Journal articles on the topic 'Rotating damage model'
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1
Yao, Hong Liang, Chun Yu Zhao, Wei Sun, and Bang Chun Wen. "Model Based Online Diagnosis of Rotating Machinery Structural Damage." Key Engineering Materials 353-358 (September 2007): 2289–92. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2289.
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Structural damage often happens in rotating machinery such as steam engines, aircraft engines, and compressors due to the high-speed rotating of the shaft. The most common structural damages in rotating machinery are rotor shaft crack, rotor to stator rub, and bolts looseness and so on. In the present paper, the model based identification method is used to detect single structural damage such as crack, rotor to stator rub, pedestal looseness, and also, coupling fault such as rotor to stator rub and crack, crack and pedestal looseness. Utilizing the characteristic that equivalent loads of rub forces are internal forces, and the equivalent loads of the crack are external moments, the coupling faults of crack and rub-impact and crack and pedestal looseness are analyzed and exampled. The merit of the method is that it is an online diagnosis method, which provides early warning of machine failure. Theoretical simulation and laboratory testing are conducted to validate the method.
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Jirásek, Milan, and Thomas Zimmermann. "Rotating Crack Model with Transition to Scalar Damage." Journal of Engineering Mechanics 124, no. 3 (March 1998): 277–84. http://dx.doi.org/10.1061/(asce)0733-9399(1998)124:3(277).
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Bhargav Sai, Cherukuri, and D. Mallikarjuna Reddy. "Dynamic Analysis of Faulty Rotors through Signal Processing." Applied Mechanics and Materials 852 (September 2016): 602–6. http://dx.doi.org/10.4028/www.scientific.net/amm.852.602.
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In this study, an effective method based on wavelet transform, for identification of damage on rotating shafts is proposed. The nodal displacement data of damaged rotor is processed to obtain wavelet coefficients to detect, localise and quantify damage severity. Because the wavelet coefficients are calculated with various scaled indices, local disturbances in the mode shape data can be found out in the finer scales that are positioned at local disturbances. In the present work the displacement data are extracted from the MATLAB model at a particular speed. Damage is represented as reduction in diameter of the shaft. The difference vectors between damaged and undamaged shafts are used as input vectors for wavelet analysis. The measure of damage severity is estimated using a parameter formulated from the distribution of wavelet coefficients with respect to the scales. Diagnosis results for different damage cases such as single and multiple damages are presented.
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Sun, He Yang, Ji Sheng Ma, Jia Jun Yao, Hai Ping Liu, and Wei Li. "Dynamic Analysis on the Rotating Band’s Engraving Process." Advanced Materials Research 139-141 (October 2010): 1285–88. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1285.
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The Johnson-Cook yielding criteria model, the initial damage model and the progressive damage and failure constitute model have been introduced into the constitutive equations of the rotating band. By using the penalty function method, the dynamic contact model has been introduced and an explicit dynamics finite element model has been established. The process of the rotating band impacting the throat bore was molded based on the elastic-plastic contact finite element theory. The rotating band pulling in and impacting the throat bore was simulated by the numerical computation. The dynamic responses of the rotating band and the projectile were obtained. And the stress distribution of the throat bore was studied. The influences of the engraving process on the interior ballistics were studied through the numerical computation.
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Huang, Shiping, Yong Tang, Zhaoxun Yuan, and Xiaopeng Cai. "An Efficient Contact Model for Rotating Mechanism Analysis and Design in Bridge Construction." Baltic Journal of Road and Bridge Engineering 16, no. 1 (March 29, 2021): 57–76. http://dx.doi.org/10.7250/bjrbe.2021-16.515.
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The rotation superstructure construction method is a widespread technique in bridge engineering. The critical issue for the successful application of this technique is the contact interface analysis and design for the rotating mechanism. A semi-analytical method predicated upon obtaining a uniform distribution of pressure on the slide plates within the interface is proposed. The surface design typically generates a nonlinear stress distribution. It leads to local damage and local asperity interlocking, which increase the contact friction dramatically during the rotation. In contrast, the proposed approach provides a surface that avoids stress concentrations and is expected to reduce the material cost of the slide plates. The proposed method is verified by the Finite Element Model. It can be used in a broad area involving contacting surface design, especially in the rotating mechanism design for bridge construction.
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Gu, Jiawei, Gang Liu, and Mengzhu Li. "Damage Detection for Rotating Blades Using Digital Image Correlation with an AC-SURF Matching Algorithm." Sensors 22, no. 21 (October 23, 2022): 8110. http://dx.doi.org/10.3390/s22218110.
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The motion information of blades is a key reflection of the operation state of an entire wind turbine unit. However, the special structure and operation characteristics of rotating blades have become critical obstacles for existing contact vibration monitoring technologies. Digital image correlation performs powerfully in non-contact, full-field measurements, and has increasingly become a popular method for solving the problem of rotating blade monitoring. Aiming at the problem of large-scale rotation matching for blades, this paper proposes a modified speeded-up robust features (SURF)-enhanced digital image correlation algorithm to extract the full-field deformation of blades. Combining an angle compensation (AC) strategy, the AC-SURF algorithm is developed to estimate the rotation angle. Then, an iterative process is presented to calculate the accurate rotation displacement. Subsequently, with reference to the initial state of rotation, the relative strain distribution caused by flaws is determined. Finally, the sensitivity of the strain is validated by comparing the three damage indicators including unbalanced rotational displacement, frequency change, and surface strain field. The performance of the proposed algorithm is verified by laboratory tests of blade damage detection and wind turbine model deformation monitoring. The study demonstrated that the proposed method provides an effective and robust solution for the operation status monitoring and damage detection of wind turbine blades. Furthermore, the strain-based damage detection algorithm is more advantageous in identifying cracks on rotating blades than one based on fluctuated displacement or frequency change.
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Maslen, E. H., C. K. Sortore, J. A. Va´zquez, and C. R. Knospe. "Synchronous Response Estimation in Rotating Machinery." Journal of Engineering for Gas Turbines and Power 124, no. 2 (March 26, 2002): 357–62. http://dx.doi.org/10.1115/1.1417482.
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Synchronous response estimation attempts to determine the forced response (displacement) of a rotor at critical points which cannot be measured directly. This type of prediction, if accurate and reliable, has broad potential use in the rotating machinery industry. Many machines have close clearance points on their shafts, such as seals, which can easily be damaged by excess vibration. Accurate estimates of the actual level of vibration at these points could usefully assist machine operators in troubleshooting and in protecting the equipment from expensive damage. This type of response information can be used both to generate less conservative alarm limits and, if magnetic bearings are available, to directly guide the bearing controllers in restricting the rotor motion at these critical points. It is assumed that the disturbance forces acting upon the rotor are predominantly synchronous. The response estimate is constructed using the measurable response in conjunction with an estimator gain matrix derived from a model of the transmissibilities of the rotor system. A fundamental performance bound is established based on the single-speed set of measurements by bounding the response to the unmeasurable component of the disturbance force. Acknowledging that some model uncertainty will always exist, a robust performance analysis is developed using structured singular value (μ) analysis techniques. Assuming some reasonable levels of uncertainty for the model parameters (natural frequencies, modal dampings, mode shapes, bearing stiffnesses, and dampings) the results of the estimator construction and analysis establish feasibility of the proposed estimation. Two reference rotor models that are representative of industrially sized machines are used to demonstrate and evaluate the estimation. The unmeasurable response estimation errors consistently lie below 25 μm for the examples examined.
