Experimental and Numerical Analysis of 60-Year-Old Sluice Gate Affected by Long-Term Operation.

Miroslav Pástor,Pavol Lengvarský,Patrik Šarga,Peter Sivák,Jozef Bocko

doi:10.3390/ma13225201

Abstract

Technological units of water reservoirs and power plants include sluice gates which are designed to completely seal the inflow or outflow of water in supply or discharge channels. This article describes the issue of technical assessment of a sluice gate made in the 1950s. Such structures are characterised by states of significant corrosive wear, permanent deformations of contact and sealing surfaces as well as increased levels of residual stresses. In such cases, it is difficult to determine service life using only numerical modelling methods, mainly due to problematic definition of material properties and boundary conditions. Therefore, for safety assessment, it is necessary to verify these facts experimentally. This article presents the procedure for assessing safe operation of the sluice gate on which places with permanent deformation and a broken part of the guide wheel flange were identified. By means of numerical modelling, we identified critical stress values at the locations of reinforcing elements, which were modified, and the stress values were reduced by about 15%. The results of numerical modelling were verified at select locations by experimental measurements during operation using strain gauges. The maximum values of operational normal stresses in the assessed places reached about 27 MPa. Based on the comparison of obtained results and taking into account values of residual stresses reaching up to 190 MPa made by shielded metal arc welding, it can be stated that, for safe operation of the sluice gate, it is necessary to follow the proposed procedure during its lowering and to modify the reinforcing elements structurally.

Highlights

Sluice gates, which are used as an integrated part of technological units of water reservoirs and power plants, block the inflow or outflow of water in supply or discharge channels
Maximum values of equivalent stresses around triangular reinforcements reached the value of 360 MPa, exceeding the yield strength of the analysed samples. Values at these critical points exceeded the yield strength of the used material taken from the sluice gate, permanent deformations were not detected during visual inspection
On a simplified model of the sluice gate, the finite element analysis was performed with boundary conditions corresponding to the most unfavourable scenario, i.e., operation at the highest water level in the water reservoir

Summary

Introduction

Sluice gates, which are used as an integrated part of technological units of water reservoirs and power plants, block (close) the inflow or outflow of water in supply or discharge channels Their correct operation is conditioned by correct design, production as well as the maintenance of a flawless technical condition during the expected period of operation. Many of them were designed and manufactured several decades ago in accordance with regulations and standards in force at that time As these standards and regulations were applied, which from today’s point of view are conservative and limited procedures, such plates were in most cases oversized in terms of strength and stiffness.

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Conclusion