Articoli di riviste: "MULTI CRACKED ROTOR"

1

Parhi, Dayal R., e Adik R. Yadao. "Analysis of dynamic behavior of multi-cracked cantilever rotor in viscous medium". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 230, n. 4 (3 agosto 2016): 416–25. http://dx.doi.org/10.1177/1464419315618033.

Testo completo

Abstract (sommario):

The present investigation is an attempt to evaluate the dynamic behaviours of multi-cracked cantilever rotor shaft with an additional mass attached at the tip of the shaft, which is partially submerged in the viscous fluid. In this work, theoretical expressions are developed to find the fundamental natural frequency and amplitude of the multi-cracked rotor shaft with attached mass, using influence coefficient method. Navier–Stoke’s equations are used for the analysis of external fluid forces acting on the rotor. Viscosities of the fluid and relative crack locations are taken as main variable parameters. For the analysis, suitable theoretical expressions are considered, and the Matlab programming is made to obtain the results. Experimental verifications are also performed to prove the validity of the theory developed.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Zheng, Zhaoli, Yonghui Xie, Di Zhang e Fahui Zhu. "Numerical investigation on the nonlinear dynamics of a breathing cracked rotor supported by flexible bearings". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, n. 19-20 (31 luglio 2019): 6815–26. http://dx.doi.org/10.1177/0954406219866473.

Testo completo

Abstract (sommario):

The steady-state response and breathing mechanism of a cracked rotor supported by flexible bearings are investigated in this paper. The generalized and efficient method proposed in this paper can be used to study the dynamics of complicated cracked structures without much modification. First, a three-dimensional finite element model of the cracked rotor-bearing system is established in the rotating frame and a general contact model for modeling the breathing crack is proposed. A component mode synthesis is used to form a reduced-order model. Then, a procedure combining multi-harmonic balance method with arc-length method is used to search the response solution. To accelerate the calculation, the analytical formulations for calculating the tangent stiffness matrix are used. Finally, the gravity induced response and breathing mechanism of a cracked rotor-bearing system are obtained. Interesting result is that the rotational speed and the crack depth will influence the breathing mechanism even if the load remains unchanged.

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Yu, Tao, Ying Yang, Qing Kai Han, Hong Liang Yao e Bang Chun Wen. "ANN-Based Crack Identification in Rotor System with Multi-Crack in Shaft". Key Engineering Materials 353-358 (settembre 2007): 2463–66. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2463.

Testo completo

Abstract (sommario):

Rotating machinery, such as steam turbo, compressor, and aeroengine etc., are widely used in many industrial fields. Among the important rotor faults, the fatigue crack fault, which can lead to catastrophic failure and cause injuries and severe damage to machinery if undetected in its early stages, is most difficult to detect efficiently with traditional methods. In the paper, based on the truth of the change of the mode shapes of the cracked structure, a new method by combining accurate finite element model of rotor with multi-crack in shaft and artificial neural network (ANN) is proposed to identify the location and depth of cracks in rotating machinery. First, based on fracture mechanics and the energy principle of Paris, the accurate FE model of the rotor system considering several localized on-edge non-propagating open cracks with different depth, is built to produce the specific mode shapes. Then a set of different mode shapes of a rotor system with localized cracks in several different positions and depths, which will be treated as the input of the designed ANN model, can be obtained by repeating the above step. At last, with several selected crack cases, the errors between the results obtained by using the trained ANN model and FEM ones are compared and illustrated. Meanwhile, the influences of crack in the different position on the identification success are analyzed. The method is validated on the test-rig and proved to have good effectiveness in identification process.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Dau, Anh Tuan, Ionel Nistor e Adinel Gavrus. "Numerical Analysis Concerning the Harmfulness of Crack Turbine Rotors Using a Multi-Scale Approach Based on a Dynamic Finite Element Method". Applied Mechanics and Materials 656 (ottobre 2014): 315–24. http://dx.doi.org/10.4028/www.scientific.net/amm.656.315.

