栓接结合部迟滞非线性建模与辨识方法

Modeling and Identification Method for Hysteresis Nonlinear of Joint Interfaces

由于栓接结合部是导致结构发生复杂非线性特性的主要因素,而对栓接结合部的传统处理方法往往忽略结合部的非线性特性或采用等效线性化的数学方法来建模,造成无法准确分析和研究栓接结合部的非线性动力行为。通过实验研究结合部上微凸体间相互挤压、搓动引起的能量耗损机理,运用Iwan模型描述栓接结合部的迟滞非线性现象。在准静态条件下获得力-位移实验数据,利用无约束非线性优化方法和Newton迭代法辨识出Iwan模型中的未知参数,从而获得随外载荷幅值变化下的迟滞非线性特性,并与实验结果进行比较。结果表明,利用Iwan模型能够准确反映出栓接结合部所表现出的能量迟滞机理和非线性行为。

The complicated nonlinear characteristic of structures is largely responsible for bolted joints.In traditional structural dynamical analysis,the nonlinearity of the joint interfaces is ignored,or the linear method is used to model for bolted joints,which causes inaccurate analysis and increases the difficulty of studying nonlinear dynamic characteristics for bolted joints.The energy dissipation mechanism in bolted joints occurs as a result of micro-slip motion between rough surfaces in contact,which is studied by experiment.The hysteresis nonlinear characteristic of bolted joints is described by the Iwan model.The unknown parameters of the Iwan model are deduced by unconstrained nonlinear optimization and the Newton iteration method under quasi-static harmonic load,and the hysteresis nonlinear characteristic of bolted joints with the change in harmonic loading can be obtained.Finally,the experimental and numerical simulation results are compared to validate the Iwan model.The results show that the Iwan model can reflect the energy dissipation mechanism and the hysteresis nonlinear characteristic of bolted joints.