设置SMA滑动摩擦阻尼器的自复位摇摆柱滞回行为理论分析与数值模拟

Analytical analysis and numerical simulation of cyclic behavior of self-centering rocking column with SMA slip friction damper

以形状记忆合金(SMA)滑动摩擦阻尼器(shape memory alloy slip friction damper, SMASFD)为基础,提出了一种自复位摇摆柱。在该自复位摇摆柱中,柱身为H型钢,SMASFD位于柱底强轴的两侧呈对称布置,为摇摆柱提供自复位能力和消能能力。推导了摇摆柱的滞回模型理论公式,并在ABAQUS中建立了精细化有限元模型。理论公式与数值模拟均分析了摇摆柱在往复荷载下的滞回行为,二者的结果吻合良好,并且均表明该摇摆柱具有“旗帜形”的滞回曲线;摇摆柱的滞回行为由SMASFD的力学性能和柱身的轴压比控制。研究结果表明:提高SMASFD的承载力可以有效提高摇摆柱的受弯承载力;增大SMASFD的刚度可以同时提高摇摆柱的屈服前刚度和屈服后刚度;在满足稳定性的前提下,增大轴压比会提高摇摆柱的消压弯矩和强度,但是由P-Δ效应所产生的负刚度随之增加,同时增大了柱底的塑性应变。此外,由数值模拟结果还发现,挡板可防止SMASFD夹板在变形过程中滑出,从而避免SMA螺栓受弯。

This paper proposed a novel self-centering(SC) rocking column with the shape memory alloy slip friction damper(SMASFD). The H-section steel column was employed and the SMASFDs which provide the SC capacity and dissipate energy were installed on both sides of the column flanges symmetrically. The emphasis was put on the analytical method of the cyclic behavior of the SC rocking column. In addition, the elaborate finite element(FE) model of the SC rocking column was established in ABAQUS. The flag-shaped hysteretic curves of the SC rocking column are obtained from the analytical method and FE model, and a good agreement can be found between them. The cyclic behavior of the SC rocking column is controlled by the behavior of the SMASFD and the axial-force ratio. The flexural strength of the column will increase with the strength of the SMASFD and increasing the stiffness of the SMASFD will increase the stiffness of the pre-yield and post-yield of the column. Under the premise of stabilization, increasing the axial-force ratio will increase the decompression moment and the strength of the column, however, this will contribute to the negative stiffness caused by the P-Δ effect increase and amplify the plastic strain of the base of the H-section steel column. Moreover, the results of FE models indicate that the side plates can prevent the middle plate from sliding sideways and thus the bending of SMA bolts can be avoided.