基于柔度指标的系杆拱桥损伤识别与寿命预测

Damage Detection and Life Prediction of Tied Arch Bridge based on Flexibility-Curvature-Difference-Rate

提出了一种柔度曲率差变化率的损伤识别指标,通过试验验证指标的有效性,并应用于系杆拱桥算例损伤识别,进而预测其构件剩余寿命。利用系杆拱桥算例中吊杆、拱肋与横撑的多种损伤工况验证了新指标的有效性与抗噪性,基于所提损伤指标建立损伤评估函数并构造相应曲线,用于精确定量评估损伤程度,并采用损伤评估函数预测构件剩余寿命。结果表明,柔度曲率差变化率可有效用于系杆拱桥损伤评估且噪声鲁棒性好,运用结构不同阶段的有损模态信息构建损伤评估函数的方法可行、合理,所提寿命预测方法考虑了损伤非线性累积,意义明确。建议在使用该方法诊断下承式拱桥吊杆时,宜采用拱肋振型向量构建损伤指标,实桥试验时应将振型传感器置于拱肋处。

A new damage indicator called flexibility-curvature-difference-rate was proposed and verified effectively by simply supported beam model experiment.The validity and noise robust- ness of the new indicator were confirmed in detecting the damage of boom,arch-rib and transverse brace of a tied arch bridge through a numerical example.The damage evaluation function and the damage curve were constructed based on the indicator to evaluate the damage degree accurately.The results can be used in damage degree inversion and quantitative assessment of damage.A new method for estimating the service life based on damage evaluation function was proposed.It is feasible and reasonable to construct damage evaluation function on the basis of structural modal information.The component life evaluation function,which can reflect the non-linear cumulative of component damage,is explicit and well-defined.The numerical example results suggest that vibration type sensor should be placed on the arch-rib.The longitudinal vibration mode vector constructing damage indicator has an ideal effect in detecting the damage of the tied arch bridge.