Publication detail

Experimental and Numerical Investigation of Thermomechanical Cycling of Notched NiTi Shape Memory Ribbon Using SMA Model Accounting for Plastic Deformation

SHAYANFARD, P. HELLER, L. ŠANDERA, P. ŠITTNER, P.

Original Title

Experimental and Numerical Investigation of Thermomechanical Cycling of Notched NiTi Shape Memory Ribbon Using SMA Model Accounting for Plastic Deformation

Type

journal article in Web of Science

Language

English

Original Abstract

Shape memory alloys (SMAs) are being increasingly applied as thermally driven actuators. The commercially available SMA elements, however, frequently contain stress risers, either due to internal or surface defects or due to the required component shape. Stress risers represent a potential danger for the preliminary fatigue failure of such actuators but its actual mechanism is not very clear. This paper presents a combined experimental (2D DIC analysis of surface strains) and numerical analysis (SMA model with plastic deformation) of the stress, strain and phase fraction fields evolving in a thin NiTi shape memory ribbon with an artificial notch subjected to cyclic cooling-heating through transformation range under constant external force. It appeared that, even if only very low tensile stress is externally applied upon thermal cycling, local tensile stress at the notch tip sharply increases during the first cooling due to the forward martensitic transformation (MT) proceeding heterogeneously in space. This heterogeneity gives rise to plastic deformation at the notch-tip, which gradually accumulates upon thermal cycling and shields the notch tip from tensile overloading. Hence, fatigue performance of thermal NiTi actuator with stress riser depends very much on the plastic deformability of the alloy.

Keywords

Shape MemoryAlloyActuator, Thermal Actuator, Stress Riser, Martensitic Transformation,Plastic deformation, Conventional Plasticity, SMA model, DIC, Finite ElementAnalysis, Double Notched Ribbon

Authors

SHAYANFARD, P.; HELLER, L.; ŠANDERA, P.; ŠITTNER, P.

Released

7. 9. 2021

Publisher

Elsevier

ISBN

2238-7854

Periodical

Journal of Materials Research and Technology

Year of study

15

Number

1

State

Federative Republic of Brazil

Pages from

1759

Pages to

1776

Pages count

18

URL

https://www.sciencedirect.com/science/article/pii/S2238785421009571

Full text in the Digital Library

http://hdl.handle.net/11012/201636

BibTex

@article{BUT172420,
  author="Pejman {Shayanfard} and Luděk {Heller} and Pavel {Šandera} and Petr {Šittner}",
  title="Experimental and Numerical Investigation of Thermomechanical Cycling of Notched NiTi Shape Memory Ribbon Using SMA Model Accounting for Plastic Deformation",
  journal="Journal of Materials Research and Technology",
  year="2021",
  volume="15",
  number="1",
  pages="1759--1776",
  doi="10.1016/j.jmrt.2021.08.132",
  issn="2238-7854",
  url="https://www.sciencedirect.com/science/article/pii/S2238785421009571"
}