应变模态试验技术在渡槽结构损伤诊断中的应用

通过简支渡槽模型试验,研究结构损伤程度与应变模态之间的关系,并根据模态节线损伤时应变模态形状不变的特点,重点分析纵轴线纵向非节线(即1阶、4阶、6阶应变模态)损伤下的应变模态变化规律.结果表明:应变模态损伤突变区范围随损伤量的增加而增大,且低阶模态影响范围大于高阶模态影响范围;1阶应变模态对底板跨中损伤最为敏感,突变区外的大多数应变也都出现下降现象;可根据低阶应变模态的敏感性确定损伤位置和程度.

Application of strain mode test to structural damage diagnosis of aqueducts

Based on the model test of simply supported aqueduct,the relationship between structural damage and strain mode was studied.According to the fact that the strain mode keeps unchanged if the damage occurs on the nodal line,the variation of strain mode under the damage in longitudinal direction on the non-nodal line(i.e.the first-order,the fourth-order,and the sixth-order strain modes) was emphatically analyzed.It is concluded that the sharp variation zone of strain mode extends with the increase of damage quantity,and the influencing range of low-order modes is greater than that of the high-order modes,that the first-order strain mode is most sensitive to the damage in the middle part of bottom plate,and most strains outside the sharp variation zone obviously decrease,and that the degree and location of damages could be determined based on the sensitivity of low-order strain modes.