Relevant bibliographies by topics / Blade-root

Academic literature on the topic 'Blade-root'

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Published: 14 March 2023

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Journal articles on the topic "Blade-root"

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Sal, Firat. "Analysis of combined passively and actively morphing blade root chord length and blade taper for helicopter control." Aircraft Engineering and Aerospace Technology 92, no. 2 (November 4, 2019): 172–79. http://dx.doi.org/10.1108/aeat-04-2019-0077.

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Purpose The purpose of this study is to examine the effect of passive and active morphing of blade root chord length and blade taper on the control effort of the flight control system (FCS) of a helicopter. Design/methodology/approach Physics-based helicopter models, which are functions of passive and active morphing, are created and applied in helicopter FCS design to determine the control effort. Findings Helicopters, having both passively and actively morphing blade root chord length and blade taper, experience less control effort than the ones having either only passively morphing blade root chord length or only blade taper or only actively morphing blade root chord length and blade taper. Practical implications Both passively and actively morphing blade root chord length and blade taper can be implemented for more economical autonomous helicopter flights. Originality/value Main novelty of our article is simultaneous application of passive and active morphing ideas on helicopter root chord length and blade taper. It is also proved in this study that using both passive and active morphing ideas on helicopter blade root chord and blade taper causes much less energy consumption than using either only passive morphing idea on helicopter blade root chord and blade taper or only active morphing idea on helicopter blade root chord and blade taper. This also reduces fuel consumption and also makes environment cleaner.
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Sal, Firat. "Effects of the actively morphing root chord and taper on helicopter energy." Aircraft Engineering and Aerospace Technology 92, no. 2 (December 16, 2019): 264–70. http://dx.doi.org/10.1108/aeat-08-2019-0165.

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Purpose The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS). Design/methodology/approach Via regarding previously mentioned purposes, sophisticated and realistic helicopter models are benefitted to examine the energy of the FCS. Findings Helicopters having actively morphing blade root chord length and blade taper consume less control energy than the ones having one of or any of passively morphing blade root chord length and blade taper. Practical implications Actively morphing blade root chord length and blade taper can be used for cheaper helicopter operations. Originality/value The main originality of this paper is applying active morphing strategy on helicopter blade root chord and blade taper. In this paper, it is also found that using active morphing strategy on helicopter blade root chord and blade taper reasons less energy consumption than using either passively morphing blade root chord length plus blade taper or not any. This causes also less fuel consumption and green environment.
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Amer, Kenneth B. "Technical Notes: Comment on the “Minimum Weight Design of Helicopter Rotor Blades with Frequency Constraints,” Journal of the American Helicopter Society, October, 1989." Journal of the American Helicopter Society 35, no. 2 (May 1, 1990): 69. http://dx.doi.org/10.4050/jahs.35.2.69.

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It appears that most of the weight saving from the reference blade to the minimum‐weight blade is in the region of the blade root. Undoubtedly, the reference blade requires this weight increase to accommodate the usual bending fatigue loads at the root. The authors do not address the question of how their minimum‐weight blade would handle blade‐root fatigue loads.
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Zhou, Peng Zhan, and Fang Sheng Tan. "Stress Characteristics Analysis on a Composite Wind Turbine Blade." Advanced Materials Research 602-604 (December 2012): 111–14. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.111.

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The stress characteristics on a composite wind turbine blade are analyzed by using a finite element method. The whole stress level of the spar cap and the blade root is higher than that of the shear web and the airfoil plate, so the spar cap and the blade root are the main force-supporting parts. If the stress concentration point on the interface corner between the blade root and the shear web is neglected, the stress of the spar cap is higher than that of the blade root, and its maximum stress and mean stress are 211 MPa and 180 MPa respectively. The maximum stress of the blade is only 34.8% of the tensile stress of the glass-fiber/epoxy composites. It indicates that the laminate structural design of the blade is inclined to be safety.
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Wiryolukito, Slameto. "Design Flaw Enhanced by Improper Workmanship to Cause Fatigue Failure on Rotor Blade of Compressor Gas Turbine." Applied Mechanics and Materials 660 (October 2014): 593–97. http://dx.doi.org/10.4028/www.scientific.net/amm.660.593.

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Ten stages of Compressor Engine S/N 123 of X-Gas Turbine failed in service prior the schedule for overhaul at 40,000 hour. At the failure event the running hour was 29,600. The maintenance was normally done every 8000 hours including filter and gasket replacement, instrument re-calibration, and bore scope examination. Upon dismantling, it was found one blade at rotor stage #3 failed with facture surface strongly indicated a fatigue failure, defective on stator and rotor blades at downstream, no defective blades at upstream. Detail examination confirm Root Cause of failure on Compressor Blade of X-Gas Turbine were combination of a sharp radius of root chamfer as the major contributor and at lesser extent enhanced by “scratches” exist on root blade free surface. There was no evidences Foreign Objects or corrosion contributed to fail the compressor blades. Blade material was sound and did not contribute to fail the blade. The recommendations to avoid failure reoccurrences were all existing installed rotor blades shall be dismantled and examined for the existence of crack at their root area. Inspection on brand new blades for the existence of scratches on blade surface prior assembly shall be strongly imposed; blade with preexisting scratch shall be rejected. In a design stages, increase the sharp chamfer radius on blade root is worth-while to be analyzed further. Workmanship during blade assembly shall not develop any scratch on blade surface especially on its root surface. A procedure and schedule for inspection on the running blades shall be refined to be able to detect any crack on the operating blades; special attention shall be given on root area.
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Hee, Lim Meng, M. Salman Leong, and K. H. Hui. "Blade Faults Classification and Detection Methods: Review." Advanced Materials Research 845 (December 2013): 123–27. http://dx.doi.org/10.4028/www.scientific.net/amr.845.123.