Testo completo

Abstract (sommario):

This work is placed in the context of the simulation of the behavior and the harmfulness of cracked rotors by Electricité de France (EDF) in order to evaluate its impact on the industrial system. Several numerical tools have been developed by the Research and Development Division of EDF and a feasibility study was conducted to prove its capacities to simulate the behavior of a rotor subject to a crack. Since the industrial context request fast response to such situation, the numerical simulation must be performed as quickly as possible. For this reason a multi-scale 1D-3D modeling has been proposed: the healthy part of the rotor is modeled by reduced Timoshenko beam finite elements since the part including the crack is modeled by 3D finite elements. The aim of the work is to prove the accuracy of this multi-scale approach, its feasibility and its CPU performance.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Kulesza, Zbigniew. "Harmonic Balance Analysis for the Rigid Finite Element Model of the Rotating Cracked Shaft". Solid State Phenomena 199 (marzo 2013): 99–104. http://dx.doi.org/10.4028/www.scientific.net/ssp.199.99.

Testo completo

Abstract (sommario):

The paper presents a multi-dimensional harmonic balance analysis utilized to study the vibration responses of the cracked rotor subject to gravity, unbalance and an additional lateral harmonic force generated by an active magnetic bearing. The nonlinear terms resulting from the shaft crack are included via an alternating frequency/time domain (AFT) method. The example addressed in this paper is a simple rotor modeled by using the rigid finite element (RFE) approach. Combination frequencies are recognized as evident symptoms of the shaft crack.

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Li, Xue Jun, K. Wang, Ling Li Jiang e T. Zhang. "Rotor Crack Detection Based on Multi-Vibration Signal Fusion Collected from the Basement of Machinery Using SVM and Statistical Characteristics Methodology". Applied Mechanics and Materials 34-35 (ottobre 2010): 1000–1004. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1000.

Testo completo

Abstract (sommario):

As the poor generability of special sensor support frame and the inconvenience of signal acquisition in the process of common fault diagnosis for cracked rotor, a new fault diagnosis method is presented in this paper. this method takes the basement of rotor test rig as the monitoring objects and makes feature fusion for time-domain statistics of multiple sensors using SVM (support vector machine). The result of experiment showed that the method using the multi-sensor signal fusion technology collected from the basement of machinery has the advantages of better diagnostic precision for rotor crack diagnosis, furthermore, it supplies a new way for rotor fault diagnosis.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Banaszek, Slawomir. "Dynamics of Large Power Rotating Machine with Cracked Shaft". Key Engineering Materials 293-294 (settembre 2005): 337–46. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.337.

Testo completo

Abstract (sommario):

The paper presents the course and results of crack propagation simulation research. The object taken into account is a large power turbo-set rotor. The computer code system NLDW is presented. It uses a non-linear model of journal bearings, and well known crack model. Crack depth is marked by a crack coefficient. It is shown the crack generates a coupled forms of lateral, axial and torsional vibrations in multi-support rotor. Their intensity depends on the axial and circumferential crack location on the shaft. The attempt at pointing a proper diagnostic indicator for crack detection in large rotating machine is made according to obtained results.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Jadhav, P. V., R. A. Barawade, S. V. Patil, Y. B. Mohite e V. R. Patil. "An Experimental and Numerical Investigation on Static Vibration Response of Multi-Cracked Rotor Shaft". IOP Conference Series: Materials Science and Engineering 377 (giugno 2018): 012041. http://dx.doi.org/10.1088/1757-899x/377/1/012041.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

9

El-Mongy, Heba H., e Younes K. Younes. "Vibration analysis of a multi-fault transient rotor passing through sub-critical resonances". Journal of Vibration and Control 24, n. 14 (7 marzo 2017): 2986–3009. http://dx.doi.org/10.1177/1077546317697828.

