Reliability Design of Rotating Machine against Earthquake Excitation

High speed rotating machines, such as the centrifugal machine, may have deviations of mass, stiffness and damping coefficient in manufacturing process, and are also exposed to the danger of earthquake. In the design of a rotor system, these factors should be accounted for from a view point of reliability. This paper deals with this problem specifically, when the statistical properties of errors of a rotor system and those of an earthquake (i. e. its period, magnitude and statistical character of wave) are known, the statistical properties of the rotor vibration are obtained, and a period of the first collision with the guard of the rotor system is calculated in a statistical sense. It is concluded that the statistical property of the seismic wave has more influence on the reliability than that of the damping coefficient in the rotor system. If the statistical relation between the magnitude and interval of an earthquake is known, the period of the first collision with the guard can be obtained.