C. Maletta, F. furgiuele, University of Calabria, Arcavacata Rende (CS), Italy
Shape memory alloys (SMAs) and in particular Nickel Titanium based (NiTi) SMAs, have seen growing use in many engineering and medical applications, because they combine special functional properties, good mechanical strength and biocompatibility. Notwithstanding that much research has been devoted to study both functional and mechanical behavior of such class of materials, many aspects related to their fracture properties are still unknown. An accurate knowledge of this topic is of major concern to improve the overall performances of NiTi based components or structures, since it is essential to predict the functional and structural life, as well as to understand the failure modes of damaged structures. Furthermore, a Stress-Induced Martensitic (SIM) transformation occurs near the crack tip, which results from highly localized stresses in the austenitic phase, and it is widely accepted from the scientific community that the SIM plays a significant role in the fracture properties of NiTi alloys, as it significantly affects the crack tip stress distribution. In the present work a novel definition of Stress Intensity Factor (SIF) in shape memory alloys is defined based on an analytical model [1], which was proposed by the authors in a previous paper. Finally, the effects of different loading conditions and thermomechanical parameters of the SMAs are analysed.
References
[1] C. Maletta, F. Furgiuele, ” Analytical modeling of stress-induced martensitic transformation in the crack tip region of nickel-titanium alloys”, Acta Materialia, doi:10.1016/j.actamat.2009.08.060.
Summary: In the present work a novel definition of Stress Intensity Factor (SIF) in shape memory alloys is defined based on an analytical model, which was proposed by the authors in a previous paper. Furthermore, the effects of different loading conditions and thermomechanical parameters of the SMAs are analysed.