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Blade faults are ranked among the most frequent causes for gas turbine failures. This paper provides a review on the types of blade faults as well as its pertinent detection methods. In this paper, blade faults are categorized into five major groups according to their nature and characteristics namely, blade rubbing, blade fatigue failures, blade deformation, blade fouling, and blade root related problems such as cracked root and loose blade. This paper aims to provide an overview on the characteristics of each type of blade fault as well as its best detection methods available to date.
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Dong, Zheng Yan, and Han Long Zhang. "Study on Finite Element Model of Bolt Strength in Blade Root." Applied Mechanics and Materials 427-429 (September 2013): 221–24. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.221.

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This study has established a 1/184 model of blade root by using finite element software (ANSYS), and analyzed the stress pipeline and errors of this blade root model. By transforming the loads in blade root and imposing axial step load, especially by analyzing models boundary conditions and the structure of contact surface, the axial stress, bending stress and the other parameters have been acquired.
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Oktay, Tugrul, and Firat Sal. "Effect of the Simultaneous Variation in Blade Root Chord Length and Blade Taper on Helicopter Flight Control Effort." International Journal of Aerospace Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6325269.

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In this study, the effect of simultaneous variation in blade root chord length and blade taper on the control effort of helicopter flight control system (i.e., FCS) of a helicopter is investigated. Therefore, helicopter models (i.e., complex, control-oriented, and physics-based models) including the main physics and essential dynamics are used. The effect of simultaneous variation in the blade root chord length and blade taper (i.e., in both chordwise and lengthwise directions dependently) on the control effort of an FCS of a helicopter and also on the closed-loop responses is studied. Comparisons in terms of the control effort and peak values with and without variations in the blade root chord and blade taper changes are carried out. For helicopter FCS variance-constrained controllers, specific output variance-constrained controllers are beneficial.
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Zhang, Yi, Ming Hui Zhang, and Yong Hui Xie. "Turbine Blade Straddle Root and Rim Structural Optimization Using Finite Element Contact Analysis." Advanced Materials Research 753-755 (August 2013): 1453–56. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1453.

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The development of turbine blade root style is one of the key problems in the blade design technology as the root carries most of the loads of the whole blade. The optimal design problem and the corresponding numerical method were established for a straddle root structure with the minimum equivalent stress of the root and rim as the optimal objective. A multi-variable parametric model of the blade and rim, which took eight critical geometrical variables of the root and rim as design variables, was built by APDL (ANSYS parametric design language) and the optimal problem was numerically solved by combining pattern search algorithm with finite element method. The results indicate that the optimized structure has better strength performance, whose maximum equivalent stress of the root sharply decreased by 25.18% comparing with the original design. It eventually confirms the feasibility and validity of the proposed optimal design method.
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Li, Zhen, Bofeng Xu, Xiang Shen, Hang Xiao, Zhiqiang Hu, and Xin Cai. "Performance Analysis of Ultra-Scale Downwind Wind Turbine Based on Rotor Cone Angle Control." Energies 15, no. 18 (September 18, 2022): 6830. http://dx.doi.org/10.3390/en15186830.

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The theoretical feasibility of the power output strategy based on rotor cone angle control for ultra-scale downwind wind turbines is studied in this paper via the Open FAST simulation platform. The performance of five cases, namely UW, DW, DWC, DW6, and DW6IC, which have different rotor parameters or control strategies compared with the reference DTU 10 MW wind turbine, are calculated and analyzed. It is found that the downwind rotors have significant advantages in reducing the blade root load. The DW case reduces the peak load at the blade root by 22.54% at the cost of 1.57% annual energy production loss. By extending the length and redesigning the stiffness of the blade, the DW6 case achieves 14.82% reduction in the peak load at the blade root and 1.67% increase in the annual energy production under the same blade weight as that of the UW. The DWC case with rotor cone angle control has the same aerodynamic performance as the DW case with the same blade parameters. However, when the wind speed achieves or exceeds the rated speed, the blade root load decreases at a greater rate with the increasing wind speeds, and achieves minimum load with a wind speed of 16 m/s. Compared with the UW case, the DW6IC case with the improved rotor cone angle control reduces the peak load of the blade root by 22.54%, leading to an increase in annual energy production by 1.12% accordingly.
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Dissertations / Theses on the topic "Blade-root"

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Khattab, M. I. A. "Optimum rotor blade configurations for minimum oscillatory root bending moment." Thesis, City University London, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353959.

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Lutschinger, Dirk. "Turbulence consideration in wind turbine design and its effect on main shaft motion and blade root strain." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/911.

