No abstract

Sloshing in medium size tanks caused by earthquake studied by SPH A numerical study of sloshing effects in medium-sized liquid storage tanks subjected to earthquake is briefly presented in the paper. The following issues are considered in the study: the phenomena occurring in tanks during excitation, the amount of pressure change during sloshing, and the effects on the tank itself. The numerical model used in the study is based on the Smoothed Particle Hydrodynamics (SPH) method. The presented method can be used for simulating main nonlinear characteristics of the fluid, such as viscosity, cavitation, wave breaking, and turbulence. The reliability of the model and some of its possibilities are illustrated on a practical example.

The paper presents the comparison of the results between the numerical model developed for the simulation of the fluid-structure interaction problem and the experimental tests. The model is based on the so called “partition scheme” in which the equations governing the fluid’s pressures and the equations governing the displacement of the structure are solved separately, with two distinct solvers. The SPH (Smoothed Particle Hydrodynamics) method is used for the fluid and the standard FEM (Finite Element Method), based on shell elements, is used for the structure. Then, the two solvers are coupled to obtain the coupled behaviour of the fluid structure system. The elasto plastic material model for the structure includes some important nonlinear effects like yielding in compression and tension. Previously experimentally tested (on a shaking table) rectangular tanks with rigid and deformable walls were used for the verification of the developed numerical model. A good agreement between the numerical and the experimental results clearly shows that the developed model is suitable and gives accurate results for such problems. The numerical model results are validated with the experimental results and can be a useful tool for analyzing the behaviour of liquid tanks of larger dimensions.

Within this paper, a 3D numerical model for the fluid structure interaction under dynamic load, has been developed. Partitioned approach has been used, where the construction and fluid are solved separately and by different methods. For the analysis of construction, a previously developed model based on the finite element method (FEM) has been used, which was improved by introducing the drilling stiffness of the degenerated isoparametric final element of the shell. For the analysis of fluid, a previously developed model based on the method of smoothed particle hydrodynamics (SPH) has been used, which was improved by introducing additional correction of fluid pressures values along the boundaries of the computer domain. The model is primarily developed for simulation of steel structures that can be described by shell elements (water tanks, reservoirs, etc.). The model can be used to describe the main nonlinear characteristics of the construction steel: flow (yield) under compression and tension and evolvent of plasticity. It is also possible to simulate the basic nonlinear characteristics of the fluid (compressibility, viscous flow and turbulence). Experimental investigations of the interaction of open rectangular reservoirs and water on the shake table were performed within this paper. Experimental investigations have contributed to additional knowledge of the real behaviour of shell structures that are in contact with the fluid and exposed to different dynamic loads. In addition, an experimental database for verification of the developed numeric model was created. Numerical tests performed by using a developed numerical model show its reliability and application. Model verification was performed on the example of the results of the experimental investigations performed within the paper but also from the numerical and experimental results from available literature. Finally, the most important conclusions of the conducted investigations are listed.

SažetakU ovome radu je prikazan numerički model za međudjelovanje konstrukcije i tekućine u uvjetima dinamičkog opterećenja. Model se zasniva na pristupu sa zasebnim rješenjima, pri čemu se za analizu konstrukcije koristi model zasnovan na metodi konačnih elemenata (eng. Finite element method -FEM), a za analizu tekućine model zasnovan na metodi hidrodinamike izglađenih čestica (eng. Smoothed particle hydrodynamics -SPH). Modelom je moguće opisati glavne nelinearne značajke konstrukcije: tečenje (popuštanje) u tlaku i vlaku i razvoj plastič-nosti. Moguće je adekvatno simulirati i osnovne nelinearne karakteristike tekućine: stišljivost, viskoznost i turbulenciju. Numerički testovi provedeni pomoću razvijenog numeričkog modela prikazuju njegovu pouzdanost i mogućnost primjene. Provjera modela izvršena je na primjeru rezultata numeričkih i eksperimentalnih rezultata iz literature. Ključne riječi: 3D numerički model, interakcija, FSI, FEM, SPHModelling fluid and shell structure interaction by combined finite element method and particle method Abstract Numerical model for the fluid structure interaction under dynamic loading is presented in this paper. The partitioned approach applied involves the use of the finite element method (FEM) for the analysis of structure, while the smoothed particle hydrodynamics (SPH) is used for the analysis of fluid. The model can be used to describe main nonlinear characteristics of the structure: flow (yield) under compression and tension, and increase in plasticity. It is also possible to simulate basic nonlinear characteristics of the fluid (compressibility, viscous flow, and turbulence). Numerical tests performed using the developed numerical model show its reliability and application. The model is validated using the numerical and experimental results from literature.

The paper presents the numerical model developed for the simulation of the fluid-structure interaction problem. The model is based on the so called "partition scheme", in which the Smoothed Particle Hydrodynamics (SPH) method is used for the fluid and the standard Finite Element Method (FEM), based on shell elements, is used for the structure. Then, the two solvers are coupled to obtain the behaviour of the coupled fluid-structure system. The effects of large displacements and small strains are taken into account in the model for shells. The elasto-plastic material model for the structure (shell), which includes some important nonlinear effects like yielding in compression and tension, is briefly discussed. Some of the model's possibilities are illustrated in a practical example of a rectangular medium sized fluid tank with rigid and deformable walls under several ground excitations.