Parts Of Blades Research Articles

Novel Engineered Materials: Epoxy Resin Nanocomposite Reinforced with Modified Epoxidized Natural Rubber and Fibers for Low Speed Wind Turbine Blades.

The objective of this study was to investigate nanocomposite materials with good outdoor resistance for wind turbine blade application. The nanocomposites based on epoxy resin with 5% of epoxidized natural rubber (ENR 50), 3% of nanofiller, and glass fibers, were subjected to experiments. The weathering resistance of nanocomposites was evaluated from the change in mechanical properties caused by accelerated aging, induced by UVB radiation in a weathering chamber. The accelerated aging improved tensile strength by about 35% at 168 h of exposure to UVB, via a curing effect. The nanocomposites were optimized for all the parts of wind turbine blades (Savonius and Darrieus types) that are generally designed for high strength, low weight, weathering resistance, and low rotational speed (2 m/s). A tree wind turbine with nanocomposite blades produced 5 kW power output when tested. Based on the findings in this work, the innovative nanocomposites have potential in manufacturing wind turbines to generate electricity.

Creep characteristics of directionally solidified turbine blades based on the difference in original casting characteristics

Due to the difference between original material and the processed material for use in turbine blades, research that solely focuses on the original materials may not fully explain the performance of operational turbine blades. In order to ensure the maximum utilization rate of turbine blades, the study examines the creep properties and differences of different parts of the directional solidification of original casting turbine blades. In this article, a set of sampling fixtures from different parts of a turbine blade were proposed to quantitatively measure the difference in creep properties caused by the complex geometric factors created during the DS process. The special fixtures would cut the blades into five different parts, which were to be further processed into small samples. Creep tests under two different conditions (980 °C/245 MPa, 980 °C/267 MPa) were carried out. Round rod specimens (standard parts) were used for creep tests under the same conditions for comparison. By employing scanning electron microscopic (SEM) and creep tests on different parts of original casting turbine blades, the mechanism of microstructure evolution and the creep fracture behavior were proposed in this condition. In addition, the original microstructure of different parts of a blade was observed by scanning electron microscopy (SEM), and the characteristics of the different parts were simulated based on an improved two-parameter creep constitutive model. The results suggest that the creep life of the different parts of the original casting blade is different, which caused by the differences in microstructure and morphology of the different parts of the original casting blade. The creep property of standard parts is better than that of original casting blades. The creep life of original casting blades from small to large is as follows: CVS, DP, LE, CCS, TT. An improved two-parameter creep constitutive model was adopted to simulate the difference in creep properties (including creep life) resulted from different parts in a turbine blade. This difference needs to be considered in designing the structure and service life of turbine blades formed by directional solidification. The research results are of great significance for improving the design of directionally solidified turbine blades and for improving the directional solidification forming process.

Towards understanding Cameraria ohridella (Lepidoptera: Gracillariidae) development: effects of microhabitat variability in naturally growing horse-chestnut tree canopy

Dwelling intensity of horse-chestnut miner (Cameraria ohridella) larvae in various leaves insolation and temperature was measured to determine whether this pest’s development follows a predictable pattern or depends more on local microenvironment conditions. Mines growing on leaves of mature host plants (Aesculus hippocastanum L.) in their natural conditions were photographed for two consecutive generations of the pest and in two separated vegetation periods. Apart from meteorological data obtained from the nearest station, the temperature of intact and mined parts of sun-exposed and shaded leaf blades was measured at various daytimes throughout the experiment. Obtained sets of digital data were analysed and combined to model mine area growth as a function of degree-days sum by adopting of Verhulst logistic equation. We showed the predictive potential of our model based on experimental data, and it may be useful in the scheduling of pest control measures in natural conditions. Our analyses also revealed that despite significant differences in microenvironment conditions depending on mines’ insolation, the horse-chestnut miner larvae could partially compensate for them and complete their development at similar endpoints expressed as the cumulative sum of degree-days. We conclude that computer-aided analysis of photographic documentation of leaf-miner larval growth followed by mathematical modelling offers a noninvasive, reliable, and inexpensive alternative for monitoring local leaf-miners populations.

