Behavior of Elastic Rod Falling into a Vibrating Circular Cylinder

抄録

An elastic rod falling into a vibrating circular cylinder is a model of a control rod falling into a thimble of PWR nuclear reactor core under an earthquake excitation. In this paper, the dynamical behavior of the rod is clarified by taking collision and friction between the rod and the thimble into consideration, and time required for the rod to fall into the thimble is estimated by a simplified analytical model, which is based on the results of a computer simulation. The influences of input acceleration, input frequency, and coefficient of friction upon the falling time of the rod are examined, and it is revealed that the friction at a guide tube located above the thimble plays an important role in determining the falling time of the rod.