初始剪切变形对铅芯橡胶支座性能影响分析

为了研究初始剪切变形对铅芯橡胶支座力学性能与大剪切变形时内部应力的影响规律，首先基于厂家提供的支座规格参数得到铅芯橡胶支座有限元模型，验证试验数据与有限元计算结果模型的正确性；然后分析支座尺寸、形状系数、竖向压力等不同参数，对有初始剪切变形的铅芯橡胶支座100%水平性能、内部钢板橡胶最大应力比的影响，并进行大剪应变下支座内部应力分析。结果表明：与无初始剪切变形相比，铅芯橡胶支座的100%水平刚度随着压应力、初始剪切变形、支座形状系数的变化最大为5%,影响程度较小；有初始剪切变形对橡胶隔震支座100%剪应变条件下的橡胶和钢板应力有一定的影响，但基本未达到橡胶材料的拉伸强度和钢板的屈服强度，支座处于安全状态；有初始剪切变形对橡胶隔震支座250%以上剪应变条件下的橡胶和钢板应力有很大的影响，不同剪应变条件下的橡胶或钢板应力均可能达到拉伸强度或钢板的屈服强度，支座有极大的损伤风险；通过分析，建议支座实际剪应变为400%、350%、300%、250%、200%及100%时，其初始变形分别不能超过0、20%、70%、120%、170%及270%。

Analysis on the influence of initial shear deformation on the performance of lead rubber bearing

In order to study the effect of initial shear deformation on the mechanical properties and internal stress of lead rubber bearing under large shear deformation, the finite element model of lead rubber bearing was established based on the support specification parameters provided by the factory,and verify the correctness of experimental data and finite element model. Then, the influence of different parameters such as bearing size, shape coefficient and vertical pressure on the 100% horizontal performance of lead rubber bearing with initial shear deformation and the maximum stress ratio of internal steel plate rubber were analyzed, and the internal stress of the bearing under large shear strain was analyzed. Compared with no initial shear deformation,the results show that the maximum change of 100% horizontal equivalent stiffness of lead rubber bearing with compressive stress, initial shear deformation and bearing shape coefficient is 5%, and the influence degree is small. The initial shear deformation has a certain influence on the stress of rubber and steel plate under 100% shear strain condition of rubber isolation bearing, but the tensile strength of rubber material and the yield strength of steel plate are basically not reached, and the bearing is in a safe state. The initial shear deformation has a great influence on the stress of rubber and steel plate under the condition of more than 250% shear strain. The stress of rubber or steel plate under different shear strain conditions may reach tensile strength or yield strength of steel plate, and the bearing has a great risk of damage. Through analysis, it is suggested that when the actual shear strain of the support is 400%,350%,300%,250%,200%and100%,the initial deformation respectively cannot exceed 0%,20%,70%,120 %,170% and 270%.