• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1681-1688
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• 2000

A dynamic model for the prediction of surface topography in high speed end milling process is developed. In this model the effect of tool runout, tool deflection and spindle vibration were taken in to account. An equivalent diameter of end mill is obtained by finite element method and tool deflection experiment. A modal parameter of machine tool is extracted by using frequency response function. The tool deflection, spindle vibration chip thickness and cutting force were calculated in dynamic cutting condition. The tooth pass is calculated at the current angular position for each point of contact between the tool and the workpiece. The new dynamic model for surface predition are compared with several investigated model. It is shown that new dynamic model is more effective to predict surface topography than other suggested models. In high speed end milling, the tool vibration has more effect on surface topography than the tool deflection.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.976-981
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• 1986

The Stress analysis based on the large deflection theory of plate for the large cylindrical storage tank is performed by considering the change of membrane force for the various parameter, i.e., thickness ratio, tank height to diameter ratio, and stretched length. The critical buckling force of cylindrical shell is obtained to investigate the safety of tank shell. By numerical result, the thickness ratio is the important parameter for the membrane force, the height of tank is related linearly with the force, and the stretched length of bottom plate is little influenced. Also, the critical buckling force of cylindrical shell is large than the edge shear force at bottom-shell junction, and hence the consideration of the shell buckling is not required.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.114-119
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• 2002

The aim of this paper is to clarify the structural compliance of the constrained flexible manipulator and to develop the force control algorithm by using the compliance of the links. The proposed structural compliance control consists of the position control to utilize a flexible manipulator model (considering the compensation for the elastic deflection of links) and the passive force control to utilize the rigid manipulator model (without considering the compensation for the elastic deflection of links). We present the experimental results for the case when applying the only position control, and when applying the structural compliance control. Finally, a comparison between these results is presented to show the performance of our method.

• Structural Engineering and Mechanics
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• v.22 no.4
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• pp.433-447
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• 2006

The problem of very large deflection of a circular cantilever arc device subjected to inward or outward polar force is studied. An exact elliptic integral solution is derived for the two cases and the results are checked using large displacement finite element analysis via the ANSYS package by performing a new novel modeling simulation technique for this problem. Excellent agreements have been obtained between the exact analytical solution and the numerical approach. From this study, a design chart for engineers is developed to predict the required value for the inward polar force for the device to switch on for a given angle forming the circular arc (${\theta}_o$). This study has several interesting applications in mechanical engineering, integrated circuit technology, nanotechnology and especially in microelectromechanical systems (MEMs) such as a MEM circular device switch subjected to attractive or repulsive magnetic forces due to the attachments of two magnetic poles at the fixed and at the free end of the circular cantilever arc switch device.

• Applied Science and Convergence Technology
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• v.23 no.5
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• pp.240-247
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• 2014

Modelling and measurements of normal and lateral stiffness for atomic force microscopy (AFM) are presented in this work. Important issues, such as element discretisation, stiffness calibration, and deflection angle are explored using the finite element (FE) model. Elements with various dimension ratios are investigated and comparisons with several mathematical models are reported to verify the accuracy of the model. Investigation of the deflection angle of a cantilever is also shown. Moreover, AFM force measurement experiments with conical and colloid probe tips are demonstrated. The relationships between force and displacement, required for stiffness measurement, in normal and lateral directions are acquired for the conical tip and the limitations of the colloid probe tip are highlighted.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.84-88
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• 2006

The effects of tip voltage, deflection setpoint, and tip velocity on height of $SiO_2$ line drawn by local anodization on Si wafer using scanning probe microscope were investigated. No local anodization was detected at smaller than -3 V of tip voltage. The line height increased at rate of 0.47 nm/V when the tip voltage is stronger than -3 V at $1{\mu}m/s$ tip velocity. From deflection setpoint, mechanical force between tip and substrate could be calculated and the threshold farce was $12\sim18nN$. The height of anodized $SiO_2$ lines is independent of the magnitude of force above the threshold force. The line height decreased as increasing the tip velocity and limited to 0.7 nm at -5 V tip voltage.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.2982-2994
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• 1993

Low-velocity impact responses of composite laminates are investigated using the finite element method based on various theories. In two-dimensional nonlinear analysis, a displacement field considering higher order shear deformation and large deflection of the laminate is assumed and a finite element formulation is developed using a C$^{o}$-continuous 9-node plate element. Also, three-dimensional linear analysis based on the infinitesimal strain-displacement assumptions is performed using 8-node brick elements with incompatible modes. A modified Hertzian contact law is incorporated into the finite element program to evaluate the impact force. In the time integration, the Newmark constant acceleration algorithm is used in conjuction with successive iterations within each time step. Numerical results from static analysis as well as the impact response analysis are presented including impact force histories, deflections, strains in the laminate. Impact responses according to two typical low-velocity impact conditions are compared each other.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.7
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• pp.550-556
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• 2002

The vibrational system of this study is consisted of a cantilever pipe conveying fluid. the moving mass upon it and an attacked tip mass. The equation of motion is derived by using Lagrange equation. The influences of the velocity and the inertia force of the moving mass and the velocities of fluid flow in the pipe haute been studied on the dynamic behavior of a cantilever pipe by numerical method. As the velocity of the moving mass increases, the deflection of cantilever pipe conveying fluid is decreased. Increasing of the velocity of fluid flow make the amplitude of cantilever pipe conveying fluid decrease. The deflection of the cantilever pipe conveying fluid is increased by moving masses. After the moving mass passed upon the cantilever pipe, the amplitude of pipe is influenced due to the deflection of pipe tilth the effect of moving mass and gravity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.781-785
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• 2005

Cutting forces and tool deflection in end milling are represented as the closed form of tool rotational angle and cutting conditions. The discrete cutting forces caused by tool entry and exit are continued using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping pan are considered for cutting forces and tool deflection estimation. Compared to numerical methods, the presented method has advantages in short prediction time and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the ferm accuracy is easily predicted by tool deflect ion curve.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.81-82
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• 2012