scholarly journals Experimental Evaluation of the Effects of Structural Changes on the Vibration Properties of CK35 Steel

2021 ◽  
Vol 15 (2) ◽  
pp. 53-57
Author(s):  
Navid Moshtaghi Yazani
Keyword(s):  
Power Plants ◽  
Structural Changes ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Damping Coefficient ◽  
Jet Engines ◽  
Modal Test ◽  
Long Run ◽  
Ferrite Structure ◽  
Non Destructive

Abstract The microstructure of some components which operate in high-temperature conditions (e.g. boiler components, turbine blades used in gas power plants, jet engines and reactors) is subjected to changes in long run, which leads to a degradation in the mechanical properties of these components and consequently, reduces their lifecycle. Therefore, it is so useful to detect the changes in the microstructure of these parts during their operation, employing an easy, fast and non-destructive method to determine their remaining life. In this study, we evaluate the effects of the microstructural changes on natural frequencies and the damping coefficient of CK35 steel, employing the experimental modal test. We aim to use the method for power plant components, if it has significant effects. To do so, we applied spheroidization heat treatment on CK35 steel samples having a primary structure of ferrite-pearlite for 24 and 48 hours. Then, we carried out the experimental modal test on samples having different metallurgical structures, but with the same dimensions and weights. According to the findings, the spherical ferrite-carbide particles in the ferrite structure increase the natural frequencies and damping coefficient. These tests show that the structural changes in this type of steel result in slight changes in the values of natural frequencies; however, it significantly changes the damping frequencies.

Magnetic Particle Inspection of Turbine Blades in Power Generating Plants

1992 ◽  
Author(s):  
Clement Imbert ◽  
Krishna Rampersad
Keyword(s):  
Preventive Maintenance ◽  
Gas Turbines ◽  
Power Plants ◽  
Magnetic Particle ◽  
Martensitic Stainless Steel ◽  
Turbine Blades ◽  
Magnetic Particle Inspection ◽  
Optimum Placement ◽  
Non Destructive ◽  
Defect Detectability

Modern societies expect and depend on regular, relatively uninterrupted, supply of electric power. Preventive maintenance is therefore vital for power generating plants. Non-Destructive Evaluation (NDE) is a significant element of the maintenance programme of power plants. Power plants use a wide variety of steam and gas turbines. Turbine failure can occur without warning and with disastrous results. Such failures are invariably caused by cracks. Such defects are readily detected by NDE techniques such as Magnetic Particle Inspection (MPI) if they are on or near the surface and accessible. This paper reports on the use of MPI in the examination of martensitic stainless steel turbine blades in power plants in Trinidad and Tobago so as to quantify the testing parameters and determine field strength in relation to defect detectability. Specific recommendations are made regarding the configuration and optimum placement of magnetizing coils for turbine blade inspection insitu and detached.

New Developments in High Temperature Materials 21 Project in Japan

2005 ◽  
Author(s):  
Hiroshi Harada ◽  
Junzo Fujioka
Keyword(s):  
High Temperature ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Jet Engines ◽  
High Temperature Materials ◽  
Design Program ◽  
Temperature Capability

Following the Kyoto Conference on Climate Change (COP3) held in 1997, the improvement of thermal efficiency in power engineering systems is becoming a major issue. In High Temperature Materials 21 Project at NIMS, materials for turbine blades and vanes are being developed to improve the temperature capability and reduce the CO2 emission of industrial gas turbines (IGT) and jet engines. The target for Ni-base superalloys was set at 1100°C for 1000h creep rupture life under 137MPa to realize ultra-efficient combined cycle power plants and advanced jet engines. A high cost-performance single crystal (SC) superalloy TMS-82+ with 1075°C temperature capability has been developed and tested in a 15MW IGT. A 4th generation SC superalloy TMS-138 exhibiting 1080°C temperature capability has also been developed and tested in a 1650°C test jet engine. TMS-138 is to be applied in the Japanese eco-engine project for 50-seater jet airplanes. A further control of the interfacial dislocation network resulted in a 5th generation SC alloy TMS-162 with 1105°C temperature capability. A virtual gas turbine (VT), which is a combination of materials design program and system design program, is being developed and becoming a powerful tool as an interface between material scientists and system engineers. Using VT, air-cooled blades with our SC superalloys have been evaluated up to 1700°C gas temperature, and a substantial improvement in thermal efficiency of a combined-cycle power generation system has been indicated.

