• International Journal of Precision Engineering and Manufacturing
• /
• v.6 no.4
• /
• pp.21-25
• /
• 2005

In the dynamic analysis of a mechanism, if one or more of the components are flexible, then the simulation will not be accurate because of the violation of the rigid body assumption. Mode shapes are used to represent the dynamic behavior of an elastic structure. A modal synthesis method which uses a combination of normal modes, constraint modes, and attachment modes, was used to represent effectively the elastic deformation of a flexible multibody. Since the combination of these modes should be different for each type of connecting part, the modal synthesis method was studied for the various types of interconnecting joints. In addition, the analysis procedure for the flexible body was explained. A satellite system with flexible solar panels was chosen as an example to show the effectiveness of the proposed method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.241-244
• /
• 2009

This paper deals with a usefulness verification of stretch forming process using flexible die. The stretch forming method is widely used in aircraft and high-speed train industries for manufacturing of skin structure, which is made of sheet metal. A great number of solid dies are originally used and developed for specific shapes with respect to different curvature radii of the skin structures. Accordingly, flexible stretch forming process is proposed in this study. It replaces the conventional solid dies with a set of height adjustable discrete punches. A usefulness of the flexible die is verified through extensive numerical simulations of the stretch forming process for simply curved sheet plate. The elastic recovery is considered and formability evaluations are conducted through a comparison of symmetry plane configurations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.408-411
• /
• 1995

In this paper, we discuss the force control of flexible manipulators. Since the force control of flexible manipulators with planar one or two links using the distributed-parameter modeling has been the subject of a considerable number of publications until now, real time computations of the force control schemes are possible. But, application of those control schemes to multi-link spatial manipulators is fairly complicated. In this paper, we apply a concise hybrid position/force control scheme for a flexible manipulators. We use a lumped-parameter modeling for the flexible manipulators. The Hamilton's principle is applied to derive the equations of motion for the system and then, state-space model is obtained by the Lagrange's method. Finally, comparison of simulation results with experimental results is given to show the performance of our method.

• Journal of the Korean Society for Railway
• /
• v.9 no.4 s.35
• /
• pp.499-503
• /
• 2006

Maglev vehicles, which are levitated and propelled by electromagnets, often run on elevated flexible guideways comprised of steel, aluminum and concrete. Therefore, an analysis of the dynamic interaction between the Maglev vehicle and the flexible guideway is needed in the design of the critical speed, ride, controller design and weight reduction of the vehicle. This study introduces a dynamic interaction simulation technique that applies structural dynamics. Because the proposed method uses detailed 3D FE models, it is useful to analyze the deformation of the elevated flexible guideway, the dynamic stress, and the motion of the vehicle. By applying the proposed method to an urban transit Maglev vehicle, UTM01, the dynamic response is simulated and validated. From the result of the study, we concluded that the simulation of dynamic interaction between the Maglev vehicle and the flexible guideway is possible and a potential of using computational mechanics.

• Journal of Korean Academy of Nursing Administration
• /
• v.13 no.2
• /
• pp.167-175
• /
• 2007

Purpose: The Purpose of this study was to identify for perception and preference on Flexible working pattern of Nurses in hospital. Method: The subjects were 260 nurses enrolled in 11 hospitals located in S and P city. Questionnaire method was utilized for data collection. Data was analyzed by SPSS statistical program. Results: 86.5% of the nurses were working 3 shifts. 70.8% of nurses agreed that they decided to give up nurses because of very irregular working pattern. They want to work 40hrs/weeks, and agree to applying to Flexible working pattern. There was statistically significant between career(F=2.839, p=.039), working place(F=3.086, p=.047), the mind of change of occupation(F=.479, p=.002) and expected life pattern change after applicating for Flexible working pattern. Conclusion: We need to Various Flexible working pattern model. As well as we need to public information about nurses' Flexible working pattern.

• Structural Engineering and Mechanics
• /
• v.41 no.5
• /
• pp.675-689
• /
• 2012

Most connections of steel structures exhibit flexible behaviour under cyclic loading. The flexible connections can be assumed as nonlinear rotational springs attached to the ends of each beam. The nonlinear behaviour of the connections can be considered by suitable moment-rotation relationship. Time-history analysis by direct integration method can be used as a powerful technique to determine the nonlinear dynamic response of the structure. In conventional numerical integration, the response is evaluated for a series of short time increments. The limitations on the size of time intervals can be removed by using Chen and Robinson improved time history analysis method, in which the integrated displacements are used as the new variables in integrated equation of motion. The proposed method permits longer time intervals and reduces the computational works. In this paper the nonlinearity behaviour of the structure is summarized on the connections, and the step by step improved time-history analysis is used to calculate the dynamic response of the structure. Several numerical calculations which indicate the applicability and advantages of the proposed methodology are presented. These calculations illustrate the importance of the effect of the nonlinear behaviour of the flexible connections in the calculation of the dynamic response of steel frames.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.4
• /
• pp.258-265
• /
• 2016

A flexible riser consists of several layers which have different materials, shapes and functions. The layers designed properly can take the design load safely, and each property of layer provides a complexity of flexible riser. Such complexity/unit-property is an input for global analysis of flexible riser. There are several approaches to calculate the complexity of flexible riser, those are experimental, numerical and theoretical methods. This paper provides a complexity from numerical and theoretical analysis for 2.5 inch flexible riser of which details and the experimental data are already produced under tension, external pressure, and bending moment. In addition, comparison of stiffness and stress are also provided. Especially, analysis of stress could lead to researches on ultimate strength or fatigue strength of flexible risers.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.595-599
• /
• 1989

A new simple method for controlling compliant motions of a flexible robot arm is presented. The method aims at controlling translational tip motion, force and moment by directly computing the base motion or torque. A numerical inversion of Laplace transform is used to obtain the results in the time domain. The results show the effectiveness of the method for the hybrid translational position/force control of a flexible robot arm.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.484-487
• /
• 2005

In order to find out LC cell spacing method suitable for flexible cholesteric LCDs with high mechanical stability, we carried out bending and mechanical shock tests by using various spacing techniques: bead spacer, photo spacer, polymer wall with bead spacer and polymer wall with photo spacer. As a result, it was found that the spacing method using polymer wall incorporated with photo spacer is the best for flexible cholesteric LCDs in terms of mechanical stability. The investigation is discussed in detail.

• Journal of the Korean housing association
• /
• v.16 no.1
• /
• pp.73-79
• /
• 2005

The ventilation efficiency of apartment housing bathroom has been measured by the flexible's diameter, length, and installation format to the exhaust In. The gas density attenuation method of Tracer Gas Method has been specifically utilized for this measurement. Full size mock-up of apartment housing bathroom, which was approximately $100 m^2$ in size, has been established for the ventilation emciency measurement. In addition, the ventilation efficiency has been studied by the possibility of air-supply In. The diameters of flexible are 100 mm, 125 mm, and 150mm. It also have the length of 1.0m, and 1.5 m. The installation formats are I shape, L shape, and S shape. As a result of this measurement, the flexible which has the highest ventilation efficiency was the one has bigger diameter, short in length, and I shape installation format.