单元模态应变能变化率对框架结构的损伤诊断

对具有一定程度损伤的框架结构来说,模态位移动力检测指标难以有效地反映结构的损伤状况。为了提高诊断效率和诊断结果的可靠性,采用结构损伤的单元模态应变能变化率方法构造框架结构损伤定位的识别指标。通过对一个典型框架结构的数值模拟研究表明:该方法仅需低阶模态参数,无论是单一位置损伤、对称部位损伤、轻微损伤,还是多种损伤共存,均具有损伤定位的能力;且在一定噪声水平下具有较强的抗噪能力。给出根据损伤单元模态应变能变化率值的大小,确定损伤程度的实用方法。

DAMAGE DIAGNOSIS FOR FRAME STRUCTURES BASED ON CHANGE RATE OF ELEMENTAL MODAL STRAIN ENERGY

Generally modal displacement indices are not very efficient to identify structural damage or diagnosis for frame structures.In order to improve efficiency and reliability for damage diagnosis,change rate of elemental modal strain energy was presented as dynamic indicator for damage locations of frame structures.The numerical simulation example of a frame structure indicated that the damage location and severity in structures,with single damage,lighter ones and multiple ones,could be detected efficiently by change rate of elemental modal strain energy with only the first order mode.The results indicated that the proposed method based on modal strain energy could accurately identify the damage location of truss structures with the noisy modal data.Furthermore,damage degree could be derived from the amplitude value of change rate of modal strain energy for the detected damage element.