• 한국정밀공학회지
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• 제21권6호
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• pp.122-130
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• 2004

It is well known that a specific experimental method, the Split Hopkinson Pressure Bar (SHPB) technique is a best experimental technique to determine the dynamic material properties under the impact compressive loading conditions with strain-rate of the order of 10$^3$/s∼10$^4$/s. This type of experimental procedure has been widely used with proper modification on the test setups to determine the varying dynamic response of materials for the dynamic boundary conditions such as tensile and fracture as well. In this paper, dynamic compressive deformation behaviors of a rubber and an Ethylene Copolymer materials widely used for the isolation of vibration from varying structures under dynamic loading are estimated using a Split Hopkinson Pressure Bar technique.

• 소음진동
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• 제10권1호
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• pp.82-96
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• 2000

The purpose of this study is to figure out the relationship between the mini-laboratory and the reverberation room for the domestic floor structures which are practically constructed in apartment houses. For this purpose, seven specimen which were varied in structures and thicknesses were tested in Chonnam National University reverberation room and in the artificial mini-laboratory which is the $\farc{1}{3}$ scale model of the former. From the result of this study, it was proved that there is a good correlation between the mini-laboratory and the reverberation room for the apartment floor structures as well as floorcovering PVC. The result of this study could save the labor and the time, etc.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.649-655
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• 2009

Traffic safety and vibration serviceability of a railway bridge set a limitation to the application of long-span cable supported bridges even though the design trend of the bridge becomes longer and lighter. In the case of high speed railway, it becomes more severe for the high speed of the train and resonance of the structure. Therefore, the cable supported bridge does not exist in Korea high speed railway until now. On the other hand, in recent, Italia, Japan and China do design and construct the long-span cable supported bridges for high speed railway recently with overcoming of traffic safety and passenger comforts. In the present study, prior to analysis of traffic safety and passenger comforts, a extradosed bridge for common railway is re-designed for high speed railway. The difference of member forces and displacements by design live load, the difference of impact coefficient and variable stresses of cables are investigated.

• 국제초고층학회논문집
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• 제10권2호
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• pp.123-135
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• 2021

Solid Viscoelastic Coupling Dampers (VCDs) provide distributed damping that improves the dynamic performance of tall buildings for both wind-storms and earthquakes for all amplitudes of vibration. They are configured in place of typical structural members in tall buildings and therefore do not occupy any architectural space. This paper summarizes the research and development at the University of Toronto in collaboration with Nippon Steel Engineering, 3M and Kinetica over the past two decades. In addition, impact studies on buildings incorporating the VCDs are presented, consisting of a wind sensitive 66-story building in Toronto, a dual-wind and seismic performance-based design of a 4-tower development in Manila and finally a 630 meter Megatall building in Southeast Asia in a severe seismic environment. In all applications the VCDs are shown to provide significant benefits in the dynamic performance under both wind and earthquake loading in a cost-effective manner.

• Advances in nano research
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• 제13권3호
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• pp.233-245
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• 2022

Resently, the use of smart structures has been heightened up rapidly. For this issue, vibration analysis related to a graphene nanoplatelet composite (GPLRC) nanodisk which is attached to a piezoelectric layer and is subjected to thermal loads is explored in the current paper. The formulation of this study is obtained through the energy method and nonlocal strain gradient theory, and then it is solved employing generalized differential quadrature method (GDQM). Halpin-Tsai model in addition to the mixture's rule are utilized to capture the material properties related to the reinforced composite layer. The compatibility conditions are presented for exhibiting the perfect bounding between two layers. The results of this study are validated by employing the other published articles. The impact of such parameters as external voltage, the radius ratio, temperature difference, and nonlocality on the vibrational frequency of the system is investigated in detail.

