• 한국소음진동공학회논문집
• /
• 제16권2호
• /
• pp.176-182
• /
• 2006

Modeling and verification for stability analysis of axially oscillating cantilever beams are investigated in this paper Equations of motion for the axially oscillating beams are derived and transformed into dimensionless forms. The equations include harmonically oscillating parameters which are related to the motion-induced stiffness variation. stability diagram is obtained by using the multiple scale perturbation method. To verify the accuracy of the modeling method, several points in the plane of the stability diagram are presented and solved. The present modeling method proves to be as accurate as a nonlinear finite element modeling method.

• 한국소음진동공학회논문집
• /
• 제19권1호
• /
• pp.10-16
• /
• 2009

Modal characteristics of a cracked beam with a concentrated mass undergoing rotational motion are investigated in this paper. Hybrid deformation variables are employed to derive the equations of motion of a rotating cantilever beam. The flexibility due to crack, which is assumed to be open during the vibration, is calculated basing on a fracture mechanics theory. To obtain more general information, the equations of motion are transformed into a dimensionless form in which dimensionless parameters are identified. The effects of the dimensionless parameters related to the angular speed, the depth and location of a crack and the size and location of a concentrated mass on the modal characteristics of the beam are investigated numerically.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제2권2호
• /
• pp.75-86
• /
• 2010

In this work the possibility of obtaining a rectilinear motion of bodies partially or totally submerged without using propellers is evaluated. The system propulsion is based on a pair of counter rotating masses that generate the thrust. The fluid-body system has been schematized in order to carry out a very simple model. Using this model an evaluation of the body motion along a longitudinal direction was performed. The motion equations of the system were written and integrated. The external forces applied to the body depend on its velocity in relation to the water. These forces were obtained by fluid dynamic simulations. Regarding the mechanical configuration suggested, the results obtained show that a certain displacement of the body along a fixed direction is obtainable.

• 산업기술연구
• /
• 제20권B호
• /
• pp.95-103
• /
• 2000

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.708-713
• /
• 2005

Modeling and verification for stability analysis of axially oscillating cantilever beams are investigated in this paper. Equations of motion for the axially oscillating beams are derived and transformed into dimensionless forms. The equations include harmonically oscillating parameters which are related to the motion-induced stiffness variation. Stability diagram is obtained by using the multiple scale perturbation method. To verify the accuracy of the modeling method, several points in the plane of the stability diagram are presented and solved. The present modeling method proves to be as accurate as a nonlinear finite element modeling method.

• 한국측량학회지
• /
• 제1권2호
• /
• pp.23-29
• /
• 1983

Degradation of image caused by relative motion between the object and the imaging system (like a camera with its platform) is detrimental to precision photogrammetry. Principal modes of relative motion are identified. The discussion is, however, concentrated on the systematic motions, translatory and rotatory. Various analogical approaches of compensating for the image motion are cited. An analytical-computational approach is presented. This one considers the relationship of transformation bet ween the image and the object, known as the collinearity condition. The standard forms of collinearity condition equations are presented. Augmentation of these equations with regard to both translatory and rotatory motions are expounded. With ever increasing use of high speed computers (as well as analytical plotters in the realm of photogrammetry), this approach seems to be more costeffective and seems to yield better precision in the long run than other approaches that concentrate on analogical corrections to the image itself.

• Advances in concrete construction
• /
• 제15권4호
• /
• pp.287-301
• /
• 2023

Hockey games attracts many fans around the world. This game requires a specific type of ball and a stick for controlling the motion and trace of the ball. This control of motion involves hitting the ball which is a direct intensive dynamic loading. The impact load transferred directly to the hand of the player and in the professional player may cause long term medical problems. Therefore, dynamic motion of the stick should be understood. In the current study, we analyze the dynamic motion of a hockey stick under impact loading from a hockey ball. In doing so, the stick geometry is simplified as a beam structure and quasi-2D relations of displacement is applied along with classical linear elasticity theory for isotropic materials. The governing equations and natural boundary condition are extracted using Hamilton's principle. The final equations in terms of displacement components are solved using Galerkin's numerical method. The results are presented using indentation and contact force values for variations of different parameters.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.314-316
• /
• 2011

This paper develops a spectral element model for the composite beams with a surface-bonded piezoelectric layer from the governing equations of motion. The governing equations of motion are derived from Hamilton's principle by applying the Bernoulli-Euler beam theory for the bending vibration and the elementary rod theory for the longitudinal vibration of the composite beams. For the PZT layer, the Bernoulli-Euler beam theory and linear piezoelectricity theory are applied. The high accuracy of the present spectral element model is evaluated through the numerical examples by comparing with the finite element analysis results.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.167-174
• /
• 1997

In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.96-100
• /
• 2001

A method is presented for determining the free vibration characteristics of a rotating blade having nonuniform span wise properies and cantilevers boundary condition. The equations which govern the coupled the coupled flapwise, choirwise, and torsional motion of such a blade are solved using an integrating matrix method. By expressing the equation of motion in matrix notation, utilizing the integrating matrix as an operator, and applying the boundary condition, the equations are formulated into an eigenvalues problem whose solution may be determined by conventional method. Computer results are compared with experimental data.