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

{"title":"The Mechanism and Quantitative Evaluation of Slip Damage of Bolted Joint With Spigot","authors":"Jie Hong, Yongbo Ma, ShaoBao Feng, Yanhong Ma","doi":"10.1115/gt2022-82788","DOIUrl":"https://doi.org/10.1115/gt2022-82788","url":null,"abstract":"\u0000 Bolted joints with spigot are widely-used in the structural design of aero-engines. There will be relative motion at the spigot interface during operating without properly design, which results in the loss of stiffness of bolted joints. In this paper, a slip damage model of the bolted joint is established by analyzing the slip behavior of spigot interface. The influence of structural and loading parameters on slip damage have been studied, and an evaluation method is proposed to quantitatively describe the slip damage of bolted joint with spigot using residual deformation. The results show that the slip damage and the loss of stiffness appear during loading and there will be residual deformation in the bolted joint after unloading because of the friction at the spigot interface. The interference of the spigot and the coefficient of friction have a significant effect to improve the slip damage. In addition, the residual deformation can be used to quantitatively evaluate the slip damage.","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":"133409603","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":"Morton Effect Calculation and Analysis of Shop Test Results for Single-Shaft Multistage Centrifugal Compressors","authors":"Naohiko Takahashi, Yohei Magara, M. Hemmi, Motoki Sato","doi":"10.1115/gt2022-80356","DOIUrl":"https://doi.org/10.1115/gt2022-80356","url":null,"abstract":"\u0000 In the manufacturing process of single-shaft multistage centrifugal compressors for process gases, factory tests are conducted to confirm that the lateral vibration satisfies the allowable limits. One of the problems that must be taken care of during the test is the increase in vibration due to the Morton Effect. The Morton Effect is a thermal bending vibration caused by the non-uniformity of the oil film temperature of the bearing, and many troubles have been reported in overhung rotors. However, there are few reports of the Morton Effect in single-shaft multistage compressors. This is thought to be because even if the Morton Effect did occur, it was often only a minor problem. Although it is a minor problem, it is necessary to predict and evaluate the Morton Effect in order to prevent a prolonged test process and costly countermeasures. In this study, a calculation method for the Morton Effect has been developed for a single-shaft multistage centrifugal compressor, and an evaluation index for the Morton Effect is proposed. The developed method is verified and the validity of the proposed evaluation index of the Morton Effect is checked using cases of increased vibration that occurred in factory tests.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"234 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":"132034956","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":"Mixed Whirl Modes in Numerical Rotordynamics Analysis","authors":"Konrad Juethner, T. Rose, J. Kumar, Jianming Cao, Gregory Savela, Chris J. Zuck, P. Mathuria","doi":"10.1115/gt2022-79755","DOIUrl":"https://doi.org/10.1115/gt2022-79755","url":null,"abstract":"During the design phase of a rotor system, the identification of whirl type carries much significance. Forward whirl (FW) critical speeds reveal themselves by harmonic peaks during spin-up. Backward whirl (BW) modes are dynamically quiet, but produce cyclic stresses and therefore contribute to material fatigue. The realization, that FW and BW can occur simultaneously in so-called mixed whirl (MW) modes, demands greater investigative scrutiny from the design team. While pure FW or BW modes can be identified by one pair of proximity probes at any single rotor location, many measurements along the rotor axis are needed to either rule out or confirm MW. Since there are practical and economic limits to the number of measurement locations and experiments, the purpose of this paper is to deliver guiding analytic insight. The proposed approach is to overcome experimental limitations by using a finite element (FE) model of the rotor system, compute its nodal whirl distributions from each of its complex-valued eigenvectors, and map the resulting whirl quantities back onto all FE grids. This delivers insightful surface and volume diagnostics to augment experimental rotor validation. Exercising this technique on simplified example models reveals unexpected insight in that FW and BW modes influence one another and become mixed across a greater rotor speed range than anticipated. Therefore, MW turns from an elusive phenomenon into a common occurrence throughout the Campbell diagram, to a point where it becomes increasingly challenging to discern pure FW and BW mode shapes — particularly, at higher modal frequencies. The most surprising and truly unexpected conclusion of this work is that all of the FW/BW pairs considered here do not intersect but veer upon closer investigation. And, as FW transforms into BW and vice versa during the veering transition in the Campbell diagram, their stability maps and root loci accentuate this shift by indicating that stability is traded between them. A mode’s ability to transition from one whirl type to another is significant from the practical design and simulation perspectives, in that engineering responsibility is shared between accurate predictions and appropriate design. As shown in this work, both numerical and eigenvector-based tracking algorithms favor intersection over veering at low rotor speed resolution and can produce believable but incorrect answers.