Nonlinear Dynamics of a Magnetic Shape Memory Alloy Oscillator

Magnetic shape memory alloys (MSMAs) constitute a class of smart materials capable of exhibiting large magnetic field induced strain (MFIS) when subjected to magneto- mechanical loadings. Two distinct mechanisms are responsible for the induced strain: martensitic variant reorientation and phase transformation. The martensitic reorientation is the most explored mechanism presenting the advantage to potential provide high-frequency actuation since it does not rely on phase transformation cycles. Despite its capabilities and potential dynamical applications, the dynamical behavior of MSMAs is not extensively explored in the literature that is usually focused on quasi-static behavior. Thereby, the objective of this work is to analyze the nonlinear dynamics of MSMAs. In this regard, an MSMA nonlinear oscillator is investigated, exploiting the system response under different bias magnetic field levels and actuation frequencies. A phenomenological model is employed to describe the MSMA magnetomechanical behavior. Numerical simulations are carried out using the operator split technique together with an iterative process and the fourth-order Runge-Kutta method. Results show that the application of a bias magnetic field can reduce the mean displacement of the system, increasing the oscillation amplitude. Furthermore, the period of oscillation can be modified, even achieving complex behaviors, including chaos. The potential use of MSMAs to dynamical systems is explored showing the possibility to provide adaptive behaviors.