Steel Gate Research Articles

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

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.

Indirect ice load monitoring and strength analysis of a steel gate considering uncertainties

One of the most significant challenges in analysing steel gate strength is to obtain plausible ice loads that are exerted on the gate. The indirect monitoring of ice-induced loads is an inverse problem of structural mechanics, and various numerical models have been developed over the years for estimating ice loads with reasonable accuracy. However, the mathematical models used to estimate ice loads are usually affected by uncertainty factors such as uncertainties in the transfer matrix, which reduces the reliability of the gate strength analyses. In this study, a D-optimal design combined with a sequential exchange algorithm or C-optimal design method was used to identify 13 candidate arrangement schemes of strain gauges based on an assumption that the transfer matrix is accurate. Every candidate arrangement scheme of the strain gauges on the steel gate corresponds to a certain number of strain gauges. An experimental structure was designed, and a benchmark experiment was conducted to estimate the error of the transfer matrix—i.e., the uncertainties in the mathematical model. Monte Carlo simulations were performed to investigate the effects of the uncertainties of the mathematical model on the estimated ice loads, and the optimal strain gauge locations were then determined. Based on the optimal arrangement scheme, the upper and lower limits of the estimated ice loads corresponding to different probabilities were obtained with the structural monitoring data of a steel gate in a cold region using the Monte Carlo simulation method. Finally, the gate strength was analysed based on the upper limits of the estimated ice loads corresponding to a probability of 99.74%. The analysis results indicate that the ice load did not threaten the gate safety during the structural monitoring period.

Hybrid reconstruction method for indirect monitoring of an ice load of a steel gate in a cold region

The steel gate of a hydraulic complex may be subjected to ice loads during freezing periods in cold regions, threatening the gate safety. The ice load on the gate is usually affected by several factors, including the ice thickness, snow cover, and changes in water level and temperature. The ice pressure distribution on the gate cannot be readily estimated by theoretical analysis or empirical formulae. Therefore, structural strain and local ice pressure data were collected over 140 days during the winter of 2016–2017 to investigate the structural deformation and local ice pressure distribution. A hybrid reconstruction method (HCM) was developed for establishing the ice pressure distribution using the monitoring data, and the effectiveness of the HCM was analysed based on several uniform load patterns and the Chebyshev polynomial functions. The ice pressure distributions on the gate were reconstructed during the entire monitoring period, considering the collected data for the lowest temperature of each day. The reconstructed ice pressure distribution, i.e., the equivalent and uniform ice pressure within every individual cell, was lower than 0.1 MPa in most parts of the gate.

Novel computation method of reducing ill-posedness for structural static distributed load identification by optimising strain gauge locations

The static distributed load exerted on engineering structures, such as the ice extrusion load on steel gates or stop logs in cold regions, is sometimes difficult to measure directly. However, load identification provides an effective approach of indirect load monitoring. Load identification is an inverse problem in structural mechanics, and the mathematical model used for load identification is typically ill-posed. This ill-posedness results in certain difficulties in the inverse calculation and decreases the precision of load identification. In this study, the condition number of the transfer matrix of the mathematical model used for load identification, called C-optimal design (COD), was employed as the objective function to overcome the ill-posedness by optimising the strain gauge locations. A successive reduction algorithm (SRA) was developed to perform the COD directly. On this basis, a block C-optimal design (BCOD) was further developed to reduce computational cost. The COD with SRA and BCOD were described in detail through a specific case study, i.e., a steel gate in a cold region, in which the mathematical model was established by dividing the ice load monitoring zone into several individual cells and assuming that the ice load exerted on every cell is equivalent and uniform. Several numerical examples were used to verify the effectiveness of BCOD. The simulation results of load identification demonstrate that the BCOD method is more beneficial for obtaining stable and accurate identification results than a D-optimal design (DOD) method. Moreover, an experiment was designed and performed to further verify the advantage of BCOD. The experimental results indicate that the BCOD can provide more accurate identification results than the DOD; these results are approximately consistent with the simulation results.

Massively Parallel Calculation and Analysis of Deepwater Plane Steel Gate

Massively Parallel Calculation and Analysis of Deepwater Plane Steel Gate

Steel Gate to Freedom: The Life of Liu Xiaobo, by Yu Jie; translated by H. C. Hsu. Lanham, MD: Rowman & Littlefield, 2015. v+240 pp. £24.95/US$39.00 (cloth).

