Structural vibration control

Piezoelectric ceramics and polymers can play the double role of sensors and actuators these materials can either generate an electric field under an applied load or change dimensions when subjected to a voltage difference. When fabrication problems associated with their embedding are solved, they will find wide application for structure vibration control. 

Dosch, J. J. Inman, D.J. Garcia, E. A self-sensing piezoelectric actuator for collocated control. J. Intell. Mater. Syst. and Struct., 3 (1992), pp. 166 185 Vallone, P. High-performance piezo-based self-sensor for structural vibration control. SPIE Smart Structures and Mater. Conf., 2443, SPIE (1995), pp. 643 655... 

Soong, T. T, Constantinou, M. C. (1994). Passive and active structural vibration control in civil engineering. New York, NY Springer. 

Ji, H. R., Moon, Y. J., Kim, C. H., Lee, I. W. (2005, December). Structural vibration control using semiactive tuned mass damper. The Eighteenth KKCNNSymposium on CivilEngineering-KA1ST6 (pp. 18-20). Taiwan. 

The recent focus on hybrid mechanism is to augment base isolation devices with semi-active magnetorheological (MR) dampers for efficient structural vibration control. MR dampers provide hysteretic damping and can operate with battery power (Dyke et al., 1996 Ali and Ramaswamy, 2008a). 

The design of smart materials and adaptive structures has required the development of constitutive equations that describe the temperature, stress, strain, and percentage of martensite volume transformation of a shape-memory alloy. These equations can be integrated with similar constitutive equations for composite materials to make possible the quantitative design of structures having embedded sensors and actuators for vibration control. The constitutive equations for one-dimensional systems as well as a three-dimensional representation have been developed (7). 

In connection to control in dynamics I would like to take here a general point of view in terms of symmetries (see Scheme 1) We would start with control of some symmetries in an initial state and follow their time dependence. This can be used as a test of fundamental symmetries, such as parity, P, time reversal symmetry, T, CP, and CPT, or else we can use the procedure to discover and analyze certain approximate symmetries of the molecular dynamics such as nuclear spin symmetry species [2], or certain structural vibrational, rotational symmetries [3]. 

A. Preumont Vibration Control of Active Structures. An Introduction. 1997... 

The design of vibration control structures and selection of materials for use in them requires a accurate determination of the viscoelastic properties of the polymers used. The modulus that is appropriate for consideration will depend upon the geometry and boundary conditions found in the vibration control structure. 

Spacecraft equipment panels supports, electronic circuit boards, optical equipment, antenna and support structures acoustic fatigue, malfunction, vibration control... 

Henderson, J.P. and M.L. Drake, "Investigation of the Effects of Damping Treatments on the Response of Heated Fuselage Structure," NoisEXPO, National Noise and Vibration Control Conference, New York, New York, March, 1976. 

The tool-electrode is mounted on a flexible structure that controls the vertical guidance of the tool. An optical sensor measures the tool displacement. An optional voice-coil motor can be added in order to control the force at which gravity-feed drilling is done. This motor can also be used to add vertical vibrations to the tool to promote the flow of the electrolyte inside the microhole. Rotation can also be included. 

Preumont A (1997) Vibration control of active structures an introduction. Kluwer Academic Publishers, Amsterdam... 

Assessment of the sources of error affecting the accuracy of the machine tool (MT) can be divided into quasi-static errors and dynamic errors. Quasi-static errors are errors in the machine that occur relatively slowly. This category is formed by geometric and kinematic error, thermal errors, etc [1]. However, dynamic errors are caused by structural vibration, spindle error motion, controller errors, etc. Unlike the quasi-static errors, these errors are more dependent on the working conditions of the machine. Overall, quasi-static errors account for about 70 percent of the total errors of a machine [2]. 

Innovative seismic control systems belongs to the world of the vibration control techniques of structures, which includes passive, semi-active, active and hybrid systems (Housner et al., 1997 Spencer, 2003 Christopoulos and Filiatrault, 2007). The experiences acquired during experimental activities and worldwide apvplications have indicated the passive control techniques as the most suitable solutions for the seismic protection of structures. These systems modify the stiffness and/or the dissipative properties of the structure, favoring the reduction of the dynamic response to seismic actions. They can be classified on the basis of... 

Balendra T, Wang C. M., Cheon N. F., (1995). Effectiveness of tuned liquid column dampers for vibration control of towers. Engineering Structures 17(9), 668-675. 

The first step in vibration control is to install the machine properly. Proper installation on isolators results in structural decoupling of the machine from the foundation, reducing the transmission of impact forces and high-frequency vibration into the foundation. The transmission of impact reaction forces back into the machine from the foundation also is reduced. Tests show that properly applied and adjusted isolators reduce structure-borne vibration up to 98%, and up to about 6 dB throughout the audible frequency range [3,4]. 

Carbon fibres can also be used to create other types of smart concretes that can sense and report structural damages. Sandia is exploring candidate smart materials that can he attached to or embedded into structural systems to enable the structure to sense disturbances, process the information and through commands to actuators, and to accomplish some beneficial reaction such as vibration control. 

The US Army is interested in developing a rotor control system in helicopters. Figure 4.1.26 shows a bearingless rotor flexbeam with attached piezoelectric strips [48]. Various types of PZT-sandwiched beam structures have been investigated for such a flexbeam application and for active vibration control [49]. 

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