Abstract
This article discusses an increase in dynamic force range in a spring–damper unit achieved by elimination of sealings’ friction. This friction is a part of damping force that cannot be controlled; therefore, it is undesirable in magnetorheological dampers. A new design of a magnetorheological damper with no friction force is described and compared with a traditional magnetorheological damper consisting of a piston and piston rod seals. In the traditional design, fluid is forced to flow by a hydraulic cylinder with high friction caused by sealings. In order to eliminate this friction, a frictionless unit made of metal bellows was designed. Elastic metal bellows can be sealed only by static seals. The measurement of force–velocity dependency was carried out for the original and the new damper with the same magnetorheological valve. The results indicate that the frictionless unit exhibits a significant improvement in the dynamic force range. In the case of adaptive-passive damping control, the increase in the dynamic force range enables the improvement of vibration elimination in the entire frequency range.
Highlights
Vibrations – an accompanying feature of movement – are generally undesirable
The method of semi-active damping is more similar to that of passive damping because both methods are based on the reduction of vibration energy within the system,[3] while the active control adds the energy to the system
Friction affects the states with non-zero currents in the coil; the damping forces of the MR damper with bellows are lower than the forces of the MR damper with a piston
Summary
Vibrations – an accompanying feature of movement – are generally undesirable. There are several ways of how to reduce them. The adaptive-passive damping control is one of the suitable methods for elimination of vibrations with harmonic excitation.[12] It is based on variable damping in time, high damping in the vicinity of resonance (equation (1)) and low damping for isolation area (equation (2)).[13] Yang et al.[5] proved that the semi-active suspension with an MR damper with a high dynamic force range and a short response time is very efficient in vibration elimination. Due to the Coulomb friction, the dynamic force range of the MR damper with a piston is insufficient, especially for small piston velocities, which is confirmed by very small differences in the transfer ratios for different currents in the coil of the MR damper with a piston, for frequencies higher than 30 Hz; see Figure 2. This hypothesis needs to be verified for the suspension parameters mentioned in this study
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
