可压缩超弹橡胶隔震支座压剪大变形的双非线性理论和应用研究

Double nonlinear theory and application of compressible superelastic rubber isolation bearings with large deformation in compression and shear

受到钢板的高强度约束,橡胶隔震支座中橡胶不可压缩性假设并不符合实际。该文基于单层橡胶压、弯理论,采用解析法将橡胶材料的可压缩变量K引入其约束方程中,结合实际工程判断虚宗量贝塞尔函数的稳定性,求解本构方程,得到隔震支座压、弯状态下等效弹模Ec和等效抗弯刚度(EI)_(eff)及内部各点应力p解析式,并比较分析考虑橡胶可压缩的必要性及橡胶材料参数K,G及支座几何形状系数S_(1)对以上结果的影响;再将隔震支座等效为符合GAs,(EI)_(eff)的均质体,基于Haringx压剪作用下隔震支座内力与变形的理论,开展与理论对应的足尺寸的隔震支座的压剪试验,结合试验,得出支座每个受力状态的G-γ,F_(H)-γ的理论与试验曲线均吻合较好,解决了压剪状态下隔震支座大剪切变形的几何、材料双非线性问题。基于以上结论,得出压剪隔震支座内力和变形分布,及支座随着轴压增加,力与变形呈非线性增长的趋势,其附加倾覆弯矩M增加较大,应力随轴压的变化也较明显;最后,设计了由支座内部局部应力反演宏观力和变形的监测程序。

Subject to the high strength constraint of a steel plate,the assumption of incompressibility of rubber in rubber isolation bearings does not conform to the reality.In this paper,based on the single-layer rubber compression and bending theory,the compressible variable K of the rubber material was introduced into its constraint equation using the analytical method,and the stability of the imaginary zoned Bessel function was judged in conjunction with the actual engineering projects,and the constitutive equations were solved to obtain the equivalent elastic modulus E_(c) and equivalent bending stiffness(EI)_(eff) and the stress p at each internal point of the seismic isolation bearing in the compression and bending states were established respectively.The necessity of considering rubber compressibility,and the influence of rubber material parameters K,G and bearing geometry coefficient S_(1) on the above results was compared and analyzed.Then the seismic isolation bearing was equated to a homogeneous body conforming to GA_(s),(EI)eff,based on the Haringx theory of internal forces and deformations of seismic isolation bearings,compressive-shear experiments were carried out on full-size seismic isolation bearings,and combined with the experiments,the theoretical and experimental G-γand F H-γcurves for each force state of the bearings were found to be in good agreement.The geometrical and material dual nonlinearities of the large shear deformation of the seismic isolation bearing in compression shear were solved.Based on the above conclusions,the distribution of internal force and deformation of the compression-shear isolated bearing was derived,as well as the trend of non-linear growth of force and deformation of the bearing with the increase of axial pressure,the increase of its additional overturning moment M is larger,and the change of stress with axial pressure is also more obvious.Finally,the monitoring procedure of inversion of macroscopic force and deformation by the internal local stress of the bearing was designed.