Semi-active dynamic absorber of a ship propulsion shafting based on MREs

According to longitudinal vibration characteristics of a marine propulsion shafting, the vibration reduction mechanism of dynamic absorbers was studied. The influences of semi-active dynamic absorbers' parameters on their vibration reduction effect were analyzed. Magneto-rheological elastomer (MRE) was a kind of smart materials, its shear modulus could be controlled by an external magnetic field. Based on this property, a semi-active dynamic absorber with adjustable stiffness was designed. Its natural frequency-shifting feature was tested. Furthermore, The vibration reduction effect tests for a model of a ship propulsion shafting with a scale ratio of 1∶4 and MREs-based SDA under the condition of varying rotating speed were conducted. The results showed that the designed MREs-based SDA has a natural frequency-shifting range of 12.3 Hz, its natural frequency-shifting feature curve has a good linearity; it has a better vibration energy absorption capacity than classic passive dynamic absorbers do under different rotating speeds; the feasibility of using MREs to design semi-active dynamic absorbers for a ship propulsion shafting is verified.