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This PhD research investigated the influence of turbulence effects on the vibration behaviour of wind turbines. A small laboratory scale wind turbine test facility was developed with special purpose instrumentation and sensors. Experimental investigations of the vibration behaviour of the turbine demonstrated the complexity of the displacements of the main rotor shaft and the strain at the roots of the rotor blade. This research will assist in the ongoing development of improved failure detection mechanisms.
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Hettasch, Georg. "Optimization of fir-tree-type turbine blade roots using photoelasticity." Thesis, Stellenbosch : University of Stellenbosch, 1992. http://hdl.handle.net/10019.1/993.

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Thesis (MEng.)-- University of Stellenbosch, 1992. 140 leaves on single pages, preliminary pages i-xi and numbered pages 1-113. Includes bibliography. Digitized at 600 dpi grayscale to pdf format (OCR),using an Bizhub 250 Konica Minolta Scanner and at 300 dpi grayscale to pdf format (OCR), using a Hp Scanjet 8250 Scanner.
Thesis (MEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 1992
ENGLISH ABSTRACT: The large variety of turbo-machinery blade root geometries in use in industry prompted the question if a optimum geometry could be found. An optimum blade root was defined as a root with a practical geometry which, when loaded, returns the minimum fillet stress concentration factor. A literature survey on the subject provided guidelines but very little real data to work from. An initial optimization was carried out using a formula developed by Heywood to determine loaded projection fillet stresses. The method was found to produce unsatisfactory results, prompting a photoelastic investigation. This experimental optimization was conducted in two stages. A single tang defined load stage and a single tang in-rotor stage which modeled the practical situation. The defined load stage was undertaken in three phases. The first phase was a preliminary investigation, the second phase was a parameter optimization and the third phase was a geometric optimization based on a material utilization optimization. This material optimization approach produced good results. From these experiments a practical optimum geometry was defined. A mathematical model which predicts the fillet stress concentration factor for a given root geometry is presented. The effect of expanding the single tang optimum to a three tang root was examined.
AFRIKAANSE OPSOMMING: Die groot verskeidenheid lemwortelgeometrieë wat in turbomasjiene gebruik word het die vraag na 'n optimum geometrie laat ontstaan. Vir hierdie ondersoek is 'n optimum geometrie gedefineer as 'n praktiese geometrie wat, as dit belas word, die mimimum vloeistukspanningskonsentrasiefaktor laat ontstaan. 'n Literatuur studie het riglyne aan die navorsing gegee maar het wynig spesifieke en bruikbare data opgelewer. Die eerste optimering is met die Heywood formule, wat vloeistukspannings in belaste projeksies bepaal, aangepak. Die metode het nie bevredigende resultate opgelewer nie. 'n Fotoelastiese ondersoek het die basis vir verdere optimeering gevorm. Hierdie eksperimentele optimering is in twee stappe onderneem. 'n Enkelhaak gedefineerde lasgedeelte en 'n enkelhaak in-rotor gedeelte het die praktiese situasie gemodeleer. Die gedefineerde lasgedeelte is in drie fases opgedeel. Die eerste fase was n voorlopige ondersoek. Die tweede fase was 'n parameter optimering. 'n Geometrie optimering gebasseer op 'n materiaal benuttings minimering het die derde fase uitgemaak. Die materiaal optimerings benadering het goeie resultate opgelewer. Vanuit hierdie eksperimente is 'n optimum praktiese geometrie bepaal. 'n Wiskundige model is ontwikkel, wat die vloeistukspanningskonsentrasiefaktor vir 'n gegewe wortelgeometrie voorspel. Die resultaat van 'n geometriese uitbreiding van die enkelhaaklemwortel na 'n driehaaklemwortel op die spanningsverdeling is ondersoek.
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Sanchez, Pena Adriano. "“Experimental Assessment of the Effectiveness of Active Flaps to Reduce the Blade Root Bending Moment of Wind Turbine Blades”." Thesis, KTH, Mekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194502.

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This thesis intends to asses the application of local flow control to wind turbines blades, in order to demonstrate that the normal root benging moment on the blades can be reduced, with the aim of increasing wind turbines life span, reducing regular maintenance and further to make a contribution to current research on wind turbines. It develops the subject by first assessing the flow characteristics of the Großer Windkannal (GroWiKa) in the Hermann-Föttinger Institute (HFI) at the Technical University of Berlin and continues with establishing the effectiveness of local flow control on the Reasearch Wind Turbine (BeRT) designed by the institute. It is divided into six chapters; the first chapter gives an overview of the literature review required, to study the different methodologies used during the experiments. In following the different experimental set-ups used will be explained, which will lead to the presentation of the different characteristics of the flow into the settling chamber of GroWiKa, so that its effects on the wind turbine can be evaluated by means of pitot tubes and hot-wires. Chapter 4 reflects the different effects of blockage calculated during the experiments and its corrections for a blockage of 40%, while chapter 5 gives an overview on the system dynamics of the flaps, where three servos has been used and compared with each other, in order to give an assesment on its effectiveness for the rotative system. The final chapter analyses the normal bending at the blade root, by yawing the wind turbine and setting the flaps into a simple prescribe motion, in pursuance of creating a 1 period disturbance and show how the normal bending at the root of the blade can be reduced by the action of local flow control. To this end it was found that the servo system was not effective enough to respond to sudden changes in the flow field. However, it will be shown that after accounting for the servos delay, it is possible to reduce the blade normal to rotor plane root bending moment up to 31%, when the correct phase shift is applied to the flap’s prescribed motion.
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Sousa, Isaac Diego Pereira de. "Design and testing Of blades for small wind turbines with different geometrical correction in root and tip of blade." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12320.

