Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration最新文献

{"title":"Study on Relationship Between Dislocation Density and Creep Strain Rate of Single Crystal Ni Based Superalloy for Gas Turbines Using the Discrete Cosine Transform","authors":"H. Hiraguchi","doi":"10.1115/gt2021-58801","DOIUrl":"https://doi.org/10.1115/gt2021-58801","url":null,"abstract":"\u0000 The discrete cosine transform (DCT) is known to be able to express the relation curve between creep strain and time, or the relation curve between creep strain rate and time very well. Moreover, recently it has been found out that the DCT can draw electron density distribution maps of crystals. In addition, the DCT always passes through all the points measured at an equal interval in any continuous curves and its interpolated values between adjacent points are very reasonable. Furthermore, a new prediction method for long term creep curves from short term creep data by using the DCT was reported at TurboExpo2020. Up to the present, the strength of single crystal Nickel based superalloys for gas turbines at elevated temperatures has been advanced by controlling the interface dislocation density and the lattice misfit at the γ/γ’ interfaces. For this reason, it has to be understood how to evaluate a relationship between interface dislocation density and creep strain rate to develop more advanced single crystal Nickel based superalloys. Therefore, in this research it was studied how to evaluate the relationship between interface dislocation density and creep strain rate of a single crystal Nickel based superalloy for gas turbines by using the DCT. As a result, useful properties on the effective stress have been obtained from the coefficients of the DCT.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127388153","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":"Analysis of Loading and Vibration Histories on Natural Frequencies and Modal Damping of Blades With Friction at Root Contact Interfaces","authors":"Junjie Chen, C. Zang, Biao Zhou, E. Petrov","doi":"10.1115/gt2021-58985","DOIUrl":"https://doi.org/10.1115/gt2021-58985","url":null,"abstract":"\u0000 Gas turbine engines change the rotation speed during operation in a wide range from zero to the speed corresponding to the cruise flight and the history of the rotation speed variation is individual for each flight. During the engine operation the bladed disks pass different resonances frequencies and may experience significant vibration amplitudes. The vibrations can affect the interaction conditions at friction contact interfaces, including contact stresses distribution and their contact status. As a result, the contact conditions can differ from those that are established at the initial bladed disk assembling and these conditions are dependent on the history of the vibration that a bladed disk experiences during every engine operation cycle. The variation of the contact conditions at friction contact interfaces affects modal properties and modal damping characteristics of a bladed disk, and it is important to assess the possible variation of these properties during the engine exploitation.\u0000 In this paper, a transient analysis is performed to simulate blade vibration under different loading histories occurred in a flight mission. The analysis is performed for different histories of the blade vibration and a method is proposed for the analysis of modal damping in the blade root joints under the influence of different loading histories. The influence of different loading histories, friction contact parameters, the vibration excitation levels and resonating modes on modal characteristics and modal damping factors is studied, The pre-stress effects due to blade assembling are also explored.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128853997","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 Methods for Calculating Component Modes for Geometric Mistuning Reduced-Order Models","authors":"Joseph A. Beck, Jeffrey M. Brown, A. Kaszynski, Daniel L. Gillaugh","doi":"10.1115/gt2021-59126","DOIUrl":"https://doi.org/10.1115/gt2021-59126","url":null,"abstract":"\u0000 Geometric mistuning models formulated from a component mode synthesis methods often require the calculation of component modes, particularly constraint and fixed interface normal modes, during substructuring. For Integrally Bladed Rotors, these calculations are required for each sector. This paper proposes methods that reuse information garnered from solving the constraint modes of a single sector on the remaining sectors to reduce memory requirements and solution times. A mesh metamorphosis tool is used to ensure finite element models match geometry obtained from a 3D optical scanner. This tool also produces a common mesh pattern from sector-to-sector. This is exploited to produce common permutation matrices and symbolic factorizations of sector stiffness matrices that are proposed for reuse in solving subsequent constraint modes. Furthermore, a drop tolerance is introduced to remove small values during constraint mode calculation to reduce memory requirements. It is proposed to reuse this dropping pattern produced from a single sector on the remaining sectors. Approaches are then extended to a parallel processing scheme to propose effective matrix partitioning methods. Finally, information gathered during the constraint mode calculations are reused during the solution of the fixed interface normal modes to improve solution time. Results show reusing permutation matrices and symbolic factorizations from sector-to-sector improves solution time and introduces no error. Using a drop tolerance is shown to reduce storage requirements of a constraint mode matrix. Additionally, it is shown that reusing the same dropping pattern introduces minimal error without degradation in solution times. Similarly, reusing the information from constraint modes for calculating fixed interface normal modes greatly improves the performance in a shift-and-invert technique for solving eigenvalue problems.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129533581","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":"Fretting Fatigue – An Integral Simulation Approach to Strengthening by Shot Peening","authors":"P. Gerken, C. Richter","doi":"10.1115/gt2021-59905","DOIUrl":"https://doi.org/10.1115/gt2021-59905","url":null,"abstract":"\u0000 Fretting fatigue is a limiting factor in blade attachment design for turbomachinery. Shot peening is known to be a strength increasing measure against fatigue. It is applied not only to free surfaces of components under fatigue but also to contacting surfaces subject to fretting fatigue.