基于应变模态变化率的弯曲薄板结构损伤研究

以应变模态变化率作为识别参数,以弯曲薄板为研究对象,采用改变单元厚度的方法模拟结构损伤,应用有限元对结构进行模态分析和瞬态分析.模态分析获取板结构应变模态,以对称位置应变模态变化率的改变确定损伤,以改变值的差值大小判断损伤程度;瞬态分析以单元处应变模态变化率突变值,作为损伤定位和损伤程度判断.结果表明:应变模态改变率对于结构的损伤的敏感性强,易于定位.在此基础上给出了通过模态变化率直方图进行损伤识别定位的新方法,与应变模态的损伤识别方法比较表明验证该方法是有效的.

Damage detection of bending plate based on modal variable ratio of strain

Vibration mode and transient mode are analyzed by using finite element method,taking modal variable ratio of strain as the identification parameter,a bending plate as the study object and simulating the structural damage by changing the thickness of elements.The strain modal of plate is gotten from the mode analysis,the damage can be determined by the changing ratio of strain on symmetrical locations,and the damage degree can be determined by the changing of numerical value.In the transient analysis,the sudden change of element strain modal variable ratio is taken as the judging criterion of the damaging location and damaging degree.The results show that the modal variable ratio of strain is sensitive to the structural damages and easily located.A new damage detection method based on vertical square charts of modal variable ratio of strain is given,which is effective by comparing with the damage detection method based on strain modal.