Relevant bibliographies by topics / Irregular hybrid structure

Academic literature on the topic 'Irregular hybrid structure'

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Published: 30 May 2022
Last updated: 31 May 2022

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Journal articles on the topic "Irregular hybrid structure"

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Chao, Hsien-Wen, Hua-Hsuan Chen, and Tsun-Hsu Chang. "Measuring the Complex Permittivities of Plastics in Irregular Shapes." Polymers 13, no. 16 (August 10, 2021): 2658. http://dx.doi.org/10.3390/polym13162658.

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This work presents the measurement of the complex permittivities of high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), polypropylene (PP), Nylon, and thermoplastic vulcanizates (TPV) in irregular shapes at the microwave frequency. A Teflon sample holder was employed to pack irregularly shaped plastic materials with various volumetric percentages. The samples were put into a resonant cavity with an enhanced electric field in its center, which is known as the enhanced-field method (EFM). The resonant frequencies and the quality factors at different volumetric percentages were measured by a network analyzer and compared with simulated results using a full-wave simulator (high-frequency structure simulator (HFSS)). Three simulation models, layer, ring, and hybrid, are proposed and compared with the experimental results. It is found that the hybrid model (denoted as Z5R5) with five heights and five radii in the partition is the most suitable. The complex permittivities of six plastic materials were evaluated by the contour maps of the HFSS simulation using the hybrid model. The measured complex permittivities of the irregularly shaped polymers agree well with their counterparts in bulk form.
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Tikhanychev, Oleg Vasilyevich. "Clarification of the structure of “hybrid forces”." Национальная безопасность / nota bene, no. 1 (January 2021): 40–48. http://dx.doi.org/10.7256/2454-0668.2021.1.33387.

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The subject of this research is the “hybrid wars”, while the object is the “hybrid forces” as a means of conducting hybrid wars. The author establishes that that currently in assessment of “hybrid forces”, the latter imply military and irregular formations opposing on the battlefield. At the same time, the analysis of the content of “hybrid wars” demonstrates that the structure of “hybrid forces” should be understood in a broader sense, considering procurement and all-round support, including those carried out covertly. This approach provides a more accurate assessment of “hybrid wars” and its actors. The main conclusion of consists in the proposal to expand the structure of “hybrid forces”, alight in with the structure of modern” hybrid” conflicts. The novelty of this research lies in the fact that based on clarification of the actors and structure of “hybrid forces”, the author formulates recommendations on clarification of the mechanisms for assessing course of “hybrid” wars, analysis of the possible vectors for “hybrid” actions;  as well as underlines the need for regulation of international legislation in the area of conducting armed conflicts and their actors. The analysis of open sources describing the subject area shows that this problem was not previously solved in such a statement
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Yujian, Wang, Tan Shaowei, Dong Weiwei, and Jing Wenpeng. "Research on 3D Modeling Method Based on Hybrid Octree Structure." Open Electrical & Electronic Engineering Journal 8, no. 1 (December 31, 2014): 323–29. http://dx.doi.org/10.2174/1874129001408010323.

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With studying deeply of the three-dimensional modeling method, this paper proposed a hybrid data model which based on Octree,the four fork tree and NURBS. The characteristic of fast convergence of Octree is used to segment the 3D entity. Describe the irregular surface of entity by NURBS, and restructure the local mesh surface. The model uses the mixture data structure of Octree and four fork tree to restructure mesh surface gradually. The storage structure is the Octree structure type; establish Hash table based on octal prefix code. Finally, an experimental model system is designed by using OpenGL. The feasibility and effectiveness of the algorithm has been verified.
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Wu, Di, Yoshihiro Yamazaki, and Hiroyasu Sakata. "Dual Equivalent Lateral Force Method for Low-Rise Wooden Horizontal Hybrid Structure with Rigid Core." Shock and Vibration 2018 (December 17, 2018): 1–8. http://dx.doi.org/10.1155/2018/1940706.