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"174 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":"124291814","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 Probabilistic Framework for Minimum Low Cycle Fatigue Life Prediction","authors":"M. Enright, Jonathan P. Moody, Yasin Zaman, J. Sobotka, R. Mcclung","doi":"10.1115/gt2022-80220","DOIUrl":"https://doi.org/10.1115/gt2022-80220","url":null,"abstract":"The traditional approach to low-cycle fatigue (LCF) life prediction involves statistical characterization of total LCF life based on extensive testing of smooth fatigue specimens under multiple stress and temperature conditions. Total LCF life is modeled as a single random variable with a unimodal probability density function (PDF) from which a minimum (e.g., B0.1) life is derived. Recent studies have shown that LCF lives for some materials consist of a short-life group that initiates cracks near the first cycle of loading and a long-life group that forms cracks later in life. The combined lives of these two groups can be modeled as a bimodal distribution. Minimum LCF lives associated with the bimodal PDF are typically longer than those associated with the traditional unimodal PDF. Minimum LCF lives of the bimodal distribution are dominated by the short-life group, and the lifetimes of this group can be estimated using probabilistic damage tolerance (PDT) concepts. In this paper, a probabilistic framework is presented for prediction of minimum LCF lives of the short-life group. It extends a previously developed minimum LCF life model for smooth fatigue specimens for application to full components. It is based on a probabilistic damage tolerance methodology that was previously developed for rare material anomalies in aircraft gas turbine engine materials. The framework is demonstrated via two illustrative examples including a representative gas turbine engine component. The results promote improved understanding of the PDT approach and its application to LCF life prediction.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"113 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":"124157251","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 an Advanced Meta Model Selection Algorithm on the Sensitivity Analysis of a Cooled Turbine Blade","authors":"Florian Diermeier, M. Voigt, R. Mailach, M. Meyer","doi":"10.1115/gt2022-83123","DOIUrl":"https://doi.org/10.1115/gt2022-83123","url":null,"abstract":"\u0000 Probabilistic methods are growing more important in the aerospace industry due to the ability to describe the behaviour of complex systems in the presence of input parameter variance. Sensitivity analysis based on meta models can be utilized for this purpose. The reliability of the results is dependent on the surrogate model quality, which in turn depends on the available data. A priori the appropriate meta model type is not known.\u0000 An approach to automatically select the best fitting model for a given data set is presented in this paper. For comparison, polynomial regression with least squares fitting, moving least squares, radial basis functions, and support vector regression are used as candidate types. The selection of the best meta model type is based on two quality criteria utilizing a cross-validation (CV) scheme. The developed approach is demonstrated on the sensitivity analysis of a cooled turbine blade.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"43 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":"129121527","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":"Optimization of a Turbomachinery Blade With Regards to Tip-Rub Events","authors":"Marin de Cherisey, L. Salles, L. Renson, A. Vizzaccaro, Chian Wong","doi":"10.1115/gt2022-82005","DOIUrl":"https://doi.org/10.1115/gt2022-82005","url":null,"abstract":"\u0000 Tip-rub events, also called blade-casing interactions, are problematic structural phenomena that can lead to complete engine failure. They mainly occur in compressors when a blade tip touches the casing and starts vibrating. If one of the blade natural modes is excited by an engine order, this can lead to an uncontrolled resonance. Therefore, the understanding and the consideration of these interactions is crucial to the development of safe aircraft engines.\u0000 Various numerical models and dynamic simulators have been developed, including the in-house one, jm62. It implements a stick-slip model and considers a potential liner and casing wear. Even if it gives precise results, it is computationally expensive and needs a significant amount of post-processing. It is therefore not really adapted to early design stages or quick automated processes (parametric study or optimization).