基于能量法的简支钢梁损伤识别试验及有限元分析

针对目前梁式结构损伤识别中识别精度和实际应用方面存在的不足，以能量耗散理论为基础，对简支工字形钢梁的损伤识别进行了数值分析及试验研究。通过结构损伤时每一单元的模态应变能耗散率与损伤前、后模态应变能变化之间的关系，推导出单元损伤变量的表达形式。研究结果表明：单元损伤变量只需要利用结构损伤前、后的模态振型即可算得，在实际应用中可通过模态扩阶技术解决实测自由度与理论自由度不匹配问题；该方法可准确识别出简支钢梁损伤单元的位置，并在一定程度上表征损伤程度。

Damage Identification Test and Finite Element Analysis of Simply Supported Steel Beam Based on Energy Dissipation Method

To solve the problems of identifiable accuracy and practical applications existing in present beam structure damage identification , on the basis of energy dissipation , numerical analysis and test research of the simply supported I-beam were carried out .According to the relationship between the modal strain energy dissipation ratio and the change of modal strain energy in each element before and after damage of structures ,the formula of damage variable of each element was deduced .The study results indicate that the calculation of damage variable only needs modal shape of damage and undamaged structure .In practical application ,the problem of mismatching between the degrees of freedoms of the measurement model and those of the finite element model can be solved by means of modal expansion algorithms .The damage identification method can successfully detect the damage position of the simply supported steel beam and describe the damage degree to some extent .