Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan.
J Mol Model. 2013 Apr;19(4):1883-90. doi: 10.1007/s00894-013-1752-9. Epub 2013 Jan 18.
The nanomechanical properties, deformation, and shape recovery mechanism of NiTi nanowires (NWs) under torsion are studied using molecular dynamics simulations. The effects of loading rate, aspect ratio of NWs, and NW shape are evaluated in terms of atomic trajectories, potential energy, torque required for deformation, stress, shear modulus, centro-symmetry parameter, and radial distribution function. Simulation results show that dislocation nucleation starts from the surface and then extends to the interior along the {110} close-packed plane. For a high loading rate, the occurrence of torsional buckling of a NW is faster, and the buckling gradually develops near the location of the applied external loading. The critical torsional angle and critical buckling angle increase with aspect ratio of the NWs. Square NWs have better mechanical strength than that of circular NWs due to the effect of shape. Shape recovery naturally occurs before buckling.
使用分子动力学模拟研究了扭转作用下镍钛纳米线（NWs）的纳米力学性能、变形和形状恢复机制。从原子轨迹、位能、变形所需扭矩、应力、剪切模量、中心对称参数和径向分布函数等方面评估了加载速率、NW 纵横比和 NW 形状的影响。模拟结果表明，位错的成核从表面开始，然后沿着{110}密排面扩展到内部。对于高加载速率，NW 扭转屈曲的发生更快，屈曲逐渐在施加外部载荷的位置附近发展。随着 NWs 纵横比的增加，临界扭转角和临界屈曲角增大。由于形状的影响，方形 NWs 的机械强度比圆形 NWs 要好。在发生屈曲之前，形状会自然恢复。