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Uhl, Tadeusz, and Wojciech Lisowski. "Example of Application of Experimental Modal Model for Damage Detection for a Rotating Shaft." Key Engineering Materials 293-294 (September 2005): 329–36. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.329.
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Structural properties of machinery elements and sub-assemblies are often used for diagnostic purpose. Occasionally in engineering practice for some technical objects there is no description of distribution of structural parameter values available. Results of experimental evaluation of this distribution are difficult to be applied for diagnostic purpose as a result of lack of a reference distribution for comparison purposes. Nevertheless, for some technical objects, the inherent properties of the structural parameter values distribution may be used in such a case. In the paper an example of a rotating shaft is considered for which the axial symmetry of structural parameter values distribution is expected. Application of impact testing for the purpose of identification of the modal model is an easy way to check this symmetry and to use the results for diagnostic purpose. The technique applied to an example shaft indicated its failure but proved to be inefficient in localization of the failure.
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Sun, He Yang, Ji Sheng Ma, Long Bo Sheng, Wei Li, and Da Lin Wu. "CDM Model and its Application to Numerical Simulation on Rotating Band’s Engraving Process." Applied Mechanics and Materials 117-119 (October 2011): 1672–76. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1672.
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A coupled constitutive model of viscoplasticity and ductile damage for penetration problems has been deduced. The model proposed by Lemaitre was based on the continuum damage mechanics. In the model, large strain, high strain-rate, thermal softening and damage evolution were taken into account. At the meanwhile, Von Mises yield criterion, Johnson-Cook hardening model and Johnson-Cook fracture strain model were adopted. The model was implemented in the explicit finite element code Abaqus\Explicit through the Vumat subroutine by using an efficient explicit time integration algorithm. Based on the model, the rotating band’s engraving process was simulated, at the same time the influence of the stress state on damage evolution and the thermal softening effect was discussed. An effective way to simulate the fire process of gun was afforded.
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de Paula Monteiro, Ronant, Amanda Lucatto Marra, Renato Vidoni, Claudio Garcia, and Franco Concli. "A Hybrid Finite Element Method–Analytical Model for Classifying the Effects of Cracks on Gear Train Systems Using Artificial Neural Networks." Applied Sciences 12, no. 15 (August 4, 2022): 7814. http://dx.doi.org/10.3390/app12157814.
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Rotating machinery is fundamental in industry, gearboxes especially. However, failures may occur in their transmission components due to regular usage over long periods of time, even when operations are not intense. To avoid such failures, Structural Health Monitoring (SHM) techniques for damage prediction and in-advance detection can be applied. In this regard, correlations between measured signal variations and damage can be inspected using Artificial Intelligence (AI), which demands large numbers of data for training. Since obtaining signal samples of damaged components experimentally is currently unviable for complex systems due to destructive test costs, model-based numerical approaches are to be explored to solve this problem. To address this issue, this work applied an innovative hybrid Finite Element Method (FEM)–analytical approach, reducing computational effort and increasing performance with respect to traditional FEM. With this methodology, a system can be simulated with accuracy and without geometrical simplifications for healthy and damaged cases. Indeed, considering different positions and dimensions of damages (e.g., cracks) on the tooth roots of gears can offer new ways of damage investigation. As a reference to validate healthy systems and damage cases in terms of eigenfrequencies, a back-to-back test rig was used. Numerical simulations were performed for different cases, resulting in vibrational spectra for systems with no damage, with damage, and with damage of different intensities. The vibration spectra were used as data to train an Artificial Neural Network (ANN) to predict the machine state by Condition Monitoring (CM) and Fault Diagnosis (FD). For predicting the health and the intensity of damage to a system, classification and multi-class classification methods were implemented, respectively. Both sets of classification results presented good prediction agreement.
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Wang, Peng, Tie Yan, Xue Liang Bi, and Shi Hui Sun. "Fatigue Life Prediction of Buckling String with Cracks in Horizontal Wells of Mining Engineering." Advanced Materials Research 577 (October 2012): 127–31. http://dx.doi.org/10.4028/www.scientific.net/amr.577.127.
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Fatigue damage in the rotating drill pipe in the horizontal well of mining engineering is usually resulted from cyclic bending stresses caused by the rotation of the pipe especially when it is passing through curved sections or horizontal sections. This paper studies fatigue life prediction method of rotating drill pipe which is considering initial crack in horizontal well of mining engineering. Forman fatigue life prediction model which considering stress ratio is used to predict drill string fatigue life and the corresponding software has been written. The program can be used to calculate the stress of down hole assembly, can predict stress and alternating load in the process of rotating-on bottom. Therefore, establishing buckling string fatigue life prediction model with cracks can be a good reference to both operation and monitor of the drill pipe for mining engineering.
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Pang, Ding, Laihao Yang, Ruqiang Yan, Xuefeng Chen, Zhibo Yang, and Yu Sun. "Digital Twin-Driven Crack Monitoring for Rotating Blade: An L1 regularization Method." Journal of Physics: Conference Series 2184, no. 1 (March 1, 2022): 012022. http://dx.doi.org/10.1088/1742-6596/2184/1/012022.
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Abstract Crack-related damage of rotating blade is one of the most common failures of aeroengines. However, conventional blade crack monitoring methods are challenging to obtain the exact location and severity of the crack. In this study, a digital twin-driven blade crack monitoring method using the L1 regularization and sensitivity-based model updating is proposed to quantify the location and severity of crack damage for rotating blade. First and foremost, a digital twin model framework for rotating blade is established, including physical entity, digital entity, and the connection between them. Then a digital entity based on finite element model and an L1 regularized objective function based on the residual of natural frequencies are constructed, where the damage parameter of crack could be obtained by using the sensitivity-based model updating technology, hereby the location and severity of crack could be determined. Finally, numerical simulations are carried out, which verify that the proposed method is capable of accurately identifying the location and severity of crack, and could provide a reference for further research in this field.
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Zhao, Zhuang, Xiaoning He, Shuqi Shang, Jialin Hou, Hao Zhu, Haiqing Wang, Yuetao Wang, et al. "Design and Testing of Discrete Element-Based Counter-Rotating Excavation Device for Cyperus esculentus." Agriculture 12, no. 10 (October 4, 2022): 1608. http://dx.doi.org/10.3390/agriculture12101608.
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Currently, the mechanized harvesting method of Cyperus esculentus is mainly based on rotary excavation, but there are problems such as high working resistance, high damage rate, and high buried fruit rate in the working process. This paper focuses on the analysis of the movement trajectory of the positive-rotating and counter-rotating Cyperus esculentus excavation device, establishes a agglomerate model of soil-Cyperus esculentus tuber-Cyperus esculentus root system-mechanism, and conducts discrete element simulation tests on Cyperus esculentus agglomerates under different soil layers. According to Expert test optimization, the optimal structural parameters of the counter-rotating blade are determined: the radius of gyration is 151 mm, the inclination angle of the cutting edge is 42.5°, and the working width is 318 mm. The comparative test of the positive-rotating rotary tillage method under the optimal structural parameters shows that the working resistance is reduced by 11.25%, and the torque of the tool shaft is reduced by 16.11%, which proves that the designed anti-rotation excavation structure has the effect of reducing resistance. To further test the harvesting performance of the Cyperus esculentus excavation device, field harvesting tests were conducted, and the results showed that the buried fruit rate of the counter-rotating excavation device was reduced by 11.6%, and the damage rate was reduced by 6.1% year-on-year. This study shows that the design of the counter-rotating excavation device can further improve the harvesting performance of Cyperus esculentus based on reduced resistance harvesting and meet the requirements of Cyperus esculentus harvesting.
