The design of pseudoelastic shape memory alloy (SMA) passive damping devices for structural vibration is dependent
on the geometry of the SMA. By changing the effective radius size of an attached SMA element, one simultaneously
changes the nonlinear stiffness and damping contributed to the system by the SMA. In order to identify the coupled
nonlinear dynamic behavior, this work focuses on the steady state frequency response functions of a simple SDOF
system with an attached SMA element under base excitation. An equivalent linearization method is used to produce a
qualitative representation of the frequency response of the structure for multiple radius sizes and excitation amplitudes.
These results are then compared to corresponding frequency response functions produced from the Seelecke, Muller,
and Achenbach SMA model. These results give insight into jump phenomenon, hysteretic damping effects, and identify
the stable branches of the nonlinear frequency response. Additionally, optimal radius sizes are presented for a range of
harmonic excitation amplitudes and frequencies. These results lead to an initial investigation into the physical
mechanisms responsible for choosing optimal radius sizes for an arbitrary excitation.
Pseudoelastic shape memory alloys (SMAs) have origin-oriented restoring forces under a tensile-compressive loading/ unloading and their restoring forces have the characteristic that they don't keep increasing as deformation increases and converge to a certain value. Using this characteristic, it is enable to restrain the transmission of force, i.e. acceleration, from the source of vibration. In this paper, we use SMA wires as softening springs and develop a base isolation system using them. The springs don't lose the origin-oriented characteristics and show good performance of softening springs. The base isolation effect of the system using SMA wires is investigated experimentally and we find that it is efficient to restrain acceleration transmission. Equivalent linear analysis is also carried out and the results correspond to experiment results. Furthermore, its durability is examined.
In this paper, we conduct finite element analysis of a pseudoelastic SMA wire with curved shape, which is designed as a spring component in the base isolation devices. A simplified constitutive equation is implemented with the finite beam elements based on the updated Lagrangian formulation to deal with the geometric and material nonlinearities of the SMA wires. The simulated deformation shapes and the force-displacement characteristics are compared with the measured results.