摘要
形状记忆合金(Shape Memory Alloys,SMAs)因其具有形状记忆效应和超弹性,在航空航天、生物医疗、微机电系统领域中得到了广泛的应用.当微结构尺度达到微纳米,表面效应对微结构力学性能的影响是十分显著的.本文基于梁弯曲变形理论以及Gurtin-Murdoch表面弹性理论,考虑拉压不对称、温度对于SMA纳米梁的影响,建立了考虑表面效应的SMA纳米梁相变力学模型.分析了弯曲载荷、温度、表面残余应力以及表面弹性模量对SMA纳米梁力学性能的影响规律.研究表明在SMA纳米梁相变阶段,忽略和考虑表面效应所得的截面应力及应变相对误差较为明显;在相同弯矩下,随温度的增加SMA纳米梁的截面应力随之增加,并且表面效应对其影响有减小趋势;表面残余应力对SMA纳米梁的影响显著.该文研究结果为SMA纳米梁在微机电领域的设计以及应用提供了一定基础与依据.
Shape memory alloys(SMAs)have been widely used in the fields of aerospace,biomedical,and micro electro mechanical systems(MEMS)due to their unique properties.When the microstructure scale reaches the nanoscale,the influence of surface effect on the mechanical properties of the microstructure is very significant.Based on the Euler Bernoulli beam theory and the Gurtin-Murdoch surface elasticity theory,and considering the influence of tension-compression asymmetry and temperature on SMA nano-beams,a mechanical model of SMA nano-beams phase transition considering surface effects is developed.The effects of bending load,temperature,surface residual stress and surface elastic modulus on the mechanical properties of SMA nano-beams were analyzed.The research shows that in the phase transition stage of SMA nano-beams,the relative errors of cross-sectional stress and strain obtained by ignoring and considering surface effects are more obvious.Under the same bending moment,the cross-sectional stress of SMA nanobeams increases with the increase of temperature,and the surface effect has a significant effect on the cross-sectional stress and strain,with a decreasing trend of influence.The influence of surface residual stress on SMA nano-beams is significant.The research results in this paper provide a basis for the design and application of SMA nano-beams in the field of MEMS.
作者
李守宝
贾晓丽
刘璐
郑磊
黄书童
柯燎亮
LI Shoubao;JIA Xiaoli;LIU Lu;ZHENG Lei;HUANG Shutong;KE Liaoliang(College of Mechanical and Transportation Engineering,China University of Petroleum-Beijing,Beijing 102249,China;College of Mechanical Engineering,Tianjin University,Tianjin 300072,China)
出处
《力学季刊》
CAS
CSCD
北大核心
2023年第3期537-550,共14页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(11872377,11402309)
国家重点研发计划(2016YFC0303700)。
关键词
形状记忆合金
表面效应
拉压不对称
相变
微机电系统
shape memory alloys
surface effect
tension-compression asymmetry
phase transition
MEMS