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Badreddine, Houssem, and Khemais Saanouni. "On the full coupling of plastic anisotropy and anisotropic ductile damage under finite strains." International Journal of Damage Mechanics 26, no. 7 (March 3, 2016): 1080–123. http://dx.doi.org/10.1177/1056789516635729.
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In this work, thermodynamically consistent, non-associative and fully anisotropic elastoplastic constitutive equations strongly coupled with ductile anisotropic damage developed in previous work are used to study the responses of the proposed model under various simple and complex loading paths. First, the complete set of the fully coupled non-associative constitutive equations based on the rotated frame formulation (RFF) for finite strains is summarized and shortly discussed. Then, the effect of the rotating frame in the model response is analyzed on the light of typical loading paths. The influence of the induced plastic anisotropies on the evolution of the anisotropic ductile damage is investigated. Finally, the responses of the model for non-proportional loading paths are studied, compared and discussed with respect to the initial and induced anisotropies of the plastic flow and the ductile damage evolution as well as with respect to the rotating frame choice.
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Obuchowski, Jakub, Agnieszka Wylomanska, and Radoslaw Zimroz. "Stochastic Modeling of Time Series with Application to Local Damage Detection in Rotating Machinery." Key Engineering Materials 569-570 (July 2013): 441–48. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.441.
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Raw vibration signals measured on the machine housing in industrial conditions are complex and can be modeled as an additive mixture of several processes (with different statistical properties) related to normal operation of machine, damage related to one (or more) of its part, some noise, etc. In the case of local damage in rotating machines, contribution of informative process related to damage is hidden in the raw signal so its detection is difficult. In this paper we propose to use the statistical modeling of vibration time series to identify these components. Building the model of raw signal may be ineffective. It is proposed to decompose signal into set of narrowband sub-signals using time-frequency representation. Next, it is proposed to model each sub-signal in the given frequency range and classify all signals using their statistical properties. We have used several parameters (called selectors because they will be used for selection of sub-signals from time-frequency map for further processing) for analysis of sub-signals. They have base in statistics theory and can be useful for example in testing of normality of data set (vibration time series from machine in good condition is close to Gaussian, damaged not). Results of such modeling will be used in the sub-signals classification procedure but also in defects detection. We illustrate effectiveness of novel technique using real data from heavy machinery system.
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Gopinath, Smitha, J. Rajasankar, and N. R. Iyer. "Nonlinear Analysis of RC Structures Using Isotropic Damage Model." International Journal of Damage Mechanics 21, no. 5 (August 17, 2011): 647–69. http://dx.doi.org/10.1177/1056789511410457.
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This article proposes a simple isotropic damage model within damage mechanics framework to represent the behavior of concrete in tension. Macroscopic evolution of tensile crack is considered as damage and is mathematically defined using an exponential function of tensile strain. A damage evolution law is formulated by applying strain equivalence principle to hyperbolic tension-softening curve. Value of damage variable is assumed theoretically to vary between ‘0’ and ‘1’ to denote uncracked and ruptured states, respectively. A smeared rotating crack model is coupled with damage formulation to simulate crack propagation effects in nonlinear finite element analysis of reinforced concrete (RC) structures. Many deficiencies of smeared crack model such as stress locking, mesh-induced directional bias, and instability in response computation for near-ultimate load are overcome using the coupled model. To verify the proposed model, nonlinear static response behavior of a RC beam is computed and compared with experimental and analytical results reported in literature. Effectiveness and applicability of the model to analyze practical structures are proved by analyzing a RC chimney. Nonlinear response of RC chimney is reviewed at global level while damage states of finite elements are studied at local level.
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Subhash, G., and W. Zhang. "Finite Element Analysis of Brittle Cracking due to Single Grit Rotating Scratch." Journal of Applied Mechanics 70, no. 1 (January 1, 2003): 147–51. http://dx.doi.org/10.1115/1.1526119.
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Finite element analysis of single grit rotating scratch on brittle materials was conducted using an “elastic-plastic-cracking” (EPC) model. The brittle material removal mechanism was modeled based on a critical crack-opening displacement criterion. It was found that the tangential and normal force profiles as well as the damage morphology observed in scratch experiments were fully captured by the EPC model. The results revealed that the induced damage zone size increases linearly with a brittleness parameter EY/σf21/3 as well as the maximum depth of cut.
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Badreddine, Houssem, and Khemais Saanouni. "Advanced Anisotropic Damage Model Fully Coupled with Anisotropic Plasticity." Applied Mechanics and Materials 784 (August 2015): 153–60. http://dx.doi.org/10.4028/www.scientific.net/amm.784.153.
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In this work, a thermodynamically-consistent framework is used to formulate a non-associative finite strain anisotropic elastoplastic model fully coupled with anisotropic ductile damage. The finite strain assumption is considered using specific large strains kinematics based on multiplicative decomposition of the total transformation gradient and assuming a small elastic strains. The objectivity principle fulfillment is assumed using the well-known rotating frame formulation. The effective variables are defined to introduce the effect of the anisotropic damage on the other variables through the total energy equivalence assumption. The non-associative plasticity framework, for which equivalent stresses in yield function and in plastic potential are separately defined, allows better plastic anisotropy description. The evolution equations for overall dissipative phenomena are deduced from the generalized normality rule applied to the plastic potential while the consistency condition is still applied to the yield function. Applications are made to an RVE with generic material parameters by considering non-proportional loading paths. For each loading path the effect of the anisotropic plasticity on the damage evolution is studied in the context of finite strains.
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Cheng, Feng, and Weixi Ji. "Cavitation erosion of a single bubble in water as a kind of dynamic damage." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 231, no. 11 (February 10, 2017): 1383–89. http://dx.doi.org/10.1177/1350650117694251.
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In this study, a rotating disk test rig was used for the cavitation test of the brass samples. A pit of single black dapple and a large pit of multiring black dapple were found on the sample surfaces after 30 h test. A cavitation model of the rotating disk test was further developed by applying a periodic water pressure into the Keller–Miksis equation, so as to obtain the bubble dynamic characteristics. A comparison with the available experimental results reveals that the velocity of the bubble wall is governed by the initial bubble radius, and the bubble collapsing mode has changed from single bubble compression with high velocity to multiple bubble compression, with a increase in the initial bubble radius. The results also show that the movement of the spherical bubble wall induces the formation of the micro-jet with high velocity, leading to cavitation erosion pits on the specimen surface in the rotating disk test, which are well verified by the present theoretical model as well as the available experimental results.
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Qian, Yi Qing, and Zu Jian Qiu. "Analysis on Rotating Dynamics of Tennis." Applied Mechanics and Materials 246-247 (December 2012): 487–91. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.487.
