Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration最新文献

{"title":"Modal Identification for Integrally Bladed Rotors Under Traveling Wave Excitation","authors":"Joseph A. Beck, Jeffrey M. Brown, Daniel L. Gillaugh, A. Kaszynski","doi":"10.1115/gt2022-83204","DOIUrl":"https://doi.org/10.1115/gt2022-83204","url":null,"abstract":"\u0000 The safety of a fielded Integrally Bladed Rotor (IBR) is often assessed through vibration testing. Responses due to various types of excitation are measured and processed and can be inputs to follow-on analyses, such as mistuning identification. One such excitation technique is the Traveling Wave Excitation (TWE) where all blades are simultaneously excited at phase differences that attempt to replicate naturally occurring mode shapes and certain operating conditions. This test relies on non-contact exciters, e.g. magnets and speakers, that are often not directly measured. As a result, formulating the Frequency Response Function (FRF) is difficult and the extraction of system modal data using FRF fitting techniques in the absence of FRFs is not possible. This paper presents an approach to use measured responses from TWE tests. It is shown that the Fast Fourier Transform (FFT) of the TWE inputs are mostly independent over the prescribed frequency range. Consequently, the output spectral density matrix can be formulated in an Operational Modal Analysis (OMA) sense, where direct measurement of the inputs is not needed. A full spectral density matrix is then formulated from a single measurement on each blade obtained during a single test, thus reducing the number of measurement locations and testing excitation conditions. This matrix is fit by a Polyreference-Least Squares Complex Frequency-domain (P-LSCF) system identification technique tailored for OMA-type measurements. The methodology is tested using simulated TWE data for an IBR model using different damping levels. Comparisons between identified modal data and those used to create the model are made and show the methodology accurately predicts underlying system information even for closely-spaced modes that are common to IBRs. Finally, the method is used on experimental TWE data of an industrial IBR.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129526208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Characterization of the OSU Rotor 67 Blisk for Future Damping and Mistuning Studies at Design Speed","authors":"C. Keener, Kiran D’Souza","doi":"10.1115/gt2022-82717","DOIUrl":"https://doi.org/10.1115/gt2022-82717","url":null,"abstract":"\u0000 To facilitate experimentation in the field of gas turbine disk dynamics, a new integrally bladed disk, or blisk, was designed and manufactured for use at The Ohio State University (OSU) Gas Turbine Laboratory. The blisk was designed using methods following the Federal Aviation Administration Code of Federal Regulations for safety analysis. Both the airfoils and the hub of the OSU blisk are realistic to accurately represent hardware in jet engines, while being publicly available for analysis to provide a design and data sets that can be published without the need to normalize and protect proprietary information.\u0000 After the blisk was manufactured, it was inspected and dynamically tested using a roving modal hammer. The natural frequencies and mistuning of each airfoil were calculated, and the finite element model was updated with this information. Knowledge of the natural frequencies and mistuning are important for the design of ring dampers that will be used to dampen vibration of the blisk during rotating testing.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"370 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131645356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation and Investigation of an Intentionally Mistuned Blisk Rotor in a High Pressure Compressor","authors":"Jingjie Yang, B. Beirow, T. Giersch","doi":"10.1115/gt2022-82576","DOIUrl":"https://doi.org/10.1115/gt2022-82576","url":null,"abstract":"\u0000 In modern aircraft engines, the blade integrated disk (blisk) technology is widely implemented. While the blisk design brings numerous advantages including weight reduction, aerodynamic efficiency improvement, and manufacturing simplification, its low mechanical damping due to the absence of friction between disk and blades makes the rotor more susceptible to vibration. Given that damages to blisk rotors sometimes require the whole assembly to be replaced, effort has been made to alleviate the unexpected vibration amplitude within operating range, among which intentional mistuning is regarded as one of the commonly used techniques. Mistuning refers to blade-to-blade deviation of mechanical properties, which is inevitable in practice due to manufacturing tolerances or wear. Through the application of intentional mistuning, it is expected that the amplitude of synchronous or non-synchronous vibration (NSV) will be reduced without severely losing aerodynamic performance.