M. Chiba

Vibration characteristics of a cantilever plate with attached spring-mass system

Abstract Coupled free vibration analysis has been performed on a cantilever thin plate carrying a spring–mass system attached on an arbitrary point by using Rayleigh–Ritz method. Influence of an attached ‘spring–mass’ system, i.e., attached position, relative values of mass and spring constant, on the coupled vibration characteristics of the system has been clarified comparing with those of uncoupled ones. Optimal attached position to maximize coupled plate natural frequency is also investigated and shown in contour diagrams. The influence of an attached mass has also been investigated, as the limiting case whereby the spring stiffness of the ‘spring–mass’ system approaches infinity.

Dynamic stability of liquid-filled cylindrical shells under horizontal excitation, part I: Experiment

Abstract Experimental studies have been carried out on the dynamic stability of a cantilever cylindrical shell partially filled with liquid, under horizontal excitation. The test cylinder was harmonically excited with constant acceleration or displacement amplitude. It was found that a combination instability resonance of sum type could occur, involving two natural vibrations with the same axial mode of vibration number but with the circumferential wave numbers differing by one. By varying the dimensionless water height from 0 to 1·0 stepwise by 0·25 increments, the instability regions and vibration modes were determined for two polyester test cylinders. The response waves, axial and circumferential vibration modes, and behavior of the free liquid surface were also observed.

Oscillations of captured spherical drop of frictionless liquid

The natural frequencies and mode shapes have been investigated for a frictionless spherical liquid globule where part of the free surface is embedded in a spherical cap of the same radius. Five different liquid systems have been considered. With increasing cap angle α and higher modes n, the natural frequencies increase. The different mode shapes exhibit a drastic change of frequencies. In addition, the response of the captured spherical drop due to harmonically forced translational excitation of the rigid cap has been determined for the two major directions.