Dynamic Vibration Absorber

About: Dynamic Vibration Absorber is a research topic. Over the lifetime, 4764 publications have been published within this topic receiving 49429 citations.

Adaptive tuned mass damper for the construction of concrete piers

Abstract: In this paper the authors have studied and proposed a control system for an adaptive tuned mass damper (TMD) for self-climbing formworks to be used in some critical construction phases of concrete piers. This dynamic vibration absorber will move together with the formwork, and must change the tuned parameters (frequency, damping) for an optimal situation in each instant of the pier construction. With this device, the structural damping of the pier will increase and consequently personal comfort (e.g., sickness and acceleration levels) and structural security (stress level) will improve. The numerical results are based on a finite element model (FEM) for the 92 m concrete pier of La-Miel Viaduct (Nerja, Spain). This model has been adjusted by means of acceleration records obtained on the top of the pier. On the basis of this model several approaches of adaptive TMDs have been studied and finally a feasible solution has been suggested.

H 2 optimization of three-element type dynamic vibration absorbers

Abstract: The dynamic vibration absorber (DVA) is a passive vibration control device which is attached to a vibrating body (called a primary system) subjected to exciting force or motion In this paper, we will discuss an optimization problem of the three- element-type DVA on the basis of the H2 optimization criterion The objective of the H2 optimization is to reduce the total vibration energy of the system for overall frequencies; the total area under the power spectrum response curve is minimized in this criterion If the system is subjected to random excitation instead of sinusoidal excitation, then the H2 optimization is probably more desirable than the popular H(infinity ) optimization In the past decade there has been increasing interest in the three-element type DVA However, most previous studies on this type of DVA were based on the H(infinity ) optimization design, and no one has been able to find the algebraic solution as of yet We found a closed-form exact solution for a special case where the primary system has no damping Furthermore, the general case solution including the damped primary system is presented in the form of a numerical solution The optimum parameters obtained here are compared to those of the conventional Voigt type DVA They are also compared to other optimum parameters based on the H(infinity ) criterion© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only

Vibration damping device, control method for vibration damping device, offset correction method for vibration damping device, and blade spring

Abstract: An automobile vibration damping device for an automobile in which a power plant in which an engine, a transmission and the like are combined is supported by a vehicle body, including a vibrating means that generates vibration separate from vibration of the engine. Thereby, it is possible to reduce the vibration amplitude of a seat portion by the reaction force of the vibrating means. Also, if the vibration mode of the vehicle body is adjusted so as to become a node in the vicinity of the seat portion, the vibration amplitude decreases in the vicinity of the seat portion, and improves riding comfort.

Experimental investigation of mega-sub isolation structure

Abstract: Summary As urban high-rise buildings increase, a mega-sub configuration is proposed by engineers, which consists of two major structural components, a megastucture as the load-bearing main structural frame and several functional substructures for residential or other usage. This paper presents a new mega-sub isolation structure, in which substructures are designed to isolate from megastructure using special isolation devices. The equations of motion of the mega-sub isolation structure are established, and its vibration mitigation mechanism is investigated systematically using a simplified lumped mass structural model. With the increase in substructure mass, working mechanism of mega-sub isolation structure is changed from tuned vibration absorber, mid-story isolation to base isolation. In the light of theoretical studies, three steel frame specimens of four mega frame stories were tested. The experimental results show that the isolated structure and lower substructure-consolidated structure perform better than aseismic structure, and transfer functions derived from the test data support the conclusion of theoretical analysis that the control mechanism of this novel mega-sub isolation structure is similar to mid-story isolated structure in the case of the mass ratio between the substructure and the megastructure closed to 1, which is the most general situation in engineering.