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High speed torque is very important in tennis batting process , this paper discusses the shoulder and torso rotation torque generated by the weight of tennis sports influence. Taking 48 tennis players as research objects, the rotation torque of professional tennis players are relatively outstanding with performance value,so we concluded that in the case of keeping the torso erect and through the process optimization of the rotation, we could combined shoulder movement and body bottom-up movement. These results suggested that some given hitting model can not only increase the performance of the tennis player on the pitch, but also reduce the risk of causing excessive damage.
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Seibold, Susanne, and Claus-Peter Fritzen. "Identification Procedures as Tools for Fault Diagnosis of Rotating Machinery." International Journal of Rotating Machinery 1, no. 3-4 (1995): 267–75. http://dx.doi.org/10.1155/s1023621x9500011x.
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System identification procedures offer the possibility to correct erroneous models, based on measurement data. Recently, this conventional field of application is being extended to fault detection and system diagnosis. In contrast to conventional approaches, identification procedures try to establish an unequivocal relation in between the damage and specific mechanical parameters, based on a suitable model. Furthermore, they can be employed during normal operation of the machinery. In this paper, several identification procedures on the basis of the Extended Kalman Filter are introduced and employed for model-based fault detection. Their feasability is proved by several examples. First, it is shown that the crack depth of a simulated Jeffcott-rotor can be calculated correctly. Then, the procedures are utilized to determine the crack depth of a rotor test rig. Finally, it is proved that identification procedures can be employed for the determination of unbalances without having to apply test masses.
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Brockman, R. A., R. John, and M. A. Huelsman. "Using deformation modes to identify cracks in turbine engine compressor disks." Aeronautical Journal 113, no. 1150 (December 2009): 811–19. http://dx.doi.org/10.1017/s0001924000003468.
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Abstract Recent studies show that analytical predictions of crack growth in rotating components can be used in conjunction with displacement measurement techniques to identify critical levels of fatigue damage. However, investigations of this type traditionally have focused on the detection of damage at known flaw locations. This paper addresses the related problem of estimating damage associated with flaws at unknown locations, through the combined use of analytical models and measured vibration signatures. Because the measured data are insufficient to identify a unique solution for the location and severity of fatigue cracks, the function of the analytical model is to bound the extent of damage occurring at life-limiting locations. The prediction of remaining life based on estimates of worst-case fatigue damage and crack locations also is discussed.
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Daiand Hongfu Zuo, Weijie. "Research on foreign object damage and grinding repair schemes of compressor blades." Journal of Physics: Conference Series 2403, no. 1 (December 1, 2022): 012024. http://dx.doi.org/10.1088/1742-6596/2403/1/012024.
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Abstract Foreign object damage (FOD) on compressor blades of aero-engines lowers the capacity of blades and poses a serious threat to civil aviation safety, so the repair of blades with FOD deserves more attention. The finite element model of the aero-engine compressor blade was established, and the finite element analysis was carried out on the damaged blades with FOD notches and the blades after grinding and repair. The natural frequencies of different types of blades and the global and local peak stress under rotating conditions were compared. It was confirmed that the stiffness of the repaired blades was acceptable, and the optimal grinding repair scheme was selected.
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Wang, Yifan, and Lihui Yin. "Research on Seismic Vulnerability of High-Pier and Long-Span Bridges Based on Improved IMK Resilience Model." Journal of Sensors 2022 (January 27, 2022): 1–11. http://dx.doi.org/10.1155/2022/6477297.
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After the fragility curve is established, the probability of structural damage reaching each level of damage under the action of the ground motion can be determined according to the ground motion parameters, so as to calculate the direct and indirect loss caused by the structural damage and complete the earthquake damage prediction. This paper combines the improved IMK resilience model to study the seismic vulnerability of high-pier and long-span bridges. Moreover, this paper obtains the parameter calculation model based on the regression analysis of PEER’s 255 column specimen data. The improved IMK model needs to modify the elastic stiffness and strain hardening rate of the rotating spring to ensure the accuracy of the lateral stiffness of the component. The experimental research shows that the seismic vulnerability research model of high-pier and long-span bridges based on the improved IMK restoring force model has a certain analytical effect.
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Kwon, Junhee, Dongwoo Hong, and Byeongil Kim. "Modeling, analysis, and control of shaft transverse vibration from rotating systems through active bearing concept." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 7 (February 1, 2023): 649–56. http://dx.doi.org/10.3397/in_2022_0088.
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Rotating parts are widely applied to mechanical systems such as pumped-storage hydroelectricity, nuclear power plant, machining tools and so on. While operating, they can be easily damaged or destroyed by unbalanced mass, bending, torsion and misalignment. In order to solve this problem, rotor vibration control can be conducted through active bearing concept. In this work, active bearing system which consists of piezo actuators and rubber grommets is proposed and applied to a rotating system motivated from a pumped-storage hydroelectricity, for performing active vibration control. The main point of this paper is to prevent damage or failure caused by harsh transverse vibration through active bearings. First, the rotating system is modeled by transfer matrix method (TMM) based on Euler-Bernoulli beam theory and in order to check accuracy of this model, the responses of TMM are compared with the responses from the finite element method (FEM). For implementing active control in real time, normalized least mean square (NLMS) algorithm is utilized. The results show that the proposed active bearing concept shows great performance on the attenuation of shaft transverse vibration.
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Mehdigholi, H., H. Rafsanjani, and Behzad Mehdi. "Estimation of rolling bearing life with damage curve approach." Polish Maritime Research 18, no. 3 (January 1, 2011): 66–70. http://dx.doi.org/10.2478/v10012-011-0019-6.
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Estimation of rolling bearing life with damage curve approach The ability to determine the bearing life time is one of the main purposes in maintenance of rotating machineries. Because of reliability, cost and productivity, the bearing life time prognostic is important. In this paper, a stiffness-based prognostic model for bearing systems is discussed. According to presumed model of bearing and fundamental of damage mechanics, damage curve approach is used to relate stiffness of vibratory system and bearing running life. Furthermore, using the relation between acceleration amplitude at natural frequency and stiffness, final relation between acceleration amplitude at natural frequency and running life time according to damage curve approach can be established and the final running time is predicted. Experiments have been performed on self alignment bearing under failures on inner race and outer race to calibrate and to validate the proposed model. The comparison between model-calculated data and experimental results indicates that this model can be used effectively to predict the failure lifetime and the remaining life of a bearing system.
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Teng, Hsiang Yu, Gow Yi Tzou, and Yeong-Maw Hwang. "FEM Simulation on Rotating Piercing Process with Coulomb Friction." Applied Mechanics and Materials 284-287 (January 2013): 127–31. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.127.
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This study proposes a new piercing technology with rotating punch; it carries out an FEM simulation on rotating piercing process using DEFORM-3D commercial software. Frictions among the punch, the blank holder, the dies and the work-piece material are assumed as Coulomb friction, but can be different. The surface of the inner diameter, the effective stress, the effective strain, velocity field, damage, burr and the shearing force can be determined form the FEM simulation. In this study, effects of various piercing conditions such as the clearance, the punch nose angle, the frictional coefficient, the rotating angular velocity, the shearing force, and burr on shearing characteristics are explored effectively to realize the feasibility of FEM model.
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Wang, Sukang, Sun Quansheng, Yu Haitao, and Wang Hongyang. "SEISMIC VULNERABILITY ANALYSIS OF CABLE-STAYED BRIDGE DURING ROTATION CONSTRUCTION." Stavební obzor - Civil Engineering Journal 31, no. 3 (October 30, 2022): 384–99. http://dx.doi.org/10.14311/cej.2022.03.0029.
