Non-linear dynamic thermomechanical behaviour of shape memory alloys

Abstract

International audienceThe non-linear dynamic thermomechanical behaviour of superelastic shape memory alloys is investigated. To this end, the Zaki-Moumni model, initially developed for quasi-static loading cases, is extended to simulate the uniaxial forced oscillations of a shape memory alloy device. First, the influence of loading rate is accounted for by considering the thermomechanical coupling in the behaviour of NiTi shape memory alloy. Comparisons between simulations and experimental results show good agreement. Then, the forced response of a shape memory alloy device is investigated at resonance. Both isothermal and non-isothermal conditions are studied, as well as non-symmetric tensile-compressive restoring force. In the case of large values of forcing amplitudes, simulation results show that the dynamic response is prone to jumps, bifurcations and chaotic solutions

Pseudoelastic Shape Memory Alloys to Mitigate the Flutter Instability: A Numerical Study

“…[2,7,10,11]. In this case the model contains, in-built within the oscillator equation, additional equations governing the evolution of the fraction of martensite, the description of heat transfer, and the thermodynamic force, which expression is derived from a pseudopotential of dissipation that can include yields functions in order to express the phase transformations [11].…”

“…In this contribution, we focus on a passive control device for mitigating the flutter instability by using springs composed of shape memory alloys (SMA). In their pseudo-elastic regime, SMA are known for showing the ability of 1 dissipating an important amount of energy thanks to the hysteresis loop appearing in their stress-strain relationship [11], and has thus already been used in numerous applications ranging from civil engineering, aeronautics to medical industry [13,14]. The goal of this study is, in a first step, not to describe the system as accurately as possible but to exhibit the interest of using an hysteretic phenomenon in the view of controlling an aeroelastic instability and studying the influence of different SMA parameters for the flutter control.…”

“…Recent contributions have considered the dynamical responses of SMA springs from the theoretical viewpoint [1,7,11] in order to properly quantify the most prominent features of the vibrations of simple single dof systems. Experimentally, a torsion pendulum has recently been used in order to clearly exhibit the softening effect of SMA oscillators [4].…”

Passive control of the flutter instability on a two-degrees-of-freedom system with pseudoelastic shape-memory alloy springs.

“…[6]. In this contribution, a simple heuristic model is used instead as it has the capacity to retrieve the main features of the dynamical behaviour within a light computational framework.…”

“…In their pseudoelastic regime, SMA are known for showing the ability of dissipating an important amount of energy thanks to the hysteresis loop appearing in their stress-strain relationship, and has thus already been used in numerous applications ranging from civil engineering, aeronautics to medical industry [2,3]. Recent contributions have considered the dynamical responses of SMA springs from the theoretical viewpoint [4][5][6] in order to properly quantify the most proeminent features of the vibrations of simple single dof systems. Experimentally, a torsion pendulum has been recently used in order to clearly exhibit the softening effect of SMA oscillators [7].…”