• Title/Summary/Keyword: physical nonlinearity

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Numerical Analysis of Nuclear-Power Plant Subjected to an Aircraft Impact using Parallel Processor (병렬프로세서를 이용한 원전 격납건물의 항공기 충돌해석)

  • Song, Yoo-Seob;Shin, Sang-Shup;Jung, Dong-Ho;Park, Tae-Hyo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.6
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    • pp.715-722
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    • 2011
  • In this paper, the behavior of nuclear-power plant subjected to an aircraft impact is performed using the parallel analysis. In the erstwhile study of an aircraft impact to the nuclear-power plant, it has been used that the impact load is applied at the local area by using the impact load-time history function of Riera, and the target structures have been restricted to the simple RC(Reinforced Concrete) walls or RC buildings. However, in this paper, the analysis of an aircraft impact is performed by using a real aircraft model similar to the Boeing 767 and a fictitious nuclear-power plant similar to the real structure, and an aircraft model is verified by comparing the generated history of the aircraft crash against the rigid target with another history by using the Riera's function which is allowable in the impact evaluation guide, NEI07-13(2009). Also, in general, it is required too much time for the hypervelocity impact analysis due to the contact problems between two or more adjacent physical bodies and the high nonlinearity causing dynamic large deformation, so there is a limitation with a single CPU alone to deal with these problems effectively. Therefore, in this paper, Message-Passing MIMD type of parallel analysis is performed by using self-constructed Linux-Cluster system to improve the computational efficiency, and in order to evaluate the parallel performance, the four cases of analysis, i.e. plain concrete, reinforced concrete, reinforced concrete with bonded containment liner plate, steel-plate concrete structure, are performed and discussed.

Dynamic Model Prediction and Validation for Free-Piston Stirling Engines Considering Nonlinear Load Damping (자유피스톤 스털링 엔진의 비선형 부하 감쇠를 고려한 동역학 모델 예측 및 검증)

  • Sim, Kyuho;Kim, Dong-Jun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.10
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    • pp.985-993
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    • 2015
  • Free-piston Stirling engines (FPSEs) have attracted much attention in the renewable energy field as a key device in the conversion from thermal to mechanical energy, and in the recycling of waste energy. Traditional Stirling engines consist of two pistons that are connected by a mechanical link, while FPSEs are formed as a vibration system by connecting each piston to a spring without a physical link. To ensure the correct design and control of operations, this requires elaborate dynamic-performance predictions. In this paper, we present the performance-prediction methodology using a linear and nonlinear dynamic analytical model considering the external load of FPSEs. We perform linear analyses to predict the operating point of the engine using the root locus technique. Using nonlinear analysis, we also predict the amplitude of pistons by performing numerical integration considering both the linear and nonlinear damping terms of the external load. We utilize the predicted dynamic behavior to predict the engine performance. In addition, we compare the experiment results and existing model predictions for RE-1000 to verify the reliability of the analytical model.