Mode Method Of Identification In Aqueduct Structural Damage Detection

Aqueduct is one of the most extensively used cross hydraulic buildings in irrigation area, it is a water-transportation building built on stilts that can span rives, roads, valleys and so on. So it plays an important role in the mountainous irrigation area. Through the scientific damage detection and evaluation of aqueduct, and learning its actual situation, the foundation of economically using aqueduct is provided, so that can avoid calamity accident. Recently, many interior and oversea scholars have been all along endeavoring to find the methods that can detect the structure's damages accurately and they obtain much prominent achievement, but there also exist many shortcomings. Especially, these methods are not ideal to deal with three dimensions problem. To solve this problem, in this paper, based on the analysis of other scholars' research results, a damage detection method based on mode parameter is put forward. This method thinks that structure mode parameters (vibration frequency, mode of vibration) are the functions of physical property parameters (mass, rigidity, damping). The damage of structures leads to the transformation of physical property parameters, and certainly leads to the transformation of structure mode parameters finally. So the damage degree of the aqueduct can be detected by the transformation of structure mode parameters with the modern technology of signal test. It is the weakness of using frequency to detect damage that it can't accurately diagnose the symmetrical points' damage, to solve this problem, a method based curvature mode is introduced to tackle it. Namely through the curvature mode detection method's aid to realize using frequency detect aqueduct's unitary damages. Then, using a kind of finite element software ANSYS analyses a simple supported beam to illuminate the curvature mode method of structure damage identification. From the numerical simulation a conclusion is drew that curvature mode is sensitive to structure's damages, and it can identify the damage locations, then using APDL compile procedures and make mode analyse of another simple supported beam. And combining MATLAB a new mode frequency method is introduced. Through the structure's different part of same degree damage's different influences on every frequency, namely the changes of structure's different part causing different frequency change assemble, form the structure's damage space information, and use it to identify the structure's damage. Numerical simulation case verifies its result. Finally, using this mode frequency method, a concrete beamed aqueduct's damage is detected, and the result is good.