The Study On Curvature Mode Method Of Engineering Structure Damage Identification

In this paper, based on analyzing the present researchhes and existing problems of the dynamic method of the damage identification in engineering structure, the curvature modal method of damage identification in structure is discussed. Up to now, indicated by some relevant documents, the method of curvature modal has not applied to damage identification of arch structure. So this thesis firstly utilizes this method to discern the arch structure damages, basing on having applied this method to identify damage of reinforced concrete simple- supported beams.Firstly, the paper dissertates the theoretic basis of the application of curvature modal method to the straight beams (only supports bending). Basing on the simple-supported beams' results, the paper also discusses the possibility of the application of curvature modal method in the damage identification of arch structure (circle arch, mainly supported axial force). Secondly, using the finite element analysis(FEA) program, called MSC. Patran (Nastran), the paper has a numeric simulation on the simple- supported beams (rectangle section) and arch structures, and gives the simulation results of the dynamic characters of the different damage degree. Basing on the results of simulation, the paper uses the curvature modal method to identify the structural damage, and its results make clear that this identification method is feasible. Finally, the paper also makes some modal experiments on the simple beams (reinforce concrete structure) and circle-arch arch structures (plain concrete structure), compared with the FEA simulation results, the paper also discusses the experiment's results.Finite element analysis shows that curvature modal method not only can accurately confirm the position of damage of simple- supported beam, but also can identify the arch structure's. The further experimental modal analysis indicates that the structural damage can be discerned only through some low modal parameters. But it also has the deficiency: curvature modal method tends to be influenced by the measure errors. So, before applying the method to the real engineering structures, there will be a large amount of work to do.