\u0000 The present work examines the effect of shot peening on fretting fatigue resistance in fixtures of rotor blades. The chosen integral approach allows the consideration of shot peening and subsequent fretting loading in one simulation. Thus, the residual stresses and material strengthening as well as the surface waviness due to the shot peening process are included in the fretting fatigue simulation. To achieve reasonable computation times a 2D model, calibrated to a 3D unit cell model, is employed. A comparative study on fatigue endurance limits is presented for the cases with and without shot peening. With view to the different failure mechanisms met in these two cases, an initiation evaluation is carried out with the Sines criterion for the un-peened condition; a fracture mechanics approach is shown to be necessary for the evaluation of the shot peened condition.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131472042","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":"Advanced Processing of a Blade Vibratory Response Obtained With Tip Timing Method Using Hyperparameter-Free Sparse Estimation Method","authors":"V. Kharyton, D. Zachariah","doi":"10.1115/gt2021-02411","DOIUrl":"https://doi.org/10.1115/gt2021-02411","url":null,"abstract":"\u0000 The study presents the application of a sparse estimation method which enables explicit identification of spectrum components of a vibratory signal of a blade obtained by means of blade tip timing measurement. The method exploits the sparse frequency content of the blade vibratory response and uses a data-adaptive weighting to achieve sparsity. In contrast to other approaches, this method obviates the need for any parameter tuning during the identification process and admits an online formulation that renders it capable of real-time data processing.\u0000 In the study only experimentally acquired data from either prototype testing or field measurements are used to evoke the method applicability. For some considered test cases there were no strain gauges available, therefore proposed method was the only means to study blades vibratory response.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123164803","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 Testing of Additively Manufactured Superalloy Lugs","authors":"S. Roychowdhury, H. Karlsson, B. Henriksson, P. Carlson","doi":"10.1115/gt2021-60070","DOIUrl":"https://doi.org/10.1115/gt2021-60070","url":null,"abstract":"\u0000 Additively manufactured parts, in spite of their many advantages, face substantial challenges on the path towards certification. This challenge is more pronounced in the quality-demanding aviation industry, where the safety considerations are paramount. A major reason for this challenge is the lack of history associated with additively built parts compared to the traditional cast and wrought components. In assessing the structural integrity of cast and wrought components, material properties obtained from laboratory coupon tests are routinely applied for design calculations of large components. However, for AM parts, questions remain over transferability of properties over multiple length scales due to possible variations in material chemistry, microstructure, and defect. In this work, this issue is investigated by conducting mechanical tests on small simplified lugs of nickel-based superalloy Haynes 282. The lugs are produced by the laser powder bed fusion process. After appropriate heat treatment and machining operations, the lugs are subjected to strength, low cycle fatigue, and crack propagation tests. Multiple tests are carried out in order to assess repeatability. Design calculations are performed to assess whether the test results can be predicted with standard methods. The results in the current work generate confidence in predictable, repeatable behavior of the AM built lugs. Continuation of this approach over larger length scales has the potential to build enough confidence so that additively manufactured parts can be used in load-bearing structural elements of the aircraft engine.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122519786","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":"Data Driven Approach to Analyzing The Impact of Power Plant Cycling on Air Preheater Degradation and Remaining Useful Life","authors":"Himanshu Sharma, V. Adetola, L. Marinovici, H. Schaef","doi":"10.1115/gt2021-59914","DOIUrl":"https://doi.org/10.1115/gt2021-59914","url":null,"abstract":"\u0000 Due to the increased penetration of renewable energy generation sources, and fluctuations of the oil and gas prices, modern coal burning power plants deal with increased variability in the demand for power generation. These varying demands result in their intermittent under-capacity operation (cycling). Periodical ramping down and back up to follow the daily power demands causes damages to the plant components reducing its operational life. In this paper we analyze the impact of cycling on a rotary Ljungstrom air preheater (APH) unit installed at a coal fire power plant in the US. An inefficient air preheater can significantly impact boiler performance. Due to the repeated boiler’s hot-cold start, the APH experiences fluctuating operating conditions that result in accelerated degradation mechanisms, such as dew-point corrosion, fouling/deposition plugging, and air heater leakage. The analysis in this paper utilizes field data related to APH basket replacement, and the number of cycles experienced by the boiler to model the life expectancy of the baskets. The data-driven model enables preventive maintenance strategies for the APH by predicting how long the APH baskets will last in a probabilistic sense. The analysis showed that an increase in cycling for a fixed operation time can reduce the APH basket remaining useful life by about 30%.