• 전자공학회논문지A
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• 제33A권6호
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• pp.206-219
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• 1996

This paper describes a data structure and evaluation algorithm to improve the perofmrances MOS logic-with-timing simulation in computation and accuracy. In order to efficiently simulate the logic and timing of driver-load networks, (1) a tree data structure to represent the mutual interconnection topology of switches and nodes in the driver-lod network, and (2) an algebraic modeling to efficiently deal with the new represetnation, (3) an evaluation algorithm to compute the linear resistive and capacitive behavior with the new modeling of driver-load networks are developed. The higher modeling presented here supports the structural and functional compatibility with the linear switch-level to simulate the logic-with-timing of digital MOS circuits at a mixed-level. This research attempts to integrate the new approach into the existing simulator RSIM, which yield a mixed-klevel logic-with-timing simulator MIXIM. The experimental results show that (1) MIXIM is a far superior to RSIM in computation speed and timing accuracy; and notably (2) th etiming simulation for driver-load netowrks produces the accuracy ranged within 17% with respect ot the analog simulator SPICE.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.459-466
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• 2001

The floor vibration aspect for building structures which are in need of large open space are influenced by the interrelation between natural frequency and working loads. Structures with a long span and low natural frequency have a higher possibility of experiencing excessive vibration induced by dynamic excitation such as human activities. These excessive vibrations make the residents uncomfortable and the serviceability deterioration. Need formulation of loads data through actual measurement to apply walking loads that is form of dynamic load in structure analysis. The loads induced by human activities were classified into two types. First type is in place loads. the other type is moving loads. A series of laboratories experiments had been conducted to study the dynamic loads induced by human activities. The earlier works were mainly concerned to parameters study of dynamic loads. In this Paper, the walking loads have been directly measured by using the measuring plate in which two load cells were placed, the parameters, the load-time history of walking loads, and the dynamic load factors have been analyzed. Moreover, the shape of the harmonic loads which were gotten by decomposition the walking loads have been analyzed , and the walking loads modeling have been carried out by composition these harmonic loads derived by functional relation.

• 한국구조물진단유지관리공학회 논문집
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• 제5권2호
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• pp.175-182
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• 2001

Five reinforced concrete frames were constructed and tested to study the structural performance of retrofitting effect reinforced concrete frame during and load revesals simultaneously. All specimens were modeling in one-third scale size. Experimental research was carried out to develop and evaluate the hysteretic behavior of reinforced concrete frame designed by high performance techniques, using carbon fiber plate, ALC panel, steel plate system with or without stiffener. Experimental programs wore carried to evaluate the structural performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. Specimens(RFCP, RFAR, RFSR, RFSR-S), designed by the improvement of earthquake-resistant performance, were attained more load-carrying capacity, energy dissipation capacity, and stable hysteretic behavior.

• 한국공간구조학회논문집
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• 제24권2호
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• pp.43-52
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• 2024

Phayathonzu temple in Myanmar was made of masonry bricks, and so it was vulnerable to lateral load such as earthquake. Especially, it has many difficulties in structural modeling and dynamic analysis because the discontinuous characteristics of masonry structure should be considered. So, it is necessary to provide the seismic performance evaluation technology through the inelastic dynamic modeling and analysis under earthquake loads for the safety security of masonry brick temple. Therefore, this study analyzes the seismic behavior characteristics and evaluates the seismic performance for the 479 structure with many cracks and deformations. Through the evaluation results, we found out the structural weak parts on earthquake loads.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.207-224
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• 2022

The mechanical behavior of prestressed concrete haunched beams (PSHBs) was investigated in depth using a finite element modeling technique in this study. The efficiency of finite element modeling was investigated in the first stage by taking into account a previous study from the literature. The first stage's findings suggested that finite element modeling might be preferable for modeling PSHBs. In the second stage of the research, a comprehensive parametric study was carried out to determine the effect of each parameter on PSHB load capacity, including haunch angle, prestress level, compressive strength, tensile reinforcement ratio, and shear span to depth ratio. PSHBs and prestressed concrete rectangular beams (PSRBs) were also compared in terms of capacity. Stochastic analysis was used in the third stage to define the uncertainty in PSHB capacity by taking into account uncertainty in geometric and material parameters. Standard deviation, coefficient of variation, and the most appropriate probability density function (PDF) were proposed as a result of the analysis to define the randomness of capacity of PSHBs. In the study's final section, a new equation was proposed for using symbolic regression to predict the load capacity of PSHBs and PSRBs. The equation's statistical results show that it can be used to calculate the capacity of PSHBs and PSRBs.