• Advances in nano research
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• 제13권1호
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• pp.63-75
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• 2022

The nonlinear dynamic behavior of a nonuniform small-scale nonlocal beam is investigated in this work. The nanobeam is theoretically modeled using the nonlocal Eringen theory, as well as a few of Von-nonlinear Kármán's theories and the classical beam theory. The Hamilton principle extracts partial differential equations (PDE) of an axially functionally graded (AFG) nano-scale beam consisting of SUS304 and Si₃N₄ throughout its length, and an elastic Winkler-Pasternak substrate supports the tapered AFG nanobeam. The beam thickness is a function of beam length, and it constantly varies throughout the length of the beam. The numerical solution strategy employs an iteration methodology connected with the generalized differential quadratic method (GDQM) to calculate the nonlinear outcomes. The nonlinear numerical results are presented in detail to examine the impact of various parameters such as nonlinear amplitude, nonlocal parameter, the component of the elastic foundation, rate of cross-section change, and volume fraction parameter on the linear and nonlinear free vibration characteristics of AFG nanobeam.

• Advances in concrete construction
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• 제14권5호
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• pp.309-315
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• 2022

This paper depicts the diagram of cylindrical shells as an essential idea. It centers around an outline of exploration and use of cylindrical shell in expansive current circumstance. In view of investigation of the current and prospect of model as a piece of present exploration work, a straightforward contextual analysis is examined with Love's shell theory based on Galerkin's method. The cylindrical shells are attached from one end of the cylindrical shells. The frequencies of ring support shells are investigated against the half axial wave mode. The frequencies increase on increasing the half axial wave mode. Also, the frequencies are downsized with ring supports. The software MATLAB is preferred to others because in this software computing coding is very easy to do. Just single command 'eig' furnishes shell frequencies and mode shapes by calculating eigenvalues and eigenvectors respectively. The shell vibration frequencies for cylindrical shells are compared with those results found in the open literature.

• Steel and Composite Structures
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• 제47권2호
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• pp.297-313
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• 2023

This study aims to extend the application of the spectral element method (SEM) to wave propagation and free vibration analysis of functionally graded (FG) plates integrated with thin piezoelectric layers, plates with tapered thickness and structure on elastic foundations. Also, the dynamic response of the smart FG plate under impact and moving loads is presented. In this paper, the dynamic stiffness matrix of the smart rectangular FG plate is determined by using the exact dynamic shape functions based on Mindlin plate assumptions. The low computational time and results' independence with the number of elements are two significant features of the SEM. Also, to prove the accuracy and efficiency of the SEM, results are compared with Abaqus simulations and those reported in references. Furthermore, the effects of boundary conditions, power-law index, piezoelectric layers thickness, and type of loading on the results are studied.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.376-385
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• 2007

Construction project is necessary element for human life to upgrade the quality and convenience. However, due to its contradictory nature to the environment preservation, environmental pollution and damage, deterioration of natural scenery, noise/vibration, water quality pollution, etc. caused in the process of construction greatly affect the environment. For the building or construction project, its possible impact on environment during construction work and after completion must be predicted at its design phase, which will result in the completion of the architecture convenient for human being with its environmental pollution reduced to minimum level. In this study, the checklist of environmental factors was suggested, which should be taken into account at its design phase in conducting the construction work. Proposed checklist was linked with the developed web-based system for the convenience of users like designer and construction manager, etc. It is expected that the checklist suggested by this study will help the designer and construction manager to continue the steady development from the environmental viewpoint during the design phase.

• Smart Structures and Systems
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• 제31권2호
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• pp.171-181
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• 2023

Using the most up-to-date system identification methods in both time and frequency domains, the dynamic monitoring data from the reinforced concrete Egebaekvej Bridge near Holte, Denmark, is examined in this investigation. The bridge was erected in the 1960s and was still standing during test campaign before demolishing. The ARTeMIS Modal was adopted to derive the modal parameters from ambient vibration data. Several Operational Modal Analysis (OMA) approaches were applied, including Enhanced Frequency Domain Decomposition (EFDD), Curve-fit Frequency Domain Decomposition (CFDD), and Frequency Domain Decomposition (FDD). Afterward, Principal Component (SSI-PC), Unweighted Principal Component (SSI-UPC) Stochastic Subspace Identification methods were utilized. Danish engineering consulting company, COWI with the allowance of the bridge contractor BARSLUND, allow the researcher for this experimental test to demonstrate the impact of OMA applications.