\u0000 An automated workflow using SALOME-MECA and its sub-modules had been developed and permits to perform simple and fast parametric studies and shape optimizations. The proposed tool has been used to study the influence of the twist, lean, sweep and tip thickness-to-chord ratio on a modified version of a NASA Rotor 37 blade. The risk of high-level vibration of a blade due to tip-rub events is assessed using the concept of clearance consumption. The clearance consumption is defined as the component of the linear or nonlinear mode shape that defines the distance between the tip of the blade and the casing. From the reference blade and the parametric study results, an optimized candidate was generated using the clearance consumption as the objective function to minimize This process resulted in a geometry with a lower twist angle and a significant forward sweep. Two scenario of tip rub events have been performed on the optimised blades. The testing relies on the in-house time integration software jm62. The candidate has showed a 85% reduction in the amplitude of the vibratory response for the first scenario, demonstrating that the clearance consumption can be used to perform successful shape optimizations for tip-rubbing.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"243 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":"131902287","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":"Accurate Blade Tip Timing Placement on a Centrifugal Impeller Using As-Manufactured Modeling","authors":"Daniel L. Gillaugh, Alexander A. Kaszynksi, Trevor C. Tomlin, Jeffrey M. Brown, Joseph A. Beck, Emily B. Carper","doi":"10.1115/gt2022-83415","DOIUrl":"https://doi.org/10.1115/gt2022-83415","url":null,"abstract":"\u0000 Non-intrusive stress measurement systems (NSMS) are commonly used during rig and engine tests to ensure safe operation of the test asset. Blade tip timing (BTT) is one form of NSMS that estimates operational stresses of a bladed rotor using time-of-arrival (TOA) data coupled with finite element analysis (FEA) predictions. Traditional FEA techniques assume nominal airfoils to generate stress-to-deflections ratios used with TOA data to predict blade stresses. Recent research has been conducted showing the significant variability in stress-to-deflection ratios when accounting for geometric variations in the blade geometry. As-manufactured finite element modeling has been shown to be a prudent way to account for these geometric variations when developing instrumentation placements and safety limits for rotors. Literature on this topic tends to focus on integrally bladed rotors where every blade is notionally identical. Centrifugal impellers alternatively have a main and splitter blade with significantly different geometries making blade tip timing placement more challenging on these components. Traditional BTT placement techniques will be tailored in this work to achieve optimal probe placement to detect specific vibratory modes of interest for both the main and splitter blades. BTT safety limits will be generated for each mode of interest, and optical scanning and mesh morphing approaches will be used to generate an as-manufactured model of the centrifugal impeller. The BTT safety limit variability due to geometric variations will be assessed for both the main and splitter blades. It will be shown that due to geometric variations within the impeller that the BTT limits can vary between blades. This research further validates the importance of using as-manufactured modeling during component design, test, and throughout the life-cycle.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"248 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":"116056149","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":"Measured and Predicted Temperature Differentials Within a Rotor at a Tilting-Pad-Journal Bearing Associated With the Morton Effect","authors":"Chris D. Kulhanek, S. Cunningham, H. Delgado, Jeff Moore, Justin R. Hollingsworth","doi":"10.1115/gt2022-83237","DOIUrl":"https://doi.org/10.1115/gt2022-83237","url":null,"abstract":"\u0000 The current work shows the implementation of a high-speed turbomachinery test rig to measure vibration and internal shaft temperature differentials at a journal bearing for a rotor system designed to induce the Morton effect rotordynamic phenomenon. The vibration and shaft temperature measurements are compared to predictions using an analytical code described by Tong and Palazzolo [6,7]. An existing high-speed test rig was adapted, including a new rotor with six equally-spaced RTDs embedded at the journal bearing centerline. The rotor configuration included an overhung rotor design with a 58 mm (2.3 inch) diameter, 5-pad tilting-pad journal bearing. The in-rotor temperature measurements were conditioned using a custom on-board amplifier and extracted with a high-speed commercial slip ring. Test conditions included various levels of unbalance, bearing oil inlet temperature, and operating speed. Test measurements show that the temperature differential across the shaft is dependent upon operating speed, as well as vibration amplitude. Operating conditions included rotational