The Method of Diagnosis for Corrosion Hydraulic Gate Based on Strain Mode and Frequency

Abstract

Abstract The gate is important equipment of hydraulic structures. However, the special underwater working environment of the gate would cause corrosion of the in-service gate inevitably. The corrosion of steel would lead to the decrease of static bearing capacity and the instability of dynamic performance of gate structure. Therefore, in recent years, more and more studies on gate corrosion have been carried out. The hydrodynamic effect has an important influence on the dynamic performance of the gates under water operation, which include natural frequencies and modes. It is worth noting that the variation of the natural frequency and the mode have been used as the overall indexes of the steel gate in the structural inspection. These indexes are insensitivity to the detection of local pitting corrosion, and strain mode is better than these overall indexes. In this paper, the finite element dynamic analysis of the radial gate has been carried out by considering the fluid-solid coupling effect, and the arm has been taken for the corrosion simulation. It is found that under the condition of small area corrosion, the natural frequency of the steel gate did not change significantly. The local evaluation index of the strain mode (the change of the strain mode around the corrosion was obvious) could clearly determine the corrosion position of the steel gate.