Search

This paper first briefly describes the numerical model for the simulation of spatial (3D) fluid-structure coupled problems. The model is primarily intended to simulate the fluid-structure dynamic interaction in seismic conditions and is based on so called “partitioned approach”. This approach allows the usage of appropriate mathematical/physical models for separate fields: structure and fluid. So, individual fields are solved independently by considering the interaction information transfer between them at every stage of the solution process, with minor modifications for the influence of interactions. The material models for structure and fluid are defined by elementary material parameters which can be easily obtained by standard tests, so that the very complex behavior of reinforced concrete structures and water can be described simply and effectively but with a sufficiently accurate model. The model can described the main important nonlinear effects of reinforced concrete structure behavior: yielding in compression and opening and propagation of cracks in tension, with tensile and shear stiffness of cracked concrete, as well as nonlinear behavior of reinforced steel. Model can also represent nonlinear behavior of water: cavitation. The developed model is suitable for problems with limited fluid motions, such as the response of dams [3] or offshore structures to earthquake. Finally, the numerical model of concrete gravitational dam “Jablanica” on Neretva River in B&H was made. Some seismic response numerical simulations of this dam are also made, and results were compared with data measured in site. Very good agreement of results demonstrates the usability of the model for simulation of real engineering structures.

This paper briefly describes the numerical models for the simulation of fluid-structure coupled problems. The applied models are primarily intended to simulate the fluid-structure dynamic interaction in seismic conditions. Models can simulate the most important non-linear effects of plane and spatial structures that are in direct contact with fluid. Some of models' possibilities are illustrated in numerical analyses of the seismic behavior for several practical examples.

The paper briefly described a numerical model for the numerical simulation of fluid-structure coupled problems. The applied model is primary intended to simulate fluid-structure dynamic interaction in seismic conditions. The partition scheme of coupled (multi-field) problem is briefly described as the most common approach for the fluid-structure dynamic analysis. Some model's possibilities are illustrated on numerical analysis of the seismic behavior of underwater oil tank of "Khazzan" type.

The paper briefly described numerical model for submerged structures under seismic load condition. The applied material model’ s primary purpose is the simulation of fluidstructure interaction in seismic conditions. It includes the most important nonlinear effects of fluid and structure. Some model's possibilities are illustrated on seismic behavior of underwater oil tank of "Khazzan" type.

The paper first presents alternative possibilities for underwater tunnel benefits for crossing deeply and widely water barieras. After that the 2D numerical model for the seismic analysis of underwater structures, which simulates dynamic interaction between structure and water in seismic conditions, is briefly presented. The main nonlinear effects of water-structure system are modeled. The analysed example of underwater tunnel over Hø ; ; gsfjord in Norway ilustrates some possibilities of the presented numerical model and the developed software.

U seizmičkim uvjetima javlja se vrlo složeno interaktivno djelovanje podvodnih konstrukcija (izvanobalne konstrukcije, uronjeni tuneli, podvodni spremnici, stupovi mostova, obalni zidovi i sl.) i okolnog volumena vode. Stoga je teško odrediti stvarno ponašanje i stvarnu sigurnost ovih konstrukcija u takvim uvjetima. U ovom su radu prikazana dva numerička modela za simulaciju dinamičke interakcije konstrukcije i okolne vode u seizmičkim uvjetima. Kod toga se jedan odnosi na primjenu kod ravninskih (2D), a drugi kod prostornih (3D) problema. U modelu za 2D probleme konstrukcija i voda su simulirani s 4, 8 i 9-čvornim izoparametrijskim ravninskim elementima. U modelu za 3D probleme voda je modelirana s prostornim ''brick'' elementima, a konstrukcija s elementima degenerirane trodimenzionalne zakrivljene ljuske. Za opisivanje ponašanja konstrukcije koristi se konstitutivni model materijala prvenstveno namijenjen simulaciji ponašanja armiranobetonskih konstrukcija. On simulira dominantne nelinearne efekte njihova ponašanja (tečenje betona u tlaku, razvoj pukotina betona u vlaku, nelinearno ponašanje armature, te utjecaje brzine opterećenja na ponašanje betona i čelika). S podešavanjem odgovarajućih parametara, ovaj model se može koristiti i za simulaciju drugih gradiva s elastičnim, elasto-plastičnim i elasto-krtim ponašanjem (stijena, tlo, čelik, drvo i sl.). Za opisivanje ponašanja vode koristi se linearni materijalni model, te nelinearni model koji simulira pojavu kavitacije. Izložen je model simulacije utjecaja suspenzija u vodi pri dinamičkoj pobudi. Prikazani modeli i odgovarajući proračunski programi primijenjeni su pri analizi složenih praktičnih podvodnih konstrukcija.

U radu je najprije naznačena alternativna mogućnost primjene uronjenih tunela pri prijelazu dubokih i širokih vodenih prepreka. Potom je sažeto opisan 2D numerički model seizmičkog odgovora podvodnih konstrukcija, koji simulira interakciju konstrukcije i vode u seizmičkim uvjetima. Modelirani su najvažniji nelinearni efekti sustava voda-konstrukcija. Za ilustraciju primjene modela, analizirano je seizmičko ponašanje planiranog uronjenog tunela preko H&oslash ; gsfjorda u Norveškoj.

U radu je sažeto opisan 3D numerički model seizmičkog odgovora podvodnih konstrukcija, koji simulira interakciju konstrukcije i vode u seizmičkim uvjetima. Modelirani su najvažniji nelinearni efekti sustava voda-konstrukcija. Za ilustraciju primjene modela, analizirano je seizmičko ponašanje podvodnog spremnika za naftu tipa “ Khazzan” .