Previous articleNext article No AccessReviewsSteel Gate to Freedom: The Life of Liu Xiaobo, by Yu Jie; translated by H. C. Hsu. Lanham, MD: Rowman & Littlefield, 2015. v+240 pp. £24.95/US$39.00 (cloth).Chongyi FengChongyi FengUniversity of Technology Sydney Search for more articles by this author PDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The China Journal Volume 80July 2018 Published on behalf of the Australian Centre on China in the World at the Australian National University Article DOIhttps://doi.org/10.1086/697618 Views: 47Total views on this site For permission to reuse, please contact [email protected]PDF download Crossref reports no articles citing this article.

Study on application of fiber-reinforced concrete in sluice gates

A sluice gate is a primary hydraulic structure in water discharge and storage facilities. Steel sluice gates are often stolen when global metal prices are high. Thus, this study proposed using fiber-reinforced concrete to fabricate sluice gates. The material mechanical properties and durability of the fiber-reinforced concrete sluice gates were tested, and field test and feasibility tests were subsequently performed. The compressive strength, flexural strength, and elastic modulus of the concrete used to construct the gates were respectively 99.3 MPa, 18.2 MPa, and 40.0 GPa. In the concrete, the depth of wear by hyperconcentrated flow was 0.5 mm h−1 mm−2; the chloride diffusion coefficient was 2.25 × 10−12 m2 s−1; and the weight loss in the soundness test was 1.02%.The results of the field testing suggested that the size and weight of the fiber-reinforced concrete sluice gates met operational needs and that the gates maintained their watertight seals and functioned normally during and after several tropical cyclones. Monthly observations revealed no noticeable cracks or rust stains on the gate surfaces. And the difference of properties of fiber-reinforced concrete before and after one year exposure is within ±6%. The fiber-reinforced concrete sluice gates were estimated to be one-tenth cheaper to produce than stainless steel gates and one-fifth cheaper than cast iron gates. The concrete sluice gates can be employed in low-head areas and drainage basins.

Indirect monitoring of distributed ice loads on a steel gate in a cold region

A steel gate is one of the major components of a hydraulic power station for storing water and monitoring the water level. In cold regions, the temperature decreases to well below the freezing point, and the water turns to ice, which can apply high loads on the steel gate, leading to large deformations and failure of the gate. This study aims to monitor and analyse the ice load distribution on a steel gate using an inverse method. As a case study, a steel gate at the hydraulic station on the Songhua River in Harbin is selected. The steel gate is equipped with several vibrating wire strain gauges, and deformation data for various locations on the structure was collected for 100 days. As experimental identification of the system transfer matrix requires information concerning the actual loads, which is not directly attainable, the transfer matrix was constructed using a finite element method. Five inverse methods were verified with a certain number of load patterns to determine the optimal method. The ice load distribution obtained using the optimal method is verified with the deformation data, indicating accurate load identification. Consequently, variation in the ice load distribution during the freezing period is monitored, and the relationship between the total ice force and temperature is obtained. During the winter of 2015–2016, the average ice line load gradually increased until reaching a maximum of approximately 25 kN/m on 11 Dec. 2015. Subsequently, the ice line load fluctuated between 17 and 25 kN/m. Finally, the ice released all of the force within 3 days beginning on 15 Mar. 2016.

Elementary Introduction of Way of Localization of Composite Sliding Bearing for Hydroelectric Engineering

This article describes the process of replacing imported bearings with domestic composite sliding bearings in the hydroelectric engineering industry from three main aspects: thrust bearing of hydraulic generator, water distributor bearing of hydraulic turbine and spherical plain bearing of steel gate of hydraulic metal structure; expounds that we have adopted the development mode of imitation and independent innovation instead of plagiarism or re-innovation after technology introduction. In the process of domestic development, we relied on our continuous learning and innovation, focused on intellectual property protection, and aimed at the advanced international level; summarizes the achievements made in the application technology level of domestic products through our own efforts over the past 40 years, i.e. achieving the replacement of imported bearings with domestic bearings and realizing the export of domestic bearings; and presents the prospect of application of composite sliding bearings in hydroelectric engineering.

