Analysis of a computer model of the behavior of a thin plate immersed in a liquid

Abstract

Modeling the oscillation of a steel plate in water under the action of loads to assess the safety of the structure is an urgent task of modern times in the design of structures. The aim of this work was to study the behavior of a plate immersed in a fluid that makes forced oscillations under the action of an applied load; the mechanism of behavior of this interaction and the determination of the connected masses of the fluid. Knowledge of the connected masses helps to assess the effect of the liquid. In this work, the oscillations of a steel plate in water under the action of two types of loads were studied. For the harmonic analysis of the oscillations of the plate, our own frequency response was constructed, which was compared with the frequency response acquired by the method of solving a series of FSI problems. From the comparison of the obtained frequency response it is concluded that it is possible to use harmonic analysis to study the stress-strain state of the plate during its oscillations. Since FSI problems are quite resource-intensive due to their nature, solving a number of such problems about plate oscillations in a fluid under various loads to study the stress-strain state of an oscillatory system is not a very convenient method. The question arises as to whether it is possible to avoid solving FSI problems and to find a simpler way to solve the problems of vibration of structures in a fluid. Since the estimation of the attached water masses of the plate is known, it can be assumed that this attached water mass is distributed around the plate evenly and in view of this fact we can perform a harmonic analysis. Due to the viscosity, water dampens the amplitude of free oscillations of the plate. Thus, in order to be able to compare the results of a series of FSI and harmonic analysis problems, the latter must be modeled taking into account the damping in the model. The method of harmonic analysis with the addition of the attached mass of water can be used at low oscillation frequencies. At all other oscillation frequencies it is not recommended to use the method of harmonic analysis taking into account the connected mass of water.