Vibrational Stresses of Damaged Steam Turbine Blades After Renovation Repair

The last-stage blades of K-1000-60/3000 steam turbines operate in a humid steam environment, which causes erosion damage in the blades and reduction in their residual life. The relevance of this work is related to the need to continue the safe operation of such turbine blades. A number of variants of the finite-element models of individual blades and last-stage blades in the disk-blade systems of the above turbines are considered. Results of the numerical study of the influence of blade part removals in erosion damage zones after renovation repair on the vibration characteristics of individual blades and blades in the disk-blade system are presented. An analysis of the stress-strain state under the conditional load from the steam flow during the forced oscillations of individual blades and blades in the disk-blade system is carried out. The loads are given as evenly distributed and linearly variable on blade surfaces. The dependence of the maximum equivalent vibration stresses on excitation frequency is determined. It is assumed that the physical and mechanical properties of the blade material are preserved (as for the original version) after the renovation repair of blades and processing of their surfaces. There is a significantly greater reduction in the vibration stresses of blades in the disk-blade system than in the stresses of individual blades. Graphs of the dependence of the maximum stresses on excitation frequency both for undamaged individual blades and blades in the disk-blade system after their renovation repair are given. Various variants of blade part removals in areas of blade leading and trailing edges are considered. It is shown that with decreasing chords of blades after renovation repair, frequency regions of increased vibration may appear in lower blade parts. In the lower parts of individual blades and blades in the disk-blade system, the maximum stresses increase in comparison with their values in undamaged blades. With the change in the stress-strain state of rotor blades in comparison with the original version of undamaged blades, the possibility of extending their safe lifetime in case of multi-cycle fatigue is assessed. The safe lifetime of the considered blades with a chord of at least 150 mm after their renovation repair can be extended according to their stresses, if the cyclic symmetry of the disk-blade system is not violated, and the physical and mechanical properties of the material are preserved after the processing of damage removal zones on blade trailing edges.

Стоянка Очью катище на р. Ижма

The Mesolithic archaeological site Ochyu katishche is located on the right bank of the Izhma river in the environs of the village Tom of the Izhma region of the Komi Republic. It is located on the pine forested terrace with a height of 12,5 m. The site was discovered in 2017 and then surveyed in 2018-2019. At the archaeological site the concentration of finds was revealed, where there was a joint occurrence of flint artefacts and a large number of faunal remains of good preservation, including small bones and fragments of large bones and horns, that were identified. The bones of beaver absolutely predominated, the bones of reindeer and elk were also found. There were single fragments of the bones of lynx and marten, as well as those of birds. The presence of a large number of segments and fragments of very large blades was noted. Short proximal segments and middle parts of large blades with irregular edge retouch and small burin spalls were serially presented. The cores in the final knapping stage and the so-called core-burins were presented. According to these indicators, the material of the site Ochyu katishche is similar to the collections of Mesolithic horizons of the archaeological site Vylys Tom 2, located 2 km to the north. Both sites are included in the so-called Izhma-Tom geoarchaeological microregion, where there are other Mesolithic sites with fundamentally different technical and typological indicators of the industry. These are the sites of Lek-Lesa 1, Turunnyur 1 and Ulys Tom 4.

Automated X-ray computer tomography segmentation method for finite element analysis of non-crimp fabric reinforced composites

In this study a complete procedure is presented of how to generate finite element models based on X-ray computer tomography data on the fibre bundle scale for non-crimp fabric reinforced composites. Non-crimp fabric reinforced composites are nowadays extensively used in the load carrying parts of wind turbine blades. Finite element analysis based on X-ray computer tomographic data will allow faster and cheaper developments of key material parameters. However, automated procedures for computer tomography data transfer into finite elements models are lacking. In the current study, an X-ray computer tomography aided engineering (XAE) process including a fully automated segmentation method and an element-wise material orientation mapping of X-ray computer tomographic data is presented for the first time. The proposed methodology combines recent research progress and improvements in image analysis, and provides a fast, accurate and repeatable data transfer and analysis process with a high degree of automation.

