Modelling and Experimental Investigation of an Active Damper

Abstract

This paper presents a validation methodology of the dynamic behavior of an active viscous damper. The damper has two flexible metallic bellows connected to a rigid reservoir filled with fluid. When one of the bellows is connected to a vibrating structure a periodic flow passes through a variable internal orifice and the damping effect is produced. The size of the orifice is adjusted by a controlled linear piezoelectric actuator that positions the conical core into a conical cavity. The device finite element structural model consists of the valve body and its conical core that are assumed rigid and the flexible bellows are represented by two pistons with elastic suspensions. The flow developed inside the damper is modeled considering the fluid-structure interation, using the Lagrangean-Eulerian formulation. To validate the proposed model a prototype was constructed and experimental tests and numerical simulations are accomplished in the time domain, applying harmonic excitations. The results are compared using curves that relate the damping coefficient with the orifice size and with the input velocity applied at the bellows face. However, for the proper control design and system operation, the direct use of the finite element model becomes unviable due to its high computational time. Then, a reduced second order discrete dynamic model for the damper was developed. The model parameters are identified by analysis in the frequency domain, using impulsive excitation force, for constant and variable orifice sizes. At low excitation frequencies, the damper prototype behaves like a single degree of freedom system which damping factor changes with the orifice size A fuzzy controller was designed and it generates the orifice reference size associated to the desired damping factor. The active system presented better performance when compared to the passive one.

Modelling and Experimental Study on Active Energy-Regenerative Suspension Structure with Variable Universe Fuzzy PD Control

“…The definition indicates both the electric-magmatic properties and mechanism properties, illustrating the physical features of the AERS model. So (14) should be simplified as a 2-order function of the control force , without the constant item:…”

“…Chen et al proposed the electromagnetic damper which can absorb the vibration energy to improve the suspension dynamic performance [12]. Guo et al proposed a hydraulic electromagnetic energyregenerative shock absorber (HESA), which can absorb the vibration energy harvest and improve the vehicle ride comfort and handling [13,14]. Although the above studies indicate that the energy-regenerative systems can obtain the electric energy via the considerable complex structures, the existing energy-regenerative suspension (ESS) systems have to increase the unsprung mass and change the original suspensions structure.…”

Study on the state-dependent path-tracking for smart pneumatic shock-absorber

“…A large number of different semi-active absorbers can be found and it includes among others frictional dampers with adjusted normal force [23,24], airbags and fluid-based absorbers with controllable valves [25][26][27] or equipped with functional materials [28,29]. Smart materials which can be applied for development of controllable shock-absorbers include electrorheological [30] and magnetorheological fluids [31,32], magnetorheological elastomers [33], magnetostrictive [34], electrostrictive [35] and piezoelectric materials [36], as well as shape memory alloys [37].…”

Research on Fluid Viscous Damper Parameters of Cable-Stayed Bridge in Northwest China

“…For cable-stayed bridges, under longitudinal earthquake input, different tower-girder connection forms will have significant influence on the internal force response of main towers and its foundations, also on the displacements of girder end, and on the relative displacements of the girder and the approach bridge [1,2]. The problem that the bridge tower internal force will be greatly increased in consolidated system and the problem that the longitudinal displacements of the girder end and the tower top will be enlarged in longitudinal floating system can be overcome by the damping system installed between the towers and girders [3,4].…”