over critical speeds

HUANG Xiu-jin，HE Li-dong，HUANG Wen-chao

（Beijing Key Laboratory of Health Monitoring & Self-recovery for High end Mechanical Equipment，

Beijing University of Chemical Technology，Beijing 100029，China）

Abstract：Aiming at the vibration problems of the multi-rotors machinery through critical speeds，the applications for tuned mass damper in two-span rotors system were studied. And based on the rotor structure，a cage-type semi-active tuned mass damper with symmetrical structure was proposed in order to control vibrations of multi-span rotors over critical speeds. A two-span rotors bench was built to experimentally study on the influence of shaft rotors vibration by installing the tuned mass dampers on each span shaft respectively，without changing the original shaft rotors support form. Experimental results show that the uncontrollable TMDs can only effectively suppress the vibration of the shaft where the TMD installed near critical speeds but little effect on the adjacent shaft. However，they will cause new formants. According to experimental results achieve dampers semi-active control by the switching control strategies. And it experimentally verified that the semi-active tuned mass damper can suppress the vibration of the shaft through the critical speeds in the case of non-stop，and avoid detuning.

Key words：tuned mass damper（TMD）；semi-active control；shaft rotors；vibration reduction