Author: Aaron Paul Thaler Publisher: ISBN: Category : Languages : en Pages : 114
Book Description
Abstract: In this study, a high fidelity finite element model of a wind turbine gearbox is constructed in an advanced gear analysis program. The 3-dimensional fully elastic model is used to analyze motions and stresses occurring in a typical modern wind turbine gearbox. The model is validated using simple loading conditions by looking at shaft deflection and bearing stiffnesses. Analysis results are compared with experimental data provided by the National Renewable Energy Laboratory. Main shaft bending strain for multiple load levels is used to understand the effect of non-torque loads on the gearbox. Load distribution of the ring gear is evaluated experimentally by placing strain gages in the root of the gear tooth and compared with predictions from the finite element model. Since micro-pitting of the gears and bearings is a major failure mode of wind turbine gearboxes, the contact stresses and load distributions of the planetary gears and planet bearings are studied to understand the component's resistance to micro-pitting. These results seek to provide insight into possible ways to improve the life and reliability in the current wind turbine gearbox design.
Author: Qingkai Han Publisher: Springer ISBN: 9811027471 Category : Technology & Engineering Languages : en Pages : 168
Book Description
This book explores the dynamics and vibration properties of gearboxes, with a focus on geared rotor systems. It discusses mechanical theories, finite-element based simulations, experimental measurements and vibration signal processing techniques. It introduces the vibration-resonance calculation method for the geared rotor system in wind turbines and load sharing of the planetary gear train, and offers a method for calculating the vibrations of geared rotor systems under either internal excitations from gear sets or external loads transferred from wind loads. It also defines and elaborates on parameter optimization for planetary gear systems based on the torsional dynamics of wind-turbine geared rotor systems. Moreover, it describes experimental measurements of vibrations on the wind-turbine gearbox performed on the test rig and on site, and analyzes the vibration signals of different testing points, showing them in both time and frequency domains. Lastly, it lists the gear coupling frequencies and fault characteristic frequencies from the vibrations of the gearbox housing. The technologies and results presented are valuable resources for use in dynamic design, vibration prediction and analysis of gearboxes and geared rotor systems in wind turbines as well as many other machines.
Author: Przemyslaw Litewka Publisher: Springer Science & Business Media ISBN: 3642129404 Category : Science Languages : en Pages : 175
Book Description
Phenomena occurring during a contact of two bodies are encountered in everyday life. In reality almost every type of motion is related to frictional contact between a moving body and a ground. Moreover, modeling of simple and more complex processes as nailing, cutting, vacuum pressing, movement of machines and their elements, rolling or, finally, a numerical simulation of car crash tests, requires taking contact into account. Therefore, its analysis has been a subject of many research efforts for a long time now. However, it is author’s opinion that there are relatively few efforts related to contact between structural elements, like beams, plates or shells. The purpose of this work is to fill this gap. It concerns the beam-to-beam contact as a specific case of the 3D solids contact. A numerical formulation of frictional contact for beams with two shapes of cross-section is derived. Further, a couple of effective methods for modeling of smooth curves representing beam axes are presented. A part of the book is also devoted to analyze some aspects of thermo-electro-mechanical coupling in contact of thermal and electric conductors. Analyses in every chapter are illustrated with numerical examples showing the performance of derived contact finite elements.
Author: Publisher: ISBN: Category : Languages : en Pages : 20
Book Description
An experimental study to investigate the bending stress in aerospace-quality spiral bevel gears was performed. Tests were conducted in the NASA Lewis Spiral Bevel Gear Test Facility. Multiple teeth on the spiral bevel pinion were instrumented with strain gages and tests were conducted from static (slow roll) to 14400 RPM at power levels to 540kW (720 hp). Effects of changing speed and load on the bending stress were measured. Experimental results are compared to those found by three-dimensional finite element analysis.
Author: G. Sander Publisher: ISBN: Category : Boundary value problems Languages : en Pages : 330
Book Description
Extensive comparison studies were run on different idealizations and on the use of different types of finite elements for the analysis of a single spar, a rectangular section box beam, a multispar swept wing and a centrally loaded rectangular plate. The results indicate that the principle of a dual analysis, with its capability to provide upper and lower bounds to the structural deflections, is of practical value. Convergence in the deflection pattern, from above and from below, is equally satisfactory. Convergence and evaluation of the stress output is sometimes more difficult. However, the more sophisticated elements generate stresses that are simpler to interpret and less sensitive to the geometrical subdivision pattern. The report contains the theory of the conforming displacement models and stress-diffusing equilibrium models required for obtaining strain energy bounds, with a description of the models that were operational in the numerical studies. It also contains a description of the ASEF, direct stiffness type, program.
Author: Siamak Amini Publisher: Springer Science & Business Media ISBN: 3642517277 Category : Technology & Engineering Languages : en Pages : 116
Book Description
This text considers the problem of the dynamic fluid-structure interaction between a finite elastic structure and the acoustic field in an unbounded fluid-filled exterior domain. The exterior acoustic field is modelled through a boundary integral equation over the structure surface. However, the classical boundary integral equation formulations of this problem either have no solutions or do not have unique solutions at certain characteristic frequencies (which depend on the surface geometry) and it is necessary to employ modified boundary integral equation formulations which are valid for all frequencies. The particular approach adopted here involves an arbitrary coupling parameter and the effect that this parameter has on the stability and accuracy of the numerical method used to solve the integral equation is examined. The boundary integral analysis of the exterior acoustic problem is coupled with a finite element analysis of the elastic structure in order to investigate the interaction between the dynamic behaviour of the structure and the associated acoustic field. Recently there has been some controversy over whether or not the coupled problem also suffers from the non-uniqueness problems associated with the classical integral equation formulations of the exterior acoustic problem. This question is resolved by demonstrating that .the solution to the coupled problem is not unique at the characteristic frequencies and that it is necessary to employ an integral equation formulation valid for all frequencies.
Author: Aaron Paul Thaler
Author: Qingkai Han
Author: Przemyslaw Litewka
Author: 
Author: G. Sander
Author: G. D. Bibel
Author: M. A AUTOR CRISFIELD
Author: Siamak Amini
Author: Juilung Julian Hsu
Author: