隔震橡胶支座屈曲稳定性的影响因素分析

Analysis on factors effect on the buckling stability of rubber bearing

采用有限元方法(FEM)对具有较低第2形状系数的隔震橡胶支座屈曲承载力的影响因数进行了分析研究。采用大型通用有限元软件Abaqus建立了隔震橡胶支座的三维有限元模型,橡胶材料考虑Neo-Hookean模型,支座内部钢板采用弹性和理想弹塑性本构关系,影响因数包括支座内部单层钢板厚度、支座内部孔洞直径、内部橡胶剪切模量和支座橡胶保护层厚度。分析结果包括水平屈曲荷载、水平屈曲位移以及支座水平变形时竖向变形。并将屈曲位移FEM结果和规范公式计算结果进行了对比。分析结果表明,内部钢板考虑弹塑性时支座更不利;内部钢板厚度的增加和支座内部孔洞直径的减少,支座的屈曲水平荷载和屈曲位移将增加,但后者影响程度大于前者;内部橡胶G值和橡胶保护层厚度对屈曲水平荷载和屈曲水平位移的影响规律比较类似,在一定范围内有影响,但超过该范围之后,影响程度有限,特别是屈曲水平位移。规范公式计算相对FEM结果而言偏于保守,前者未能考虑支座内部单层钢板厚度及橡胶保护层厚度的影响,有待进一步完善。

In this paper, the influence factors of buckling capacity of rubber bearing with lower second shape factor have been analyzed, in which the finite element method （ FEM ） was employed. A large general finite element software Abaqus was used, the three dimensional finite element model of isolator was established,the Neo-Hookean model was considered for the rubber material, the elastic and elastic-perfectly plastic constitutive model were used for the inner steel material. The influence factors included thickness of the single inner steel, diameter of the internal hole, shear modulus of inner rubber and thickness of rubber cover of isolator. The analysis results included the horizontal critical buckling load and horizontal critical buckling displacement and the vertical deformation of isolator when horizontal displacement occurring. And FEM results of the buckling critical displacement and results of the cede formula were compared. The analysis results show that the inner steel plate considering elastic-plastic may be more adverse. Thickness of the inner steel plate increasing and the internal hole diameter of bearing decreasing will cause the horizontal critical buckling load and displacement to increase, but the degree of the latter influence is greater than that of the former. The shear modulus of the inner rubber and thickness of cover rubber effect on the horizontal critical buckling load and displacement are similar,there are a few influence in a certain range, but excess to this range, the influence will be limited, especially for the horizontal critical buckling displacement. The results of the code formula relative to FEM results tend to be conservative, which failed to consider the effect of thickness of the inner steel plate and thickness of rubber cover and needs to be further investigation.