PSI - Issue 16

Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 16 (2019) 67–72

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers The influenc of stress ratio on functio al properties of pseudoela tic NiTi alloy are studied. The changes of resi ual strain, str in ratio a d dissipate energy on the stre s ratio of shape memory alloy are inv stigated. The functional f tigue of the NiTi alloy under the stress-controlled cyclic lo ding is dependent on the stress range and stress rati . Dissipated nergy and strain range are i variant to the loading cycles for stress ratio 0 and 0.5. When stress ratio increases from 0 to 0.5 at the same maximal stress, the strain range and energy dissipation are decreasing. With the change of the stress ratio from 0 to 0.5 the residual strain in the first and next cycles inc eases significantly even at lower values of maximal stress. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” Influence of stress ratio on functional fatigue of pseudoelastic NiTi alloy Volodymyr Iasnii*, Petro Yasniy Ternopil Ivan Puluj National Technical University, 56 Ruska St.,46001 Ternopil, Ukraine 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” Influence of stress ratio on functi nal fatigue of pseudoelastic NiTi alloy Volodymyr Iasnii*, Petro Yasniy Ternopil Ivan Puluj National Technical University, 56 Ruska St.,46001 Ternopil, Ukraine Abstract The influence of stress ratio on functional properties of pseudoelastic NiTi alloy are studied. The changes of residual strain, strain ratio and dissipated energy on the stress ratio of shape memory alloy are investigated. The functional fatigue of the NiTi alloy under the stress-controlled cyclic loading is dependent on the stress range and stress ratio. Dissipated energy and strain range are invariant to the loading cycles for stress ratio 0 and 0.5. When stress ratio increases from 0 to 0.5 at the same maximal stress, the strain range and energy dissipation are decreasing. With the change of the stress ratio from 0 to 0.5 the residual strain in the first and next cycles increases significantly even at lower values of maximal stress. Keywords: pseudoelastic alloy; energy dissipation; residual stress; stress ratio. Abstract

Keywords: pseudoelastic alloy; energy dissipation; residual stress; stress ratio.

1. Introduction

1. Introduction

Shape memory alloys (SMA) are the functional materials characterized by the shape memory effects and pseudoelasticity. Their application depends on mechanical and functional properties, the phase transformation temperatures and types of loading (static, cyclic, multiaxial or thermo-mechanical) (Hsu et al. (2019)). Shape memory alloys (SMA) are the functional materials characterized by the shape memory effects and pseudoelasticity. Their application depends on mechanical and functional properties, the phase transformation temperatures and types of loading (static, cyclic, multiaxial or thermo-mechanical) (Hsu et al. (2019)).

* Corresponding author. Tel.: +38-035-251-9701; fax: +38-035-225-4983. E-mail address: v_iasnii@tntu.edu.ua

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers * Corresponding author. Tel.: +38-035-251-9701; fax: +38-035-225-4983. E-mail address: v_iasnii@tntu.edu.ua

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. 10.1016/j.prostr.2019.07.023