基于测试频率的损伤定位技术及其有效性的检验

探讨了基于测试频率平方变化比的损伤定位方法,对1个压力管道结构进行了单元损伤状态下的有限元模态分析,同时用形状记忆聚合物(SMP)材料制作了该结构的损伤可控单元,以电加热的方式控制其刚度变化,模拟了结构出现损伤的情形,并具体应用于模态测试实验中.有限元数值模拟和模型实验结果均表明结构频率的平方变化比是损伤位置和损伤程度的函数,据此可构建结构的安全信息库,对工作中的结构进行实时状态监测,将采集到的结构模态信息与信息库中的数据相比较,实现结构状态实时监测与损伤定位,进而可采取应对措施.

Damage positioning technique based on frequency test and checking of its validity

A method for damage positioning is developed on the basis of testing the variation ratio of squ-ared frequency.Analysis of finite element model on the condition of element damage is performed for the construction of a pressure pipline.The emerging process of damage in the construction is simulated,where a damage controllable physical modal is made for this construction by using SMP material,and its stiffness variation is controlled by means of electric heating.All above mentioned are adopted in the experiment of modal test.It is shown by both the FEM numeric simulation and model test that the variation ratio of squared frequency is the function of damage position as well as damage degree.On this basis,a safety message library of the construction can be built up and real-time condition monitoring is implemented for the construction on duty.According to the comparison between montored message and standards in the message library,the damage positioning can be made so that remedial meassure will be adopted.