Testo completo

Abstract (sommario):

Various faults may simultaneously occur in a rotor dynamic system. It is crucial to detect and monitor these faults to ensure the safe operation of machinery. Usually, vibration response is utilized for fault diagnosis; however, the identification process becomes more challenging when multiple faults exhibit similar symptoms in the vibration response. In this paper, the vibrational transient response of a cracked rotor is analyzed in the presence of unbalance and coupling misalignment. The study focuses on investigating the possibility, advantages and limitations of using the sub-critical startup response in solving the fault identification problem. Numerical simulations using finite element modeling and experimental investigations are carried out for different individual and multi-fault conditions. Various factors are taken into consideration, including sub-critical limit speed, crack parameters, unbalance parameters and misalignment severity. Numerical and experimental investigations showed that the sub-critical transient response is suitable for the fault detection and diagnosis of the simultaneously existing faults studied. Compared to the critical response, the sub-critical response is more informative and each fault shows a unique feature that can be extracted without the need for sophisticated post signal processing. The study provides useful insights on the interaction between the various fault effects on the vibratory response and presents a simple method for condition monitoring of industrial equipment.

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Xiong, Libo, Chunrong Hua, Funing Yang, Dawei Dong e Huajiang Ouyang. "Dynamic Characteristics Analysis of a Coupled Multi-crack Rotor System". Journal of Physics: Conference Series 2184, n. 1 (1 marzo 2022): 012040. http://dx.doi.org/10.1088/1742-6596/2184/1/012040.

Testo completo

Abstract (sommario):

Abstract This paper establishes a coupled model for multi-crack rotor using Timoshenko beam element with six degrees of freedom, and derives the stiffness matrix in the equations of motion accounting for the coupling between multiple cracks (the interaction between cracks). Then the effects of crack orientation angles (the relative angle between cracks, γ) on dynamic characteristics of the coupled multi- crack rotor near 1/3 and 1/2 subcritical speeds are analysed. The coupling between cracks induces more complex nonlinear dynamic characteristics such as large magnitudes of the super-harmonic components, which can be used as the indicators of early crack and for multi-crack identification. This work has a promotive significance for the application of the model-based method in the field of multi-crack detection of actual rotors.

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Wang, Chongyu, Zhaoli Zheng, Ding Guo, Tianyuan Liu, Yonghui Xie e Di Zhang. "An Experimental Setup to Detect the Crack Fault of Asymmetric Rotors Based on a Deep Learning Method". Applied Sciences 13, n. 3 (19 gennaio 2023): 1327. http://dx.doi.org/10.3390/app13031327.

Testo completo

Abstract (sommario):

Crack is a common fault of rotor systems. The research on crack fault detection methods is mainly divided into numerical and experimental studies. In numerical research, the current fault detection algorithms based on deep learning are mostly applied to bearings and gearboxes, and there are few studies on rotor fault diagnosis. In experimental research, the rotors used in an experiment are mostly single-span rotors. However, there are complex structures such as multi-span rotor systems in the actual industrial field. Thus, the fault detection algorithms that have been successfully applied on single-span rotors have not been verified on complex rotor systems. To obtain a fault signal close to the actual asymmetric shaft system of an asymmetric rotor system and validate the fault detection method, the crack fault detection platform is designed and built independently. We measure the vibration signals of three channels under five working conditions and establish an intelligent detection method for crack location based on a residual network. The factors that influence fault detection performance are analyzed, and the influence laws are discussed. Results show that the accuracy and anti-noise performance of the proposed method are higher than those of the commonly used machine learning. The average accuracy is 100% when SNR (signal-to-noise ratio) is greater than or equal to −2 dB, and the average accuracy is 98.2% when SNR is −4 dB.

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Li, Chao Feng, Qin Liang Li, Jie Liu e Bang Chun Wen. "Research on Periodic Motion Stability of Multi-DOF Rotor-Bearing System with Crack Fault". Applied Mechanics and Materials 148-149 (dicembre 2011): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.3.