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Due to the swivel construction, the structural redundancy of cable-stayed bridge is reduced, and its seismic vulnerability is significantly higher than that of non-swirling construction structure and its own state of formation. Therefore, it is particularly important to study the damage changes of each component and stage system during the swivel construction of cable-stayed bridge under different horizontal earthquakes. Based on the construction of Rotary Cable-stayed Bridge in Haxi Street, the calculation formula of damage exceeding probability is established based on reliability theory, and the damage calibration of cable-stayed bridge components is carried out, and the finite element model of cable-stayed bridge rotating structure is established. The vulnerable parts of the main tower and the stay cable components of the cable-stayed bridge are identified and the incremental dynamic analysis is carried out. Finally, the seismic vulnerability curves of the main tower section, the stay cable and the rotating system are established. The results of the study show that the vulnerable areas of the H-shaped bridge towers are the abrupt changes in the main tower section near the upper and lower beams, and the vulnerable diagonal cables are the long cables anchored to the beam ends and the short cables near the main tower；At the same seismic level, the damage exceedance probability of main tower vulnerable section of cable-stayed bridge under transverse earthquake is greater than that under longitudinal earthquake, the damage exceedance probability of vulnerable stay cables under transverse seismic action is less than that under longitudinal seismic action；On the premise of the same damage probability, the required ground motion intensity of the system can be reduced by 0.35g at most compared with the component；Under the same seismic intensity, the system damage probability is 6.60 % higher than the component damage probability at most. The research results have reference significance for the construction of rotating cable-stayed bridges in areas lacking seismic records.
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Huo, Li. "Introduce the Quantitative Identification Method of Rolling Bearing in the Application of Fault Detection." Applied Mechanics and Materials 742 (March 2015): 147–49. http://dx.doi.org/10.4028/www.scientific.net/amm.742.147.
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Rolling bearing is an important part of rotating machinery. Its failure will directly affect the normal operation of the whole machinery. This study proposed an intelligent diagnosis model based on Fuzzy support vector description for the quantitative identification of bearing fault. The proposed model constructs the spherically shaped decision boundary by training the features of normal bearing data, and then calculates the fuzzy monitoring coefficient to identify the bearing damage.
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Trapp, Robert J., Geoffrey R. Marion, and Stephen W. Nesbitt. "The Regulation of Tornado Intensity by Updraft Width." Journal of the Atmospheric Sciences 74, no. 12 (December 1, 2017): 4199–211. http://dx.doi.org/10.1175/jas-d-16-0331.1.
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Abstract Strong to violent tornadoes cause a disproportionate amount of damage, in part because the width and length of a tornado damage track are correlated to tornado intensity (as now estimated through enhanced Fujita scale ratings). The tendency expressed in the observational record is that the most intense tornadoes are often the widest. Herein the authors explore the simple hypothesis that wide intense tornadoes should form more readily out of wide rotating updrafts. This hypothesis is based on an application of Kelvin’s circulation theorem, which is used to argue that the large circulation associated with a wide intense tornado is more plausibly associated with a wide mesocyclone. Because a mesocyclone is, strictly speaking, a rotating updraft, the mesocyclone width should increase with increasing updraft width. A simple mathematical model that is quantified using observations of mesocyclones supports this hypothesis, as do idealized numerical simulations of supercellular thunderstorms.
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Szuwalski, Krzysztof, and Aneta Ustrzycka. "Mathematical and Numerical Modelling of Large Axisymmetric Creep Strains and Damage." Applied Mechanics and Materials 784 (August 2015): 241–48. http://dx.doi.org/10.4028/www.scientific.net/amm.784.241.
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The paper presents a simulation model for the creep process of rotating disks under radial tensional pressure subjected to of body force. The finite strain theory is applied. The material is described by the Norton-Bailey law generalized for true stresses and logarithmic strains. The mathematical model is formulated in form of set of four partial differential equations with respect to radial coordinate and time. Necessary initial and boundary conditions are also given. To make the model complete, the numerical procedure for solving this set is proposed. What is worth noticing the classical FEM is not applicable, because not only geometry, but also loading (body forces) change in time during the creep process. It would demand redefinition of finite elements at each time step. In uniaxial problem similar model was presented in [4], but now it is developed for complex stress state. Possible different formulations of initial and boundary conditions may be found in [5]. The procedure may be useful in problems of optimal design of full disks in [6].
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Zhou, Chuanlu, Long Qin, Ming Chen, and Jingxiang Zhang. "Coriolis Force Sliding Mode Control Method for the Rotary Motion of the Central Rigid Body-Flexible Cantilever Beam System in TBM." Advances in Civil Engineering 2021 (December 23, 2021): 1–7. http://dx.doi.org/10.1155/2021/9866453.
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Beam slab structure is often encountered in a complex tunnel boring machine. Beam slab structure is subject to dynamic load, which is easy to cause fatigue damage and affect its service life. Therefore, it is necessary to control the vibration of this kind of beam slab structure. In this study, the central rigid body-flexible beam model is established for the rotating beam and plate rotating around the y-axis. Based on the Hamilton variational principle, the dynamic equation of the central rigid body-flexible beam system is established, and the dynamic model of the central rigid body-flexible beam system considering the influence of Coriolis force and centrifugal force is given. The vibration control of the central rigid body-flexible beam system is studied. The vibration mode of the rotating Euler Bernoulli beam is determined by using the elastic wave and vibration mode theory. The influence of the rotating motion on the beam vibration is analyzed, and the variable structure control law is designed to suppress the beam vibration. Numerical simulation results show that the control method can effectively suppress the first-order and second-order vibration of the beam and verify the effectiveness of the control strategy.
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Jiang, Xiaomo, Fumin Wang, Haixin Zhao, Shengli Xu, and Lin Lin. "Novel Orbit-based CNN Model for Automatic Fault Identification of Rotating Machines." Annual Conference of the PHM Society 12, no. 1 (November 3, 2020): 7. http://dx.doi.org/10.36001/phmconf.2020.v12i1.1147.
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Various faults in high-fidelity turbomachinery such as steam turbines and centrifugal compressors usually result in unplanned outage thus lowering the reliability and productivity while largely increasing the maintenance costs. Condition monitoring has been increasingly applied to provide early alerting on component faults by using the vibration signals. However, each type of fault in different types of rotating machines usually require an individual model to isolate the damage for accurate condition monitoring, which require costly computation efforts and resources due to the data uncertainties and modeling complexity. This paper presents a generalized deep learning methodology for accurately automatic diagnostics of various faults in general rotating machines by utilizing the shaft orbits generated from vibration signals, considering the high non-linearity and uncertainty of the sensed vibration signals. The sensor anomalies and environmental noise in the vibration signals are first addressed through waveform compensation and Bayesian wavelet noise reduction filtering. Shaft orbit images are generated from the cleansed vibration data collected from different turbomachinery with various fault modes. A multi-layer convolutional neural network model is then developed to classify and identify the shaft orbit images of each fault. Finally, the fault diagnosis of rotating machinery is realized through the automated identification process. The proposed approach retains the fault information in the axis trajectory to the greatest extent, and can adeptly extract and accurately identify features of various faults. The effectiveness and feasibility of the proposed methodology is demonstrated by using the sensed vibration signals collected from real-world centrifugal compressors and steam turbines with different fault modes.
