【摘要】 为了快速准确地对黄河某特大桥进行损伤识别,采用了一种环境激励状况下,基于优化理论的有限元模型修正方法.首先通过振动测试,利用环境激励下的功率谱峰值法,获得模态参数.使用ANSYS建立桥梁的参数化有限元模型,选取灵敏度高的刚度参数,根据最优化理论进行迭代修正,最终得到了黄河某特大桥有限元修正模型.通过对有限元模型进行动力特性分析,结果表明:修正后模型的模态特征值与实测值吻合度更好,前20阶主要振型的频率误差基本在2%以下,精度较高;修正后,桥梁混凝土整体弹性模量确定在每平方毫米340 000～370 000N之间,箱梁刚度分布基本符合现场的表观损伤调查结果.在正常通车情况下即可检测桥梁,无需交通管制,相对传统的人工激励方式,不会对桥梁构成额外伤害;利用现有的有限元软件ANSYS,不用计算繁琐的质量、刚度矩阵即可进行损伤识别,适合于大跨度连续刚构桥损伤识别的应用.更多还原

【Abstract】 To identify the damages of a Huang River extra-large bridge,a updating method of finite element model which was based on optimization theory under the environment excitation,was introduced.Firstly,the power spectrum peak method under environment excitation was used to get the modal parameters through the vibration test.Next,parametric finite element model was set up in software ANSYS.According to optimization theory,the high sensitive parameter was chosen to iteratively update.In the end,the updated finite element model of long-span continuous rigid-frame bridge was obtained.Through the dynamic property analysis of the finite element model,the result shows that the updated finite element modal eigenvalues preferably coincide with the measured values;after the update,frequency errors of the first 20 modes are controlled below 2%;concrete elastic modulus of the bridge is between 340 000~370 000 N per square millimeter;the apparent damage result by site investigation is conformed to box girder stiffness distribution.Bridge inspection is made under the condition of normal traffic by the method without traffic control,and doesn’t cause extra damage to the bridge compared with traditional artificial excitation.By using the software ANSYS,damage is identified without rigidity matrix and mass matrix.The method is suitable for damage identification of long-span continuous rigid-frame bridge.更多还原