Testo completo

Abstract (sommario):

Multi-DOF model of double-disc rotor-bearing system taking crack and oil film support into account is established, and the continuation shooting method combined with Newmark is also applied to stability analysis of continuous system. This paper mainly studied the variation law of five parameters domain in crack depth and location, then a number of conclusions are found: first, it’s feasible to study the stability of nonlinear rotor-bearing system with crack faults using FEM; secondly, the crack depth and location has a certain impact on instability speed, but the impact is not great and owns its certain law. As the crack depth and location is getting close to the middle position of rotor, due to its impact on the oil film support, the instability speed of system increases. This method and results in this paper provides a theoretical reference for stability analysis and vibration control in more complex relevant rotor-bearing system with crack fault.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Ha, Je Chang, Joon Hyun Lee, Masaaki Tabuchi e A. Toshimitsu Yokobori Jr. "Estimation of Creep Crack Growth Properties Using Circumferential Notched Round Bar Specimen for 12CrWCoB Rotor Steel". Key Engineering Materials 297-300 (novembre 2005): 397–402. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.397.

Testo completo

Abstract (sommario):

Most heat resisting materials in structural components are used under multi-axial stress conditions and under such conditions ductile materials often exhibit brittle manner and low creep ductility at elevated temperature. Creep crack initiation and growth properties are also affected by multi-axial stress and it is important to evaluate these effects when laboratory data are applied to structural components. Creep crack growth tests using circumferential notched round bar specimens are a simple method to investigate multi-axial stress effects without using complicated test facilities. Creep crack growth tests have been performed using a 12CrWCoB turbine rotor steel. In order to investigate the effects of multi-axial stress on creep crack growth properties, the tests were conducted for various notch depths at 650°C. The circumferential notched round bar specimen showed brittle crack growth behaviour under multi-axial stress conditions. Creep crack growth rate was characterized in terms of the C* parameter. A 12CrWCoB turbine rotor steel has been tested using circumferential notched round bar specimens with different multi-axiality. Circumferential notched round bar specimens show increased brittle creep crack growth behaviour due to the multi-axial stress condition. Creep crack growth properties could be predicted by allowing for the decrease of creep ductility under multi-axial conditions.

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Wang, Ke Ming, e Song Xiang. "A Finite-Width Crack Model for Rotor Dynamic Analysis by Transfer Matrix Method". Key Engineering Materials 324-325 (novembre 2006): 1003–6. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.1003.

Testo completo

Abstract (sommario):

Understanding dynamic behavior of a rotor system with a transverse crack is of great significance for operation reliability of rotating machinery. The transfer matrix method is widely used for rotor dynamic analysis, but it encounters difficulties modeling a crack. This study proposes a finite-width crack model that simulates the local stiffness reduction effect of a gaping crack in transfer matrix method. This model is obtained by comparing finite element analysis results of a shaft with a zero-width crack and its counterpart transfer matrix calculation results with a trial equivalent finite-width slot. Different shaft geometry and loading modes are considered to improve the generality of the model. An application example is given that uses the proposed model to calculate critical speeds of a multi-disk rotor system with a transverse crack at different positions.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Sun, Lin Gen, Zhi Peng Cai, Ji Luan Pan, Xia Liu, Xiao Jin Xu e Yu Ming Ding. "Influence of Prior Austenite Grain Size on the Dispersion of Fatigue Crack Propagation Thresholds in Weld Metal". Applied Mechanics and Materials 576 (giugno 2014): 111–20. http://dx.doi.org/10.4028/www.scientific.net/amm.576.111.

