Numerical modeling of seismic behavior of ellipse and peanut-shaped auxetic steel plate shear walls

Abstract

This study proposes a new auxetic-shaped steel plate shear walls (simply referred to as ASSPSWs) consisting of boundary members and built-in perforated infill plates. The connection type between the boundary members is a hinge joint. The hole forms on the infill plates include orthogonal ellipse-shaped (ASSPSW-OE) and orthogonal peanut-shaped (ASSPSW-OP). This paper studied the hysteretic performance of two steel plate shear walls’ types based on the finite element analysis method. Within the study context, a parametric analysis was carried out to investigate the influence of various factors, such as hole size and hole distance, on the seismic performance of steel plate shear walls (SPSWs). The results indicated that reducing the the ratio of the ligament thickness to ellipse major axis ( t/D ) in orthogonal ellipse-shaped SPSWs can effectively increase the porosity while reducing the bearing and energy dissipation capacities. Under the condition with the t/D unchanged, increasing the ratio of the major to minor axis of the ellipse ( d/D ) raises the porosity and does not significantly reduce the bearing capacity and energy dissipation capacity of the SPSWs. For orthogonal peanut-shaped SPSWs, the holes’ geometrical parameters significantly influence the hysteretic performance. Particularly, with the increase in the radial ratio of large to small circles in a peanut-shaped hole ( R/r ), the spacing between cells decreases. When drift exceeds 2%, the equivalent viscous damping ratio decreases sharply. Unlike the orthogonal ellipse-shaped SPSWs, changing the arrangement angle of peanut-shaped cells has no significant effect on orthogonal peanut-shaped SPSWs. However, the larger the angle, the greater the out-of-plane buckling of orthogonal ellipse-shaped SPSWs; thus, the energy dissipation capacity is reduced. The similarities lie in that the larger cell arrangement angle will make the steel plates have a complete stress field, and the bearing capacity will be slightly improved. When the cell arrangement angle ( θ ) is 45°, the SPSWs can develop high initial stiffness. 本文提出了一种新型负泊松比钢板剪力墙（ASSPSW），主要由边缘构件和内置的开孔填充板组成，边缘构件之间连接形式采用铰接。填充板的开孔形式包括正交椭圆型（ASSPSW-OE）和正交花生型（ASSPSW-OP）两种负泊松比构型。本文基于有限元分析方法，针对两类钢板剪力墙，开展了钢板剪力墙（SPSW）抗震性能研究，分析了开孔大小、孔距等参数对SPSW滞回性能的影响规律。研究结果表明，对于正交椭圆型SPSW，减小胞体间距与椭圆长径比值（t/D）可以有效增大孔隙率，但降低了承载力和耗能能力。在保持t/D不变的情况下，增大椭圆短径与长径比值（d/D）不仅可以增加开孔率，而且SPSW承载能力和耗能能力并未出现明显降低。对于正交花生型SPSW，开孔的几何参数对于滞回性能都有较大影响，特别的是，增大形成花生型胞体大圆与小圆的半径比值（R/r），胞体之间的间距减小。当SPSW层间位移角超过2%时，等效粘滞阻尼比出现剧烈下降。与正交椭圆型不同的是，改变花生型胞体排布的角度对于正交花生型影响不明显，但是角度越大，正交椭圆型SPSW发生较大平面外屈曲从而降低耗能能力。相同点在于较大的胞体排布角度会使得钢板拥有完整的应力场，承载力会稍有提升，在胞体布置角度为45°时，可使得SPSW获得较大的初始刚度。