Research on rational layout of strut arms of tainter gate in vertical frame

The overall stability of hydraulic tainter steel gate decrease seriously, and they are caused by improper structure layout of the two-way eccentric compression of struts. Chinese and American specification method, structural mechanics method and finite element method are respectively used to study rational structural layout of strut arms in vertical frame. First of all, a unified method for rational layout of struts of tainter gate in vertical frame is deduced by using structural mechanics method that simplifies curve girder as straight girder on the basis of zero rotation in vertical girder. Second, rational layouts of struts were researched by utilizing spatial finite element method according to zero rotation in vertical girder. The 756 groups rational layout results of the above three methods with different water heads, different number of struts and different unit stiffness ratios were researched. The differences of struts stress and material dosages of various rational layout methods were evaluated. From the point of view of the forces of tainter gate struts in vertical frame, as the results shown, the layouts of struts by Chinese and American specification method, straight beam method and finite element method are large eccentric compression, small eccentric compression and axial compression respectively. The layout of struts with specification method in lower head is quite different from straight beam method and finite element method, and the layouts of deep water head with straight beam method and finite element method are tend to be consistent. Unit stiffness ratio between vertical girder and strut has little effect on layout of tainter gate struts, but has a great influence on material dosages of tainter gate. Compared with specification method, layout of tainter gate with two struts and three struts by using straight beam method and finite element method can improve stability of struts and save materials of overall tainter gate structure, and the material saving rates of tainter gate with two struts and three struts with finite element method are respectively [32.63, 47.58] (%) and [21.61, 30.01] (%). Rational layout concise charts of tainter gate with two struts and three struts by specification method, straight beam method and finite element method are given, which can be used directly for projects designs. Compared with specification method, the layout of struts of straight beam method and finite element method is not only security and economy, but also method and mechanics concept are simple, which can provide the theoretical basis for specification revision of Chinese and American.

Dynamic Performance of Water Seals and Fatigue Failure Probability Updating of a Hydraulic Steel Sluice Gate

AbstractThe main objective of this paper is to study the dynamic performance of seals and the fatigue failure probability updating of a hydraulic steel sluice gate by experiments. First, water seal modifications involving of top, side, and bottom water seals and the rotation hinge water seal were performed in order to identify and test for the desired shape and functionality. Water sealing experiments under a variety of conditions were performed. It is indicated that the preset compressive deformation of various water seals changed at varying water head conditions. Moreover, the transformation law of the preset compressive deformation of different sealing parts under the reservoir water head was discovered. Second, a hydraulic steel gate’s fatigue reliability was evaluated based on Bayes’ theorem. The findings indicate that fatigue cracks can be detected for existing structures while the fatigue reliability assessment can be updated by nondestructive testing (NDT). Based on the probabilistic characteristi...

개량형 가동보에 적용하기 위한 하이브리드 강판/GFRP 패널 게이트의 강판게이트 표면형상에 따른 휨 및 계면 부착 특성 평가

The purpose of this study was to improved the durability of a improved movable weir by replacing the improved movable weir's metal gate with a hybrid steel/glass fiber reinforced polymer composites panel gate. Because the metal gate of a improved movable weir is always in contact with water, its service life is shortened by corrosion. This study made four type of hybrid steel/glass fiber reinforced polymer composites panel gate with different steel gate surface deformation (control, sand blast, scratch and hole), flexural. Fracture properties tests were performed depending on the steel gate surface deformation. According to the test results, the flexural behavior, flexural strength and fracture properties of hybrid steel/glass fiber reinforced polymer composites panel gate was affected by the steel panel gate surface deformation. Also, the sand blast type hybrid steel/glass fiber reinforced polymer composites panel gate shows vastly superior flexural and fracture performance compared to other types.

The Lightweight Design and Simulation of Hydraulic Steel Gate with Metal Sandwich Construction

The paper applies composite technology into the field of hydraulic metal structures and hydropower construction mechanical equipment design, and presents the method of optimum design of hydraulic steel gate metal sandwich construction and simulation analysis. According to characteristics of the structure of the flat hydraulic steel gate and selecting the appropriate metal sandwich construction, this paper optimize the design of a hydraulic steel gate of metal sandwich construction from the perspective of light-weight purpose of structure. Considering the overall mechanical behavior of steel gate structures and using technology of three-dimensional modeling and numerical simulation, this paper has a numerical simulation analysis on the optimum hydraulic steel gate. Numerical simulation analysis and theoretical calculation results show the optimum structure of hydraulic steel gate is reasonably practicable.

