一种考虑截面翘曲的剪力墙宏模型

A macro-model of shear wall considering buckling of cross section

提出了一种六自由度刚杆-弹簧单元,可以像有限元法那样根据精度和计算量的要求,以适当密度在水平和垂直方向拼装成剪力墙的宏模型。这一宏模型不仅可以反映中和轴的移动,而且不再受现有宏模型中平面假定的限制,可以反映初始平截面的剪切翘曲。这对于分析剪跨比较小的剪力墙是有一定必要性的。该模型竖向弹簧布置在Gauss积分点处,从而有效提高了计算精度和效率。利用该模型计算了五个剪力墙的弹塑性"推覆"过程,取得了与实验较为一致的结果。对一些有关宏模型中本构关系选取及变形假定的问题进行了讨论。

A rigidbarspring element with six degrees of freedom is initiated, which can be laid out like the conventional finite element in both vertical and horizontal directions to compose the macromodel for shear walls with a proper density satisfying the requirements of accuracy and computational work. This scheme reflects not only the shift of the neutral axis, but also the shear buckling of the cross section, and thus it is free of the restriction of plane assumption in existing models. This treatment is certainly necessary for the cases of small shear span ratio. Moreover, the method by which the vertical springs in this model are located at the points of Gaussian integration effectively enhances the computational accuracy and efficiency. The elastoplastic pushover analyses of five shear walls are carried out by using current model with results close to those of experiments. Some points on choosing constitutive relations and deformation hypotheses in macro modeling are discussed.