Dynamic Analysis of Flexible Rectangular Fluid Containers Subjected to Ground Motion

Abstract Seismic response analysis of p partially filled flexible rectangular liquid storage tanks sububjected to horizontal ground motion is preessented in this paper. The coupling between liquid sloshing mod de ses and wall vibrational modes is weak; con nssequently, for the analysis it is appropriate to consider the two o uuncoupled systems separately. This includdees the liquid-wall system and the free surface gravity waves, inin a similar rigid tank. Fluid-structure interaacction effects on the dynamic responses of partially filled fluid ccontainers, incorporating wall flexibility, arree accounted for in evaluating impulsive pressure. The velocity ppotential in which boundary conditions aree satisfied is solved by the method of separation of variabless using the superposition principle. Based oon the achieved solution, the impulsive pressure distribution is s ccomputed. Solutions based on three-dimen nssional modeling of the rectangular containers are obtained by appplying the Rayleigh-Ritz method using thhee vibration modes of flexible plates with suitable boundary cconditions. Trigonometrical functions that ssa atisfy boundary conditions of the storage tank such that the flel exibility of the wall is thoroughly considereed d are used to define the admissible vibration modes. The analy sysis is then performed in the time domain. TThe influence of tank flexibility on the convective response com pmponents is generally small and may be negglle ected. Therefore, an analytic procedure is developed for derivin gng a simple formula that evaluates convectiivve pressure and surface displacements in a similar rigid tank. TThe results of this study are compared wwith previous published results. The variation of dynamicc response characteristics with respect to d dififferent parameters involved of the tank is investigated.