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Hybrid structure has shown some great features in the earthquake-resistant design. However, due to the different properties between the combined building systems, the distributions of structural mass and stiffness are prevalently irregular in breadth or height, which makes the widely used equivalent lateral force (ELF) method powerless to predict the seismic shear force of such hybrid structure. This study proposed a simple design procedure for determining the concerned seismic shear force of low-rise wooden horizontal hybrid structure in the preliminary linear design. The dual equivalent lateral force (DELF) method is presented that permits the extension of the ELF method by separating the hybrid structure into two independent substructures. It is shown that the proposed DELF method is sufficient to provide a reasonable estimation of the seismic shear force with satisfied accuracy.
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Fradet, Alain, Jiazhong Chen, Karl-Heinz Hellwich, Kazuyuki Horie, Jaroslav Kahovec, Werner Mormann, Robert F. T. Stepto, Jiří Vohlídal, and Edward S. Wilks. "Nomenclature and terminology for dendrimers with regular dendrons and for hyperbranched polymers (IUPAC Recommendations 2017)." Pure and Applied Chemistry 91, no. 3 (March 26, 2019): 523–61. http://dx.doi.org/10.1515/pac-2016-1217.

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Abstract The present document provides recommendations for (i) definitions of terms related to dendrimers with regular dendrons and to hyperbranched polymers, and (ii) nomenclature for naming these complex compounds on the basis of structure-based nomenclature for regular and irregular organic polymers, including adjustments required for specifying dendritic and hyperbranched macromolecular structures. The recommendations and the examples deal with organic-chemical structures only. Nevertheless, the general principles described in this document can similarly be applied to inorganic and to hybrid inorganic-organic dendrimers and hyperbranched macromolecules.
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Jaworski, Łukasz, Alexander Shkarovskiy, and Aleksandr Chernykh. "An Improved Method of Serial Balancing of Hybrid Boiler Station Systems." Rocznik Ochrona Środowiska 23 (2021): 214–23. http://dx.doi.org/10.54740/ros.2021.014.

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This paper presents a prototype of a thermo-hydraulic distributor for a hybrid boiler station supplying a small hotel in Koszalin. The task of the device was to balance the hybrid system with four circuits with different operating parameters, also changing in an extremely irregular manner. A prototype of a thermo-hydraulic distributor with improved internal structure was developed, ensuring the operation of the device in accordance with the temperature logic. Dimensions of the device have been calculated in accordance with the existing design principles of hydraulic distributors.
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Lewińska, Agnieszka, Marta Domżał-Kędzia, Kinga Kierul, Michał Bochynek, Dominika Pannert, Piotr Nowaczyk, and Marcin Łukaszewicz. "Targeted Hybrid Nanocarriers as a System Enhancing the Skin Structure." Molecules 26, no. 4 (February 18, 2021): 1063. http://dx.doi.org/10.3390/molecules26041063.

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The skin is constantly exposed to external and internal factors that disturb its function. In this work, two nanosystems-levan nanoparticles and a surfactin-stabilized nanoemulsion were preserved (tested for microbial growth) and characterized (size, polydispersity, Zeta potential, and stability). The nanosystems were introduced in the model formulations-cream, tonic, and gel, and confirmed by TEM. The analysis showed that nanoemulsion has a spherical morphology and size 220–300 nm, while levan nanoparticles had irregular shapes independently of the use of matrix and with particle size (130–260 nm). Additionally, we examined the antiradical effect of levan nanoparticles and nanoemulsion in the prototype of formulations by scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl; EPR spectroscopy). The model cream with both nanosystems and the whole range of products with nanosystems were evaluated in vivo for hydration, elasticity, smoothness, wrinkles and vascular lesions, discoloration, respectively. The cream improved skin condition in all tested parameters in at least 50% of volunteers. The use of more comprehensive care, additionally consisting of a tonic and gel, reduced the previously existing skin discoloration to 10.42 ± 0.58%. The presented prototype formulations are promising in improving skin conditions.
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Zhang, Hong Mei, Xi Lin Lu, and Chun Guang Meng. "Experimental and Simulation Study of a Hybrid Frame Structure with Viscous Dampers." Advanced Materials Research 446-449 (January 2012): 894–99. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.894.

