SMA绞线预制梁-柱自复位耗能节点数值研究与参数优化

Numerical study and parameter optimization of self-centring precast beam-column joint with SMA cables

为了提高预制混凝土框架的抗震能力并控制震后残余变形,提出了一种新型的混合自复位预制混凝土梁柱节点(self-centring precast concrete beam-column connection,SC-PCBCC),其中采用了旋转摩擦阻尼器(rotational friction hinge damper,RFHD)和形状记忆合金(shape memory alloy,SMA)并联的结构。重点探讨了使用SMA绞线控制的自复位装置对SC-PCBCC进行改进。首先,介绍了SC-PCBCC的结构和工作原理;其次验证对比了1.0%、1.5%、2%和2.0%预应变下的超弹性1×7 SMA绞线、RFHD和SC-PCBCC的有限元模型,并进行了初步验证。研究结果表明,该节点具有较高的刚度、承载力、耗能能力以及较好的复位性能;最后对SC-PCBCC中SMA绞线的关键参数:SMA绞线预应变、直径和长度进行了参数分析,以优化其抗震性能。建议SC-PCBCC使用的SMA绞线初始预应变、直径和长度范围分别为1.5%~2.0%、15~18 mm和175~205 mm,以实现SC-PCBCC的优异承载性能、能量耗散和自复位性能。此外,节点中的SMA绞线和RFHD可在震后快速更换,实现高效灾后修复。总体而言,所提出的SC-PCBCC表现出了卓越的减震能力、自复位能力和可修复性。

To enhance the seismic capacity of precast concrete frames and mitigate residual deformation following earthquakes,this research presents a novel hybrid self-centring precast concrete beam-column connection(SC-PCBCC)incorporating rotational friction hinge damper(RFHD)and shape memory alloy(SMA)parallel structure.The primary focus of this study is to improve the SC-PCBCC using a self-centring mechanism controlled by SMA cables.Initially,the structure and operational principles of the SC-PCBCC are introduced.Subsequently,the finite element(FE)models of super-elastic 1×7 SMA cables with 1.0%,1.5%,2.0%and 2.5%pre-strains were verified and compared,along with the RFHD and SC-PCBCC,with preliminary verifications conducted.The research findings indicate that the proposed joint has high stiffness,bearing capacity,energy dissipation capacity and good self-centring performance.Parametric analysis was then performed on key parameters of SMA cables in SC-PCBCC:SMA cables pre-strain,diameter and length were analysed to optimize its seismic performance.It is recommended that the SC-PCBCC design includes SMA cables with initial pre-strains ranging from 1.5%to 2.0%,diameters between 15 mm and 18 mm,and lengths from 175 mm to 205 mm to achieve optimal load-bearing capacity,energy dissipation and self-centring performance as proposed.Moreover,the SMA cables and RFHD can be readily replaced after earthquake to achieve efficient post-disaster repair.Overall,the proposed SC-PCBCC demonstrates exceptional shock-absorption,self-centring,and repairability properties.