Testo completo

Abstract (sommario):

Fatigue crack propagation threshold is an important property for the structures with long life, such as nuclear turbine welded rotor. The fatigue crack propagation thresholds of multi-layer, multi-pass SAW weld metal of nuclear turbine rotor simulate are tested. But a big dispersion is found among test values, even at the same stress ratio . The dispersion of critical points between stable propagation zone and near-threshold zone is confirmed as an important reason. After the observation of microstructures around the critical points by backward inference method in different specimens, a good correspondence between the sizes of prior austenite grains and the maximum sizes of monotonic plastic zone at the crack tip is established. The inhomogeneous microstructures in SAW weld metal are the basic cause to dispersion of fatigue crack propagation thresholds at the same stress ratio.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Yu, Guo-Fei, Yi-Jui Chiu, Chia-Hao Yang, Jing Sheng e Xiao-Yun Li. "Exploration of coupled-vibration phenomena in multi-disk rotor with blades with multi-cracks". Advances in Mechanical Engineering 11, n. 4 (aprile 2019): 168781401983739. http://dx.doi.org/10.1177/1687814019837398.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Liu, Yuan Feng, e Mei Zhao. "Detection of Rotor Cracks Based on Multi-Scale Singular Spectrum Analysis". Key Engineering Materials 245-246 (luglio 2003): 273–78. http://dx.doi.org/10.4028/www.scientific.net/kem.245-246.273.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Li, Wei, e Daqian Pang. "Analytical investigation on geared rotor system with multi-body fault based on finite element method". Journal of Vibration and Control 25, n. 2 (26 giugno 2018): 408–22. http://dx.doi.org/10.1177/1077546318783366.

Testo completo

Abstract (sommario):

With the rapid development of modern industry, the situation of high speed and heavy load is becoming even more relevant in the gear transmission system. Under the condition of high speed and heavy load, the fault type and frequency of the gear transmission system are gradually increasing. Effective and accurate detection of fault location and fault type is one of the difficult problems in today’s fault diagnosis. In the case of high speed and heavy load, the probability of multi-body fault is greatly increased. However, most of the current fault diagnosis methods are limited to the study of single fault characteristics, and do not take into account the multi body fault. In this paper, the single crack, gear coupling crack, single shaft crack, and gear and shaft coupling crack signal are analyzed by means of the short-time Fourier transform, and the corresponding fault characteristics of different fault types are found out. The modal analysis of the fault state of the gear transmission system is carried out, the structural characteristics of the gear drive are verified, and the influence of the different fault forms on the vibration characteristics of the gear is compared.

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Rosemeier, M., D. Melcher, A. Krimmer, W. Wroblewski e A. Antoniou. "Validation of crack initiation model by means of cyclic full-scale blade test". Journal of Physics: Conference Series 2265, n. 3 (1 maggio 2022): 032045. http://dx.doi.org/10.1088/1742-6596/2265/3/032045.

Testo completo

Abstract (sommario):

Abstract Wind turbine rotor blades are subject to highly dynamic loads and designed for life cycles of at least 20 years, which means that materials are subjected to high-cycle fatigue. Fatigue is a design-driving loading for current and future blades. Bond lines of blades are exposed to a multi-axial stress-state due to the anisotropic thin-walled blade structure and curved, tapered, twisted, and airfoil-shaped blade geometry. To eliminate undesirable failure modes and thus increase the reliability of wind turbine rotor blades, standards and guidelines recommend that the multi-axial stress-states be taken into consideration for the limit state analysis. In addition, thermal residual stresses that develop during manufacture can have a significant impact on the fatigue life of the bond line. By means of a cyclic full-scale blade test of a commercial 81.6m long offshore blade, we validate a crack initiation model, which takes into account multi-axial thermal and mechanical stress-states, as well as the probabilistic stress-life, to predict the edge of crack initiation in the adhesive as well as the span-wise position. Both observations agreed well with the simulations. All residual normal stress components and cross-sectional plane shear stress made up the major part of the mean equivalent stress, while the mechanical stress amplitude components - longitudinal, peel, and cross-sectional plane shear stress - made up the major part of the equivalent stress amplitude.