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Butler, Shaoluo, Mark Gurvich, Anindya Ghoshal, Gregory Welsh, Paul Attridge, Howard Winston, Michael Urban, and Nathaniel Bordick. "Effect of embedded sensors on interlaminar damage in composite structures." Journal of Intelligent Material Systems and Structures 22, no. 16 (August 30, 2011): 1857–68. http://dx.doi.org/10.1177/1045389x11414225.
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This research focuses on developing an embedded sensor system to monitor the health of a composite rotor component. To support this objective, simulations were developed to investigate the impact of sensor insertions on local structural micro-mechanics and sensor responses. In particular, the potential side-effects (e.g., delamination onset and growth) of imbedding lead zirconate titanate (PZT) piezoelectric sensors in composite structures were studied. A modeling approach for evaluating interlaminar damage under the influence of embedded PZT sensors is proposed. The approach uses finite element cohesive zone models to describe interlaminar damage between plies or at ply ends. In addition, an embedded multi-ply PZT model was developed and integrated with the damage models. The approach presented in this paper analyzes the propagation of interlaminar damage in the vicinity of sensors and quantifies the effect of sensor presence on damage growth. A parametric study was performed to understand how damage zones, the size and geometry of resin pockets, and the locations and properties of PZT sensors affected interfacial strength. Damage behavior, under the influence of an embedded PZT sensor, was examined in specimens having a configuration similar to that of a selected rotating rotorcraft component. Finally, optimal locations of embedded PZT transducers were determined for the specimen under consideration.
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Cui, Li. "A new fatigue damage accumulation rating life model of ball bearings under vibration load." Industrial Lubrication and Tribology 72, no. 10 (June 1, 2020): 1205–15. http://dx.doi.org/10.1108/ilt-05-2019-0180.
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Purpose Bearings in electric machines often work in high speed, light load and vibration load conditions. The purpose of this paper is to find a new fatigue damage accumulation rating life model of ball bearings, which is expected for calculating fatigue life of ball bearings more accurately under vibration load, especially in high speed and light load conditions. Design/methodology/approach A new fatigue damage accumulation rating life model of ball bearings considering time-varying vibration load is proposed. Vibration equations of rotor-bearing system are constructed and solved by Runge–Kutta method. The modified rating life and modified reference rating life model under vibration load is also proposed. Contrast of the three fatigue life models and the influence of dynamic balance level, rotating speed, preload of ball bearings on bearing’s fatigue life are analyzed. Findings To calculate fatigue rating life of ball bearings more accurately under vibration load, especially in high speed and light load conditions, the fatigue damage accumulation rating life model should be considered. The optimum preload has an obvious influence on fatigue rating life. Originality/value This paper used analytical method and model that is helpful for design of steel ball bearing in high speed, light load and vibration load conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2019-0180/
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Zhu, Kang, Xinwen Zhao, Liming Zhang, and Hang Yu. "A Hybrid Method to Predict the Remaining Useful Life of Scroll Wheel of Control Rod Drive Mechanism." Science and Technology of Nuclear Installations 2022 (August 29, 2022): 1–11. http://dx.doi.org/10.1155/2022/2383789.
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As one of the rotating components in the reluctance motor type control rod drive mechanism (CRDM), the life of the scroll wheel is closely related to the service life of the CRDM. In addition, the prediction of the remaining useful life of the scroll wheel helps to optimize the maintenance process of the CRDM. This paper proposes a hybrid method to predict its remaining useful life when the available degradation data are rare and the failure threshold cannot be accurately defined. First, the particle filtering algorithm, whose state transfer equation is established on the segmental damage physical model, is used to predict the degradation state of the scroll wheel. Second, the proportional hazard model for the relationship between the scroll wheel damage characteristics and reliability model is established to predict the remaining useful life of it. The proposed method focuses on the establishment of segmental damage physical model and the clustering analysis of damage characteristics extracted from vibration signals, which can be used to predict the remaining useful life of the scroll wheel. In addition, the results provide an opportunity for the condition-based preventive maintenance of the CRDM.
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Kang, Gui Wen, and Fei Hu Zhang. "Research on Material Removal of Magnetorheological Finishing." Key Engineering Materials 329 (January 2007): 285–90. http://dx.doi.org/10.4028/www.scientific.net/kem.329.285.
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Magnetorheological finishing (MRF) is a novel precision optical machining technology. Owing to its flexible finishing process, MRF can eliminate subsurface damage, smooth rms micro roughness and correct surface figure errors. The finishing process can be easily controlled by a computer. Material removal model in MRF is established. According to Preston equation in optical machining, mathematic model of material removal rate in MRF rotating at fixed rate is established through hydrodynamic analysis of the MR fluid flow in the polishing zone. The validity of the model is examined by the experimental results.
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Бурау, Надія Іванівна, and Ольга Ярославівна Паздрій. "Фізичне моделювання та діагностика попадання сторонніх предметів в обертову систему." Aerospace technic and technology, no. 4sup1 (August 27, 2021): 62–67. http://dx.doi.org/10.32620/aktt.2021.4sup1.09.
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The paper analyzes the vibroacoustic signals obtained by physical modeling of the rotating system, for example, an aircraft gas turbine engine, in the conditions of steady-state and non-steady-state modes. An air starter (supercharger) is used as a physical model of a rotating system, which is driven by a DC motor. The measuring system uses a dynamic microphone with an amplifier, a tachometer, a two-channel digital oscilloscope, a personal computer with technological and special software. The simulation of the ingress of foreign objects into the rotating system is performed by throwing paper balls during the rotation. The multilevel processing based on sequential application of methods of frequency-time analysis, multispectral analysis, and fractal analysis is proposed and substantiated for processing of measured vibroacoustic signals. The results of the frequency-time analysis showed that at the time of throwing the balls the intensity of the components at higher frequencies increases. For fragments of signal realization without throwing and with the throwing of balls the multispectral analysis is carried out and estimates of the bispectrum modulus are received in the form of contour images. At the third level of signal processing, the Minkowski dimension of the contour images of the bispectrum module estimates is determined. The Minkowski dimension is an integral quantitative indicator of the geometry of isolines and differs in value for the selected fragments of the vibroacoustic signal. So it can be used as a diagnostic sign of a foreign object entering the rotating system at the final level of processing. The obtained results can be used to improve the systems of condition monitoring of complex rotating systems, increase sensitivity, expand functionality and provide multi-class diagnostics in the event of damage and violation of normal operating modes
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Yoder, Nathanael C., Timothy J. Johnson, and Douglas E. Adams. "Near Real-Time Monitoring of Bead Area Damage in Rolling Tires Using a Rotating Wheel Model and Multi-Directional Vibration Data." Key Engineering Materials 347 (September 2007): 233–38. http://dx.doi.org/10.4028/www.scientific.net/kem.347.233.