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A Concrete-filled Rectangular Steel Tube (CRST) frame structure is studied in this paper by shaking table model test and nonlinear simulation. A number of viscous dampers are employed to insure the function of the building especially under seismic action for some of the main vertical elements of the building are not continuous. A shaking table test of a scaled model was conducted under different earthquake waves to investigate the structural behavior. And the nonlinear time-history analysis for the shaking table test model was also carried out by finite element analysis program according to the shaking table test. The simulation model was constructed in accordance with the tested specimen and the simulation effect was then validated by the tested results. To sum up, (1) there are no obvious weak stories on the damping equipped structure; (2) the dampers can reduce the displacement of the irregular to a certain degree.
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Akça, Irfan, and Ahmet Tuğrul Basokur. "Extraction of structure-based geoelectric models by hybrid genetic algorithms." GEOPHYSICS 75, no. 1 (January 2010): F15—F22. http://dx.doi.org/10.1190/1.3273851.

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A major difficulty in electrical resistivity imaging is the identification of the lithologic units, especially in the sedimentary environments. The geologic interpretation generally is realized by visual inspection of the final resistivity section. Although sharp boundary inversion techniques based on a local linearization could allow the delineation of interfaces between geologic units, these techniques will succeed only if an initial model already close to the best solution is available. Stochastic algorithms might localize a point around the global minimum of the misfit function; however, they are not efficient at finding the precise solution. For this reason, our previously published hybrid genetic algorithms, derived from evolution theories, are used to verify structure-based models. The geometric parameters are defined by thickness values of the lithologic units at control points distributed along the horizontal axis. A zero thickness value indicates the nonexistence of a certain unit at the corresponding con-trol point. An unstructured grid composed of irregular triangles is constructed by the application of Delaunay triangulations to represent complicated structural boundaries. In addition, the computation time for the calculation of model response is reduced greatly by this strategy. Because the suggested parameterization reduces the number of unknown parameters to a few tens and the computation time for the model responses is reduced by the Delaunay triangulation, the implementation of hybrid genetic algorithms for 2D problems becomes possible. A huge number of models are generated randomly in the first generation (a population of parameters) and then updated in subsequent generations by the simulation of biological processes. The suggested algorithms consist of two computational phases. In the first stage, the physical property of each subsurface layer is represented by a distinct resistivity value. After some succeeding genera-tions, laterally varying resistivities within the same lithologic unit are permitted to simulate lateral changes in geologic conditions.
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Zhang, Jun. "Hybrid Wave Models and Their Applications for Steep Ocean Waves." Marine Technology Society Journal 33, no. 3 (January 1, 1999): 15–26. http://dx.doi.org/10.4031/mtsj.33.3.3.

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Bound-wave components resulting from inter-actions among free-wave components have significant effects on resultant wave properties, especially in a steep ocean wave field. Hybrid Wave Models (HWM) distinguish the bound-wave from free-wave components in the decomposition of an irregular wave field as well as the prediction of its resultant proper-ties. To ensure the convergence, the HWMs selectively use the conventional and phase modulation approaches to address the nonlinear interactions between-free-wave components of different frequency ratios. The models are able to predict resultant wave properties accurately and deterministically based on the time-series measurements at fixed points. Four examples of their applications to the prediction of wave properties and wave-structure interactions are presented, which demonstrate the usefulness of HWMs to the studies of ocean surface waves.
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Dissertations / Theses on the topic "Irregular hybrid structure"

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Бондаренко, И. Н., and А. В. Галич. "Resonant irregular hybrid structures." Thesis, 2016. http://openarchive.nure.ua/handle/document/6781.

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Numerical model simulation and experimental device examination defines the conditions of excitation and types of high-Q oscillations in irregular hybrid structures and the conditions for communication of high-Q oscillations with an aperture of a coaxial probe parts are also identified. Irregular hybrid structure in configurations discussed can be effectively used to create high-Q resonator transducers for contactless microwave diagnostics of different objects. The possibilities of the use of irregular resonator structures for the formation of ionizing microwave fields in the electrodeless sulfur lamps, and as a guide elements of light are also investigated. The analysis of resonator structures of different geometry, configuration of the field strength, which are formed, and magnitude of the field strength, amplitude-frequency characteristics are carried out.
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Book chapters on the topic "Irregular hybrid structure"

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"Seismic evaluation of a braced plan irregular steel structure using hybrid testing." In Behaviour of Steel Structures in Seismic Areas, 177–84. CRC Press, 2012. http://dx.doi.org/10.1201/b11396-26.

