Vibration Control Capabilities Research Articles

An Adaptive Beam Model with Electrorheological Material Based Applications

In this investigation a theoretical model for adaptive beam structures with various boundary conditions was developed, and its potential applicability to electrorheological (ER) material based adaptive beams was introduced. The cross-sectional configuration of the beam selected was based on sandwiching a damping material between elastic face plates. The transverse continuous vibration model developed is based on thin plate theory. In the model shear and rotary inertia effects are neglected, and it is assumed that no slipping between the elastic layers and the damping layer occurs. All layers are considered to have the same transverse displacement. The resulting analytical model is able to predict the structural vibration response at any location on the beam surface, and is applicable to generalized sets of boundary conditions. In this study, different boundary and external excitation conditions were considered. The transverse vibration response was studied for different boundary conditions. Variations in the mode shapes, natural frequencies, and loss factors, as functions of mode number and excitation frequency, were analyzed. ER material based adaptive beam semi-active vibration control capabilities were analyzed from the observed model results.

Modelling and analysis of non-linear orifice type damping in vibration isolators

The effects of non-linear orifice type damping on the response of one- and two-degree of freedom (DOF) systems are studied. The damping is formulated through the hydraulic resistance of the fluid path as a function of the frequency of flow oscillation and mean flow velocity for the laminar and turbulent flows. A comparison is made to demonstrate the vibration control capability of linear and non-linear damping models in terms of displacement transmissibility ratios for a 1-DOF system and for a 2-DOF system with an optimally tuned absorber, providing the minimum peak displacement of the isolated mass over the complete frequency range of interest. The results show a significant shift in resonant frequency between the linear and non-linear damping approaches.

Optimum Placement of Vibration Control Actuators in Planar Structures Using Voronoi Diagram.

A method determining the optimum placement of vibration control actuators using the Voronoi diagram was proposed focusing on the continuous planar structures. The entire plane is partitioned by a Voronoi diagram which consists of the same number of polygons as that of vibration control actuators. The objective function consisting of the locations of actuators and vibration mode amplitude is minimized for optimization. The location of actuators obtained by the proposed method was found to have effective vibration control capability through finite-element response analyses.

Vibration Control Using Multiple Tuned Mass Dampers

This paper examines multiple tuned mass dampers (TMD's) with natural frequencies distributed over a frequency range. An integral form for the impedance is developed by asymptotic techniques. The result is used to analyze the vibration control capabilities of multiple TMD's for structures subjected to wide-band input. Calculus of variations is used to optimize the design of the TMD's with a constraint on the total mass. It is found that multiple TMD's can be more effective and more robust than a single TMD with equal total mass.

Vibration Control of Truss Structure by Piezoelectric Actuator

An active vibration control technique is one of the important technical subjects for the large space structures (LSS). In the LSS, the one-board instruments need more strict directional precision as the sizes and flexibility of structures increase. With this background, a piezoelectric actuator Type-II for vibration control has been experimental developed, which has five multilayered piezo-electric devices. An attempt has been made to incorporate the actuator Type-II into active members of a truss structure, which is a 6-bay, 1.8m-high truss, and to control its vibration. This paper presents an outline of the piezo-electric actuator Type-II and some experimental results which show the vibration control capabilities of the actuator Type-II.

A new tuned vibration absorber for wide-band excitations

The vibration control capability of a modified tuned vibration absorber is investigated. Numerical simulations have shown clearly that using an impact damper may significantly improve the performance of a conventional vibration absorber at its first natural frequency. Attenuations are also observed at the second natural frequency. In addition, the minimal amplitude at the original tuning frequency could be maintained. Experiments performed to check the validity of the numerical approach produced close agreement.