Boundary Element Method for Fluid-Structure Interaction Problems in Liquid Storage Tanks

1989 ◽  
Vol 111 (4) ◽  
pp. 435-440 ◽  
Author(s):  
I.-T. Hwang ◽  
K. Ting

The dynamic response of liquid storage tank, including the hydrodynamic interactions, subjected to earthquake excitations is studied by the combinations of boundary element method and finite element procedure in this paper. The tank wall and inviscid fluid domain are treated as two substructures of the total system-coupled through the hydrodynamic pressures. The boundary element method is employed to determine the hydrodynamic pressures associated with small amplitude excitations and negligible surface wave effects in fluid domain which are expressed as the frequency-dependent terms related with the natural vibration modes of elastic tank alone. These terms are incorporated into the finite element formulation of elastic tank in frequency domain and the generalized displacements are computed by synthesizing their complex frequency response using Fast-Fourier Transform procedure. Thus, the hydrodynamic interactions between the elastic flexible tank wall and the fluid are then solved. To demonstrate the accuracy and validity of the solution procedure developed herein, numerical examples are analyzed. Good correlations between the computed results with the referenced solutions in literature can be noted. The effects of fluid compressibility and tank flexibility are also evaluated in this work. Finally, the dynamic response of liquid storage tank due to seismic excitations is also analyzed.

1993 ◽  
Vol 21 (2) ◽  
pp. 66-90 ◽  
Author(s):  
Y. Nakajima ◽  
Y. Inoue ◽  
H. Ogawa

Abstract Road traffic noise needs to be reduced, because traffic volume is increasing every year. The noise generated from a tire is becoming one of the dominant sources in the total traffic noise because the engine noise is constantly being reduced by the vehicle manufacturers. Although the acoustic intensity measurement technology has been enhanced by the recent developments in digital measurement techniques, repetitive measurements are necessary to find effective ways for noise control. Hence, a simulation method to predict generated noise is required to replace the time-consuming experiments. The boundary element method (BEM) is applied to predict the acoustic radiation caused by the vibration of a tire sidewall and a tire noise prediction system is developed. The BEM requires the geometry and the modal characteristics of a tire which are provided by an experiment or the finite element method (FEM). Since the finite element procedure is applied to the prediction of modal characteristics in a tire noise prediction system, the acoustic pressure can be predicted without any measurements. Furthermore, the acoustic contribution analysis obtained from the post-processing of the predicted results is very helpful to know where and how the design change affects the acoustic radiation. The predictability of this system is verified by measurements and the acoustic contribution analysis is applied to tire noise control.


1993 ◽  
Vol 115 (3) ◽  
pp. 262-267 ◽  
Author(s):  
J. Q. Ye

The postbuckling behavior of thin plates under combined loads is studied in this paper by using a mixed boundary element and finite element method. The transverse and the in-plane deformation of the plates are analyzed by the boundary element method and the finite element method, respectively. Spline functions were used as the interpolation functions and shape functions in the solution of both methods. A quadratic rectangular spline element is adopted in the finite element procedure. Numerical results are given for typical problems to show the effectiveness of the proposed approach. The possibilities to extend the method developed in this paper to more complicated postbuckling problems are discussed in the concluding section.


Author(s):  
S Ilincic ◽  
G Vorlaufer ◽  
P A Fotiu ◽  
A Vernes ◽  
F Franek

A novel formulation of elastic multi-asperity contacts based on the boundary element method (BEM) is presented for the first time, in which the influence coefficients are numerically calculated using a finite element method (FEM). The main advantage of computing the influence coefficients in this manner is that it makes it also possible to consider an arbitrary load direction and multilayer systems of different mechanical properties in each layer. Furthermore, any form of anisotropy can be modelled too, where Green's functions either become very complicated or are not available at all. The rest of the contact analysis is then performed applying a custom-developed boundary element algorithm. The scheme was tested by considering the frictionless contact between a flat surface and a sphere. The obtained results are in good agreement with the analytical solution known for a Hertzian contact. Applied to either a frictionless or a frictional contact between real surfaces of different samples, our FEM-BEM method has shown that the composite roughness of surfaces in contact uniquely determines the contact pressure distribution.


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