• Earthquakes and Structures
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• 제16권6호
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• pp.655-664
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• 2019

Behavior factor of a structure plays a crucial role in designing and predicting the inelastic responses of it. Recently, irregular buildings have been interested in many designers. To design irregular structures, recognizing the inelastic behavior of them is necessary. The main objective of this study is to determine the behavior factor of irregular Reinforced Concrete Moment Resisting Frames (RCMRFs) via nonlinear Incremental Dynamic Analysis (IDA). To do so, first, several frames are designed according to the regulations of the Iranian national building code. Then the nonlinear incremental dynamic analysis is performed on these structures and the behavior factors are achieved. The acquired results are compared with those obtained using pushover analysis and it is shown that the behavior factors acquired from the nonlinear incremental dynamic analysis are somewhat larger than those obtained from pushover analysis. Eventually, two practical relations are proposed to predict the behavior factor of irregular RCMRFs. Since these relations are based on the simple characteristics of frames such as: irregularity indices, the height and fundamental period, the behavior factor of irregular RCMRFs can be achieved efficiently using these relations. The proposed relations are applied to design of four new irregular RCMRFs and the outcomes confirm the accuracy of the aforementioned relations.

• 터널과지하공간
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• 제16권5호
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• pp.394-404
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• 2006

암반구조물의 동적 거동은 구조물이 위치하는 동적 물성과 입력지진파의 특성에 따라 크게 다르며, 절리군이 발달한 암반은 블록의 역학적인 특성과 함께 불연속면의 구조적, 역학적 특성에 따라 다르다. 본 연구에서는 불연속체 해석 기법인 UDEC을 이용하여 지하구조물 주변에 발달한 불연속체의 구조적인 특징에 따라 변화하는 암반의 동적 거동을 평가하고, 이를 연속체 해석 기법인 $FLAC^{2D}$의 결과와 비교를 통해 절리 암반의 지진에 대한 동적 거동의 타당성을 비교 검토하였다. 그 결과, 불연속체가 고려된 해석 결과는 절리의 거동에 의한 영향으로 구조적인 형상에 따른 변화가 나타났으며, 연속체 해석 결과는 불연속체 해석 결과에 비해 과다 평가되는 것으로 나타났다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.471-474
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• 2001

Recently, due to demands of faster speed and extra features for the chip mounters, there has been ever-demanding needs for the basic technology. Until four or five years ago, chip mounters placing 0.3sec/chip were considered to be in the high speed category, but since then it has become a borderline for categorizing high speed machines capable of placing 0.1sec/chip. In this study, in order to analyze the vibration of head generated by the dynamic behavior of x-frame, FEM model is composed and modal analysis is performed to identify the dynamic characteristics of the structure. Those results are compared with the modal test in order to verify the model. In this paper, Several other factors, such as definition of dynamic accuracy, static accuracy and tolerance of the axis settling range, that might affect the dynamic behavior the head are discussed.

• Advances in aircraft and spacecraft science
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• 제5권3호
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• pp.385-400
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• 2018

In this paper dynamic behavior (modal analysis and dynamic transient response) of a novel sandwich T-joint is numerically and experimentally investigated. An epoxy adhesive is selected for bonding purpose and making the step wise graded behavior of adhesive region. The effect of the step graded behavior of the adhesive zone on dynamic behavior of a sandwich T-joint is numerically studied. Finite element analysis (FEA) of the T-joints with carbon fiber reinforced polymer (CFRP) face-sheets is performed by ABAQUS 6.12-1 FEM code software. Modal analysis and dynamic half-sine transient response of the sandwich T-joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of the manufactured sandwich panels and T-joint modeling. It has been shown that the step wise graded adhesive zone cases have changed the second natural frequency by about 5%. Also, it has been shown that the different arranges in the step wise graded adhesive zone significantly affect the maximum stresses due to transient dynamic loading by 1112% decrease in maximum peel stress and 691.9% decrease in maximum shear stress on the adhesive region.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.325-330
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• 1999

The dynamic behavior analysis of air-lubricated tilting pad journal bearing which considers start-up, running and shutdown Process were performed. By carrying out the experiment of shaft vibration, measurement of the vibration amplitudes supported by air lubricated tilting pad bearing and analysis of the result, we found more accurate dynamic behavior of the system. There were many investigations in these bearings, but dynamic behavior of startup, shutdown and running process were lacked. By using the experimental data we found the accurate dynamic behavior of the system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1011-1016
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• 2004

