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Stress Prediction In Turbine Blades Under Forced Excitation
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Book Synopsis Stress Prediction in Turbine Blades Under Forced Excitation by :
Download or read book Stress Prediction in Turbine Blades Under Forced Excitation written by and published by . This book was released on 2016 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traditional turbine blades have root attachments which are sites of fretting fatigue failures due to the frictional sliding of the blades during vibration. Newer integrally bladed rotors (IBR) eliminate the root attachment by manufacturing the rotor disk and blades as a unitized structure. IBRs eliminate sites of fretting fatigue failure but in doing so they also eliminate frictional damping that is provided by the root attachments. The absence of frictional damping leads to larger forced-response vibration amplitudes and premature high-cycle fatigue failure in IBRs. Furthermore, IBRs also tend to exhibit blade vibrations in simultaneous multiple modes. Including these multi-mode vibration responses in estimating blade stress is critical for accurately estimating life of the blade. Conventional methods to estimate blade stresses during engine tests subjected to the forced-responses rely on vibration strain measurement techniques that measure surface strains using strain gauges. Frequency decomposition of these strain gauge data provides information on which modes are excited. The peak stress is computed using the measured strain amplitude for the particular mode and previously computed gauge factors. Strain measurement techniques are intrusive in nature and can only provide the response of the instrumented blade. Recently non-intrusive techniques such as blade tip timing (BTT) analysis have been used to measure the tip amplitude of the vibrating blade and this in conjunction with modal stresses obtained from finite element analysis can be used to estimate the peak stresses on the blade due to multi-mode excitation. This thesis demonstrates a time-domain stress superposition method, combined with a search over spatial and temporal coordinates to estimate the peak blade stresses that occur due to multi-mode excitation. A critical stress limit surface is also developed for use by test engineers in ground vibration tests to implement safety limits based on measured BTT vibration amplitudes and phase angles.
Book Synopsis Stress Analysis of Rotating Propellers Subject to Forced Excitations by :
Download or read book Stress Analysis of Rotating Propellers Subject to Forced Excitations written by and published by . This book was released on 2015 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbine blades experience vibrations due to the flow disturbances. These vibrations are the leading cause for fatigue failure in turbine blades. This thesis presents the finite element analysis methods to estimate the maximum vibrational stresses of rotating structures under forced excitation. The presentation included starts with the derived equations of motion for vibration of rotating beams using energy methods under the Euler Bernoulli beam assumptions. The nonlinear large displacement formulation captures the centrifugal stiffening and gyroscopic effects. The weak form of the equations and their finite element discretization are shown. The methods implemented were used for normal modes analyses and forced vibration analyses of rotating beam structures. The prediction of peak stresses under simultaneous multi-mode excitation show that the maximum vibrational stresses estimated using the linear superposition of the stresses can greatly overestimate the stresses if the phase information due to damping (physical and gyroscopic effects) are neglected. The last section of this thesis also presents the results of a practical study that involves finite element analysis and redesign of a composite propeller.
Book Synopsis Turbine Blade Life Estimation by : J. S. Rao
Download or read book Turbine Blade Life Estimation written by J. S. Rao and published by Alpha Science Int'l Ltd.. This book was released on 2000 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: The blade life estimation is a multifaceted technology, involving free and forced vibration forces, that lead to the determination of steady and dynamic stresses at different critical speeds during the startup and shutdown procedures, as well as in the operational speed range. Propagation and unstable fracture are described with practical examples to estimate blade life.
Book Synopsis Turbomachine Blade Vibration by : J. S. Rao
Download or read book Turbomachine Blade Vibration written by J. S. Rao and published by New Age International. This book was released on 1991 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue Failures Of Blades Is One Of The Most Vexing Problems Of Turbomachine Manufacturers, Ever Since The Steam Turbine Became The Main Stay For Power Generating Equipment And Gas Turbines Are Increasingly Used In The Air Transport. The Problem Is Very Complex, Involving The Excitation Due To Aerodynamic Stage Interaction; Damping Due To Material Deformation, Friction At Slip Surfaces And Aerodynamic Damping; Vibration Of An Asymmetric Aerofoil Tapered Along Its Length And Mounted On A Rotating Disc At A Stagger Angle. The Problem Is Also Governed By Heat Transfer Analysis And Thermal Stresses.His Book Deals With A Basic Understanding Of Free Vibratory Behaviour Of Turbine Blades- Free Standing, Packetted, And Bladed-Discs. The Analysis Is Based On Continuous And Discrete Models Using Energy Principles And Finite Element Techniques. A Clear Understanding Of The Interference Phenomenon In A Thin Cambered Airfoil Stage In Subsonic Flow Is Presented To Determine The Nonsteady Excitation Forces Acting On The Blades. A Comprehensive Treatment On The Blade Damping Phenomenon That Occurs In Turbines Is Given. The Nonlinear Damping Models Account For Material Damping And Friction Damping As A Function Of Rotational Speed For Each Mode. Resonant Response Calculation Procedures For The Steadily Running As Well As Accelerating Blades Are Given.Cumulative Damage Calculations Are Then Outlined For Fatigue Life Estimation Of Turbomachine Blades. The Book Also Deals With Heat Transfer Analysis And Thermal Stress Calculations Which Help In A Comprehensive Understanding Of The Blade Problems.
