Optimal sensor placement and parameter identification model test of flood discharge structure under flow excitation

The sensor placement for dynamic tests of flood discharge structure is subject to water conditions, and this adverse condition has great impact on the accuracy of structure modal parameter identification and damage detection. Thus, in the noise environment, the flood discharge structure modal parameter information will be identified through limited sensor placement. So the optimal sensor placement for flood discharge structure dynamic test is significant. Taking a cantilever as an example which lies in a discharge sink, this paper studies on optimal sensor placement method based on finite element model and QR decomposition and MAC criterion. Based on the optimal sensor placement result, a cantilever model modal test under flow excitation in the discharge sink is carried out, and the cantilever modal parameter is identified with dynamic response output only under flow excitation. The result shows that the optimal sensor placement improves the accuracy of the modal parameter identification. This optimal sensor placement method provides an important prerequisite for dynamic test and damage detection of flood discharge structure.