VIBRATION CONTROL OF AUTOPARAMETRIC SYSTEM USING SMA SPRING AND MR DAMPERS IN THE PENDULA JOINTS

摘要

This work is concerned with the problem of nonlinear dynamical motion of a non-ideal autoparametric system with two active elements - shape memory alloys (SMA) spring and the magnetorheological (MR) pin joint dampers in the neighbourhood internal and external resonance. A polynomial constitutive model was assumed to describe the behaviour of SMA's spring and there was observed the pseudoelastic effects associated with martensitic phase transformations. The simplified resistance moment generated by the MR pin joint can be approximated using the hyperbolic tangent function. The influence of damping forces in MR dampers on the phenomenon of energy transfer and pseudoelastic effects associated with the martensitic phase transformation was studied. It was shown that in this type system one mode of vibrations might excite or damp another mode, and that except different kinds of periodic vibrations there may also appear chaotic vibrations. For the identification of the responses of the system various techniques, including chaos techniques such as bifurcation diagrams and time histories, power spectral densities (FFT), Poincare maps and exponents of Lyapunov may be used. The SMA spring and MR damper can be used to change the dynamic behaviour of the autoparametric system giving reliable semiactive control possibilities.