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

{"title":"Semi-Analytical Model for High-Speed Rotor Whirl Prediction: An Assumed Modes Formulation for an Axisymmetric Rotor With Non-Uniform Properties","authors":"Riju Chatterjee, Ashutosh Patel, N. Kumar, Pramod Kumar","doi":"10.1115/gt2022-82632","DOIUrl":"https://doi.org/10.1115/gt2022-82632","url":null,"abstract":"\u0000 Most fully analytical treatments of rotor whirl are restricted to very simple rotor geometries, and have limited use while studying real-world rotors. Analysis of more complex rotors is routinely carried out in Finite Element software such as Ansys, but this is less effective at generating fundamental insights to inform the design process. This paper is motivated by the ongoing development of a Supercritical-CO2 turbine rotor, and illustrates a rotor model of intermediate complexity. Such a model, given the relative novelty of the turbine design task stemming from the very high rotational speeds required, will improve confidence in rotordynamic simulations and is expected to help with any future troubleshooting. The approach used is to consider the rotor’s rigidity and inertia to vary along its length as functions of spatial coordinate x, and obtain predictions of whirl speeds through a Lagrangian formulation with assumed modes. This method can accommodate axisymmetric rotors with variation in cross-section or material properties, or both. It is first demonstrated on a simple and analytically tractable rotor geometry. Then, it is applied to a simplified version of the turbine rotor, whose properties’ x-dependence is approximated by curves fit to a small number of datapoints obtained from simpler (non-rotordynamic) simulations.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"17 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":"117181005","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 Validation of Creep Damage on Grain Boundary of Polycrystalline Alloy 247","authors":"T. D. Nguyen, Lucas Mäde, D. Kulawinski","doi":"10.1115/gt2022-82003","DOIUrl":"https://doi.org/10.1115/gt2022-82003","url":null,"abstract":"\u0000 In this paper, the cavitation process on a grain boundary in polycrystalline Alloy 247 is simulated and modelled. The cavitation process includes mechanisms such as nucleation, growth and coalescence of creep pores and was used for characterization of polycrystalline Alloy 247 in terms of creep damage and especially creep pore sizes. Two main parameters were defined that are either responsible for pore nucleation or pore growth and that are calculated from simulation variables and material coefficients. Therefore, a Design of Experiment (DOE) was carried out to identify the effect of each material coefficient and simulation variable on the cavitation process as well as the ranges of the main parameters for pore nucleation and pore growth. As a result of the investigation, a series of Monte Carlo simulations was run with designated combinations of main parameters within the identified range. The simulation results were used as training and test data to create a model by machine learning methods. Different machine learning methods such as neural network, random forest tree and k-nearest neighbor were applied and compared to determine the best fitted model. Based on metallographic images, a first calibration of the model’s parameters has also been carried out. The resulting machine learning model allows the prediction of creep pore sizes in the grain boundary of Alloy 247 for any given temperature and stress.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"15 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":"127144347","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":"Condition Monitoring Insight Using Bayesian Inference and Rotor Dynamics Modelling for Rotating Machinery","authors":"Greg Nelson, I. Palmer","doi":"10.1115/gt2022-80976","DOIUrl":"https://doi.org/10.1115/gt2022-80976","url":null,"abstract":"\u0000 Rotor dynamics modelling can be used to predict vibration levels for given inputs, such as unbalance levels and location, which may be of interest for condition monitoring or diagnosis. However, given measured vibration, using rotor dynamics models to find the corresponding root cause inputs is not straightforward.\u0000 In the method presented in this paper, Gaussian Process models are developed as surrogates for the rotor dynamics finite element models, and are used with Bayesian Inference to determine the probability distributions of model inputs for a given vibration response. This method allows parameters describing the machine condition, such as unbalance location and magnitude, and bearing clearances, to be determined as well as the confidence in these predictions.\u0000 The method is demonstrated by simulating the vibration response of a compressor rotor, adding noise to it, and then using the technique to accurately infer useful information such as the unbalance magnitude and location, and the clearance in each bearing.\u0000 This technique can be applied as a risk-based approach to condition monitoring of rotating machinery. Further development of this approach as part of a digital twin which uses in-service measurements would provide operators with insight into the likelihood of different root causes of vibration, and the corresponding machine condition.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"26 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":"125946957","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":"Application of Intentional Mistuning to Reduce the Vibration Susceptibility of a Steam Turbine Wheel","authors":"B. Beirow, M. Golze, F. Popig","doi":"10.1115/gt2022-82208","DOIUrl":"https://doi.org/10.1115/gt2022-82208","url":null,"abstract":"\u0000 Intentional mistuning is employed for a last stage turbine wheel featuring 51 blades to alleviate both the flutter susceptibility and maximum forced response. Primarily, operations at nominal speed under part-load conditions may cause unfavorable flow conditions facilitating flow separation. As a consequence, the original design intention with identical blades features negative aerodynamic damping ratios with respect to the first bending mode family. In order to prevent any self-excited vibration phenomena, intentional alternate mistuning is utilized to increase the least aerodynamic damping ratio as far as it takes a positive value and hence, to contribute to a stabilization of the rotor. For the purpose of numerically analyzing the vibration behavior, reduced order models are built up, which are based on modal reduction techniques, namely the subset of nominal system modes and the fundamental mistuning model. These types of models conveniently allow for considering both different mistuning distributions in terms of probabilistic analyses and the aeroelastic interaction by means of prescribing aerodynamic damping ratios and aeroelastic natural frequencies of the tuned counterpart or aerodynamic influence coefficients, respectively. A detailed study is presented regarding the correction of frequency mistuning magnitudes in terms of considering the impact of centrifugal stiffening, which plays a significant role in case of long low pressure turbine blades featuring high aspect ratios.