Development of Parametric Design Software for Shearer Spiral Drum

In order to improve the design efficiency of the shearer drum and achieve rapid optimization, it is proposed to establish a parametric design system for the shearer spiral drum centered on design, optimization system and parametric modeling technology. The overall idea of implementing the system, the function and design analysis of each module are expounded, and the key technologies are discussed. Using Solidworks as the platform, the parametric design of the shearer spiral drum was developed with VB.Net, including the modification of the drum size, the automatic drawing of the cutting diagram, the load calculation of the pick and the automatic generation of the loading blade parts and their unfolding engineering drawings. Finally, it was verified with a 1800x630 roller. Tests prove that the system can quickly optimize the shearer drum, improve the speed and accuracy of drum development, and reduce costs.

Effect of Foreign Object Damage at Different Impact Parts for TC4 Titanium Alloy Blades

The effect of foreign object damage at different impact parts of TC4 Titanium Alloy blades is studied in this paper and impact damage from common foreign objects at different parts of the inlet side of the blade has been simulated in the process of aircraft skidding using the ANSYS/LS-DYNA software based on the Kinematic hardening plastic constitutive model. The results show that the damage depth of the sandstone increases linearly with the increase of relative kinetic energy when the same foreign object strikes different parts, but there is a critical relative kinetic energy of 2.54J and 2.50J for the steel ball and screw, respectively. When the relative kinetic energy is less than the critical value, the damage depth increases continuously with the relative kinetic energy, and when the relative kinetic energy is greater than the critical value, the damage depth decreases continuously with the relative kinetic energy.

Micro-chronology of Palaeolithic open-air sites: The model

This paper presents the model dealing with the micro-chronology of Palaeolithic open-air sites based on the curation of blade parts and on patterns in wind direction. The production of tools and the spatial replacement of blade parts within a given site or between different sites, as well as redepositional processes, are considered through the set of equations. The utility of the model is confirmed by its test on Late Palaeolithic Federmesser and Swiderian materials from Lubrza 10 in western Poland. Instead of a widely-spread clear-cut synchronization of all flint concentrations belonging to the same cultural unit, the model confirms the more gradual relocation of people within a Swiderian camp.

The study of deformation of the blade parts of tillage after their electro arc

Annotation Purpose. Establishment of the relationship between the deformation of the blade parts of tillage and design parameters after electro arc. Methods. Planning an experiment, mathematical statistics and analytical processing of experimental data. Results. The dependences of the deformation of the blade parts of tillage equipment on the design parameters after their recovery and hardening by electro arc are established. Conclusions 1. It has been established that the magnitude of the deformation Δ, mm of the part of tillage, is inversely depends on the thickness δ after hardening. 2. It has been established that the magnitude of the deformation Δ, mm of the part of tillage, is inversely dependent on the width B after hardening. 3. The rational modes of electro arc were established when hardening parts of tillage with a thickness of 4–10 mm, a width of 20 mm to 60 mm and a length of 230 mm to 500 mm, namely, a current of 350–400 A, a voltage of 50–55 V and a temperature cooling medium in the bath of the installation for simultaneous electro arc sharpening and hardening – 20–60 °С. Such rational modes of electro arc ensure the absence of deformation of parts of tillage less than 5 mm, which is permissible according to the requirements of regulatory, technical and design documentation. Keywords: deformation, length, operation, electro arc, hardening, parts of tillage, thickness, width.

