Experimental Research Of Truss Structural Damage And Test Study Based On Frequency And Mode Of Vibration

With the development of the economic and science, modern project structures are proceeding at the direction of maximization and complication. To guarantee the structures’safety, the damage researches must be done to the structures to get the correct operation conditions, then the accurate repairing work can be done to the damage timely. The truss structures are used in many large factory buildings and bridges for its light weight and higll utilization ratio, so it is meaningful to research how to identify the damage of the truss structures.In this thesis, vibration based on damage detection theories and methods are discussed, a new method which combines the static test and dynamic test is proposed and studied in detail. And it discusses the theory and method of damage identification using strain modal. This thesis can be summarized as follows:(1) The damage identification method based on vibration modal analysis theory is discussed and analyzed. During the process, natural principle and detected procedure of this analysis theory are introduced, natural principle、predominance and shortcomings of every capabilities and applicable scope about these methods based on modal frequency、 modal shape curvature、Stiffness Matrix/Flexibility Matrix、curvature modal shape and artificial neural network are systematically analyzed.(2) Using the Midas software based on the finite element model steel truss, into action to model, static analysis, the dynamic analysis before and after damage simulation for comparison, observation vibration mode and the change of frequency and the damage of the relationship.(3) Design a truss entity model of4meters for the into action, static test analysis, through the nodes in artificial damage simulation component damage, before and after damage to test data is analyzed, and the results verify the validity of the finite element analysis.