scholarly journals Electron Microscopy Characterization of the High Temperature Degradation of the Aluminide Layer on Turbine Blades Made of a Nickel Superalloy

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3240
Author(s):  
Mariusz Bogdan ◽  
Witold Zieliński ◽  
Tomasz Płociński ◽  
Krzysztof Jan Kurzydłowski
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Turbine Blades ◽  
Nickel Superalloy ◽  
Rotor Blades ◽  
Jet Engines ◽  
Destructive Testing ◽  
Alumina Layer ◽  
Microscopy Characterization ◽  
Aluminide Layer

The effects of exposure to overheating (temperature above 1000 °C) on the degradation (modification) of layers of coatings (coatings based on aluminum) of uncooled polycrystalline rotor blades of aircraft turbine jet engines were investigated under laboratory conditions. In order to determine the nature of the changes as well as the structural changes in the various zones, a multi-factor analysis of the layers of the coating, including the observation of the surface of the blades, using, among others, electron microscopy, structural tests, surface morphology, and chemical composition testing, was carried out. As a result of the possibility of strengthening the physical foundations of the non-destructive testing of blades, the undertaken research mainly focused on the characteristics of the changes occurring in the outermost layers of the coatings. The obtained results indicate the structural degradation of the coatings, particularly the unfavorable changes, become visible after heating to 1050 °C. The main, strongly interacting, negative phenomena include pore formation, external diffusion of Fe and Cr to the surface, and the formation and subsequent thickening of Fe-Cr particles on the surface of the alumina layer.

Combination of optical metrology and non-destructive testing technology for the regeneration of aero engine components

2021 ◽  
Vol 88 (4) ◽  
pp. 237-250
Author(s):  
Nils Melchert ◽  
Maximilian K.-B. Weiss ◽  
Tim Betker ◽  
Wojciech Frackowiak ◽  
Renè Gansel ◽  
...  
Keyword(s):  
Turbine Blades ◽  
Regeneration Process ◽  
Detailed Knowledge ◽  
Jet Engines ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Before And After ◽  
Testing Technology ◽  
Engine Components ◽  
Non Destructive

Abstract The maintenance and repair of jet or gas turbine components has a considerably high share in the overall turbine operating costs. The authors deal with the regeneration process of complex capital goods considering jet engines as an example, with turbine blades being the most important components to be regenerated. In order to decide on a reasonable and economical regeneration path, maintenance approaches typically require detailed knowledge of the shape and wear condition of the components. In order to select suitable repair strategies for each component, the best possible knowledge about geometry, damages and surface topologies is necessary. In order to meet these requirements, a novel combination of non-destructive testing and measuring methods will be presented. Each process can be adapted for inline operation. The presented methods also enable quality control of the regenerated components that have completed their individual regeneration path. Due to the high variety of possible defects on turbine blades, the individually presented methods can be combined to form an inspection sequence. Detailed status monitoring before and after maintenance becomes possible for each component. This provides the basis for further decisions in the regeneration process.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu
Keyword(s):  
Shear Modulus ◽  
Arc Welding ◽  
Natural Frequencies ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cored Wire ◽  
Flux Cored Arc Welding ◽  
Longitudinal Elastic Modulus ◽  
Vibration Tests ◽  
Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

scholarly journals Fractal Nature of Advanced Ni-Based Superalloys Solidified on Board the International Space Station

2021 ◽  
Vol 13 (9) ◽  
pp. 1724
Author(s):  
Vojislav Mitić ◽  
Cristina Serpa ◽  
Ivana Ilić ◽  
Markus Mohr ◽  
Hans-Jörg Fecht
Keyword(s):  
International Space Station ◽  
Fractal Analysis ◽  
Power Plants ◽  
Materials Science ◽  
Structural Characteristics ◽  
Turbine Blades ◽  
Space Station ◽  
Casting Process ◽  
Cross Sectional ◽  
International Space

