基于敏感模态单元应变能法结构损伤识别

摘要

According to the rate of change of eigenvalues of undamaged and damaged structure,modals with higher sensitivity for the damage element strain energy change were selected.Based on this,an efficient structural damage identification method with better robustness was established.Starting from the structural vibration equation,the relationship between the rate of change of the eigenvalue and strain energy changes before and after structural damage was derived.A structural damage identification equation consisted of the rate of change of a characteristic value,the element damage factor,element damage sensitivity factor and element damage correction factor was built.A damage location indicator of structure was established by applying the element damage correction factor and an analytical expression of the element damage factor was derived using structural damage identification equation.The proposed method was applied to a new shell breakwater structure to identify the location and degree of damage,including a single damage and multiple damage.Finally,the noise immunity of the proposed damage identification method was tested.The results show that this method has better robustness and high accuracy recognition results,which shows that the proposed method has a high efficiency.%根据结构损伤前后特征值变化率选择对损伤单元应变能变化灵敏度较高的模态,建立一种高效的并具有较好鲁棒性的结构损伤识别的方法.从结构振动方程出发,推导结构损伤前后特征值变化率和应变能变化的关系式,建立一个由特征值变化率、单元损伤因子、单元损伤灵敏度因子以及单元损伤修正因子组成的结构损伤识别方程.应用单元损伤修正因子建立结构的损伤定位指标,并应用结构损伤识别方程式推导出单元损伤程度因子的解析表达式.应用本方法对一新型防浪提结构进行单一处损伤和多处损伤的损伤位置识别和损伤程度识别,最后,对本文提出的损伤识别方法的抗噪声性能进行测试.研究结果表明:本方法具有较好的鲁棒性,并且识别结果具有较高的精度,表明本文提出方法具有高效性.