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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
The work aims to build , using the BEM (Blade Element Moment) theory , and test three wind rotors , each one consisting of three blades, which were constructed and used for assembling three SWT (Small Wind Turbine) with TSR (Tip Speed Ratio) equal to seven. The three rotors with blades of 2 meters length, distinguished themselves in their geometries as follows: 1) blades without any correction, 2) blades with only tip correction, 3) blades with only root correction. The NREL S809 airfoil developed by the U.S. National Renewable Energy Laboratory (NREL) was used. This airfoil is characterized by having been specially developed for wind turbines. The airfoil experimental data, such as the lift and drag coefficients as a function of angle of attack, were obtained based on wind tunnel test results for Reynolds number of 3 x 105. Also, field tests were conducted to collect torque in the main shaft of the wind rotor [N ∙ m], angular velocity [rad/s] and wind speed [m/s] data, using proper instrumentation and a data collection system. The data collected in the field for each turbine, were analyzed by statistical inference. The power coefficient data were grouped by TSR ranges, and was observed that the data of the last two ranges were the only intervals that showed a normal distribution of data of the Cp . These data were subjected to a one-way ANOVA. And the results showed no significant difference between the average of the rotors SC and CP. Already the data did not exhibit a normal distribution were analyzed by Exponentially Weighted Moving Average (MMEP). It was also observed that the three rotors showed no difference between the power coefficients, of the statistical point of view. An important finding of the experiments was that the CR blades had higher average values of power coefficients for each band TSR.
O trabalho visou construir, atravÃs da Teoria do BEM (Blade Element Moment), e testar trÃs rotores eÃlicos, cada um destes constituÃdos de trÃs pÃs, as quais foram construÃdas e aplicadas na montagem de trÃs TEPP (Turbinas EÃlicas de Pequeno Porte) com TSR (Tip Speed Ratio de projeto igual a sete. Os trÃs rotores, com pÃs de 2 metros de comprimento, distinguiram-se, em suas geometrias, do seguinte modo: 1) pÃs sem correÃÃo alguma, 2) pÃs com correÃÃo somente na ponta e 3) pÃs com correÃÃo somente na raiz. O aerofÃlio aplicado foi o NREL S809, desenvolvido pelo laboratÃrio norte americano de energias renovÃveis (NREL). Este aerofÃlio à caracterizado por ter sido projetado para uso especÃfico em turbinas eÃlicas. Os dados experimentais do aerofÃlio, como os coeficientes de sustentaÃÃo e arrasto em funÃÃo do Ãngulo de ataque, foram obtidos com base nos resultados de testes em tÃnel de vento para um nÃmero de Reynolds de 3 x 105. Realizou-se, tambÃm, testes em campo, utilizando-se de uma instrumentaÃÃo necessÃria para a coleta de dados de torque no eixo principal do rotor eÃlico [N.m], velocidade angular do rotor [rad/s], e velocidade do vento, por meio de um sistema de coleta de dados. Os dados colhidos em campo, de cada turbina, foram analisados por inferÃncia estatÃstica. Os dados de Cp foram agrupados por faixas de TSR, e observou-se que os dados das duas Ãltimas faixas foram os Ãnicos intervalos que apresentaram uma distribuiÃÃo normal de probabilidade dos dados de Cp . Estes dados foram submetidos a uma ANOVA com um fator. E os resultados mostraram que nÃo hà uma diferenÃa significativa entre as mÃdias dos rotores SC e CP. Jà os dados que nÃo apresentaram uma distribuiÃÃo normal foram analisados pela MÃdia MÃvel Exponencialmente Ponderada (MMEP). Verificou-se tambÃm que os trÃs rotores nÃo apresentaram diferenÃa entre os coeficientes de potÃncia, do ponto de vista estatÃstico. Uma importante constataÃÃo dos experimentos realizados foi a de que as pÃs CR apresentaram valores mÃdios de Cp superiores para cada faixa de TSR.
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Meijer, Gerrit Johannes. "New methods for in situ measurement of mechanical root-reinforcement on slopes." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/c8857b54-36cb-4e68-83b1-cf1e78df30d9.

