Choi Eunsoo, Chae Seung-Wook, Park Hancheol, Nam Tae-Hyun, Mohammadzadeh Behzad, Hwang Jin-Ha
Department of Civil Engineering, Hongik University, Seoul 04066, Korea.
School of Materials Science and Engineering and ERI, Gyeoungsang National University, Jinjoo 52828, Korea.
J Nanosci Nanotechnol. 2018 Sep 1;18(9):6228-6232. doi: 10.1166/jnn.2018.15635.
This study investigated the pull-out resistance of superelastic shape memory alloy (SMA) short fibers in mortar with consideration of various end-anchorages that provide different anchoring actions. For the purpose, four types of SMA fibers were prepared using NiTi SMA wires with a diameter of 1.0 mm and the following four end shapes: straight (ST), L-shaped (LS), N-shaped (NS), and spearhead-shaped (SH). The straight-ended fiber was a reference with no working on the end, and the fiber with the spearhead-shaped end was crimped to make the end part flat. The fibers with L- and N-shaped ends were bent with single or double bending. The results showed that only the spearhead-shaped fibers showed self-centering behavior because of the superelasticity of the SMA after slip occurred. This paper discusses the reasons that the ST, LS, and NS fibers do not show self-centering behavior and proposes a concept to induce superelastic behavior in SMA fibers in mortar or concrete.
本研究考虑了提供不同锚固作用的各种端部锚固方式，对超弹性形状记忆合金（SMA）短纤维在砂浆中的拉拔阻力进行了研究。为此，使用直径为1.0 mm的NiTi形状记忆合金丝制备了四种类型的形状记忆合金纤维，并采用以下四种端部形状：直形（ST）、L形（LS）、N形（NS）和矛头形（SH）。直端纤维作为未对端部进行处理的参考，而矛头形端部的纤维经过压接以使端部平整。L形和N形端部的纤维进行了单弯或双弯处理。结果表明，由于形状记忆合金在发生滑移后的超弹性，只有矛头形纤维表现出自对中行为。本文讨论了直形、L形和N形纤维未表现出自对中行为的原因，并提出了一种在砂浆或混凝土中的形状记忆合金纤维中诱导超弹性行为的概念。