\u0000 Since alternate intentional mistuning cannot be implemented perfectly, every bladed wheel as manufactured will exhibit small but unavoidable structural deviations from the design intention, which are known as random mistuning. To ensure the robustness of the intentional mistuning solution in terms of positive aerodynamic damping ratios at any time, comprehensive probabilistic analyses are conducted with respect to superimposing random structural mistuning at first. Secondly, the impact of varying mistuning magnitude is analyzed. Thirdly, the robustness towards aerodynamic mistuning is investigated by means of small variations of aeroelastic influence coefficients and consequently, the inter blade phase angle dependent aerodynamic damping curves. Moreover, it becomes apparent that alternate intentional mistuning superimposed with both, random structural and aerodynamic mistuning also mitigates the maximum forced response at part-speed conditions.","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":"116157282","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":"Development of an Acoustic Excitation Test Bench to Support the Validation of Bladed Disks","authors":"J. Ligot, S. Denis, Sébastien Hoffait, Jean de Cazenove, J. Golinval","doi":"10.1115/gt2022-81933","DOIUrl":"https://doi.org/10.1115/gt2022-81933","url":null,"abstract":"\u0000 This paper proposes a mixed hardware and software solution to impose different controlled dynamic load patterns to a bladed disk using non-intrusive acoustic excitation. The test bench is coupled to an autonomous measurement system consisting of an infrared Laser Doppler Vibrometer (LDV) placed on a robotic arm.\u0000 The development of the test bench is described from the definition of the requirements up to the calibration of the different components (acoustic excitation devices, power amplifiers, LDV positioning, etc.). The relation between the supplied voltage and the resulting pressure acting on the blade is also assessed.\u0000 The main application of the developed test bench consists in the imposition of Standing or Traveling Waves Excitation in order to appropriate a given nodal diameter content and experimentally study the response to typical excitation pattern encountered when integrated on motor.\u0000 Another application consists in the experimental mistuning measurement through modal analysis and the use of the Inverse Component Mode Mistuning method.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"84 2 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":"116414677","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":"The Impact of Mistuning and Material Damping on Bladed Disks of Similar Geometries","authors":"Jarred A. Nix, A. M. Rodríguez, Jeffrey L. Kauffman","doi":"10.1115/gt2022-82309","DOIUrl":"https://doi.org/10.1115/gt2022-82309","url":null,"abstract":"\u0000 As advances in turbomachinery manufacturing have continued to improve, integrally bladed rotors or blisks have become more prevalent due to the aerodynamic improvements that can be derived from those designs. Despite increases in efficiency, these blisks are prone to significantly higher vibrations due to the removal of friction damping that naturally occurs at the interfaces between each blade and the disk. Mistuning is characterized by a lack of symmetry due to the inevitable imperfections and non-homogeneity that arise across blades from manufacturing inaccuracies and use. Here we report on the frequency response functions of multiple tuned and mistuned academic blisks. The various blisks also exhibit different damping levels based on the material and thickness. These blisks were tested experimentally to determine how the different damping would affect the system response.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"11 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":"123683218","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":"Research on the Nonlinear Behavior of the Turbine Rotor Assembled by Rabbet Joints","authors":"Zhuoluo Han, Yifeng Li, Yongfeng Wang, Jie Hong","doi":"10.1115/gt2022-82784","DOIUrl":"https://doi.org/10.1115/gt2022-82784","url":null,"abstract":"\u0000 Double-stage turbine rotor assembled by rabbet joints is widely used in aero-engine, the mechanical properties of which depends highly on the compression state of the joints’ contact interfaces. The accumulated damages during operation lead to the deterioration of the contact state, which could cause the sliding or partial separation on the interface, and will affect the dynamic characteristics of the rotor system. In this paper, the static mechanical properties, mainly angular stiffness, were studied using the static contact Finite Element Analysis (FEA) method to reveal the nonlinear variation in different conditions. One dynamic model of the rotor with rabbet joints was built based on the Lagrange equations, which was numerically solved by the Runge-Kutta method for the dynamic response of the rotor with nonlinear stiffness. The results show that the rabbet joints stiffness nonlinearity will decrease the critical speed of the flexural mode and cause amplitude sudden jump phenomena during acceleration or deceleration. Moreover, the chaotic motion and impact dynamic response may appear in the vicinity of the flexural mode critical speed. The axial preload is an essential influencing factor affecting the nonlinear response characteristics of the flexural mode, and an adequate preload will minimize or prevent the effects of stiffness nonlinearity during operation.