Параметры высоковольтных разрядов на лопастях винтов вертолета и создаваемых ими электромагнитных помех

Abstract Parameters of pulsed electric discharges arising between insulated metal parts of helicopter rotor blades, which generate electromagnetic interferences for onboard radio stations operating in the very short wave (VSW) and ultrashort wave (USW) bands have been studied. These discharges appear as a result of the in-flight engine-driven differential charging of helicopters. In-flight and laboratory experiments were used to determine the range of discharge voltages and currents and the amplitude and spectral characteristic of electromagnetic interferences produced by these discharges for onboard antennas.

Experimental and numerical investigation on gas turbine blade with the application of thermal barrier coatings

The engine parts material used in gas turbines (GTs) should be resistant to high-temperature variations. Thermal barrier coatings (TBCs) for gas turbine blades are found to have a significant effect on prolonging the life cycle of turbine blades by providing additional heat resistance. This work is to study the performance of TBCs on the high-temperature environment of the turbine blades. It is understood that this coating will increase the lifecycles of blade parts and decrease maintenance and repair costs. Experiments were performed on the gas turbine blade to see the effect of TBCs in different combinations of materials through the air plasma method. Three-layered coatings using materials INCONEL 718 as base coating, NiCoCrAIY as middle coating, and La2Ce2O7 as the top coating was applied. Finite element analysis was performed using a two-dimensional method to optimize the suitable formulation of coatings on the blade. Temperature distributions for different combinations of coatings layers with different materials and thickness were studied. Additionally, three-dimensional thermal stress analysis was performed on the blade with a commercial code. Results on the effect of TBCs shows a significant improvement in thermal resistance compared to the uncoated gas turbine blade.

The Effect of Some Physical and Mechanical Properties of Cermet Coating on Petroleum Pipes Prepared by Thermal Spray Method

The cermet materials have wide industrial applications, one of which is the protection of damaged petroleum pipelines as a result of working and environmental conditions coated with those materials. The current research aims to treat damaged parts of petroleum pipes, turbine blades and other parts of the devices which are exposed to heat and damage. Using thermal spray method with different spraying distances (8, 10, 12, 14 and 16 cm), the coating material ensures the foundation (TiO2) and supportive material (Al–Ni) with supportive ratios (25, 35, 50 and 65%) for the formation of cermet coatings. Physical tests (porosity and adhesion force) as well as mechanical (hardness and wear rate), compositional tests (atomic force microscope) were conducted for only 2 h before and after heat treatment (1000 °C) The results showed that the best supportive ratio is 50% and the best spray distance is 12 cm at heat treatment (1000 °C) for 2 h, where the porosity gave a magnitude of 8.1% and adhesion force of 27.6 Mpa, the hardness is 42.4 Hv and the lowest wear rate at the sliding speed is 4.5 m/s. Meanwhile, atomic force microscope clarification to be the best topographical surface was at the same standard conditions mentioned above. Microscopic hardness was also calculated at different temperatures (450, 650, 850, 950, 1150 °C). It was observed that the best hardness value was with heat treatment at 950 °C.

Risk Assessment and Value of Action Analysis for Icing Conditions of Wind Turbines Close to Highways

The paper presents research results from the Marie Skłodowska-Curie Innovative Training Network INFRASTAR in the field of reliability approaches for decision-making for wind turbines and bridges. This paper addresses the application of Bayesian decision analysis for installation of heating systems in wind turbine blades in cases where an ice detection system is already installed in order to allow wind turbines to be placed close to highways. Generally, application of ice detection and heating systems for wind turbines is very relevant in cases where the wind turbines are planned to be placed close to urban areas and highways, where risks need to be considered due to icing events, which may lead to consequences including human fatality, functional disruptions, and/or economic losses. The risk of people being killed in a car passing on highways near a wind turbine due to blades parts or ice pieces being thrown away in cases of over-icing is considered in this paper. The probability of being killed per kilometer and per year is considered for three cases: blade parts thrown away as a result of a partial or total failure of a blade, ice thrown away in two cases, i.e., of stopped wind turbines and of wind turbines in operation. Risks due to blade parts being thrown away cannot be avoided, since low strengths of material, maintenance or manufacturing errors, mechanical or electrical failures may result in failure of a blade or blade part. The blade (parts) thrown away from wind turbines in operation imply possible consequences/fatalities for people near the wind turbines, including in areas close to highways. Similar consequences are relevant for ice being thrown away from wind turbine blades during icing situations. In this paper, we examine the question as to whether it is valuable to put a heating system on the blades in addition to ice detection systems. This is especially interesting in countries with limited space for placing wind turbines; in addition, it is considered if higher power production can be obtained due to less downtime if a heating system is installed.