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125757168","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":"Crystal Visco-Plastic Model for Directionally Solidified Ni-Base Superalloys Under Monotonic and Low Cycle Fatigue","authors":"Navindra P. Wijeyeratne, Firat Irmak, A. Gordon","doi":"10.1115/gt2021-59581","DOIUrl":"https://doi.org/10.1115/gt2021-59581","url":null,"abstract":"\u0000 Nickel-base superalloys (NBSAs) are extensively utilized as the design materials to develop turbine blades in gas turbines due to their excellent high-temperature properties. Gas turbine blades are exposed to extreme loading histories that combine high mechanical and thermal stresses. Both directionally solidified (DS) and single crystal NBSAs are used throughout the industry because of their superior tensile and creep strength, excellent low cycle fatigue (LCF), high cycle fatigue (HCF), and thermomechanical fatigue (TMF) capabilities. Directional solidification techniques facilitated the solidification structure of the materials to be composed of columnar grains in parallel to the <001> direction. Due to grains being the sites of failure initiation the elimination of grain boundaries compared to polycrystals and the alignment of grain boundaries in the normal to stress axis increases the strength of the material at high temperatures. To develop components with superior service capabilities while reducing the development cost, simulating the material’s performance at various loading conditions is extremely advantageous. To support the mechanical design process, a framework consisting of theoretical mechanics, numerical simulations, and experimental analysis is required. The absence of grain boundaries transverse to the loading direction and crystallographic special orientation cause the material to exhibit anisotropic behavior. A framework that can simulate the physical attributes of the material microstructure is crucial in developing an accurate constitutive model. The plastic flow acting on the crystallographic slip planes essentially controls the plastic deformation of the material. Crystal Visco-Plasticity (CVP) theory integrates this phenomenon to describe the effects of plasticity more accurately. CVP constitutive models can capture the orientation, temperature, and rate dependence of these materials under a variety of conditions. The CVP model is initially developed for SX material and then extended to DS material to account for the columnar grain structure. The formulation consists of a flow rule combined with an internal state variable to describe the shearing rate for each slip system. The model presented includes the inelastic mechanisms of kinematic and isotropic hardening, orientation, and temperature dependence. The crystallographic slip is accounted for by including the required octahedral, cubic, and cross slip systems. The CVP model is implemented through a general-purpose finite element analysis software (i.e., ANSYS) as a User-Defined Material (USERMAT). Uniaxial experiments were conducted in key orientations to evaluate the degree of elastic and inelastic anisotropy. The temperature-dependent modeling parameter is developed to perform non-isothermal simulations. A numerical optimization scheme is utilized to develop the modeling constant to improve the calibration of the model. The CVP model can simulate material behavior ","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"49 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133558423","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":"Energy Dissipation Metrics for Fatigue Damage Detection in the Short Crack Regime for Aluminum Alloys","authors":"Susheel Dharmadhikari, A. Basak","doi":"10.1115/gt2021-58787","DOIUrl":"https://doi.org/10.1115/gt2021-58787","url":null,"abstract":"\u0000 In this paper, three distinct energy dissipation metrics are proposed to enable fatigue damage detection in aluminum specimens. The metrics are (i) Energy Dissipation Rate, (ii) Cumulative Energy Dissipation, and (iii) Material Stiffness. They are created by using the force and displacement signals obtained from the fatigue testing apparatus during the testing of Al7075-T6 specimens. The apparatus is also equipped with a confocal microscope which calibrates the fatigue damage detection at a crack thickness of 10 μm, thereby, enabling precise detection in the short crack regime. Using all the three metrics, optimal thresholds are computed using receiver operating characteristics and the average accuracy of damage detection in quantified. Accordingly, the three metrics show an accuracy of 84.06%, 100%, and 84.32%, respectively in detecting the cracked specimens.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124935893","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":"Effect of Bladed Packets on Transient Vibration Localization Behaviors of Mistuned Whole Bladed Disk System","authors":"X. Kan","doi":"10.1115/gt2021-58722","DOIUrl":"https://doi.org/10.1115/gt2021-58722","url":null,"abstract":"\u0000 The multi-packets whole bladed disks are usually used in the turbo-machineries. The most different characteristic of the multi-packets whole bladed disk is that some blades are connected by lacing forming a bladed packet, and several bladed packets are assembled to form a multi-packets whole bladed disk system. Mistuning of blades is an attractive vibration subject due to vibration localization problems that vibration energy focuses on some blades. The vibration localization characteristics of steady state of bladed disk are mainly discussed in previous studies, and few works focus on the transient vibration localization behaviors of the multi-packets whole mistuned bladed disk. Transient vibration characteristics of bladed disk are crucial during startup. Therefore, in this paper, transient vibration characteristics of the multi-packets whole bladed disk are studied. A developed mathematical model is used to calculate the transient vibration response of the multi-packets whole bladed disk. The number of bladed packets on the transient vibration localization of the multi-packets mistuned whole bladed disk is discussed. The results indicate that the bladed packets are able to reduce the transient vibration localization. The results suggest that the bladed packet is an alternative approach to reduce the vibration localization of bladed disk caused by mistuning. Moreover, the different number of bladed packets will produce various behaviors of transient vibration localization of multi-packets whole mistuned bladed disk system.","PeriodicalId":143309,"journal":{"name":"Volume 9B: Structures and Dynamics — Fatigue, Fracture, and Life Prediction; Probabilistic Methods; Rotordynamics; Structural Mechanics and Vibration","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127127690","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}