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Conference papers on the topic "Irregular hybrid structure"

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Li, Yuyu, Dayan Cao, Tao Liu, and Yan Xiao. "Seismic Design of an Irregular Shape Hybrid Hotel Building Structure." In 10th International Conference on Advances in Steel Concrete Composite and Hybrid Structures. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2615-7_102.

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Johnson, James J., Oleg R. Maslenikov, David K. Nakaki, Philip S. Hashimoto, Yahya Bayraktarli, and Olivier Zuchuat. "A Hybrid Method to Develop SSI Parameters for Rigid Embedded Foundations of Arbitrary Shape." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25350.

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CLASSI and SASSI are two sub-structuring approaches to analyze the phenomena of soil-structure interaction (SSI) with extensive applications in the nuclear power industry. Many similarities exist in the two methods; both approaches treat the SSI problem as a linear problem (soil and structure are modeled as behaving linearly), solve the problem in the frequency domain, and treat complex free-field wave propagation mechanisms, including incoherence of ground motion. SASSI has distinct advantages in modeling embedded foundations of irregular shapes, including foundation flexibility. Standard versions of CLASSI treat the foundation of the structures as behaving rigidly with respect to earthquake motions and the calculation of overall response. Structures are modeled in CLASSI using their fixed-base eigen-system. This permits very detailed structure models of 100,000s degrees of freedom represented by 1000s of fixed-base modes to be incorporated directly into the SSI analysis. Other advantages of CLASSI are the ability to interrogate sub-structure elements of the problem efficiently, and the ability to cost-effectively perform probabilistic response analyses of soil-structure systems. The limitation of CLASSI is its inability to treat embedded foundations of complex geometry and the assumption of rigid foundation behavior. This paper summarizes the general CLASSI approach to the SSI problem. Next, a Hybrid approach to developing SSI parameters is presented, whereby the advantages of SASSI for foundation modeling are used in the development of foundation impedances and scattering functions for embedded foundations and analysis in CLASSI. The computer program RIGID is validated and verified against published results. An application to the modeling of the SSI parameters for the Mu¨hleberg Nuclear Power Plant Reactor and SUSAN Buildings is presented.
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de Lemos, Marcelo J. S., and Renato A. Silva. "Turbulent Flow Around a Wavy Interface Between a Porous Medium and a Clear Domain." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45457.

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Flow over forests and vegetation can be characterized by some sort of porous structure of irregular surface through which a fluid permeates. Also, in engineering systems one can have components that make use of a working fluid flowing over irregular layers of porous material. This paper presents numerical solutions for such hybrid medium, considering here a channel partially filled with a sinusoidal porous layer saturated by a fluid flowing in turbulent regime. One unique set of transport equations is applied to both regions. Effects of Reynolds number, porosity and permeability on mean and turbulence fields are investigated. Results indicate that around the peaks of the sinusoidal layer values of the turbulent kinetic energy are higher.
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Bachynski, Erin E., Maxime Thys, Thomas Sauder, Valentin Chabaud, and Lars Ove Sæther. "Real-Time Hybrid Model Testing of a Braceless Semi-Submersible Wind Turbine: Part II — Experimental Results." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54437.

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Real-Time Hybrid Model (ReaTHM) tests of a braceless semi-submersible wind turbine were carried out at MARINTEK’s Ocean Basin in 2015. The tests sought to evaluate the performance of the floating wind turbine (FWT) structure in environmental conditions representative of the Northern North Sea. In order to do so, the tests employed a new hybrid testing method, wherein simulated aerodynamic loads were applied to the physical structure in the laboratory. The test method was found to work well, and is documented in [1]. The present work describes some of the experimental results. The test results showed a high level of repeatability, and permitted accurate investigation of the coupled responses of a FWT, including unique conditions such as blade pitch faults. For example, the influence of the wind turbine controller can be seen in decay tests in pitch and surge. In regular waves, aerodynamic loads due to constant wind had little influence on the structure motions (except for the mean offsets). Tests in irregular waves with and without turbulent wind are compared directly, and the influence of the wave-frequency motions on the aerodynamic damping of wind-induced low-frequency motions can be observed.
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Jeongsoo, Kim, Park Min-Su, Jeong Youn-Ju, and Hwang Yoon-Koog. "Experimental and Numerical Analysis of Hybrid 3kW Ocean Wave-Power Generation System Subjected to Regular and Irregular Wave Forces." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61245.