STRESS AND VIBRATION ANALYSES OF THE WIND TURBINE BLADE (A NREL 5MW)

Owing to the fast development in the energy filed, the demand is increasing to improve energy efficiency and lifetime of wind turbine. Therefore, it's important to understand deeply the behavior of wind turbine under different load conditions. This research paper provides an approach to study and analyze the stresses and deformations under the steady-state condition. Also, it was investigated the vibration characteristics of the NREL offshore 5-MW blade (HAWT) with a long of (61.5 m) and with rotor diameter (126 m). The 3D model of wind turbine blade was created by using SOLIDWORKS and then exported to ANSYS/Workbench19 in order to achieve the numerical simulation based on Finite element method. The steady-state analysis of the selected wind turbine blade was performed at maximum rated power (maximum rotation velocity =12.1 rpm). In this work, three different materials (E-glass fiber, Kevlar, and Carbon fiber reinforced plastic) were selected to build the body of the wind blade parts. The results presented the von-Mises stresses, total deformations, first ten natural frequencies and mode shapes of NREL 5-MW wind turbine blade. In steady-state analysis, it was found that the optimum material was (CFRP) where the minimum level of stresses occurred. In vibration analysis, it was found the material that has a higher structural stiffness is CFRP material which avoids high frequencies and mode shapes.

Neutron diffraction analyses of Bronze Age swords from the Alpine region: Benchmarking neutron diffraction against laboratory methods

Bronze Age swords represent the peak of craftsmanship in terms of prehistoric weapon production. Following an extensive study on the manufacture and usage of Bronze Age swords from the Alpine region, we have used non-destructive time-of-flight neutron diffraction to analyse a selection of bronze swords. The diffraction patterns were used to determine the phase compositions and crystallographic textures of the copper tin alloys, in order to reveal information about the working treatment at different parts of the sword blades. Neutron diffraction analyses are benchmarked against results from reference bronze samples, as well as against X-ray fluorescence and metallographic analyses applied to the same objects. Comparing different working intensities of cold working in various areas of the sword blades can lead to information about the usage of the swords as mainly thrusting or as cut-and-thrust used weapons.

Concepts for Reusing Composite Materials from Decommissioned Wind Turbine Blades in Affordable Housing

The very rapid growth in wind energy technology in the last 15 years has led to a rapid growth in the amount of non-biodegradable, thermosetting fiber reinforced polymer (FRP) composite materials used in wind turbine blades. This paper discusses conceptual architectural and structural options for recycling these blades by reusing parts of wind turbine blades in new or retrofitted housing projects. It focuses on large-sized FRP pieces that can be salvaged from the turbine blades and can potentially be useful in infrastructure projects where harsh environmental conditions (water and high humidity) exist. Since reuse design should be for specific regional locations and architectural characteristics the designs presented in this paper are for the coastal regions of the Yucatan province in Mexico on the Gulf of Mexico where low-quality masonry block informal housing is vulnerable to severe hurricanes and flooding. To demonstrate the concept a prototype 100 m long wind blade model developed by Sandia National Laboratories is used to show how a wind blade can be broken down into parts, thus making it possible to envision architectural applications for the different wind blade segments for housing applications.