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Vegetation can increase the resistance of slopes against landsliding. The mechanical contribution of roots to the shear strength of the soil is however difficult to measure in situ. Existing methodologies are time-consuming and therefore not suitable to quantify spatial variability on the slope. Furthermore, some existing methods, for example large in situ shear box testing, can be difficult to apply on remote sites with difficult access, e.g. steep slopes. Therefore in this thesis novel, simple and portable methods to quantify mechanical root-reinforcement in the field were developed. The ‘blade penetrometer method’, one of these new methods, was based on standard penetrometer testing but used an adapted tip shape to increase sensitivity to roots. Root depths and diameters could be quantified based on characteristics of the depth–resistance trace, both in the laboratory and in the field. Several new analytical interpretive models were developed to predict the force–displacement behaviour of roots loaded under various conditions: one assuming roots broke in tension and another assuming roots broke in pure bending. Both methods did take root–soil interaction into account. Based on these models, some roots were shown to have broken in bending and others in tension, depending on plant species and root diameter. Two new methods were developed to measure the root-reinforced soil strength directly. The ‘pin vane’ was an adaptation of a standard field shear vane, replacing the cruciform blades of the latter by prongs to minimise the effects of soil disturbance and root breakage during installation. This was one of the main problems encountered when using standard vanes in rooted soil. This ‘pin vane’ method was qualitatively shown to be able to measure the reinforcing effects of both fine and thick roots (or root analogues), both in the laboratory and the field. This method will be most useful when the strength of densely rooted surface layers is to be analysed, e.g. for erosion resistance purposes. Another newly developed shear device was the ‘corkscrew’. Rotational installation of the screw ensured minimal soil and root disturbance. During vertical extraction the root-reinforced shear strength was mobilised along the interface of the soil plug caught within the screw. The measured extraction force could be related to the reinforced soil strength. This method underestimated the strength in surface layers (especially at 0–125 mm and less so at 125–250 mm depth) but functioned well in deeper soil layers important for landsliding. Although laboratory results were promising, during in situ testing in deeper layers ( > 125 mm) local variation in soil stress, gravel content and water content, combined with low root volumes, made it difficult to accurately quantify the effect of the roots. Where the effect of roots was pronounced, e.g. in more heavily rooted surface layers (0–125 mm), significant positive trends between the measured soil strength and root strength and quantity were found. Measured reinforcements were small compared with various root-reinforcement model predictions but comparable to direct shear tests on rooted soil reported by others. These new methods, although still in the early stages of development, showed promising results for practical use in field conditions. The equipment was simple to use and portable, enabling measurements on sites with difficult accessibility. However, more work is required to validate the interpretive models developed and to calibrate these methods for a wider range of soil and root conditions.
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Wong, Vui-Hong, and n/a. "Finite Element Analysis and Improvement of Impeller Blade Geometry." Griffith University. School of Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030825.150853.

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Stratification of water in large reservoirs occurs in summer, or at anytime in hot climates where the water surface is exposed long-term to sunlight and the water surface is heated. Natural mixing will not occur due to the cooler and denser water always staying at the lower levels. Therefore, mechanical circulators are designed to prevent water quality problems related to stratification and depletion of dissolved oxygen. Impellers that produce the flow in mechanical circulators are available in different sizes and these impellers are designed to produce different flow rates. Due to hydraulic loadings, impellers have to be strong and durable. Loadings on impellers depend on their geometries and therefore, a durable impeller is a good combination of the use of correct materials and good geometry. Long and slender impellers are prone to failure when subjected to high hydrodynamic loadings. Nowadays, designers have very limited information on predicting the stresses on impellers and the deflection patterns of impellers because there are no design rules in designing these impeller blades and there is no such thing as "best geometry". A good impeller blade design is by guesswork and experience. In order to design the geometry that suits this application, trial-and-error finite element analyses have been conducted in this project to minimize stress levels on the blades. This research involves the use of finite element analysis (FEA) to predict stress and deflection of impeller blades used on large (5m diameter) ducted axial flow impellers as the first step in the design process. Then, based on the results, improvements have been done to the models until the final design was made. As far as the author has been able to determine, this has not been researched before. Finite Element Analysis has been used on wind turbine blades, rudders and hulls of boats but not on axial flow impeller blades of the type used in this project. For the purpose of this project, commercial finite element computer program packages STRAND6 and STRAND7 were used as the main analysis tools. A static line load increasing linearly with radius along the blade has been used to simulate the assumed hydrodynamic loading, and applied to all FEA blade models. The analysis results proved the stresses on blades are largely dependant on the blade geometry. From the analysis results, the author modified the stacking arrangement of the FEA elements in order to minimize both the tensile stresses and the displacements of the blades at the tip. Parametric studies have been done in order to obtain the best FEA impeller blade model.
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Цьонь, Олег Петрович, and O. P. Tsion. "Удосконалення конструкції дообрізувача гички цукрових буряків активного типу." Thesis, Тернопільський національний технічний університет ім. Івана Пулюя, 2014. http://elartu.tntu.edu.ua/handle/123456789/5432.