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In current tire durability tests, technicians must stop tests periodically to inspect each tire, resulting in a time consuming, expensive, and relatively subjective process. Online tire monitoring would thus be a dramatic improvement over the current methodology. If such a system could be extended to on-line vehicle use, it could dramatically increase safety, reduce downtime, and lead to better fuel efficiency in commercial and passenger cars and trucks. A near real-time system to monitor the initiation of bead area damage in rolling tires was developed using vibration data collected from the wheel end spindle. To generate an accurate model of the forced response of the wheel end spindle, a tire on a fixed spindle was impacted with a modal punch while the tire was preloaded against a plate. The frequency response functions acquired from this system were then used to develop a rotating tire model consisting of time-delayed forcing functions applied to the tire patch at the rolling frequency; this model was used to assist in interpreting the results from the near real-time monitoring system. The near real-time continuous monitoring system has been deployed in a manufacturing test environment and utilizes frequency data from three mutually orthogonal acceleration measurements. These data are combined to create a highly sensitive composite index that identifies when the initiation of bead area damage has occurred.
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Lee, Jeong-In, Tae-Kyoung Bang, Hoon-Ki Lee, Jong-Hyeon Woo, Junghyo Nah, and Jang-Young Choi. "Design of the High-Speed PMSG with Two Different Shaft Material Considering Overhang Effect and Mechanical Characteristics." Applied Sciences 11, no. 16 (August 20, 2021): 7670. http://dx.doi.org/10.3390/app11167670.
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In general, high-speed machines should be designed to satisfy electromagnetic and mechanical characteristics. In this study, the design of high-speed permanent magnet synchronous generator with two different shaft materials considering overhang effect and mechanical characteristics was performed. It was confirmed that the leakage magnetic flux generated by the two shaft materials electromagnetically affects the high-speed generator. Additionally, it is important to accurately predict the natural frequency mode and critical speed to prevent damage and vibration of the rotating body owing to scattering during high-speed rotation. Therefore, the mechanical characteristics of the designed model were analyzed. In this study, we propose a design method that considers both the electromagnetic effects and mechanical characteristics. Subsequently, verification was performed through experiments and comparisons for the validity and reliability of the proposed design method.
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Zhang, Jianfei, Guangqiao Cao, Yue Jin, Wenyu Tong, Ying Zhao, and Zhiyu Song. "Parameter Optimization and Testing of a Self-Propelled Combine Cabbage Harvester." Agriculture 12, no. 10 (October 4, 2022): 1610. http://dx.doi.org/10.3390/agriculture12101610.
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On account of a lack of suitable and specialized harvesting equipment for cabbage species and planting modes in China, in this study, a type of 4GCSD-1200 type cabbage harvester was designed to further optimize the working performance of the cabbage harvester. First, the structure and working principles of the harvester were introduced, and the cabbage harvesting process was analyzed. Based on the test method and theoretical analysis, a single-factor test was carried out on the main working parameters of the sample machine, the advancing speed, rotating speed of the pulling roller, rotating speed of the conveyor belt, and the cutter-head were taken as independent variables, and the qualifying rate of cabbage harvesting was taken as the response value. According to the Box–Behnken test design principles, a four-factor three-level response surface analysis was adopted to establish a mathematical model between all test factors and the qualifying rate of cabbage harvesting, then all test factors and their interaction effects were analyzed. The test results showed that the optimal working parameters of the harvester were: the advancing speed was 1.1 km/h, the rotating speed of the pulling roller was 90 r/min, the rotating speed of the conveyor belt was 205 r/min, and the rotating speed of the cutter-head was 395 r/min. The verification test results showed that the qualifying rate of cabbage harvesting was 96.3%, showing a good harvesting effect, with uniformly cut notches and a low damage rate. The test indicates that by optimizing the working parameters, the damage during the mechanized harvesting of cabbage can be reduced and the qualifying rate of harvesting can be improved; the working effect could, therefore, satisfy the requirements of market harvesting.
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Li, W. R., Y. F. Du, S. Y. Tang, and L. J. Zhao. "Structural Damage Identification Based on the Minimum System Realization and Sensitivity Analysis." Mathematical Problems in Engineering 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/405760.
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On the basis of the thought that the minimum system realization plays the role as a coagulator of structural information and contains abundant information on the structure, this paper proposes a new method, which combines minimum system realization and sensitivity analysis, for structural damage detection. The structural damage detection procedure consists of three steps: (1) identifying the minimum system realization matrixes A, B, and R using the structural response data; (2) defining the mode vector, which is based on minimum system realization matrix, by introducing the concept of the measurement; (3) identifying the location and severity of the damage step by step by continuously rotating the mode vector. The proposed method was verified through a five-floor frame model. As demonstrated by numerical simulation, the proposed method based on the combination of the minimum realization system and sensitivity analysis is effective for the damage detection of frame structure. This method not only can detect the damage and quantify the damage severity, but also is not sensitive to the noise.
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Nayebi, Ali, Ali Tirmomenin, and Mohsen Damadam. "Elasto-Plastic Analysis of a Functionally Graded Rotating Disk Under Cyclic Thermo-Mechanical Loadings Considering Continuum Damage Mechanics." International Journal of Applied Mechanics 07, no. 02 (April 2015): 1550026. http://dx.doi.org/10.1142/s175882511550026x.
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The goal of this work is to study the influence of continuum damage mechanics on a functionally graded rotating disk subjected to cyclic temperature gradient loading through nonlinear kinematic hardening rule employed to model the back stress. The formulations have been developed on the basis of von Mises' yield criterion. The material properties are assumed to be independent of temperature and vary according to a power law volume fraction relation but Poisson's ratio is assumed to be constant. Return mapping algorithm (RMA), an incremental method, has been used in the numerical procedure. Material behaviors such as elastic shakedown, plastic shakedown and ratcheting were specified in the existence of continuum damage mechanics to obtain the Bree's interaction diagram for different temperatures and angular velocities.
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Lin, Chih-Jer, Wen-Lin Chu, Cheng-Chi Wang, Chih-Keng Chen, and I.-Ting Chen. "Diagnosis of ball-bearing faults using support vector machine based on the artificial fish-swarm algorithm." Journal of Low Frequency Noise, Vibration and Active Control 39, no. 4 (July 31, 2019): 954–67. http://dx.doi.org/10.1177/1461348419861822.
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Ball bearings are important parts of all modern rotating machines. Their function is to reduce friction, support rotating shafts and spindles, and bear loads. Bearing damage can result in abnormal vibrations, cause machine malfunction, and even be dangerous. In this study, analysis of four different ball-bearing conditions was carried out: normal bearings and bearings with inner ring, rolling body, and outer ring malfunction. This was based on electromechanical vibration signals produced on a fault diagnosis simulation platform. The objective was to use a series of signal processing analytical methods to build a set of identification models used to forecast malfunction. Wavelet packet transform technology was first used to process the vibration signal. The signals were pre-processed and analyzed before eigenvalue calculation was done to analyze the signal changes which allowed determination of the nature of the bearing malfunction to be made. The extracted eigenvalues and ball-bearing status categories were input to the support vector machine for model training and testing. Finally, the constructed model parameters were integrated with particle swarm optimization, and the artificial fish-swarm algorithm was used to obtain the optimal parameters for the classifier, and this improved the accuracy of malfunction classification.
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Alexandrova, Nelli N., and Paulo M. M. Vila Real. "Preliminary Design of a Composite Material Flywheel." Materials Science Forum 623 (May 2009): 21–35. http://dx.doi.org/10.4028/www.scientific.net/msf.623.21.