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Zhao. "IDENTIFICATION OF MULTI-CRACKS IN THE GATE ROTOR SHAFT BASED ON THE WAVELET FINITE ELEMENT METHOD". American Journal of Engineering and Applied Sciences 6, n. 3 (1 marzo 2013): 309–19. http://dx.doi.org/10.3844/ajeassp.2013.309.319.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Lu, Zhiwen, Feng Li, Shancheng Cao, Rui Yuan e Yong Lv. "Crack Localization in Operating Rotors Based on Multivariate Higher Order Dynamic Mode Decomposition". Sensors 22, n. 16 (16 agosto 2022): 6131. http://dx.doi.org/10.3390/s22166131.

Testo completo

Abstract (sommario):

A novel output-only crack localization method is proposed for operating rotors based on an enhanced higher-order dynamic mode decomposition (HODMD), in which the nonlinear breathing crack-induced super-harmonic characteristic components from multiple vibration measurement points are simultaneously extracted to compose the corresponding super-harmonic transmissibility damage indexes. Firstly, the theoretical background of the HODMD is briefly reviewed. Secondly, the proposed crack localization method is dedicated which improving the HODMD for multivariate signals by casting the total least square method into standard HODMD and adaptively selecting the order parameter of Koopman approximation by optimizing the super-harmonic frequency vector. In addition, the super-harmonic characteristic components are evaluated and harnessed to derive the damage index based on super-harmonic transmissibility and fractal dimension. Finally, the proposed method is investigated and demonstrated by numerical simulations and experiments. Both numerical and experimental results show that the proposed method is powerful in realizing multi-crack localization for running rotors accurately and robustly in the case of no baseline information on intact rotors. Moreover, the interferences from commonly existing steps and misalignment can also be eliminated.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Vashisht, Rajiv Kumar, e Qingjin Peng. "Simultaneous Fault Detection and Multivariable Adaptive Hybrid Control for Unbalanced Vibrations of Cracked Flexible Rotor Systems". Journal of Dynamic Systems, Measurement, and Control 142, n. 12 (7 agosto 2020). http://dx.doi.org/10.1115/1.4047818.

Testo completo

Abstract (sommario):

Abstract For the reduction of unbalanced vibrations in a multi-input and multi-output flexible rotor system with electromagnetic actuators (EAs), conventional adaptive feedforward controllers (AFFCs) are very sensitive for changes in rotor spin frequencies. Although frequency updating is used in these controllers, a small variation in the rotor spin frequency can completely reduce their effectiveness. An adaptive notch filter is used in this research for the frequency estimation. By using this external frequency estimation, the performance of the conventional AFFCs can be enhanced. During changes in the rotor spin frequency, fundamental harmonics of the flexible rotor are also excited. Their amplitude is much higher compared to steady-state unbalanced vibrations, which can accelerate the wear and tear of components of EAs. By using feedback controllers, the amplitude of these fundamental harmonics can be reduced significantly. In real rotors with flexible bearing supports, any looseness of bolts and presence of transverse cracks can change system parameters significantly. Multiple harmonics are generated corresponding to even single spinning speed of the rotor. Robust stability as well as performance can be achieved in the presence of uncertainty and rotor crack nonlinearities using feedback controllers designed by mu-synthesis. By using the multiharmonic hybrid control, the higher harmonics can be compensated efficiently in case of a crack in rotor systems. The fast Fourier transform of the control signal can indicate the presence of a transverse crack in an online manner. In this way, active vibration control as well as rotor crack fault detection can be done simultaneously.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Pan, Chuang, Yuande Dai e Yaocheng Li. "Simulation study of crack parameters’ effects on the vibration characteristics of a bladed disk system". Journal of Vibroengineering, 1 agosto 2023. http://dx.doi.org/10.21595/jve.2023.23337.

Testo completo

Abstract (sommario):

As a key component of the turbo machine rotor in harsh operating conditions, high cycle fatigue failure and even cracks are common in bladed disks. In this paper, modal analysis was carried out for a single cracked bladed disk system, the effects of crack depth, crack height and rotating speed on its vibration characteristics were studied by the method of both numerical simulation and orthogonal test, and the effects of crack distribution on the vibration characteristics of multi-crack bladed disk systems were also studied. Finally, some conclusions have been drawn, they provide a fundamental understanding of blade health monitoring and fault prediction, and are important to improve the reliability and safety of turbine operation.

