The Research Of Health Monitoring And Damage Identification Based On The Difference Of Modal Curvature For Arch Rib

The vertical load can be transformed into a uniform stress distribution of the thrust cross section in arch structure, arch structure can fully play the role of the material, they have been widely used in bridges, building roof truss and tunnel lining structure, and so it is particularly important to the arch structure damage detection and accurate location.According to the bridge damage identification for the current situation is less,a through tied arch bridge is made. The structural damage detection based on dynamic parameters of theories and methods is discussed and studied, and finite element numerical simulation and experimental study are carried out to through tied arch bridge, model curvature difference and flexibility curvature difference are applied to the structure damage identification. Specific research studies are as follows:(1)Described the significance of the damage identification of structure, research status and results of damage identification in china and abroad; elaborates the present research field in damage identification and research, and puts forward the main research contents.(2) Discusses the method, criteria and application of parameter identification.(3) Discussed the theory of curvature mode method which is applied to the structural damage identification of straight beam bending, on the bases of the theory, discussed the curvature difference mode basis which is used in the structure of curved beam; described the principle of flexibility matrix and flexibility curvature difference, which provided the basis for the application of modal curvature difference method.(4) Used Midas/Civil finite element analysis program for the through tied arch bridge to numerical simulation of arch rib, analysis the natural frequencies and corresponding vibration mode vector in relationship with the damage identification, used the modal curvature difference and flexibility curvature difference for damage identification, the results demonstrate the damage identification indicators of modal curvature difference is feasibility, validity and applicability to local damage identification of arch rib; low order modes can be a good method for identifying location and extent of damage with indicators of flexibility curvature difference. The changes of the damage before and after the natural frequency are also studied(5) Described modal parameters method of stochastic subspace identification; through the dynamic testing of ambient excitation to the tied arch bridge, verified the modal curvature difference in the real test is effective.(6) Summarized the contents and results of this paper, and pointed out the problem in using the difference of mode curvature damage identification in the bridge structure damage identification and health monitoring.