Materials science is highly significant in space program investigation, energy production and others. Therefore, designing, improving and predicting advanced material properties is a crucial necessity. The high temperature creep and corrosion resistance of Ni-based superalloys makes them important materials for turbine blades in aircraft engines and land-based power plants. The investment casting process of turbine blades is costly and time consuming, which makes process simulations a necessity. These simulations require fundamental models for the microstructure formation. In this paper, we present advanced analytical techniques in describing the microstructures obtained experimentally and analyzed on different sample’s cross-sectional images. The samples have been processed on board the International Space Station using the MSL-EML device based on electromagnetic levitation principles. We applied several aspects of fractal analysis and obtained important results regarding fractals and Hausdorff dimensions related to the surface and structural characteristics of CMSX-10 samples. Using scanning electron microscopy (SEM), Zeiss LEO 1550, we analyzed the microstructure of samples solidified in space and successfully performed the fractal reconstruction of the sample’s morphology. We extended the fractal analysis on the microscopic images based on samples solidified on earth and established new frontiers on the advanced structures prediction.

scholarly journals Novel Application and Validation of a Method to Assess Visual Impacts of Rotating Wind Turbine Blades Within Woodland Areas

2021 ◽  
Vol 89 (1) ◽  
pp. 1-14
Author(s):  
U. Nopp-Mayr ◽  
F. Kunz ◽  
F. Suppan ◽  
E. Schöll ◽  
J. Coppes
Keyword(s):  
Environmental Impact ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Power Plants ◽  
Laser Scanning ◽  
Forest Canopy ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Environmental Impact Assessments ◽  
Independent Field

AbstractIncreasing numbers of wind power plants (WPP) are constructed across the globe to reduce the anthropogenic contribution to global warming. There are, however, concerns on the effects of WPP on human health as well as related effects on wildlife. To address potential effects of WPP in environmental impact assessments, existing models accounting for shadow flickering and noise are widely applied. However, a standardized, yet simple and widely applicable proxy for the visibility of rotating wind turbines in woodland areas was largely lacking up to date. We combined land cover information of forest canopy extracted from orthophotos and airborne laser scanning (LiDAR) data to represent the visibility of rotating wind turbines in five woodland study sites with a high spatial resolution. Performing an in-situ validation in five study areas across Europe which resulted in a unique sample of 1738 independent field observations, we show that our approach adequately predicts from where rotating wind turbine blades are visible within woodlands or not. We thus provide strong evidence, that our approach yields a valuable proxy of the visibility of moving rotor blades with high resolution which in turn can be applied in environmental impact assessments of WPP within woodlands worldwide.

scholarly journals A Vibration-Based Structural Health Monitoring System for Transmission Line Towers

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 515 ◽  
Author(s):  
Long Zhao ◽  
Xinbo Huang ◽  
Ye Zhang ◽  
Yi Tian ◽  
Yu Zhao
Keyword(s):  
Structural Health Monitoring ◽  
Transmission Line ◽  
Natural Frequency ◽  
Health Monitoring ◽  
Structural Changes ◽  
Natural Frequencies ◽  
Transmission Tower ◽  
Health Monitoring System ◽  
Wind Speeds ◽  
Before And After

In this paper, we present a vibration-based transmission tower structural health monitoring system consisting of two parts that identifies structural changes in towers. An accelerometer group realizes vibration response acquisition at different positions and reduces the risk of data loss by data compression technology. A solar cell provides the power supply. An analyser receives the data from the acceleration sensor group and calculates the transmission tower natural frequencies, and the change in the structure is determined based on natural frequencies. Then, the data are sent to the monitoring center. Furthermore, analysis of the vibration signal and the calculation method of natural frequencies are proposed. The response and natural frequencies of vibration at different wind speeds are analysed by time-domain signal, power spectral density (PSD), root mean square (RMS) and short-time Fouier transform (STFT). The natural frequency identification of the overall structure by the stochastic subspace identification (SSI) method reveals that the number of natural frequencies that can be calculated at different wind speeds is different, but the 2nd, 3rd and 4th natural frequencies can be excited. Finally, the system was tested on a 110 kV experimental transmission line. After 18 h of experimentation, the natural frequency of the overall structure of the transmission tower was determined before and after the tower leg was lifted. The results show that before and after the tower leg is lifted, the natural frequencies of each order exhibit obvious changes, and the differences in the average values can be used as the basis for judging the structural changes of the tower.

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