\u0000 In this paper, the effect of intentional mistuning has been investigated for the blisk rotor of a 1.5-stage transonic research compressor at Technical University of Darmstadt. According to the previous test campaign, the baseline rotor has shown its susceptibility to NSV due to the first torsion mode in the near stall region. Attempts have been made to alleviate this problem by using intentional mistuning. In order to have a comprehensive understanding of the effect of the applied mistuning pattern, simulations were performed using a finite-volume-method (FVM) based CFD solver to produce comparable results as shown in the test campaign. In the simulation, mistuned systems were modeled in comparison with the nominal tuned reference. Geometrical disturbance and frequency disturbance were introduced to the tuned model first separately and then simultaneously. In this way, the contribution of aerodynamic and structural mistuning to suppress NSV is identified based on the aeroelastic output.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123520942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical Behaviour of Variable Nozzle Guide Vane Systems Based on Full-Scale Testing","authors":"G. Macoretta, B. Monelli, P. Neri, F. Bucciarelli, Enrico Giusti, D. Checcacci, Gianfranco Maffulli","doi":"10.1115/gt2022-83241","DOIUrl":"https://doi.org/10.1115/gt2022-83241","url":null,"abstract":"\u0000 A full-scale test bench for the analysis of frictional and modal behavior of Nozzle Guide Vanes (NGV) is an advanced tool enabling high design accuracy for these components equipped in an increasing number of turboexpanders. This sub-assembly is a key feature enabling operational flexibility for the expander. Great attention must be paid during the NGV’s design to the natural frequencies of its kinematic chain, which are influenced by internal clearances and by friction. In this paper the results of a testing campaign performed on an NGV assembly employing actual blade geometry are presented together with details concerning the test bench commissioning and set-up procedure. The testing campaign involves three different combinations of blade orientation and pre-load corresponding to typical design conditions of the expander. In addition, two different bushing clearances values corresponding to worn out conditions were investigated. The measurements of the global friction coefficient based on actuator force detection are summarized. After that, the reconstruction of mode shapes based on experimental modal analysis is explained. The results highlight the importance of loading conditions on the actual value of friction force and their influence on blade natural frequencies. The testing campaign was used to properly validate Finite Element Models to be used for further investigations.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123552016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of New Numerical Analysis Tools for Nonlinear Forced Response in Anisotropy-Mistuned Bladed Disks With Friction Joints","authors":"Adam Koscso, A. Hartung, E. Petrov","doi":"10.1115/gt2022-82040","DOIUrl":"https://doi.org/10.1115/gt2022-82040","url":null,"abstract":"\u0000 New numerical tools ContaDyn and InterDyn have been developed at University of Sussex for the analysis of nonlinear forced response for tuned and anisotropy mistuned bladed disks with friction contact interfaces. The tools offer capabilities for calculating the nonlinear forced response and its sensitivity with respect to the anisotropy orientation variation of single crystal blades in tuned and mistuned bladed disk assemblies. The calculation method is based on the high-accuracy reduction techniques and the multi-harmonic balance method.\u0000 A comprehensive validation campaign has been done to validate these numerical capabilities. The calculated nonlinear forced responses are compared with the experimental values obtained for different bladed disk configurations and excitations. The friction contact interfaces at blade roots, blade shrouds and under-platform dampers are considered. For the validation, the measurement data, that were obtained earlier at MTU Aero Engines AG using their rotating test rig, are used. The vibratory measurements were carried out with the contact-less expected time-of-arrival method allowing capturing the vibratory amplitudes for all blades in a mistuned bladed disk assembly.\u0000 The nonlinear forced response for tuned and anisotropy mis-tuned bladed disks have been calculated for four different resonances and compared with the minimum, maximum and mean values of the measured amplitudes. Moreover, the individual blade forced response levels obtained from measurements and calculations are compared with the maximum amplitude distributions in the mistuned bladed disks. Parametric studies considering the number of harmonics used in the multiharmonic representation of periodic response, the number of mode shapes, the contact stiffness and friction coefficient values have been performed.