• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.233-238
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• 2008

Ambient Media (or ambient displays, Wisneski et al 1998) is one of newly emergent dynamic design objects, representing information through subtle changes of everyday objects and environments. Unlike the existing GUI-based media focusing on the situation that a user is concentrating the media, ambient media enable a user to be peripherally aware of the information without his/her concentration. In order to design ambient media, it is necessary to interpret the basic elements of dynamic changes in physical space and the proper method to apply them for peripherally representing information in ambient media. The aim of this study is to investigate dynamic design elements and the method to apply them for ambient media design in physical space. We explored and refined the type of the dynamic design elements, analyzing dynamic qualities of ambient media cases as well as various time based design fields. As a result, 4 dynamic elements - tempo, connectivity, intensity and rhythm- were proposed. By literature reviews related to peripheral awareness in psychology or ambient media, we analyzed the characteristics of dynamic design elements. Based on that, we developed a new ambient media, 'Cyber Pung-Kyung', and applied dynamic elements for designing the prototype system. The research outcome is expected to contribute designing ambient media which can represent information peripherally or centrally as needed. Understanding the dynamic design elements is helpful for designing various time based design outcomes as well.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.590-595
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• 2001

To improve the modeling accuracy for the finite element method, this paper proposes a method to make a combined use of finite elements and exact dynamic elements. Exact interpolation functions for a Timoshenko beam element are derived and compared with interpolation functions of the finite element method (FEM). The exact interpolation functions are tested with the Laplace variable varied. The exact interpolation functions are used to gain more accurate mode shape functions for the finite element method. This paper also presents a combined use of finite elements and exact dynamic elements in design problems. A Timoshenko frame with tapered sections is tested to demonstrate the design procedure with the proposed method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.2
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• pp.141-149
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• 2002

Although the finite element method has become an indispensible tool for the dynamic analysis of structures, difficulty remains to quantify the errors associated with discretization. To improve the modeling accuracy, this paper proposes a method to make a combined use of finite elements and exact dynamic elements. Exact interpolation functions for the Timoshenko beam element are derived using the exact dynamic element modeling (EDEM) and compared with interpolation functions of the finite element method (FEM). The exact interpolation functions are tested with the Laplace variable varied. A combined use of finite element method and exact interpolation functions is presented to gain more accurate mode shape functions. This paper also presents a combined use of finite elements and exact dynamic elements in design/reanalysis problems. Timoshenko flames with tapered sections are tested to demonstrate the design procedure with the proposed method. The numerical study shows that the combined use of finite element model and exact dynamic element model is very useful.

• Steel and Composite Structures
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• v.45 no.5
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• pp.697-713
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• 2022

In the context of the finite elements method, the dynamic behavior of porous functionally graded double wishbone vehicle suspension structural system incorporating joints flexibility constraints under road bump excitation is studied and analyzed. The functionally graded material properties distribution through the thickness direction is simulated by the power law including the porosity effect. To explore the porosity effects, both classical and adopted porosity models are considered based on even porosity distribution pattern. The dynamic equations of motion are derived based on the Hamiltonian principle. Closed forms of the inertia and material stiffness components are derived. Based on the plane frame isoparametric Timoshenko beam element, the dynamic finite elements equations are developed incorporating joint flexibilities constraints. The Newmark's implicit direct integration methodology is utilized to obtain the transient vibration time response under road bump excitation. The presented procedure is validated by comparing the computational model results with the available numerical solutions and an excellent agreement is observed. Obtained results show that the decrease of porosity percentage and material graduation tends to decrease the deflection as well as the resulting stresses of the control arms thus improving the dynamic performance and increasing the service lifetime of the control arms.