Research on the Radial Gate Fluid-Structure Coupling of Hydraulic Steel Gate

With the rapid development of China's water conservancy decades, the application of hydraulic steel gate demand is increasing. Among the many types of hydraulic steel gate, the radial gate because of its closed orifice area, pier height is small, over-water conditions are good, open and close rapidly, less embedded parts, etc., are a very wide range of applications. But the survey found that there are many curved steel gate accident in the history of its application. Most accidents are caused due to the instability of the arm, the ultimate reason is the traditional design methods flawed. According to the traditional method of checking the experience plus the theoretical design out of the gate structure, the safety factor is too large, but the overall stress distribution is very uneven, resulting in the investment project is too large, it is difficult to ensure the safe operation of the whole structure. Therefore, it is necessary for radial gate design method to improve it. In this paper, based on the continuum topology optimization theory, combined with structural finite element analysis software, representing a new systematic method of designing curved steel gate.

Nonlinear Finite Element Static and Corrosion Sensitive Analysis of Radial Steel Gate

Using nonlinear finite element method, the three dimensional nonlinear analysis of the radial steel gate of a reservoir is carried out. In the analysis, the radial steel gate considering and without considering the stiffeners of the panel is analyzed to investigate the effect of the stiffener to the panel. In the corrosion sensitive analysis, the panel of the gate is divided into three sections, and the nonlinear analysis is carried out for each section that is rusted with different corrosion depth. The corrosion sensitive section and the stress variation with the corrosion depth are present.

A Research on the Intelligent System of Plane Steel Gates

The classification of the main structure is introduced in Hydraulic flat steel gates intelligent design system, shape parameters, attributes parameters and constraints forms of basic components are established, and method of collection, storage and extraction of associated information in related components is invented. Grid line is selected as the skeleton-driven to make all components associated. The methods above-mentioned are used to construct the intelligent design system of Hydraulic flat steel gates, which is built on the Autodesk Inventor, and in which the computation, modeling, automatic detailing are combined, and which has broad application prospects after successful application of certain steel gate design project.

Establishment of Template Library for Data Graphics of Flat Steel Gate and the Application in Software

This article presents main structure of hydraulic flat steel gates, control parameters and constraint conditions in 3D Modeling and construction template library, featuring different hierarchies and levels and inclusive of graphics and associated information, for data graphics of flat steel gate. In the template library, components for template of every level are separable and assembled automatically, providing a flexible assembly and disassembly mode for a whole steel gate design. The template library can accumulate knowledge and experiences, thus greatly improving design efficiency and accuracy.

Study on Automatic Drawing and Dimension of Hydraulic Flat Steel Gates on Inventor

A method of automatic drawing and dimensioning for hydraulic flat steel gates, which determines the projection of 3D model and data in two-dimensional space by data graphic method, which orientates by local coordinate system, which automatic dimensions by Brep and location dimension, is presented. Automatic drawing program is written by VB.Net and C# on Inventor API, which can be directly used to practical engineering.

Determination of Technological Parameters of Vibratory Stress Relief for Radial Steel Gate Structure Based on Finite Element Method

In order to determining technological parameters and effective range of vibratory stress relief (VSR) treating for the radial steel gate structure, kinetic analysis was carried out according to the industrial standard. The natural frequency, vibration mode and the curves of amplitude-frequency were obtained by using Finite Element Analysis (FEA),which gave some suggestions for reference on how to determine the technological parameters for large-sized welding structures.

Structural Stress Based Fatigue Analysis Method for Plane Steel Gate

Though fatigue failure is often happened in steel gate, fatigue design has not yet been included in design or evaluation standards in China. In this paper, analytical theory based structural stress method and structural stress based fatigue analysis method are combined and employed for fatigue life evaluation of plane steel gate. The variation of water head is taken into consideration for the conditions of gate running and resting. In order to give a valid evaluation, the weld located among all components is considered as rigid connection when calculating structural stress. Master S-N curve in ASME code is used for life evaluation. Example shows the method can be used for fatigue analysis of plane steel gate, and can be used to identify fatigue failure zone.