• Ocean Systems Engineering
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• 제2권1호
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• pp.1-16
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• 2012

Offshore wind turbines are complex structural and mechanical systems located in a highly demanding environment. This paper proposes a multi-level system approach for studying the structural behavior of the support structure of an offshore wind turbine. In accordance with this approach, a proper numerical modeling requires the adoption of a suitable technique in order to organize the qualitative and quantitative assessment in various sub-problems, which can be solved by means of sub-models at different levels of detail, both for the structural behavior and for the simulation of loads. Consequently, in a first place, the effects on the structural response induced by the uncertainty of the parameters used to describe the environmental actions and the finite element model of the structure are inquired. After that, a meso-level FEM model of the blade is adopted in order to obtain the detailed load stress on the blade/hub connection.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.110-122
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• 2015

In this paper, the unsteady aerodynamics and blade structural dynamics of an experimental bearingless rotor were analyzed. Due to the multiple load path and nonlinear behavior of a bearingless rotor, sophisticated structural modeling and structural-aerodynamic coupled analysis is required. To predict the internal load and deformation of an experimental bearingless rotor, trim analysis was implemented. The results showed good agreement when compared with those predicted by CAMRAD II the rotorcraft comprehensive analysis. It is possible to extend the present structural-aerodynamic combined analysis to further advanced configurations of the bearingless rotor in the future.

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.419-439
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• 2014

In this study, the structural performance of a seven span masonry arch bridge was evaluated. Investigations were performed on Aspendos (Belkis) Masonry Arch Bridge which was located on road of Aspendos Acropolis City in Antalya, Turkey. The old bridge was constructed in the early of fourth century AD, but it was exposed to the earthquakes in this region and the overloading by the river water. The old bridge was severely damaged and collapsed by probably an earthquake many years ago and a new bridge was then reconstructed on the remains of this old bridge by Seljuk in the 13th century. The bridge has also been affected from overflowing especially in the spring of each year, so some protective measures should be taken for this monumental bridge. Therefore, the structural performance under these loading has to be known. For this purpose, an initial finite element model was developed for the bridge and it was calibrated according to ambient vibration test results. After that, it was analyzed for different load cases such as dead, live, earthquake and overflow. Three load combinations were taken into account by deriving from these load cases. The displacements and the stresses for these combination cases were attained and compared with each other. The structural performance of Aspendos Masonry Arch Bridge was determined by considering the demand-capacity ratio for the tensile stress of the mortar used in Aspendos Masonry Arch Bridge. After these investigations, some concluding remarks and offers were presented at the end of this study.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.55-62
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• 2005

In this paper, a CAB/CAE integrated optimal design system is developed, in which design and analysis process is automated using CAD/CAE softwares, for a complicated model for which parametric modeling provided by CAD software is not possible. CAD modeling process is automated by using UG/OPEN API function and UG/Knowledge Fusion provided by Unigraphics. The generated model is transferred to the analysis code ANSYS in parasolid format. Visual DOC software is used for optimization. The system is developed for PLS(Plasma Lighting System), which is a next generation illumination system that is used to illuminate stadium or outdoor advertizing panel. The PLS system consists of more then 20 components, which requires a lot of human efforts in modeling and analysis. The analysis for PLS includes static load, wind load and impact load analysis. As a result of analysis, it is found that the most critical component is a tilt assembly, which links lower & upper body assembly. For more reliable analysis, experiment is conducted using MTS and compared with the Finite element analysis result. The objective in the optimization is to minimize the material volume under allowable stresses. The design variables are three parameters in the tilt assembly that are chosen to be the most sensitive in stress values of twelve parameters. Gradient based method and RSM(Response Surface Method) are used for the algorithm and the results are compared. As a result of optimization, the maximum stress is reduced by 57%.

• 항공우주시스템공학회지
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• 제17권2호
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• pp.45-55
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• 2023

본 연구에서는 V-22 Osprey 틸트로터의 25% 축소 모델인 TRAM에 대하여 회전익기 통합 해석 코드인 CAMRAD II를 이용하여 프롭로터의 Aeromechanics 모델링과 블레이드 및 피치 링크에 대한 구조 하중 해석을 수행한 후, DNW 풍동 시험 및 선행 해석 연구 결과와 상호 비교하였다. 본 연구에서는 저속 전진 비행 시 블레이드 플랩 굽힘 모멘트의 구조 하중 및 진동 하중 변화를 풍동 시험 결과에 대하여 비교적 잘 예측하였다. 리드-래그 굽힘 및 비틀림 모멘트의 구조 하중 및 진동 하중 해석은 풍동 시험과 다소 다르게 얻어졌으나, 평균값을 제거하였을 때 로터 회전 한 바퀴당 구조 하중 해석 결과가 풍동 시험 및 선행 해석 연구와 비교적 유사하였다. 피치 링크의 구조 하중 및 진동 하중 해석은 전반적으로 선행 연구의 시험 및 해석 결과와 유사하게 얻어졌다. 마지막으로 블레이드 구조 진동 하중의 조화 성분 해석 및 비교를 통하여 블레이드 리드-래그 굽힘 및 비틀림 모멘트의 오차 발생 원인을 분석하였다.