低硬度大直径橡胶隔震支座竖向荷载作用下钢板应力研究

Research on Stresses of Steel Plates of Isolator with Large Diameter and Low IRHD Rubber under Vertical Loading

采用大型通用有限元程序,对低硬度大直径橡胶隔震支座在竖向荷载作用下的基本性能进行了精细有限元分析。分析了在竖向荷载作用下支座上下封板、内部钢板的各种应力分布,以及支座顶部是否施加竖向同位移约束、支座孔径比、橡胶材料G值、内部单层橡胶厚度与内部单层钢板厚度之比对支座内钢板受力的影响。结果表明,内部钢板最大Mises应力、最大径向水平正应力约为支座竖向压力的4倍、2.5倍;支座顶部是否施加竖向同位移约束对支座用钢板内力影响较大,特别是支座上封板;橡胶G值的变化对内部钢板受力基本没影响;支座孔径比对靠近孔边缘部分内部钢板应力不均匀性分布影响较大;内部单层橡胶厚度与内部单层钢板厚度的比值对内部钢板的Mises应力、径向正应力、环向正应力影响较大,但对其竖向正应力基本没影响。

Linear natural rubber bearing（LNR） isolators with large diameter and low IRHD rubber are analysed with FEM program.The stresses of the upper cover steel plate,the bottom cover steel plate and the inner steel plate of the isolator are researched.Some factors are considered,such as the constraints at the top of isolator,shear modules of the inner rubber,the ratio between thickness of one inner rubber and thickness of one inner steel plate etc.The results show that the maximum value of Mises stresses of the inner steel plate and the maximum value of normal stresses in the radius direction of the inner steel plate,are about 4 and 2.5 times the vertical pressures respectively;the stresses of steel of isolator are affected by the constraints at the top of isolator,especially for the upper cover steel plate of isolator.There is no effect on the stresses of the inner steel plate of isolator while changing shear modules of the inner rubber of isolator. The change of ratio between the diameter of core and the diameter of isolator will affect the distribution of the stresses of inner steel plate near the core.The ratio between thickness of inner rubber and thickness of inner steel plate has considerable influence on Mises stresses and normal stresses（in radial and circumferential direction of isolator） of the inner steel plate,but slight influence on the vertical normal stresses of the inner steel plate.