<title>Active vibration control of frame structures with a smart structure using magnetostrictive actuators</title>

Abstract

For active vibration control of buildings in Japan. new system altcrnative to current active mass dampers arc required. Smart structures are candidates for the alternative systems. In order to investigate the possibility, a smart structure was tested for active vibration control of frame structures. in which bending moment of the columns was controlled by magnetostrictive actuators integrated into the columns. The actuators were installed in stages in the bottom part of the column of a H-section. The stages had a different section for effective integration of the actuators into the column, while they had the same bending stiffnesses of the column in the two lateral directions. Excitation tests were carried out for a 3-story building model of a 3.4 m height and a 1600 kg total mass by using a shaking table. In the building model, each column had 2 stages in its bottom part in the first story, and 4 actuators were installed in each stage of one column. i'hus 32 actuators in total were used. The magnetostrictive actuator developed for the building model consisted of a magnetostrictive rod of a 40 mm length and a 20 mm diameter surrounded h a driving coil. The controllers for the building model were designed by the model-matching method and the H control theory to control the 1st-, 2nd-. and 3rd-mode responses, and both controllers were designed so that the system had a 1 r damping ratio in all modes. Through the tests, it was shown that the smart structure could effectively reduce the responses of the building model, and the two control strategies had almost the same performance.

Smart materials in architecture for actuator and sensor applications: A review

“…Also magnetostrictives could potentially be applied for seismic vibration control. Fujita et al (1998) conceptualized an active vibration control system for buildings in Japan. For this, the bending moment of the columns of a frame structure was controlled via magnetostrictive actuators inside of them.…”

Review of magnetostrictive materials for structural vibration control

“…Patterned magnetostrictive actuators can also provide large actuation power for civil engineering applications. Fujitaet al [61] replaced the existing current-active vibration absorbers by 32magnetostrictive actuators to actively attenuate seismic vibrations in a three-story building. A 15% modal damping ratio was achieved up to the 3rd mode of the structure.…”