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Flywheel rotor performance monitoring and damage detection are increasingly gaining the interest of manufacturers of aircraft engines. This is primary due to the fact that there is a necessity for improving safety during operation as well as a need for lower maintenance costs. Applied techniques for damage detection and health monitoring of rotors are essential for engine safety, reliability and life prediction. Preliminary design of such a flywheel studied here is based on a simple model of annular rotating disk with stress-free boundary conditions. In addition to the critical rotational speed, the paper analyses the influence of the leading design parameter - material plastic anisotropy - on the development of plastic zone and stress/strain distributions.
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Gu, Guimei, Rang Hu, and Yuanyuan Li. "Study on Identification of Damage to Wind Turbine Blade Based on Support Vector Machine and Particle Swarm Optimization." Journal of Robotics and Mechatronics 27, no. 3 (June 20, 2015): 244–50. http://dx.doi.org/10.20965/jrm.2015.p0244.
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<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270003/03.jpg"" width=""340"" />Classification results of SVM-PSO</div> In order to identify two failures of crack damage and edge damage to wind turbine blade, a damage identification system was designed by acoustic emission technique. This system took advantage of wireless technique for signal collection and transmission and upper computer for receiving and processing data. This system adopted acoustic emission sensor, NRF905 wireless transmission, upper computer designed by VB language, and the serial communication function of VB for data receiving. Data was firstly normalized after being received. Then, the energy features of data were abstracted by db wavelet. With the abstracted features, support vector machine model was established and verified, and the machine parameters were optimized by particle swarm optimization. Results show that the system is reliable in data collection and transmission, and the correctness of damage identification obviously increases by optimizing the support vector machine with particle swarm. The design provides method to monitor the status of rotating object, so this system can provide model base for subsequent studies.
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Toumi, M. Y., S. Murer, F. Bogard, and F. Bolaers. "Numerical simulation and experimental comparison of flaw evolution on a bearing raceway: Case of thrust ball bearing." Journal of Computational Design and Engineering 5, no. 4 (January 31, 2018): 427–34. http://dx.doi.org/10.1016/j.jcde.2018.01.004.
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Abstract Bearings are essential elements in the design of rotating machines. In an industrial context, bearing failure can have costly consequences. This paper presents a study of the rolling contact fatigue damage applied to thrust ball bearings. It consists in building a dynamic three-dimensional numerical model of the cyclic shift of a ball on an indented rolling surface, using finite element analysis (FEA). Assessment of the evolution in size of a surface spall as a function of loading cycles is also performed using FEM coupled with fatigue laws. Results are in good agreement with laboratory tests carried out under the same conditions using a fatigue test cell dedicated to ball bearings. This study may improve knowledge about estimating the lifetime of rolling components after onset of a spall using FEA and accounting for structural damage state. Highlights The experimental apparatus and damaged thrust ball bearing are described. We model a portion of the thrust ball bearing featuring a spherical indent. Numerical results in terms of stress field are compared to analytical results from the literature. A fatigue software is used to assess the evolution of spalling size. Good agreement is obtained between experimental test campaigns at different loads and FEA results.
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Lu, Chun, Jiliang Mo, Ruixue Sun, Yuanke Wu, and Zhiyong Fan. "Investigation into Multiaxial Character of Thermomechanical Fatigue Damage on High-Speed Railway Brake Disc." Vehicles 3, no. 2 (June 1, 2021): 287–99. http://dx.doi.org/10.3390/vehicles3020018.
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The multiaxial character of high-speed railway brake disc thermomechanical fatigue damage is studied in this work. Although the amplitudes and distributions of temperature, strain and stress are similar with uniform and rotating loading methods, the multiaxial behavior and out-of-phase failure status can only be revealed by the latter one. With the help of a multiaxial fatigue model, fatigue damage evaluation and fatigue life prediction are implemented, the contribution of a uniaxial fatigue parameter, multiaxial fatigue parameter and out-of-phase failure parameter to the total damage is discussed, and it is found that using the amplitude and distribution of temperature, stress and strain for fatigue evaluation will lead to an underestimation of brake disc thermomechanical fatigue damage. The results indicate that the brake disc thermomechanical fatigue damage belongs to a type of multiaxial fatigue. Using a uniaxial fatigue parameter causes around 14% underestimation of fatigue damage, while employing a multiaxial fatigue parameter without the consideration of out-of-phase failure will lead to an underestimation of about 5%. This work explains the importance of studying the thermomechanical fatigue damage of the brake disc from the perspective of multiaxial fatigue.
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Oguma, Noriyasu, Naoya Sekisugi, Katsuyuki Kida, Yasuhiro Odake, and Tatsuo Sakai. "Period of Fine Granular Area Formation of Bearing Steel in Very High Cycle Fatigue Regime." Advanced Materials Research 891-892 (March 2014): 434–39. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.434.
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In order to examine the period of fine granular area (FGA) formation of bearing steel in very high cycle fatigue regime, rotating bending fatigue tests were carried out at the stress amplitude 1100 MPa below the fatigue limit. The tests were interrupted at the cumulative damage values ranging from 0.1 to 0.5 with an increment of 0.1 to charge hydrogen to the specimens. After the charge, the rotating bending tests were continuously carried out. The crack origin areas on all fracture surfaces were checked by a scanning electron microscope (SEM), and it was discovered that FGA was not formed in some of them. From a view point of fracture mechanics, the stress intensity factor ranges of FGA areas, ΔKFGA, were calculated by using Murakamis area model. The ΔKFGA values increase with the increase of the cumulative damage values. Furthermore, ΔKFGA values in this study were smaller than 5 MPam which was obtained from usual fatigue testing. Therefore, we conclude that the stable crack growth stage starts when the threshold stress intensity factor range decreases due to hydrogen embrittlement in the middle of formation of FGA.
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Huang, Chang Wu, Guang Xue Yang, Nian Jun Fu, and Ji Long Xie. "Research on Fretting Fatigue Life of Interference Fit and its Influencing Factors." Applied Mechanics and Materials 251 (December 2012): 293–300. http://dx.doi.org/10.4028/www.scientific.net/amm.251.293.
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Interference-Fit Components, Especially under Rotating Bending Loads, Usually Suffer Fretting Fatigue, which Tremendously Reduces Service Lives of the Components. by Taking Specimens with Different Interference-Fit Parameters for Fatigue Test, their Fretting Fatigue Lives Could Be Obtained. and through Using Finite Element Analysis (FEA) Software ABAQUS, the Ruiz Fretting Damage Parameter K(x) for each Tested Fatigue Specimen Were Achieved. then, According to the Test Data and the Results of Calculations, Two Fretting-Fatigue Life Prediction Models (model 1：N=c•K-α, and Model 2：N=λN0—m•Kn) )based on the Ruiz Fretting Damage Parameter Were Fitted, and their Ratλionalities and Validities Were Analyzed. at the same Time, the Influences of Interference-Fit Parameters -Interference Value (V), Casing outside Diameter (D), and Casing Length (L), Contact Pressure (p) and Friction Shear Stress (τ) on Fretting Fatigue Life Have Been Analyzed. the Results Showed that the Two Fitalic Textretting Fatigue Life Prediction Models Used in this Paper Were Valid, but, in Contrast, the Second One Was More Accurate and Rational; and that Fretting Fatigue Life (N) Decreased as V, D, L, P or τ Increasing.