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129948455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Linear Numerical Simulation of Pre-Loaded Turbine Blades With Frictional Shroud Contact Under Dynamic Conditions","authors":"Hugo de Filippis, F. Thouverez, L. Blanc, P. Girard, F. Chevillot","doi":"10.1115/gt2022-79918","DOIUrl":"https://doi.org/10.1115/gt2022-79918","url":null,"abstract":"\u0000 In a process of permanent innovation and increase of turbojet efficiency, the low pressure turbine is designed to run at higher rotational speed in future engines. Such an evolution requires a precise evaluation of their effects on dynamic behavior of the turbine. Low-pressure turbine blades in aeronautical industry are generally composed of a shroud, whose main purpose is to keep the tightness of the primal air stream, but it produces in consequence a mechanical damping into the dynamic response of the full blade turbine assembly through frictional contacts. Depending on the industrial design choices, the geometry of these blades can induce a pre-torsion effect which will straighten the shrouds during the assembly process, in this way they are brought into contact and the blades are pre-loaded. Predicting the dynamic behavior of such structure and calculating forced responses is a major challenge considering the complexity involved. The numerical model used in this article is based on the geometry of a test bench which was designed to reproduce the pre-torsion assembly loading on the blades through a geometrical interpenetration, and to evaluate the dynamics of the contact between the shrouds. It includes only three blades with a simplified geometry but represents the main dynamic characteristics of a real turbine. A static analysis on a commercial FE software of the test bench blades assembly has been carried out to evaluate the contact area on the shrouds, and determine the deformation related to the pre-torsion loading. Modal analyses were also realized to determine the natural frequencies of the structure and the modal shapes according to the imposed contact status. Then a reduced order model of the structure is generated, and is used into a specific numerical code. A procedure is implemented to handle the interpenetration generated by the pre-torsion of the blades, which is the key part of the static loading of the structure. In order to solve this non-linear dynamic problem in the frequency domain, based on the static loading results, the Harmonic Balance Method (HBM) is coupled to the Dynamic Lagrangian Frequency Time (DLFT) method or a classic penalty method to evaluate the non-linear contact forces. Numerical results around the first and third bending modes of the structure are computed and a parametric study is presented, pointing out the impact of the static normal load distribution depending of the method used, the friction coefficient between, the excitation force level, etc. The precision of the nodal coupling scheme used to manage the contact between the shrouds meshes for the numerical simulation is also evaluated by changing the meshing, in order to quantify such hypothesis.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126308079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated Data-Driven Physics Discovery of Turbine Component Damage","authors":"Sheng Zhang, Ryan Jacobs, Sayan Ghosh, Ambarish Kulkarni, Liping Wang","doi":"10.1115/gt2022-83372","DOIUrl":"https://doi.org/10.1115/gt2022-83372","url":null,"abstract":"\u0000 We propose an automated physics discovery algorithm for turbine component damage modeling. Our algorithm utilizes operational data of a mechanical component and discovers an interpretable symbolic formula that describes the physics. We illustrate our algorithm through two numerical examples and demonstrate that the discovered formulas can predict the future damage accurately. Our framework is flexible and easily applicable to all areas of science and engineering. With cutting-edge machine learning tools, researchers can simply input the experimental data and then the physics formulas are printed out automatically. The application of this new algorithm may reduce the time spent on research and development of physics models significantly, while achieving almost the best accuracy in prediction.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127133486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Dedicated Model Reduction Method for Turbo-Machines Using a Critical Speed Subspace","authors":"Francesco D’Alessandro, Hugo Festjens, G. Chevallier, S. Cogan, T. Benamara, C. Sainvitu","doi":"10.1115/gt2022-79691","DOIUrl":"https://doi.org/10.1115/gt2022-79691","url":null,"abstract":"\u0000 Finite element models representing industrial scale turbo-machines have reached today a very large number of degrees of freedom. The large size of these models requires the use of reduced order modelling to make the simulations computationally affordable. However, the physical characteristics (i.e. modes shapes and natural frequencies) of a rotating machine depend on the rotating speed of the system and classical modal reduction approaches are not efficient in this case. A classical modal basis does not allow to decompose the unbalance response of a rotating system into independent components because the normal modes are evaluated for a constant rotating speed. They are thus invariant and insensitive to the rotating speed variation. In this work a method is proposed to evaluate a reduction basis composed only by the modes excited when the system runs through its own critical speeds. This method produces an essential basis of modes which is optimal for the identification of the main components of the unbalance response of a rotating system. The development of this reduction basis is firstly formulated mathematically. Then, the ‘critical speed basis’ is employed to reduce a real finite element model of about 100 DOFs and it is compared with a classical modal basis. Finally, the efficiency of the proposed reduction method is tested in a non-linear framework.