All the loads in the real world are dynamic loads and it is well known that structural optimization under dynamic loads is very difficult. Thus the dynamic loads are often transformed to the static loads using dynamic factors. However, due to the difference of load characters, there can be considerable differences between the results from static and dynamic analyses. When the natural frequency of a structure is high, the dynamic analysis result is similar to that of static analysis due to the small inertia effect on the behavior of the structure. However, if the natural frequency is low, the inertia effect should not be ignored. Then, the behavior of the dynamic system is different from that of the static system. The difference of the two cases can be explained from the relationship between the homogeneous and the particular solutions of the differential equation that governs the behavior of the structure. Through various examples, the difference between the dynamic analysis and the static analysis are shown. Also the optimization results considering dynamic loads are compared with static loads.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1248-1253
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• 2005

The study is indispensable for the dynamic behaviors because this Cable-stayed long span bridge ; has a more flexible structure than normal bridge can have weaknesses which are impact factor, deflection and defectives etc. This study analyze the dynamic behavior by an analysis of the moving constant train force on railway with Midas/Civil that is a commercial finite element analysis tool about Extradosed PSC Bridge. Also it will be checked the dynamic behavior features and standard of the dynamic capability.

• 한국소음진동공학회논문집
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• 제22권9호
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• pp.889-895
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• 2012

A vertical launching system(VLS) is a system for holding and firing missiles on surface ships. When a missile is launched in VLS, relative motion between canister and missile and drag force induced by wind can cause initial unstability of a missile. Thus dynamic analysis of initial behavior of vertically launched missile should be performed to prevent collision with any structure of a ship. In this study, dynamic analyses of initial behavior of vertically launched missile are performed using Monte-Carlo simulation, which relys on random sampling and probabilistic distribution of variables. Each parameter related with dynamic behavior of a missile is modeled with probability variables and Recurdyn, a commercial software for multi body dynamic analysis, is used to perform Monte-Carlo simulation. As a result, initial behavior of a missile is evaluated with respect to various performance indexes in a probabilistic sense and sensitivity of the each parameters is calculated.

• Steel and Composite Structures
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• 제33권3호
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• pp.333-346
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• 2019

Foam ceramic materials contribute to the explosion effect weakening on concrete structures, due to the corresponding excellent energy absorption ability. The blast resistance of concrete members could be improved through steel-foam ceramics as protective cladding layers. An approach for the modeling of dynamic response of steel-foam ceramic protected reinforced concrete (Steel-FC-RC) slabs under blast loading was presented with the LS-DYNA software. The orthogonal analysis (five factors with five levels) under three degrees of blast loads was conducted. The influence rankings and trend laws were further analyzed. The dynamic displacement of the slab bottom was significantly reduced by increasing the thickness of steel plate, foam ceramic and RC slab, while the displacement decreased slightly as the steel yield strength and the compressive strength of concrete increased. However, the optimized efficiency of blast resistance decreases with factors increase to higher level. Moreover, an efficient design method was reported based on the orthogonal analysis.

• Geomechanics and Engineering
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• 제31권4호
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• pp.423-437
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• 2022

The objective of the study is to evaluate the feasibility of the dynamic behavior of slope through both 1 g shaking table test and numerical analysis. Accelerometers were installed in the slope model with different types of seismic waves. The numerical analysis (ABAQUS and DEEPSOIL) was used to simulate 1 g shaking table test at infinite boundary. Similar Acceleration-time history, Spectral acceleration (SA) and Spectral acceleration amplification factor (Fa) were obtained, which verified the feasibility of modeling using ABAQUS and DEEPSOIL under the same size. The influence of the size (1, 2, 5, 10 and 20 times larger than that used in the 1 g shaking table test) of the model used in the numerical analysis were extensively investigated. According to the similitude law, ABAQUS was used to analyze the dynamic behavior of large-scale slope model. The 5% Damping Spectral acceleration (SA) and Spectral acceleration amplification factor (Fa) at the same proportional positions were compared. Based on the comparison of numerical analyses and 1 g shaking table tests, it was found that the 1 g shaking table test result can be utilized to predict the dynamic behavior of the real scale slope through numerical analysis.