新型部分自复位耗能段的滞回性能与简化力学模型研究

Hysteresis performance and simplified mechanical model of a novel partial self-centering shear link

提出一种用于偏心支撑结构中的部分自复位耗能段,主要包括自复位形状记忆合金(shape memory alloy,SMA)支撑和扩孔螺栓连接型耗能段,具有耗能能力和自复位能力强、构件损伤小、震后功能可恢复等特点。基于部分自复位耗能段的设计方法,合理设计其试验模型,由此得到变形模式和滞回曲线等。随后采用校正的有限元法对部分自复位耗能段力学性能进行研究,主要考虑SMA面积、高强螺栓预拉力和垫片滑移系数的影响。研究结果表明:滑移阶段自复位耗能段中耗能段处于滑移并保持相对静止状态;随后非滑移阶段耗能段开始承载、耗能和非弹性变形等,整个过程中自复位SMA支撑提供耗能和复位能力,以及减小构件残余变形。基于不同因素下的分析结果,提出滑移阶段和非滑移阶段下自复位耗能段简化的力学模型,为偏心支撑结构的抗震设计与分析提供新的思路和理论基础。

By combining the partial self-centering shape memory alloy(SMA)braces(SCB)with the shear slotted bolted connection-very short shear link(SSBC-VSSL),an innovative self-centering shear link(SC-SL)used in the eccentrically braced frame(EBFs)that has an advantage of good energy dissipation capacity and self-centering capacity,low damage and excellent seismic resilience capacity is developed.Cyclic tests were carried on SC-SL specimens designed by the proposed method,so the deformation modes and hysteresis curves can be obtained.Based on the test results,ten SC-SL models with the effect of SMA areas,high-strength bolt pretensions and shim friction coefficients were designed and analyzed by the validated finite analysis(FE)method.The results show that the VSSL is in the relative static during the slip stage,then the development process of very short shear link(VSSL)in SSCB-VSSL including yield,bearing,energy dissipation and inelastic deformation are appeared sequentially during the non-slip stage,while the SMAs in SCB are always subjected to elongation,thus increasing the energy dissipating capacity and self-centering capacity.Finally,the simplified mechanical models of SC-SL in the slip stage and non-slip stage are proposed by using the FE results,which can provide a new way to give important seismic design reference for EBFs.