Loose Coupling Mechanism and Fault Characteristics Analysis of Multiple Connections in Full Ceramic Bearing-Pedestal-Foundation System Within Wide Temperature Ranges

Loose coupling exists in the full ceramic bearing-pedestal-foundation system within wide temperature ranges, which brings difficulties to the status monitoring and fault identification. In response to this problem, a dynamic model including the coupling effects in the system is established considering thermal-related fit clearance and pedestal looseness clearance within wide temperature ranges. The numerical integration method is applied in the simulation of system dynamic responses with the loose faults, and the relationship between the loosening impact force and peak values in vibrations is set up. The coupling mechanism between the two faults is thereby revealed, and the results are verified through experiments. Results show that the occurrences of outer ring looseness and pedestal looseness lead to new frequency components in dynamic responses, and the amplitudes of corresponding frequencies increase with the looseness clearances. The real-time running status of the system can be obtained by identifying the amplitude of the fault feature frequencies. This study reveals the fault coupling mechanism in full ceramic bearing-pedestal-foundation system within wide temperature ranges and provides theoretical basis and technical support for the safe and reliable operations for related equipment.