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Робота виконана у Тернопільському національному технічному університеті імені Івана Пулюя Міністерства освіти і науки України. Захист відбувся “ 27 ” січня 2015 року о “ 14 ” годині на засіданні спеціалізованої вченої ради Д 58.052.02 в Тернопільському національному технічному університеті імені Івана Пулюя за адресою: 46001, м. Тернопіль, вул. Руська, 56, аудиторія 79.
Удосконалення конструктивної схеми доочисника головок коренеплодів, який забезпечує підвищення показників надійності та якості виконання технологічного процесу, можливо досягти шляхом розроблення гичкозрізуючого пристрою з активним плоским ножем. Перевагою запропонованого конструктивного рішення, порівняно з активним дисковим ножем, є підвищена експлуатаційна надійність, значно менша маса та простота виготовлення.
Дисертацію присвячено питанням підвищення ефективності та надійності технологічного процесу дообрізування залишків гички з головок коренеплодів цукрових буряків на основі обґрунтування конструктивно-технологічних параметрів механізму дообрізувача гички активного типу. Теоретично досліджено: процес взаємодії активного плоского ножа з головками коренеплодів при режимі різання з ковзанням; НДС ножа при приведенні у рух; модель руху дообрізувача гички з активним робочим органом по рядках коренеплодів цукрових буряків; коефіцієнт ковзання в системі “коренеплід – плоский ніж”. Експериментально досліджено залежність сили різання головок цукрових буряків активним плоским ножем від робочої швидкості бурякозбирального агрегату; зворотно-поступальної швидкості ножа та товщини його леза; діаметра коренеплодів. Встановлено корозійний вплив на функціональну здатність конструкційних матеріалів ножів середовища соку цукрових буряків. Застосування запропонованої конструкції дообрізувача активного типу дозволить підвищити ефективність та надійність процесу доочищення головок коренеплодів цукрових буряків від залишків гички.
The thesis is dedicated to the problem of improving the efficiency and reliability of technological topping the residual tops of sugar beet crowns taking into consideration the structural and technological parameters of an active type topper. The following aspects are theoretically researched: interaction of an active flat knife with the root beet crowns in mode of cutting with sliding; tensely deformed status of that knife when moving; model of moving the topper with active working bodies along sugar root beets rows; coefficient of sliding in the system “root – flat knife”. The dependence of sugar beet crowns cutting force by means of active flat knife on the working speed of a beet harvester, as well as on the knife reciprocating speed, knife blade thickness, root diameter, is developed experimentally. The corrosion effect of beet juice on functional capability of knife structural materials is researched. The use of active type topper design will improve the efficiency and reliability of toping the sugar beet crowns.
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Chen, Li-ru, and 陳麗如. "Effects of Blade Root Angle of Attack and Blade Twist on Fan Performance and Flow Characteristics." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/88011204003200186188.

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碩士
國立臺灣科技大學
機械工程系
96
This study uses the STAR-CD, a commercial code of Computational Fluid Dynamics, to calculate and analyze the flow field characteristics and performance curve of an axial fan. The static grid is employed in the computation. A new computational approach other than the conventional simulation method, which is widely used by investigators, is developed. The flow field were obtained by changing the root angle, attack angle and blade torsion. Based on the data gathered from computer simulations, result show at least three emphases. First, the deviation of the calculated fan performance curve by using the new approach from the experimental results can attain a level less than 2%, which is a drastic improvement over that obtained by using the convention method. Second, during the separation, attach, vortex and recirculation flow at the surface of rotator blade, tip clearance and surface of stator blade will decay the fan’s performance. Such flow phenomenon dramatically decrease the worse performance of fan. Third, for the flow structure, changing the torsion angle will make the flow to become turbulent than changing the attack angle. Changing the fan’s attack angle guarantees better performance than changing the torsion angle.
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Anusonti-Inthra, Phuriwat. "Helicopter vibration reduction using cyclic variations in blade root stiffness." 1998. http://www.etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-194/index.html.

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Books on the topic "Blade-root"

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S, Reddy E., and United States. National Aeronautics and Space Administration., eds. Root damage analysis of aircraft engine blade subject to ice impact. [Washington, DC]: National Aeronautics and Space Administration, 1992.

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Root damage analysis of aircraft engine blade subject to ice impact. [Washington, DC]: National Aeronautics and Space Administration, 1992.

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Book chapters on the topic "Blade-root"

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Thomre, Muktai, and K. Ramesh. "Analysis of Crack Growth in Compressor Blade Root Subjected to Fatigue." In Challenges in Mechanics of Time Dependent Materials, Fracture, Fatigue, Failure and Damage Evolution, Volume 2, 109–13. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-29986-6_17.

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Allara, Marco, Stefano Zucca, and Muzio M. Gola. "Effect of Crowning of Dovetail Joints on Turbine Blade Root Damping." In Damage Assessment of Structures VII, 317–22. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-444-8.317.

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Bhamu, Rajesh K., Akash Shukla, S. P. Harsha, and Satish C. Sharma. "Vibration Response of Fir Tree Root Blades with the Variation in Fixing Condition on Blade Root Interfaces." In Lecture Notes in Mechanical Engineering, 881–87. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8025-3_83.

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Ramakrishnan, C. V., and M. A. W. Usmani. "Finite Element Modelling of Dynamic Contact Application for Blade Root Damping Estimation." In Computational Mechanics ’86, 385–92. Tokyo: Springer Japan, 1986. http://dx.doi.org/10.1007/978-4-431-68042-0_51.

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Thomre, Muktai, and K. Ramesh. "Evaluation of Fracture Parameters of Cracks in Compressor Blade Root Using Digital Photoelasticity." In Reliability, Safety and Hazard Assessment for Risk-Based Technologies, 557–66. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9008-1_46.

