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Machining Dynamics
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
A dynamic absorber or tuned mass damper is an alternative form of vibration control. It consists of a secondary mass attached to the primary vibrating component via a spring, which can be either damped or undamped. This secondary mass oscillates out of phase with the main mass and applies an inertial force (via the spring), which opposes the main mass. For maximum effectiveness, the natural frequency of the vibration absorber is tuned to match the frequency of the exciting force. Auxiliary mass dampers can be used on machine columns, spindles, and rams.
Comparison between structure- and crowd-based mitigation strategies on vibrating footbridges
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
Because increasing structural mass or stiffness implies high costs and undesired aesthetic impact, mitigation measures on footbridges generally consist in adding supplemental damping devices, such as viscous dampers (Dallard et al. 2001) and friction dampers (Law et al. 2004). A similar purpose can be accomplished by transferring most of the structural vibration energy to an attached Tuned Mass Damper
Models of Complex Systems Behaviour
Published in Philip D. Bust, Contemporary Ergonomics 2007, 2018
These models are only representations of complex systems behaviour. Movement of linked modules may produce a form of resonance thus allowing an emergent behaviour to occur, often described as design characteristic but sometimes related to catastrophic failure. Spinal complex behaviour may act as an un-tuned mass damper preventing resonance. Critical point behaviour of pulsed equilibrium may be observed in many systems and may model for complex behaviour. Further work needs to be undertaken.
Hybrid coupled damper for the mitigation of torsional vibrations and rotational irregularities in an automotive crankshaft: Concept and design subtleties
Published in Mechanics Based Design of Structures and Machines, 2023
Guillaume Paillot, Simon Chesné, Didier Rémond
Tuned Mass Dampers are passive mechanical devices in which a mass is appended to vibrating structures by a spring in order to create an escape way for the energy of the vibration and an additional damping. They are consequently much easier to further hybridize than viscous or rubber dampers. At the critical frequency of the primary structure, the energy is trapped in the TMD, which enables a limited vibration for the primary structure. Concept introduced by Frahm (1909), its design parameters have been formally established mainly by Den Hartog via the Equal Peak design formalism (Den Hartog 1956). They can be found in many applications where a narrow band excitation can be found, and the research currently focuses on seismic applications. Torsional TMDs are on the contrary more unusual, even though some studies have emerged for buildings (Singh, Singh, and Moreschi 2002) or drilling (with adaptive features—Abu Seer, Vahdati, and Shiryayev 2019), and additional design formalism has been derived by Nguyen (2020) using various methods. The inertia here replaces the mass as the main physical parameter. Such dampers can therefore be seen as conventional mass-spring absorbers that are located at a certain distance from the axis of rotation, and that consequently move tangentially to the rotation.