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In particular of coastal area, needs of ocean energy development have emerged with global demands on non-pollution energy. Although there are several types of wave-power generation systems, such as an attenuator and an overtopping device, these have problems related to frequent damages or limited applicable area. This study is concerned with development of a new hybrid wave-power system, which is expected to provide higher power efficiency than the previous system, and experimental and numerical estimations on performance of the new system. The proposed wave power absorber is composed of a generator embedded in the floating shield cylinder, pendulum plate to accelerate rotation of generator, self-dynamic positioning devices, and a support column to fix the entire power generation system to the seabed. To determine major design parameters and to conduct a specific concept design of the proposed power generation system, hydrodynamic tests of the floating shield cylinder were carried out. The cylinder was scaled with a scale factor 0.12. Several test specimens were fabricated to examine effects of the following physical characteristics on the system performance: draft depth of the cylinder, diameter of the cylinder, longitudinal projective area of the cylinder, a number of blades attached on the cylinder, blade length. Each specimen was subjected to 8 regular and 4 irregular wave loads for 5 minutes; an extreme water wave condition was also included. In the hydrodynamic tests, rotation numbers of the cylinder per a minute were measured. Although consistent patterns of the angular velocity of the cylinder was not observed from the experimental results, the results showed that the ratio of draft depth to diameter mainly effects on the angular velocity of the cylinder, and that the cylinder quickly rotates at the crest of an incident wave while it inversely and slowly rotates at the through. Furthermore, to supplement the above tests and to analyze mechanical behaviors of the support system, numerical simulations of the system were also conducted. To calculate water pressure on the cylinder and the support column, the commercial computational program ANSYS AQWA was used. The distribution and the magnitude of the predicted water pressure were then mapped into the finite element model of the cylinder and the support structure to examine the structural responses and stability against overturning.
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Bondarenko, Igor, and Aleksandr Galich. "Resonant irregular hybrid structures." In 2016 13th International Conference on Modern Problems of Radio Engineering. Telecommunications and Computer Science (TCSET). IEEE, 2016. http://dx.doi.org/10.1109/tcset.2016.7452007.

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de Lemos, Marcelo J. S., and Renato A. Silva. "Laminar Flow Around a Sinusoidal Interface Between a Porous Medium and a Clear Fluid." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41452.

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A number of natural and engineering systems can be characterized by some sort of porous structure through which a working fluid permeates. Atmospheric boundary layers over tropical forests and vegetation can be modeled as flow over a porous layer of irregular surface. In addition, in engineering systems one can have components that make use of a working fluid flowing over irregular layers of porous material. This paper presents numerical solutions for such hybrid medium, considering here a channel partially filled with a sinusoidal porous layer saturated by a fluid flowing in laminar regime. One unique set of transport equations is applied to both regions. Effects of Reynolds number, porosity and permeability on mean and turbulence fields are investigated. For a fixed inlet mass flow rate, increase of either porosity or permeability reduced the strength of the recirculating motion over the porous layer.
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Nakaki, David K., Philip S. Hashimoto, James J. Johnson, Yahya Bayraktarli, and Olivier Zuchuat. "Probabilistic Seismic Soil Structure Interaction Analysis of the Mu¨hleberg Nuclear Power Plant Reactor and SUSAN Buildings." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25343.