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Sirigu, M., E. Faraggiana, A. Ghigo, E. Petracca, G. Mattiazzo, and G. Bracco. "Development of a simplified blade root fatigue analysis for floating offshore wind turbines." In Trends in Renewable Energies Offshore, 935–41. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003360773-103.

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Fazeli Nahrekhalaji, A. R., M. Sohrabi, and S. M. Izadi. "Investigation of Influences of Wheel Speed on Root Geometrical Dimension of Gas Turbine Blade." In Proceedings of the 36th International MATADOR Conference, 101–4. London: Springer London, 2010. http://dx.doi.org/10.1007/978-1-84996-432-6_23.

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Doliński, Łukasz, Marek Krawczuk, and Arkadiusz Żak. "Damage Detection in the Wind Turbine Blade Using Root Mean Square and Experimental Modal Parameters." In Lecture Notes in Mechanical Engineering, 728–42. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8331-1_57.

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Schimke, D., Uwe T. P. Arnold, W. Geißler, R. Kube, and W. R. Splettstösser. "Active Rotor Control by Servo-Flap and Blade Root Control Recent Results from Flight Test and Wind Tunnel." In Notes on Numerical Fluid Mechanics (NNFM), 386–93. Wiesbaden: Vieweg+Teubner Verlag, 1999. http://dx.doi.org/10.1007/978-3-663-10901-3_50.

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Alarcón Cabana, Daniel J., Jie Yuan, and Christoph W. Schwingshackl. "A Novel Test Rig for the Validation of Non-linear Friction Contact Parameters of Turbine Blade Root Joints." In Nonlinear Structures & Systems, Volume 1, 215–26. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04086-3_29.

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Conference papers on the topic "Blade-root"

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KOTTAPALLI, SESI. "Blade root torsional dampers to reduce hub loads." In 33rd Structures, Structural Dynamics and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1992. http://dx.doi.org/10.2514/6.1992-2449.

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Akay, Busra, Carlos Ferreira, Gerard van Bussel, and G. Tescione. "Experimental Investigation of the Wind Turbine Blade Root Flow." In 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2010. http://dx.doi.org/10.2514/6.2010-641.

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Botto, Daniele, Veronica Iannotti, and Federica Cuccovillo. "Experimental Investigation of Friction Damping in Blade Root Joints." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-81663.

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Abstract The design of disk assemblies requires the capability to predict their dynamic behavior. To achieve this objective, knowledge of friction damping on the contact between blade and disk is of paramount importance. This paper proposes an experimental technique to measure the loss factor and the dynamics, in terms of natural frequencies, of blade-disk attachment. The free decay is used to infer the dynamic parameters from dummy blades. The identification method is based on the Hilbert transform that allows extracting the dynamic parameters from non-linear system. This paper shows the test rig utilized in the experimental analysis and details the excitation system used to displace the dummy blade. This system must be a real or a “virtual” non-contact system to avoid injecting external damping into the blade under test. Tests were performed on both a dovetail and a fir-tree type attachments. On the dovetail, tests were performed both with dry contact surfaces and with contact surfaces covered by a film of lubricant to achieve a low coefficient of friction. This low coefficient of friction better simulates dry surfaces at high temperatures, as friction coefficients decrease with temperatures. This paper presents the results obtained on the first and second bending mode. The experimental results show the loss factor and the natural frequency for different axial loads. The measured loss factor depends on the amplitude of vibrations. As predicted with theoretical analyses the loss factor shows a maximum then approaching zero for large amplitude of vibrations. As a rule, it decreases with increasing centrifugal loads.
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Šimurda, David, Martin Luxa, Pavel Šafařík, Jaroslav Synáč, and Bartoloměj Rudas. "Aerodynamic Data for Two Variants of Root Turbine Blade Sections for a 54″ Turbine Rotor Blade." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25323.

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Aerodynamic investigations were performed on planar blade cascades representing two alternative root sections of rotor blades 54″ in length with straight fir-tree root. Each of the variants was designed for different number of blades in the rotor. This paper presents the results of measurements showing the dependency of the kinetic energy loss coefficient and the exit flow angle on the exit isoentropic Mach number and the angle of incidence. Images of the flow fields are also presented. The experimental data is analyzed to assess and document the difference between the two root section designs. Results show that requirement of straight fir tree root leading to high design incidence angles significantly limit operation range. Also in case of root sections with high exit Mach numbers a limit load conditions are an issue. In order to utilize available pressure drop blade cascade throat/pitch ratios should be kept as high as possible which favorites variant with lower number of blades and higher outlet metal angle (relative to axial direction).
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Allara, Marco, Sergio Filippi, and Muzio M. Gola. "An Experimental Method for the Measurement of Blade-Root Damping." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90774.