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"76 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":"116355174","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":"Experimental Study on the Optimization of the Sensor Arrangement for Blade Tip Timing Measurement","authors":"J. Tian, Zhiwei Zhang, Pengfei Chai, Shang Wang, Yong Chen, H. Ouyang","doi":"10.1115/gt2022-82488","DOIUrl":"https://doi.org/10.1115/gt2022-82488","url":null,"abstract":"\u0000 As a means of non-contact measurement of blade vibrations, blade tip timing (BTT) has good application prospects for blade design verification and health monitoring. In BTT, the sensor arrangement directly determines the effectiveness of the extracted signal and ultimately affects the quality of the identified vibration parameters. In previous research on optimizing sensor arrangements, the position of each sensor is often selected from among multiple uniformly distributed virtual positions, which limits the optimization space. Moreover, to verify the performance of a sensor arrangement, a high-precision experimental calibration platform is required. However, it is often difficult for the precision to meet the requirements for a benchmark due to an inability to measure the actual blade vibrations. This paper optimized the sensor arrangement by simultaneously considering the mutual coherence and the approximate distance between sensing matrices for an equiangular tight frame in arbitrary-angle compressive sensing method. To avoid the uncertainty in blade displacement conversion in traditional calibration, such as with strain gauges, a laser displacement sensor connected to a slip ring was used to measure directly the displacement of the blade due to vibration. Besides, a macro-fiber composite was used to apply an excitation with a precise frequency to the blade at different speeds to make the blade vibrate synchronously or asynchronously. Then the performance of sensor arrangements optimized by the proposed method as well as other methods, such as mutual coherence, were verified on the self-developed BTT experimental calibration platform. The experimental results show that the signals identified with the optimized sensor arrangements are in good agreement with measurements made by the laser displacement sensor. The amplitude accuracy was more than 76.5% and 91.3% for synchronous and asynchronous vibrations, respectively. Moreover, the identification results were stable after data from 1 or 2 random sensors were removed. This shows the method has good reconstruction accuracy and sensor redundancy.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"7 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":"134097850","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":"Vibration Failure Analysis of Multi-Disk High-Speed Rotor Based on Rotary Inertia Load Model","authors":"Jie Hong, Qi Yan, Bo Sun, Yanhong Ma","doi":"10.1115/gt2022-83174","DOIUrl":"https://doi.org/10.1115/gt2022-83174","url":null,"abstract":"\u0000 The fan rotor of an advanced low-bypass turbofan engine is usually composed of multistage blisk, a typical multi-disk highspeed rotor working in the postcritical range. A fan rotor test rig had been well balanced, but the phenomenon of excessive vibration occurred several times. This phenomenon showed that the traditional balance theory based on mass eccentricity control has limitations for multi-disk high-speed rotors. Therefore, an analysis model was established in this paper that described the rotor’s mass distribution and the rotary inertia load by two kinds of parameters: the eccentricity and the skew angle of the principal axis of inertia. Then the dynamic response properties of the rotor were simulated and analyzed. The model and simulation results showed that if the principal axis of inertia of the rotor skewed, the amplitude of bearing dynamic load continues to increase with speed, which agrees with the experimental data. Therefore, for the multi-disk rotor, it is necessary to control its eccentricity and the skew angle of the principal axis of inertia at the same time to effectively reduce its dynamic response at high speed.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"245 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":"115637674","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":"Experimental Modal Analysis of a Full-Scale Rotating Fan","authors":"Corentin Jorajuria, C. Gibert, F. Thouverez, Cécile Esteves","doi":"10.1115/gt2022-82540","DOIUrl":"https://doi.org/10.1115/gt2022-82540","url":null,"abstract":"Experimental modal analysis of a full-scale aeronautic fan is performed at design rotating speed and under vacuum conditions. The composite woven fan is excited through embedded piezoelectric actuators and the dynamic response of the system is measured with strain gauges. Presented experiments achieve high quality data measurements of forced responses thanks to a strict control of experimental conditions, an extended instrumentation of the fan and a careful testing method. The study focuses on the two first bending mode families with nodal diameters. The modal testing of the system is performed using frequency stepped sine excitations over a close range around investigated resonances and using travelling wave excitations allowing to investigate specific nodal diameter modes in each family. The forced response measurements are used to estimate the frequency response functions of the rotating fan under different experimental parameters. In particular, the first mode family exhibits a higher modal density which is challenging for modal parameters estimations. Used frequency domain modal identification techniques are presented and adapted to the fitting of frequency response functions. At the end, these techniques are applied to investigate sensitivity of extracted natural frequencies and modal damping ratios with respect to different parameters such as rotational speed, excitation level and nodal diameter content of the excitation pattern.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"2 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":"131098207","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}