The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS...The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS) of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable.展开更多
Most energy-conversion machines (e.g. vehicle engines and electric motors) involve rotating components (e.g. roller bearings and gears), which generate vibrations. The behavior of a pump which includes a deliberate fa...Most energy-conversion machines (e.g. vehicle engines and electric motors) involve rotating components (e.g. roller bearings and gears), which generate vibrations. The behavior of a pump which includes a deliberate fault was chosen to illustrate this assertion. The test bearing at the driven end of the pump’s motor was deliberately damaged using a 1.5mm wire-cutting method and an adjustable coupling disk introduced to impose a shaft misalignment of 40. The resulting undesirable behavior of the pump was observed. Experimental data were measured at various speeds of the rotor. The sample period at various operating frequencies were 0.9, 0.6 and 0.45s respectively. The ball-passage frequency was observed at 4.4, 8.8, 13.2 and 17.6Hz. A computer-based analytical model was developed, in visual basic, for monitoring the machine failures: this led to an integrated system-process algorithm for diagnosis of faults in rotating components.展开更多
基金funded by the National Natural Science Foundation of China under grant No.50578125
文摘The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS) of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable.
文摘Most energy-conversion machines (e.g. vehicle engines and electric motors) involve rotating components (e.g. roller bearings and gears), which generate vibrations. The behavior of a pump which includes a deliberate fault was chosen to illustrate this assertion. The test bearing at the driven end of the pump’s motor was deliberately damaged using a 1.5mm wire-cutting method and an adjustable coupling disk introduced to impose a shaft misalignment of 40. The resulting undesirable behavior of the pump was observed. Experimental data were measured at various speeds of the rotor. The sample period at various operating frequencies were 0.9, 0.6 and 0.45s respectively. The ball-passage frequency was observed at 4.4, 8.8, 13.2 and 17.6Hz. A computer-based analytical model was developed, in visual basic, for monitoring the machine failures: this led to an integrated system-process algorithm for diagnosis of faults in rotating components.