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Stresses produced by vibrations reduce the life of turbo engine blades. The design of disk assemblies requires the capability to predict their dynamic behavior. In order to achieve this objective, knowledge of damping associated with the contact between blade and disk is fundamental. This paper proposes a technique to measure the influence of blade-disk attachment on the dynamics of turbo engine blades. Moreover, experimental values of damping and resonance frequencies are presented as a function of the amplitudes of vibration and of centrifugal load at the attachment.
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Gavelli, Filippo, Jude Foulds, Robert Sire, and Harri Kytomaa. "Root Cause Analysis of a Gas Turbine Compressor Stator Blade Failure." In ASME 2005 Power Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pwr2005-50125.

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Three identical 85 MW combustion turbines experienced cracking and failure of several first stage compressor stator (S1) blades. The root cause analysis involved the following distinct stages: 1. Examination of failed blades including fractography and analyses of the mechanics of their fracture; 2. Blade vibration analysis to determine the modes of vibration and corresponding resonant frequencies; 3. Inlet plenum flow and acoustical analysis to identify possible sources of excitation. This paper summarizes the methodology and results of the root cause analysis investigation and outlines the convergence of results obtained from the independently conducted mechanical and acoustical analyses.
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Gowda, Kumar K., S. L. Ajit Prasad, and Vinayaka Nagarajaiah. "Design Optimization of T-Root Geometry of a Gas Engine HP Compressor Rotor Blade for Lifing the Blade Against Fretting Failure." In ASME 2016 Power Conference collocated with the ASME 2016 10th International Conference on Energy Sustainability and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/power2016-59331.

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Stress Concentration Factor (SCF) is significant in machine elements as it gives rise to localised stresses which lead to peak stresses introducing cracks which propagate further and hence the component fails before the desired design life. Turbine blades are subjected to high centrifugal stresses and vibratory stresses in a Gas Engine HP Rotor. The vibratory stresses arise due to air wake flow excitations called Nozzle Passing Frequency (NPF). Hence, Turbomachinery industry calls for an optimum structurally rigid blade root geometry. An optimum blade root was defined, as a root with practical geometry, which when loaded returns the minimum fillet SCF. In the present work an approach has been done for design optimization of fillet stresses at sharp edges of T-root blade, optimization of platform dimensions, shank dimensions, root land dimensions and to ensure that stress distribution is uniformly spread along the filleted width of the root land on both sides of the blade, which otherwise will lead to crack initiation, propagation and hence, fretting failure at blade root lands. This may further lead to blade lift and effect on stage and overall gas engine failure over a period of cycles. Hence, a special attention is made on SCF of the T root -blade which fails and to guarantee for safe and reliable operation under all possible service conditions. Finite Element Analysis (FEA) is used to determine the fillet stresses and Peterson’s SCF chart is effectively utilized to modify the blade root. The root is modified due to the difficulty in manufacturing the butting surface of the tang which grips the blade to the disk crowns having small contact area. The blade height is suitably designed using Campbell diagram by ensuring the working frequency is well within 6e excitations for the specified operating speeds. Hence, increasing the life of the HP compressor blade.
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Guerrant, Dan, and Dale Lawrence. "Heliogyro Solar Sail Blade Twist Stability Analysis of Root and Reflectivity Controllers." In AIAA Guidance, Navigation, and Control Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2012. http://dx.doi.org/10.2514/6.2012-4842.

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Zucca, Stefano, Christian M. Firrone, and Muzio Gola. "A Method for the Calculation of Friction Damping in Blade Root Joints." In ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-24948.

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In turbomachinery, the complete detuning of turbine blades in order to avoid high cycle fatigue damage due to resonant vibration is often unfeasible due to the high modal density of bladed disks. To obtain reliable predictions of resonant stress levels of turbine blades, accurate modelling of friction damping is mandatory. One of the most common sources of friction damping in turbine blades is the blade root, where energy is dissipated by friction due to microslip between the blade and the disk contact surfaces held in contact by the centrifugal force acting on the blade. In this paper a method is presented to compute the friction forces occurring at blade root joints and to evaluate their effect on the blade dynamics. The method is based on an upgraded version of the state-of-the-art contact model, currently used for the non-linear dynamic analysis of turbine blades. The upgraded contact model is implemented in a numerical solver based on the harmonic balance method able to compute the steady-state dynamic response of turbine blades. The proposed method allows solving the static and the dynamic balance equations of the blade and of the disk, without any preliminary static analysis to compute the static loads acting at the contact interfaces.
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Simmons, Harold R., and Vishwas Iyengar. "Effect of Non-Uniform Blade Root Friction and Sticking on Disk Stresses." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46689.

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Stress levels predicted by conventional disk modeling assumptions are lower than expected to cause conventional creep or fatigue damage consistent with slot failures experienced in some compressor and turbine disks. It was suspected that disparate slot to slot friction at the blade root surface will result in sticking of some blade roots as the turbine is shut down while adjacent blades slip; the un-resisted stuck root would pry the steeples apart causing additional bending stress. Testing of a blade root/disk slot pair in a load frame found that the blade root will stick in place as imposed radial loads decrease. Simulation of blade root movement during shutdown indicates peak stress can increase by 20% or more depending on geometric factors. The slot stress only rises above its maximum speed condition on shutdown (at 80% Max Speed in the example case). This brief stress rise will not cause significant creep damage, but can shorten disk life based on low cycle fatigue or hold time fatigue damage.
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