• Journal of KSNVE
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• v.10 no.3
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• pp.437-443
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• 2000

The optimal design problem for increasing dynamic stiffness using hybrid model which composed of original detailed BIW(body in white) and impinged beam elements is investigated. Using the characteristics of the beam elements and design sensitivity analysis this approach utilizes an optimization technique to determine the optimal section properties of beam elements. The constraint is to increase the first natural frequency by five percent compared with original one. The results show that the first torsion and bending natural frequencies are increased by five percent using hybrid model and optimization. These results indicate that this optimization method can be employed to enhance the dynamic stiffness of vehicle body structure in design concept stage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.76-82
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• 2010

In this study, we carried out to evaluate the shock-proof of a large scale motor for the naval vessel using dynamic design analysis method (DDAM) and full transient dynamic analysis. Analytical models for main assemblies (motor frame, rotor and stator assembly) were consisted of the tetrahedral solid elements and the equipments which installed in the upper side of the motor were substituted the mass elements. And we also modelled resilient mounts of a motor using the beam elements with appropriate directional stiffness. The DDAM was conducted according to NRL memorandum report 1396 and the full transient dynamic analysis was performed applying directional triple half triangle shock wave to the motor using ANSYS 12. As a result, we could compare of the results according to each analytic method and find the motor to satisfy the design criteria of the maximum stress and deformation.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.11a
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• pp.92-97
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• 2004

This purpose of this study was about the analysis on the dynamic expression of geometric manipulation in interior composition elements. The paradigm of contemporary times became different from paradigm of modern times. The change of paradigm is caused by the side effect of paradigm of pre-times. In the contemporary architectural condition, architecture have a tendency to plural characteristics. This study investigates systemically ‘the DYNAMISM’ as a part of contemporary interior space's feature, based on geometric manipulation in interior composition elements. First of all, the dynamic characteristics of architectural space. The second, relationship between the architecture and geometric manipulation.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.3
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• pp.121-128
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• 2020

In this paper, the ASCE 7 equivalent static approach for seismic design of non-structural elements is critically evaluated based on the measured floor acceleration data, theory of structural dynamics, and linear/nonlinear dynamic analysis of three-dimensional building models. The analysis of this study on the up-to-date database of the instrumented buildings in California clearly reveals that the measured database does not well corroborate the magnitude and the profile of the floor acceleration as proposed by ASCE 7. The basic flaws in the equivalent static approach are illustrated using elementary structural dynamics. Based on the linear and nonlinear dynamic analyses of three-dimensional case study buildings, it is shown that the magnitude and distribution of the PFA (peak floor acceleration) can significantly be affected by the supporting structural characteristics such as fundamental period, higher modes, structural nonlinearity, and torsional irregularity. In general, the equivalent static approach yields more conservative acceleration demand as building period becomes longer, and the PFA distribution in long-period buildings tend to become constant along the building height due to the higher mode effect. Structural nonlinearity was generally shown to reduce floor acceleration because of its period-lengthening effect. Torsional floor amplification as high as 250% was observed in the building model of significant torsional irregularity, indicating the need for inclusion of the torsional amplification to the equivalent static approach when building torsion is severe. All these results lead to the conclusion that, if permitted, dynamic methods which can account for supporting structural characteristics, should be preferred for rational seismic design of non-structural elements.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.309-317
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• 2007

In this study, we conducted a vibration fatigue analysis of the lower control arm in a vehicle suspension system. The vehicle was driven during the tests so that the dynamic effects could be taken into account. The dynamic load of the frequency domain was superimposed on the frequency response analysis. We performed a virtual proving ground test using multi-body dynamics, along with a finite element analysis and fatigue life predictions. Shape optimization was also considered using the design of the experimental approach, and a response surface analysis was performed to improve the durability performance of the lower control arm. We identified the elements that had the most influence on the optimal shape of the finite element model and analyzed the sensitivity of those elements. Then the optimal points that minimized the amount of damage to the areas of interest were determined through a response surface analysis. The results suggested that the fatigue life of the model increased as its mass was not increased excessively, and demonstrated that these design procedures yielded an appropriate optimized lower control arm model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.35-38
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• 2007

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Modular Program for Conceptual Design of LRE is reviewed, and a modeling and dynamic analysis of rocket engine system with reference to Rocket Engine Dynamic Simulator(REDS) is outlined. Component modeling is based on classical thermodynamic and inviscid theories, and were formulated mathematically in terms of essential parameters. Essential design parameters are addressed. The rocket engine is modeled as a system of pipes with various hydraulic elements, and then the operate characteristic of that elements are simulated by solving conservation equation sequentially.