Controle passivo de vibrações de sistemas não-lineares empregando ligas com memória de forma

Abstract

One of the major engineering problems is the search for efficient techniques for the control and reduction of vibrations and mechanical systems noise. In this context, several passive vibration control techniques have been proposed, for example, the use of viscoelastic material and the pseudoelastic effect present in shape memory alloys (SMAs). With regard to the use of SMAs, it is known materials that are able to recover the plastic deformation induced by mechanical loading when subjected to a thermal load. This characteristic is called the shape memory effect. Another feature of SMAs is called pseudoelastic effect that is its behavior when it is subjected to mechanical loading cycles in an operating condition in which the temperature is equal to or higher than the final temperature of the austenite phase. Therefore, many researchers have used this feature of SMAs to control and mitigate the vibrations of dynamical systems. This work is devoted to the numerical and computational modeling of the pseudoelastic behavior of shape memory alloys to the passive control systems structural vibrations in large displacements of the type thin plates of industrial interest. After the calculation of system responses in the time domain, are discussed the major parameters of influence as regards the reduction of the amplitudes and onset of non-linear characteristics. From the results it can be noted that the shape memory alloys are capable of reducing the vibration amplitudes under circumstances where the system is apparently linear or in cases where the system presents nonlinearities. However, in some cases they were observed instabilities in the system.