On extracting mechanical properties from nanoindentation at temperatures up to 1000 °C

Alloyed MCrAlY bond coats, where M is usually cobalt and/or nickel, are essential parts of modern turbine blades, imparting environmental resistance while mediating thermal expansivity differences. Nanoindentation allows the determination of their properties without the complexities of traditional mechanical tests, but was not previously possible near turbine operating temperatures.Here, we determine the hardness and modulus of CMSX-4 and an Amdry-386 bond coat by nanoindentation up to 1000 °C. Both materials exhibit a constant hardness until 400 °C followed by considerable softening, which in CMSX-4 is attributed to the multiple slip systems operating underneath a Berkovich indenter.The creep behaviour has been investigated via the nanoindentation hold segments. Above 700 °C, the observed creep exponents match the temperature-dependence of literature values in CMSX-4. In Amdry-386, nanoindentation produces creep exponents very close to literature data, implying high-temperature nanoindentation may be powerful in characterising these coatings and providing inputs for material, model and process optimisations.

Effects of short blades on performance and inner flow characteristics of a low-specific-speed centrifugal pump

A low-specific-speed centrifugal pump equipped with long and short blades is studied. Emphasis is placed on the pump performance and inner flow characteristics at low flow rates. Each short blade is intentionally shifted towards the back surface of the neighboring long blade, and the outlet parts of the short blades are uniformly shortened. Unsteady numerical simulation is conducted to disclose inner flow patterns associated with the modified design. Thereby, a comparison is enabled between the two schemes featured by different short blades. Both practical operation data and numerical results support that the deviation and cutting of the short blades can eliminate the positive slope of pump head curve at low flow rates. Therefore, the modification of short blades improves the pump operation stability. Due to the shortening of the outlet parts of the short blades, velocity distributions between impeller outlet and radial diffuser inlet exhibit explicitly altered circumferential flow periodicity. Pressure fluctuations in the radial diffuser are complex in terms of diversified periodicity and amplitudes. Flow rate influences pressure fluctuations in the radial diffuser considerably. As flow rate decreases, the regularity of the orbit of hydraulic loads exerted upon the impeller collapses while hydraulic loads exerted upon the short blades remain circumferentially periodic.

Indirect Morphogenesis and Regenerative Ability of Tissues of Rosa Damascena Mill

Obtaining of morphogenic callus of Lan variety of ROSA and formation of the regenerant plants from callus tissues is a necessary issue nowadays. For the research we used Rosa Damascena Mill. variety of Ukrainian selection Lan. For obtaining of the callus tissue we used sterile leaf plates and parts of stems with axillary buds cultured in nutrient media with the addition of the various groups of cytokinins and auxins. Plant tissue was stained with hematoxylin by Heidenhain and acetofuxin. Plant material was recorded for 24 hours by Chamberlain's method. We have obtained the following results. Firstly, on the medium, the beginning of the callusogenesis of aromatic rose's explants was recorded on parts of leaf plates after 7-9 days, and for microstems – 10-14 days of cultivation. Later callus was subcultured on the nutrient media, supplemented with growth regulators – BAP, NAA, IAA and TDZ. Visually, the first signs of the morphogenesis of callus culture were fixed on the 2nd day of cultivation. The differentiation of cells and the formation of callus tissue of morphogenic structures is largely dependent on the concentration and ratio of growth regulators that under relevant competences of cells stimulate processes hemogenesis. Analysis of experimental data shows that usage of only BAP in the MS medium did not lead to the initiation of the morphogenic callus formation. Secondly, under the influence of hormonal stimuli callus tissues actively formed on the basal parts of shoots of explants and on the surfaces of leaves contacting to the culture medium that contained the required components for the cell proliferation. Thus under these conditions the organogenesis occurs de novo, the first metameres, with absence of the necessary environment, biochemical and spatial disorder carry out the signs of teratogenesis. As a result of conducted studies we have determined that in Lan variety callus begins to form twice as actively in the parts of the leaf blades than in stem parts. Morphogenic zones in the system of callus cells of Rosa Damascena Mill. are represented as meristemoids. Primary bodies have limited growth; however they perform an important function: actively take part in photosynthesis, form hormones and growth regulators that are required for normal development.