Control of vibrations in the frame structure using dynamic vibration absorber

Resumo

Structures are physical systems subjected to external actions that cause transmission of efforts. These
actions can be classified as dynamic when they vary with time, in magnitude, direction, position, and/or direction
and generate relevant loads. They are responsible for causing vibrations in the structure that can damage it, cause
fatigue of the materials, and affect the users' comfort. The Dynamic Vibration Absorber (DVA) device aims to
control these unwanted vibrations, increasing the life of the structure and providing comfort to users. This study
aims to develop a dynamic analysis of a frame structure and design an DVA-type device to control the vibration
of the structure. Initially, a numerical dynamic analysis of the primary structure was performed to identify the
frequency response function and the first modes of vibration, using the Finite Element Method (FEM). From this
analysis, the ideal parameters of the device were determined: stiffness, the mass ratio between the mass of the
DVA and the primary structure, and the damping ratio to control the vibrations in the first natural frequency of the
frame. The DVA was modeled as a cantilever beam with concentrated mass at the tip, using the Euler-Bernoulli
equation. This DVA was coupled to the structure and the same previous numerical analysis were performed, where
a reduction in displacement amplitude was observed. This result demonstrates that the device is efficient to control
of vibration in the first mode of vibration of the frame under study.