Shape-memory alloy devices in earthquake engineering: mechanical properties, constitutive modelling and numerical simulations

Student: Davide Fugazza
Supervisors: Prof. F. Auricchio, Dr. A. Pavese, Dr. L. Petrini

 

Abstract

Shape-memory alloys (SMAs) are a class of solids showing mechanical properties not present in materials usually employed in engineering. SMAs have the ability to undergo reversible micromechanical phase transition processess changing their cristallographic structure. This capacity results in two major features at the macroscopic level which are the superelasticity and the shape-memory effect.

Due to these unusual characteristics, materials made of SMAs lend themselves to innovative applications in many scientific fields ranging from biomedical devices, such as stents or orthodontic archwires, to apparatus for the deployment and control of space structures, such as antennas and satellites.

Experimental and numerical investigations have also shown the possibility of using such smart new materials in vibration control devices. In particular, they seem to be an effective mean of improving the response of buildings and bridges subjected to seismic loads.

Despite the availability of a large number of mechanical tests conducted by many authors, few works deal with their constitutive modelling for earthquake engineering applications. Also, their dynamic response under high-frequency loading conditions would need further studies. As a consequence, the main aim of the present work is to cover this lack of information.

The main objectives of the present dissertation are the following:

  • To present and comment the mechanical properties of SMA materials with emphasis on their response under dynamic loading conditions.
  • To study the constitutive modelling of SMAs for seismic applications.
  • To implement a robust uniaxial constitutive model for superelastic SMAs.
  • To understand the influence of the SMA's mechanical properties on their dynamic behavior through parametric analyses.

You may download a digital version of this MSc dissertation here.