分离式减震榫的阻尼力模型研究-基于Ramberg-Osgood模型

RESEARCH ON DAMPING FORCE MODEL OF SEPARATED SHOCK ABSORBER BASED ON RAMBERG-OSGOOD MODEL

如何更好地模拟分离式减震榫在地震过程中的滞回性能,是分离式减震榫减震设计中的重要组成部分。针对从材料层次描述分离式减震榫在往复荷载作用下力学性能的理论研究相对不足的问题,提出一种基于Ramberg-Osgood模型推导分离式减震榫骨架曲线的计算方法,并基于该方法提出一种适用于工程计算的双线性本构的简化算法。通过ABAQUS有限元软件对比Ramberg-Osgood模型,Chaboche本构和理想弹塑性本构下分离式减震榫骨架曲线的差异,并以一座通用的两跨32 m双线铁路预应力混凝土简支梁桥为背景,分析双线性本构简化算法在桥梁抗震设计中的适用性。结果表明:基于Ramberg-Osgood模型推导的分离式减震榫的骨架曲线,能够较好拟合Chaboche本构下的骨架曲线;在近断层脉冲地震动作用下通过双线性本构计算得到的支座位移峰值和墩底弯矩峰值,与Chaboche本构下得到的计算结果的平均误差分别为−2.67%和6.56%。该文提出的双线性模型的简化方法用于桥梁工程抗震设计是安全且合理的。

How to better simulate the hysteretic performance of separated shock absorber under earthquake is an important part of the seismic design of separated shock absorber.Because theoretical research on describing the mechanical properties of separated shock absorber from material level is relatively insufficient,a calculation method based on the Ramberg-Osgood model to derive the skeleton curve of separated shock absorber is proposed.Based on this method,a simplified algorithm for deriving bilinear model is also proposed.The difference in skeleton curve of separated shock absorber under the bilinear model,Chaboche model and ideal elastoplastic constitutive model is compared using ABAQUS.The applicability of the simplified algorithm in seismic design of bridge engineering is analyzed using an example of a 32 m railway simply-supported beam bridge.The results show that the skeleton curve of separated shock absorber derived based on the Ramberg-Osgood model can better fit that of the Chaboche model.Under near-fault earthquake with velocity-impulse effect,the average errors of bearing displacement and pier bottom bending moment calculated with the bilinear model and Chaboche model are−3.6%and 6.5%,respectively.The proposed simplified algorithm of bilinear model is safe and reasonable for the seismic design in bridge engineering.