Nobuyoshi Murai

Active vibration control of frame structures with smart structures using piezoelectric actuators (Vibration control by control of bending moments of columns)

A smart structure was tested for active vibration control of frame structures in which the bending moment of the columns was controlled by stack-type piezoelectric actuators integrated into the columns. Excitation tests were carried out for a model of a four-storey building 3.7 m in height and 2000 kg in total weight in which thirty-two piezoelectric actuators were used for bending moment control. The actuators were installed in two ways: in one case eight actuators were attached to each column of the first storey, and in the other case four actuators were attached to each column of the first and second storeys. Two control strategies, a model-matching method and the control theory, were examined for the smart structure. The tests showed that the smart structure could effectively reduce the responses of the building model, and all combinations of actuator installation method and the control strategy yielded almost the same performance.

Active vibration control of flexural-shear type frame structures with smart structures using piezoelectric actuators

To apply smart structures to buildings, a new vibration control strategy is proposed for flexural-shear type frame structures with smart structures using piezoelectric actuators. Actuators are incorporated in columns, and the response of the entire structure is reduced by control of the bending moment and axial force of the columns. Combined application of these two controls is performed by arrangement of actuators. Two control strategies were tested: one involves the use of a model matching method and the other is based on control theory. Excitation tests were conducted with a four-storey frame structure with a total weight of 2000 kg and a height of 3.7 m, having H-section steel beams incorporating actuators as columns. The effectiveness of combined use of bending moment control and axial force control of columns with smart structures was confirmed.

Active microvibration control of precision manufacturing factories with smart structure using piezoelectric actuators

In order to achieve more perfect vibration-free environment in precision manufacturing facilities such as semiconductor manufacturing factories, and apply steel frame structures to semiconductor manufacturing factories of the next generation, a smart structure was tested for active microvibration control of a 2-story steel frame building model of a 5 X 3 X 4H m outer size and a 2,500 kg total weight which was excited by ambient ground vibration. In the structure, piezoelectric actuators attached to the columns and the beams were used for the microvibration control by bending moment control of them. The controller was designed using the H-infinity control theory. The tests showed that the smart structure could effectively reduce the 3D microvibration of the building model, and its applicability to floors and even entire buildings of semiconductor manufacturing factories having steel frame structures.

Active vibration control of frame structures of shear and bending type with smart structure using piezoelectric actuator

To apply smart structures to buildings, a new vibration control strategy is proposed for flexural-shear type frame structures with smart structures using piezoelectric actuators. Actuators are incorporated in columns, and the response of the entire structure is reduced by controlling the bending moment and axial force of columns. Combined application of these two control is performed by arrangement of actuators. Two control strategies were tested. One is model matching method and author is H(infinity) control theory. Excitation tests were conducted with a 4-story fame structure of total weight 2,000 kg and height 3.7 m having H-steels incorporating actuators as columns. Effectiveness of combined use of bending moment control and axial force control of columns with smart structures was confirmed.

Active Microvibration Control of Precision Manufacturing Facilities with Smart Structure Using Piezoelectric Actuator.

A smart structure was tested for active microvibration control of a 2-story steel frame building model of a 5×3×4Hm outer size and a 2 500 kg total weight which was excited by ambient ground vibration. In the structure, piezoelectric actuators attached to the columns and the beams were used for the microvibration control by bending moment control of them. The controller was designed using the H ∞ control theory. The tests showed that the smart structure could effectively reduce the three-dimensional microvibration of the building model, and its applicability to floors and even entire buildings of semiconductor manufacturing factories having steel frame structures.