An equivalent mechanical model with nonlinear damping for sloshing rectangular tank with porous media

Tuned liquid dampers (TLDs) utilize sloshing fluid to absorb and dissipate structural vibrational energy, thereby reducing wind induced dynamic motion. By selecting the appropriate tank length, width, and fluid depth, a rectangular TLD can control two structural sway modes simultaneously if the TLD tank is aligned with the principal axes of the structure. This study considers the influence of the TLD tank orientation on the behavior of a 2D structure-TLD system. The sloshing fluid is represented using a linearized equivalent mechanical model. The mechanical model is coupled to a 2D structure at an angle with respect to the principal axes of the structure. Equations of motion for the system are developed using Lagrange’s equation. If the TLD and structure are not aligned, the system responds as a coupled four degree of freedom system. The proposed model is validated by conducting structure-TLD system tests. The predicted and experimental structural displacements and fluid response are in agreement. An approximate method is developed to provide an initial estimate of the structural response based on an effective mass ratio. The results of this study show that for small TLD orientation angles, the performance of the TLD is insensitive to TLD orientation.

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Dynamic Property Analysis of Damping Rubber in Rail Fastenings under Different Deformation Condition

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.494-495.706 ◽

2014 ◽

Vol 494-495 ◽

pp. 706-710

Author(s):

Bin Zhang ◽

Yan Yun Luo ◽

Zhi Nan Shi

Keyword(s):

Mechanical Model ◽

Dynamic Stiffness ◽

Excitation Frequency ◽

Nonlinear Damping ◽

Deformation Condition ◽

Damping Force ◽

Restoring Force ◽

Dynamic Mechanical ◽

Large Distortion ◽

Hydraulic Servo

This paper studies the experimental research on dynamic characteristics of the damping rubber in high elastic fastening by the electro-hydraulic servo movement tester. Based on a hypothesis superposition theory of nonlinear elastic restoring force and nonlinear damping force, a non-linear dynamic mechanical model is proposed. The dynamic stiffness and damping parameters of the rubber are obtained in different deformation conditions based on the dynamic mechanical model. The dynamic stiffness is analyzed, and the results show that dynamic stiffness is closely related to excitation frequency and amplitude. Furthermore the dynamic stiffness is analyzed under different free surface of rubber components by using FEM. That also reveals the changeable characteristics and affected factors of the damping rubber of the high elastic fastenings in large distortion condition.

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