Experimental Studies on a Nonlinear Hydroelastic Vibration of a Clamped Cylindrical Tank Partially Filled With Liquid

Abstract

Experimental studies have been carried out on the nonlinear hydroelastic vibrations of a clamped circular cylindrical tank with a flexible wall and a rigid bottom. In the studies, two test cylinders, made of polyester, with radius R = 240 mm, thickness h = 0.254 mm, and length L = 480 and 160 mm (L/R = 2.0 and 2/3), respectively, were used. The tank is fully or partially filled with water having a free surface. The nonlinearity of the response of the flexible wall when the wall of the tank is harmonically excited by points was investigated, with varying liquid height. It was found that the degree of the nonlinearity depends on the vibration mode, i.e., a circumferential wave number and an axial wave number of the shell, on the length of the tank, as well as on the height of the liquid contained in it. The results obtained here were compared with the experimental results of a cantilevered tank, which was previously carried out. The influence of a thin film floating on the free surface upon the bulging-type responses, in which shell wall response is predominant, was also examined. On the free surface, sub-harmonic response with order 1/2 was observed when the amplitude of the shell wall became large.