Research On Damage Detection Technology Of Plate Structure Based On Vibration

Civil structures such as tunnel or culvert are becoming a more and more useful traffic way across water. And the security of this traffic way has been paid more and more attention. With this reason, damage detection technology developed rapidly. Many structures such as tunnel or culvert have plate feature, so reseach on damage detection of plate structure will give the theoretical foundation and reference value for damage detection of civil structure. Damage detection method based on vibration is a widely used global method to detect damage, and the way has been applied on some structures such as bridge, tunnel. Moreover, a method of damage detection based on damage index as one of the methods based on vibration, has easy but effective usage on damage detection. Meanwhile, in order to reduce the number of sensors placed on structure and improve testing precision and reliability, research on optimal sensor placement has theoretical and practical significance.This paper studies plate structure and does the research on damage detection method based on damage index of this structure, no only theoretically but also experimentally. Meanwhile, optimal sensor placement is an important aspect for research on this paper. This paper built FE model of the structure and calculated modal features of this model under the free boundary condition. Based on data from calculation, optimal sensor placement had been obtained using the genetic algorithm (GA). Compared with effective independent method, GA has a good result. This paper studied principle of structure damage detection based on damage index, and used this method to study damage detection on this structure model. The result showed 22 percent rigid decrease could be calculated using just the first modal data based on this method. When modal order increases, the result is better.This paper built this plate structure and got its modal frequency and modal shape using impact hammering method. FE model had been modified based on experimental result. This paper used two ways of placing sensors on this model, the result showed the way using optimal sensor placement was better than that without using it. Based on experimental modal parameters when the structure has damage, damage index distribution has been calculated using the method of damage detection based on damage index. The result showed damage detection method based on damage index could locate position of damage.In the end of thesis, Fluid solid interaction was considered and how fluid solid interaction influenced optimal sensor placement was discussed.