speeds up to 19.5 krpm and vibration levels approaching the magnitude of the bearing clearance. Testing near the rotor first lateral natural frequency (or critical speed) with a high level of initial unbalance resulted in the highest temperature differentials across the shaft of approximately 11 °C (20 °F) plus. Vibration measurements show hysteresis in the synchronous vibration response in the Bode and polar plots. This measured vibration hysteresis is consistent with the rotor hot spot or temperature differential changing the unbalance level of the rotor. Overall, both the test measurements and predictions show notable temperature differentials and hysteresis behavior in the vibration response that are believed to be associated with the Morton Effect. These conditions are considered precursors to the spiral vibration or fully developed synchronous instability typically associated with the Morton Effect.","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":"115459923","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":"Gradient Enhanced Kriging Using Modal Sensitivity Approximations in a Reduced Basis Space for As-Manufactured Airfoil Analysis","authors":"Jeffrey M. Brown, Emily B. Carper, A. Kaszynski, Daniel L. Gillaugh, Joseph A. Beck","doi":"10.1115/gt2022-83402","DOIUrl":"https://doi.org/10.1115/gt2022-83402","url":null,"abstract":"\u0000 This work develops a new process to efficiently predict the effect of as-manufactured geometry variations on airfoil modal response. A gradient enhanced kriging approach is formulated that uses two sets of results at the training model sites in order to reduce the total number of models required. The first set of results are the frequency or mode shape values and the second are their respective gradients. Computational efficiency is achieved through analytical calculations of eigenvalue and eigenvector sensitivities. This approach avoids the need to recompute full eigensolutions for finite difference sensitivity approximation. Efficiency in mode shape approximation is further enabled through transformation of displacement variations into a principal component reduced-basis space. This allows prediction of the full mode shape variation without emulating each degree of freedom independently. In order to perform gradient enhanced kriging with this space, a novel approach is developed to calculate reduced basis space gradients. The process projects the modal displacement principal component vectors onto first-order Taylor series expansions of the physical mode shape variation at each training site. The resulting perturbed principal component coordinates are used in finite difference estimates of sensitivity that make gradient enhanced kriging in this space possible. This new process is demonstrated on three cases, and it is shown that the new approach provides significant improvements in accuracy and efficiency compared to traditional kriging methods.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"182 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":"115482371","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":"Numerical Investigation on HCF Weak Link Locations of a Wide-Chord Laminated Composite Fan Blade With Coupled Modal Vibrations","authors":"Xue-Yan Tang, Yong Chen, Jiguo Zhang","doi":"10.1115/gt2022-83613","DOIUrl":"https://doi.org/10.1115/gt2022-83613","url":null,"abstract":"\u0000 High cycle fatigue (HCF) of laminated composite fan blade (LCFB) caused by vibration is important content within airworthiness certification. This paper proposed a method suitable for LCFB to evaluate its HCF failure location under complex excitations. First, a high-fidelity finite element model (FEM) of LCFB was built and the classification of modal shapes was carried out. By setting the resonance margin threshold on the campbell diagram, the modal superposition vibration that may be excited at the common rotation speed was found out. Then, a postprocessing strategy was proposed to evaluate HCF weak link locations. Constant life diagrams (CLD) for the unidirectional lamina were employed to determine the HCF weak link location of LCFB in combination with the steady and vibratory stresses along the corresponding material principal directions. For the coupled mode vibration, the HCF weak link locations with different stress components were calculated and the critical failure stress component was identified. For the coupled mode vibrations, the HCF weak link locations with the resultant stresses were calculated with different combination of modal participating coefficients. The results indicated that the HCF weak link locations may change to locations different from that in single mode vibration. Furthermore, the critical failure stress components may be transferred to directions with larger vibratory stress margins. This work presented a useful numerical technique to study the effect of mode coupling on LCFB HCF characteristics under complex operating conditions.","PeriodicalId":171593,"journal":{"name":"Volume 8B: Structures and Dynamics — Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"63 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":"128259718","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}