Vibration Characteristics of High Natural Frequency Mechanical Structures

Recently, it has been reported that a rupture of the piping in an earthquake is produced not by a momentary large load but by cumulative fatigue damage. Then it is expected that the rupture of equipment and piping that have high natural frequency is also caused by cumulative fatigue damage. Therefore it is very important to grasp this effect accurately. In this study, vibration characteristics at high frequency band are investigated. At first numerical analyses are carried out. In the analysis, elasto-plastic model that gives the system elasto-plastic behavior by differential equation is adopted. Then fundamental experiments by using simple single-degree-of-freedom model are carried out to investigate property of experiment model and vibration characteristic. The experiments consist of static experiments, free vibration experiments, and forced vibration experiments.