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Ranjan, Gyan, Rajiv Tiwari e H. B. Nemade. "Fault identification in cracked rotor-AMB system using magnetic excitations based on multi harmonic influence coefficient method". Inverse Problems in Science and Engineering, 17 luglio 2021, 1–31. http://dx.doi.org/10.1080/17415977.2021.1952409.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Hua, Chunrong, Libo Xiong, Lumei Lv, Dawei Dong e Huajiang Ouyang. "Multi-fault classification of rotor systems based on phase feature of axis trajectory in noisy environments". Structural Health Monitoring, 16 giugno 2023. http://dx.doi.org/10.1177/14759217231178652.

Testo completo

Abstract (sommario):

As it is difficult to distinguish multiple rotor faults with similar dynamic phenomena in noisy environments, a multi-fault classification method is proposed by combining the extracted trajectory phase feature, a parameter-optimized variational mode decomposition (VMD) method and a light gradient boosting machine (LightGBM) model. The trajectory phase feature is extracted from an axis trajectory by fusing the frequency, amplitude, and phase information related to rotor motion and can comprehensively describe the dynamic characteristics induced by different rotor faults. First, the vibration displacement signals in two orthogonal directions are collected to construct the axis trajectories with 12 rotor states including healthy, unbalance, misalignment, single crack, multiple cracks, and a mixture of them. Second, the trajectory phase feature is extracted from the vectorized axis trajectories, and the frequency spectra of trajectory phase angles under different rotor faults are analyzed through Fourier transform. Finally, a parameter-optimized VMD method combined with a LightGBM model is applied to classify multiple faults of rotor systems in different noisy environments based on the extracted trajectory phase feature. The 12 rotor states can be classified into nine categories based on the harmonic information of 1X–7X components (X is the rotating frequency of a rotor system) and other components with smaller amplitudes in the frequency spectra of trajectory phase angles. The average classification accuracy of the 12 rotor states exceeds 93.0%, and the recognition rate for each kind of fault is greater than 77.5% in noisy environments. The simulated and experimental results demonstrate the effectiveness and adaptability of the proposed multi-fault classification method. This work can provide a reference for the condition monitoring and fault diagnosis of rotor systems in engineering.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Gajjar, Mrugesh, Christian Amann e Kai Kadau. "High-Performance Computing Probabilistic Fracture Mechanics Implementation for Gas Turbine Rotor Disks On Distributed Architectures Including Graphics Processing Units (GPUS)". Journal of Engineering for Gas Turbines and Power, 10 agosto 2021. http://dx.doi.org/10.1115/1.4052078.

Testo completo

Abstract (sommario):

Abstract We present an efficient Monte Carlo (MC) based probabilistic fracture mechanics simulation implementation on heterogeneous high-performance (HPC) architectures including CPUs and GPUs for large heavy-duty gas turbine rotor components for the energy sector. A reliable probabilistic risk quantification requires simulating millions to billions of MC samples. We apply a modified Runge-Kutta algorithm to solve numerically the fatigue crack growth for this large number of cracks for varying initial crack sizes, locations, material and service conditions. This compute intensive simulation was demonstrated to perform efficiently and scalable on parallel and distributed architectures with hundreds of CPUs utilizing Message Passing Interface (MPI). In this work, we include GPUs in parallelization strategy. We develop a load distribution scheme to share one or more GPUs on compute nodes distributed over network. We detail technical challenges and strategies in performing the simulations on GPUs efficiently. We show that the key computation of the modified Runge-Kutta integration step speeds up over two orders of magnitude on a typical GPU compared to a single threaded CPU supported by use of GPU textures for efficient interpolation of multi-dimensional tables. We demonstrate weak and strong scaling of our GPU implementation, i.e., that we can efficiently utilize large number of GPUs/CPUs to solve for more MC samples, or reduce the computational turnaround time, respectively. On seven different GPUs spanning four generations, our probabilistic fracture mechanics simulation tool ProbFM achieves speedups ranging from 16.4x to 47.4x compared to single threaded CPU implementation.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Zhang, Wei, Yan Huang, Dawei Dong, Bing Yan e Chunrong Hua. "A fast identification method of train axle crack parameters based on semi-inverse Kriging method". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 22 novembre 2022, 095440972211396. http://dx.doi.org/10.1177/09544097221139641.

