基于模态测试与模型修正的结构损伤识别方法

Structural damage identification method based on modal testing ground and model modification

结构损伤通常以结构中刚度损失为特征,在有限元模型修正中以弹性模量降低来表示。文中以模态参数对结构弹性模量变化的灵敏度出发,应用FEMtools软件中贝叶斯参数估计的模态灵敏度方法进行有限元模型修正。对三根无损伤和有损伤的悬臂梁钢板试件,用力锤激励试件测量振动响应,在试件无损伤和有损伤的状态下获取结构模态频率和振型,通过实测模态参数与模型修正的三个损伤识别实验,寻求一种最佳的结构损伤识别方法。

Structural damage is usually featured by the loss of stiffness in structure and is expressed by the decrease of elastic modulus in the finite element model modification.In the paper,according to the sensitivity of modal parameters to structural elastic modulus changes,the finite element model is modified by using the modal sensitivity method of Bayesian parameter estimation in FEMtools software.The vibration response of three non-damaged and damaged cantilever steel plate specimens is measured by hammering,and the modal frequencies and modes of the structure are obtained in the state of non-damaged and damaged specimens.Through the three damage identification experiments of measured modal parameters and model correction,an optimal method for structural damage identification is sought.