We notice that changes of structural parameter due to damage must change dynamic characteristic of structure . it may be possible to detect and identify structural damage by detecting the change of dynamic characteristic and detect structural damage on the whole even damage in area beyond of reach 我们注意到,损伤引起的结构参数的变化必然会改变结构的动力特性,自然可以用监测动力特性的改变来检测与识别结构的损伤,而且可以从整体意义上检测结构的损伤,包括处于无法到达位置的损伤。