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Probabilistic seismic soil-structure interaction (SSI) analysis was performed for the Mu¨hleberg Nuclear Power Plant Reactor and SUSAN Buildings in support of the seismic probabilistic saftety assessment of the plant. An efficient hybrid method, employing computer programs SASSI2000 and CLASSI presented in a companion paper, was used in this analysis. The method takes advantage of the capability of SASSI2000 to analyze embedded structures with irregular geometry and the computational efficiency of CLASSI to rapidly perform the SSI response analysis of large structure models. Fixed base finite element models of the buildings were first developed from which the structure geometry, nodal masses, natural frequencies, and mode shapes were extracted. The structure embedments were modeled using SASSI2000. Impedance functions and scattering vectors were calculated by imposing rigid body constraints to the embedded foundation. The fixed base structure dynamic properties and the foundation impedances and scattering functions were input to CLASSI to perform the response analysis. The probabilistic analysis was performed following the Latin Hypercube Simulation (LHS) approach documented in NUREG/CR-2015. Variables defined by probability distributions were sampled according to a stratified sampling approach. The combination of the parameters for each simulation was determined by Latin Hypercube experimental design. Variables in the LHS included the earthquake ground acceleration time histories, structure stiffness and damping, and soil stiffness and damping. Thirty response simulations were performed using CLASSI in which the variable values were randomly selected. The use of CLASSI has the advantage that the response analysis simulations can be executed in a fraction of the time that would be required with SASSI2000 alone. For each simulation, in-structure response spectra (ISRS) were calculated at selected locations in the buildings. Probabilistic distributions, described by the median and 84th percentile response spectra, were calculated from the thirty simulations. The probabilistic ISRS are subsequently used in the seismic fragility evaluations of selected essential equipment.
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Ribeiro Machado da Silva, Vinicius, and Breno Serrano de Araujo. "Convolutional Neural Networks Applied to Flexible Pipes for Fatigue Calculations." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18212.

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Abstract The industry standard approach for the design of flexible pipes makes use of non-linear finite element analysis (FEA) in time domain to simulate the physical responses of the structure in different environmental conditions. Wave dynamics can be represented either by an irregular wave (IW) or an equivalent regular wave (RW) approach, which simplifies the analysis. Irregular wave modeling approximates better the structural responses, due to the stochastic nature of the environmental loading, having the drawback of being more computationally expensive. The computer processing time of IW-FEA often becomes intractable due to the large number of scenarios that need to be simulated, for different values of Hs (significant height), Tp (peak period) and different wave directions. Reducing the time needed to simulate each scenario would reduce significantly the total processing time. In order to achieve this, alternative hybrid methods have been proposed in the literature, combining FEA with machine learning models. This paper proposes the use of nonlinear autoregressive exogeneous convolutional neural networks (NARX-CNN) to predict tension and curvature responses along the length of a flexible riser. Experimental results show that the proposed model can generate more accurate responses than previous models. This work also extends the region analyzed by forecasting responses beyond the bending stiffener level, going down to the end-fitting and touch down zone locations. It is the first time that such regions, prone to fatigue issues, are evaluated with these types of algorithms for flexible pipes, as per authors’ knowledge.
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Russell, Colin, and Bertrand Vignaud. "Hydrodynamic Loading on Mid Water Arch Structures." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49751.

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In the design and analysis of subsea structures, the hydrodynamic coefficients play a significant role in determining the behaviour of the system, particularly when they are under the combined action of steady and oscillatory flow. For small regularly shaped structures and slender members there is a significant amount of literature that provides assistance in the selection of suitable values, however this is not the case for larger and irregular shaped structures where there is a scarcity of information. This paper details the results of a study to develop techniques to derive hydrodynamic coefficients for representative mid water arch configurations commonly used in shallow water flexible riser system applications. The results of a literature review are presented outlining where these structures fit into the different theoretical models. The use of the potential flow approach is verified by means of computational fluid dynamic simulations for a representative structure and both methods are utilised to assist in the generation of appropriate coefficients. A case study on a typical shallow water North Sea project is presented that demonstrates the importance of selecting appropriate hydrodynamic values to represent the structure. The influence of each of the coefficients on the arch motion, which has an impact on the riser response, is studied. It is shown that it is not always possible to be conservative and instead it is important to select appropriate coefficients for the structure in question, which may differ from those typically used. The method developed has wide ranging applicability and can in principle be applied to the determination of hydrodynamic coefficients for other large structures subject to hydrodynamic loading, including disconnectable turret buoys and hybrid riser tower systems.
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