Book Synopsis Advances in wind turbine blade design and materials by : A.P. Vassilopoulos
Download or read book Advances in wind turbine blade design and materials written by A.P. Vassilopoulos and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue life prediction of wind turbine rotor blades is a very challenging task, as blade failure is led by different failure types that act synergistically. Inherent defects like wrinkles, fiber misalignments and voids, that can be introduced during fabrication, can constitute potential damage initiation points and rapidly develop to failure mechanisms like matrix cracking, transverse-ply cracking, interface cracking, debonding, fiber breakage, etc. Different methods have been established to address this problem, some based on phenomenological and others on actual damage mechanics modeling. This chapter aims to provide an overview of fatigue life modeling and prediction methodologies for the composite materials and structural composite elements that compose a wind turbine rotor blade under complex loading conditions.
Book Synopsis The Prediction of Temperature and Stress Patterns in Cooled Turbine Blades and the Estimation of Blade Life by : D. B. James
Download or read book The Prediction of Temperature and Stress Patterns in Cooled Turbine Blades and the Estimation of Blade Life written by D. B. James and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Stress Analysis and Life Prediction of Gas Turbine Blade by : H. C. Hsiung
Download or read book Stress Analysis and Life Prediction of Gas Turbine Blade written by H. C. Hsiung and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Prediction of Periodic Forced Response of Frictionally Constrained Turbine Blades by : Jin-Jae Chen
Download or read book Prediction of Periodic Forced Response of Frictionally Constrained Turbine Blades written by Jin-Jae Chen and published by . This book was released on 1999 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Forced Response Prediction for Industrial Gas Turbine Blades by :
Download or read book Forced Response Prediction for Industrial Gas Turbine Blades written by and published by . This book was released on 2006 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Turbomachinery turbine blade vibratory stress prediction by : Mario Guerra
Download or read book Turbomachinery turbine blade vibratory stress prediction written by Mario Guerra and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fatigue Life Estimation of Turbine Blades Due to Transient Thermal, Vibratory, and Centrifugal Stresses by : Deepak Dhar
Download or read book Fatigue Life Estimation of Turbine Blades Due to Transient Thermal, Vibratory, and Centrifugal Stresses written by Deepak Dhar and published by . This book was released on 1994 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1988 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Finite Element Stress Analysis of Turbine Blade Hooks by : Thiripuramadevi Venkatesan Balasubramanian
Download or read book Finite Element Stress Analysis of Turbine Blade Hooks written by Thiripuramadevi Venkatesan Balasubramanian and published by . This book was released on 1970 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fatigue Data Editing for Blades of Horizontal Axis Wind Turbines by : Pratumnopharat Panu
Download or read book Fatigue Data Editing for Blades of Horizontal Axis Wind Turbines written by Pratumnopharat Panu and published by LAP Lambert Academic Publishing. This book was released on 2015-11-12 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: In predicting performance of wind turbines, the blade element momentum (BEM) theory is still commonly used by wind turbine designers and researchers. This book deals with several up-to-date models added to the BEM theory to get more realistic prediction. In evaluating fatigue damage of wind turbine blade, stress-life approach and Miner's linear cumulative damage rule are mentioned. Wind turbine blades are the most critical components of HAWT. Full-scale blade fatigue testing is required to verify that the blades possess the strength and service life specified in the design. Unfortunately, the test must be run for a long time period. This problem led the blade testing laboratories to accelerate fatigue testing time. To achieve the objective, two novel methods called STFT- and WT-based fatigue damage part extracting methods are used to generate the edited stress-time history. Blade testing laboratories can use this history to accelerate fatigue testing time. STFT- and WT-based fatigue damage part extracting methods proposed in this book are suggested as alternative methods in accelerating fatigue testing time, especially for the field of wind turbine engineering.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Prediction of High and Low Engine Order Forced Responses for a Low Pressure Turbine Blade by : M. Vahdati
Download or read book Prediction of High and Low Engine Order Forced Responses for a Low Pressure Turbine Blade written by M. Vahdati and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
