Methods And Research Of Structural Damage Location By Curvature Model

With the rapidly development of civil engineering of China, the damage detection of structure has got more and more attention in the field. Among evaluation methods, the system identification techniques are very effective and appealing. Most structural identification methods nowadays commonly used only perform well when the input excitation and output response are known. However, the input excitation is generally unknown and the measurement of structural response is incomplete in the filed of dynamic test situation. Therefore, it is essential to develop some effective methods matching the actual measuring technique. This dissertation, based on the real fund project, gives the definition of the curvature model, and through the research of theory and the method of calculate, the theory and method of the detection of location of damage.The body of this dissertation consists of four parts:The first gives the definition of the curvature model and the connection of curvature and strain. The natural mode of vibration of structures can be expressed in the form of the curvature model. And it is connected correspondingly to strain. Therefore, there must be a distribution of curvature corresponding displace model. This distribution of curvature of natural mode of vibration, which corresponding to the displacement model, is called curvature model.The second discusses the curvature model as a theoretical method of the damage from the knowledge of mechanics of materials the curvature and the moment shared a linear relationship. The curvature is the second order derivative of displacement. Also, it has a liner relationship with stain. While strain is related with stiffness, the curvature model may be a key to the detection of the change of the stiffness. While structure damage is reflected by the change of stiffness. Sothe curvature may detect the damage of structure.The third part of this dissertation gives the steps of detection of structuredamage with the method of hypothesis of part damage. Firstly, from test in site, mode can be gotten, got curvature model. Then erect and divide the model. Later assuming the location of damages, the nature model as well as the curvature model can be got. At last, after compassing the seal damage model to assumed one, the location of damages can be got.The last part offers some examples. It includes the single site damage detection of continuous beam, simple support beam, fixed end beam, overhanging beam, truss, and the multipoint damage detection of simple support beam.