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128800578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility Analysis of the Rotor Elastic Support With Piezoelectric Damping","authors":"Yuhong Hu, Lin Li, Yaguang Wu, Yu Fan","doi":"10.1115/gt2022-81683","DOIUrl":"https://doi.org/10.1115/gt2022-81683","url":null,"abstract":"\u0000 The squirrel cage is a widely-used elastic support in aeroengine. The combination of the squirrel cage and damping structures, such as squeeze film dampers, can effectively suppress rotor vibration. The squeeze film damper, although providing significant damping, requires a specific auxiliary lubricant supply system, which occupies space and brings additional weight. Piezoelectric materials have the advantages of light weight, high energy density, and wide bandwidth. The electromechanical coupling effect ensures that they can be used as energy transducers, and the corresponding piezoelectric damping has attracted extensive attention. In this study, we propose an elastic support-piezoelectric damper system for rotors by integrating the piezoelectric damping to the squirrel cage. The purpose of this study is to demonstrate the feasibility of the piezoelectric squirrel cage to suppress the vibration of the low pressure rotor of aero-engine from both the aspects of vibration and strength. To do that, the finite element model of a dummy rotor with elastic support-piezoelectric damper system is established first. The polarization direction and the network topology are optimized to reduce the amount of circuit impedance under the premise of ensuring the modal electromechanical coupling factor. An in-house code to simulate the dynamic performance of the rotor with the elastic support-piezoelectric damper system is developed in ANSYS/MATLAB environment. To reduce the computational cost, the following acceleration techniques are adopted: 1) the specific modal synthesis method dedicated to piezoelectric structures is implemented to reduce the dimension of the governing equations; 2) the equivalent linearization method is carried out to transfer the synchronized switch damping (SSD) with nonlinear nature to a frequency-dependent impedance, thus the time-consuming nonlinear solver is avoided. The unbalance response of the rotor is analyzed numerically. The damping effects of two promising piezoelectric damping technologies, i.e. the resonant damping and the SSD, are compared and discussed. Results show that the SSD network can reduce the vibration level of the rotor significantly with good robustness; the number of the SSD control circuit is only the half of the number of squirrel cage bars; the failure strength margin is sufficient.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114261508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Linearization Method Based on 3D Contact Model for the Steady-State Analysis Towards Complex Engineering Structures Containing Friction","authors":"Fucai Xiao, Lin Li, Yaguang Wu, Yu Fan, Hui Zhang","doi":"10.1115/gt2022-82413","DOIUrl":"https://doi.org/10.1115/gt2022-82413","url":null,"abstract":"\u0000 In this paper, a linearization method based on 3D contact model for the steady-state response analysis of dry friction systems is proposed from the perspective of engineering application. The core is to equivalently express the nonlinear force described by the 3D contact model into distributed local linear damping and stiffness by means of linearization, and apply it to the finite element model of linear substructures with MATRIX 27 elements. In this way, the steady-state response can be calculated in ANSYS. The 3D contact model ensures the accuracy of the algorithm, and the linearization improves the efficiency. Besides, the stress can be directly displayed in ANSYS post-processing. The effectiveness and efficiency are verified both on the contact interface level and the structure level. Finally, the proposed method is applied to a real multi-stage stator casing with a friction ring damper. Results show that for this finite element model with 1944 nonlinear degrees of freedom, the average calculation time for one frequency is less than 5 s. The larger the scale of the model, the greater the benefit of efficiency.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132691184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}