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针对大型复杂结构的整体监测常常面临测量信息不足等困难,提出只利用局部动态响应进行子结构损伤识别的局部主频率方法。子结构的局部主频率指:如果整体模态中含有以局部子结构位移为主的模态,即等价于在局部激励作用下,整体结构的振动主要体现为子结构的振动,并且主要以这阶局部模态振动为主,那么对应的该阶频率即定义为子结构的局部主频率。局部主频率主要反映子结构的局部特性,对子结构损伤的灵敏度高,所以只利用局部主频率就可以识别子结构。当子结构特征不明显时,提出通过附加质量使子结构具有局部主频率的有效方法。该文进行了大型空间桁架的局部动力测试试验,试验中通过附加质量使杆件子结构具有局部主频率,并能准确地识别出杆件损伤的位置和程度。
For the large-scale complex structure of the overall monitoring is often faced with the lack of measurement information and other difficulties, the proposed local dynamic response only using substructural damage identification of the local main frequency method. The local main frequency of substructures means that if the overall modal contains modal dominated by partial substructure displacements, which is equivalent to the local excitation, the vibration of the whole structure is mainly reflected in the substructure vibration, This local modal vibration is dominant, then the corresponding frequency of this order is defined as the local main frequency of the substructure. The local main frequency mainly reflects the local characteristics of the substructures and has high sensitivity to the damage of the substructures. Therefore, the substructures can be identified by using only the local main frequency. When the substructural features are not obvious, we propose an effective method to make the sub-structure have a local main frequency by using additional mass. In this paper, the local dynamic test of large space truss is carried out. In the experiment, the sub-structure of the rod has local main frequency by the additional mass, and the position and degree of the rod damage can be accurately identified.