This paper bases on the equivalent linearization method and pseudo excitation method to conduct random vibration analysis of cylindrical LNG isolation tanks under seismic excitation and investigates the influence of the liquid level and shape of the isolation tanks on the random seismic response. First, based on the acceleration response spectrum, a seismic power spectral density function is obtained according to the Kaul method, and a Haroun-Housner model of the LNG tank is established. Second, the equivalent stiffness and damping of the isolation system are obtained according to the equivalent linearization method, and the frequency domain equations of motion of the equivalent linear system are established, and a pseudo excitation method is developed to solve them iteratively. Finally, numerical examples are given, where the random responses of isolated storage tanks under different liquid levels and radii are calculated and the effects of tank radius and liquid level height on the response are studied, so as to provide certain reference for the optimization design of isolated storage tanks.

LNG storage tank  /  seismic analysis  /  Haroun-Housner model  /  equivalent linearization  /  pseudo excitation method