으로 생각되었다.

• International Journal of Aeronautical and Space Sciences
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• 제14권2호
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• pp.152-161
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• 2013

This paper presents a control effectiveness analysis of the hawkmoth Manduca sexta. A multibody dynamic model of the insect that considers the time-varying inertia of two flapping wings is established, based on measurement data from the real hawkmoth. A six-degree-of-freedom (6-DOF) multibody flight dynamics simulation environment is used to analyze the effectiveness of the control variables defined in a wing kinematics function. The aerodynamics from complex wing flapping motions is estimated by a blade element approach, including translational and rotational force coefficients derived from relevant experimental studies. Control characteristics of flight dynamics with respect to the changes of three angular degrees of freedom (stroke positional, feathering, and deviation angle) of the wing kinematics are investigated. Results show that the symmetric (asymmetric) wing kinematics change of each wing only affects the longitudinal (lateral) flight forces and moments, which implies that the longitudinal and lateral flight controls are decoupled. However, there are coupling effects within each plane of motion. In the longitudinal plane, pitch and forward/backward motion controls are coupled; in the lateral plane, roll and side-translation motion controls are coupled.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.677-682
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• 2003

The non-linear dynamic characteristics of a semi-circular pipe conveying fluid are investigated when the pipe is clamped at both ends. To consider the geometric non-linearity for the radial and circumferential displacements, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe, considering the fluid inertia forces as a kind of non-conservative forces. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigate the dynamic characteristics of the system, the discretized equations of motion are derived form the Galerkin method. The natural frequencies varying with the flow velocity are computed fen the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. Finally, the time responses at various flow velocities are directly computed by using the generalized- method. From these results, we should to describe the non-linear behavior to analyze dynamics of a semi-circular pipe conveying fluid more precisely.