INVESTIGATIONS ON DAMPING CHARACTERISTICS OF LIQUID COLUMN VIBRATION ABSORBER

Document Type : Original Article

Author

Assistant professor, Mechanical Design Dept., Faculty of Engineering – Mataria, Helwan University, Cairo, Egypt.

Abstract

ABSTRACT
This work deals with the damping characteristics and optimum performance of a
passive liquid column vibration absorber (LCVA) which is effective to decrease the
vibration of engineering systems. A numerical technique is applied to solve the
nonlinear equations of motion to study the influence of the design parameters such
as frequency tuning ratio, length ratio, area ratio, blocking ratio and mass to mitigate
excessive vibrations. A constrained multi-objective optimization problem is
constructed and solved numerically to minimize the maximum master structure
displacement in a broad range of excitation frequency with considering a limit of the
maximum liquid displacement in the vertical tube as an extra objective. It is found
that the best vibration attenuation can be achieved by using the LCVA with a uniform
cross-section area while the non-uniform LCVA offer greater flexibility to modify the
non-appropriate total length. The TCVA mass and the structural damping have an
influence on all optimum parameters. The optimal values of the blocking ratio are
proportional and depend on the intensity of the excitation. The list of necessary
optimal parameters and the corresponding performance indices are presented in
design tables as a guidance for industrial practices.

Keywords