Testo completo

Abstract (sommario):

On-line monitoring of crack parameters can prevent axle breaking accidents and potentially disastrous consequences, while satisfying the requirement of the damage tolerance, and improving the economy in operation. A fast and reliable crack parameters identification method is required for on-line monitoring of a large number of axles. Based on the response surface characteristics of crack position and depth at two sensors, a new method is proposed adopting two Kriging surrogate models constructed by the 2xRev values of vibration signals from two measurement points. Firstly, by exchanging part of inputs and outputs, a semi-inverse Kriging model is constructed to obtain a crack equivalent line. Then, the crack equivalent line is projected on another Kriging model as the convergence path, which is the key step transforming a two-objective optimization problem into a one-dimensional searching problem. Finally, an improved dichotomy method is used to obtain the result, by which the total number of steps and the calculation time is controlled on the premise of ensuring accuracy. Different from current multi-objective optimization algorithms searching with parallel computing, the proposed method reduces the number of parameters and searching model space to be one, belonging to serial computing. The comparison to other methods shows excellent features in computing speed and stability, and the experiment was implemented on a double-disk rotor system with similar structure to a wheelset, validating the proposed methodology.

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Peduto, Dario, Mariantonia Santoro, Luigi Aceto, Luigi Borrelli e Giovanni Gullà. "Full integration of geomorphological, geotechnical, A-DInSAR and damage data for detailed geometric-kinematic features of a slow-moving landslide in urban area". Landslides, 6 ottobre 2020. http://dx.doi.org/10.1007/s10346-020-01541-0.

Testo completo

Abstract (sommario):

Abstract The reconnaissance, mapping and analysis of kinematic features of slow-moving landslides evolving along medium-deep sliding surfaces in urban areas can be a difficult task due to the presence and interactions of/with anthropic structures/infrastructures and human activities that can conceal morphological signs of landslide activity. The paper presents an integrated approach to investigate the boundaries, type of movement, kinematics and interactions (in terms of damage severity distribution) with the built environment of a roto-translational slow-moving landslide affecting the historic centre of Lungro town (Calabria region, southern Italy). For this purpose, ancillary multi-source data (e.g. geological-geomorphological features and geotechnical properties of geomaterials), both conventional inclinometer monitoring and innovative non-invasive remote sensing (i.e. A-DInSAR) displacement data were jointly analyzed and interpreted to derive the A-DInSAR-geotechnical velocity (DGV) map of the landslide. This result was then cross-compared with detailed information available on the visible effects (i.e. crack pattern and width) on the exposed buildings along with possible conditioning factors to displacement evolution (i.e. remedial works, sub-services, etc.). The full integration of multi-source data available at the slope scale, by maximizing each contribution, provided a comprehensive outline of kinematic-geometric landslide features that were used to investigate the damage distribution and to detect, if any, anomalous locations of damage severity and relative possible causes. This knowledge can be used to manage landslide risk in the short term and, in particular, is propaedeutic to set up an advanced coupled geotechnical-structural model to simulate both the landslide displacements and the behavior of interacting buildings and, therefore, to implement appropriate risk mitigation strategies over medium/long period.

Gli stili APA, Harvard, Vancouver, ISO e altri

Articoli di riviste sul tema "MULTI CRACKED ROTOR"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili