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1
Liu, Xiaoyang, Haizhou Huang, and Jiawei Xiang. "A Personalized Diagnosis Method to Detect Faults in a Bearing Based on Acceleration Sensors and an FEM Simulation Driving Support Vector Machine." Sensors 20, no. 2 (January 11, 2020): 420. http://dx.doi.org/10.3390/s20020420.
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Classification of faults in mechanical components using machine learning is a hot topic in the field of science and engineering. Generally, every real-world running mechanical system exhibits personalized vibration behaviors that can be measured with acceleration sensors. However, faulty samples of such systems are difficult to obtain. Therefore, machine learning methods, such as support vector machine (SVM), neural network (NNs), etc., fail to obtain agreeable fault detection results through smart sensors. A personalized diagnosis fault method is proposed to activate the smart sensor networks using finite element method (FEM) simulations. The method includes three steps. Firstly, the cosine similarity updated FEM models with faults are constructed to obtain simulation signals (fault samples). Secondly, every simulation signal is separated into sub-signals to solve the time-domain indexes to generate the faulty training samples. Finally, the measured signals of unknown samples (testing samples) are inserted into the trained SVM to classify faults. The personalized diagnosis method is applied to detect bearing faults of a public bearing dataset. The classification accuracy ratios of six types of faults are 90% and 92.5%, 87.5% and 87.5%, 85%, and 82.5%, respectively. It confirms that the present personalized diagnosis method is effectiveness to detect faults in the absence of fault samples.
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Li, Lingwei, Yuan Yuan, Xinglong Zhang, Songwei Wu, and Tianhong Zhang. "Fault-Tolerant Control Scheme for the Sensor Fault in the Acceleration Process of Variable Cycle Engine." Applied Sciences 12, no. 4 (February 17, 2022): 2085. http://dx.doi.org/10.3390/app12042085.
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This paper presents a fault-tolerant control scheme for the sensor fault in the acceleration process of the variable cycle engine. Firstly, an adaptive equilibrium manifold model with multiple inputs and multiple outputs is established. Combined with the Kalman filter bank, sensor fault diagnosis is carried out to realize the diagnosis and signal reconstruction of the engine in the case of a single sensor and double sensor faults. On this basis, isolation and group isolation are used to diagnose sensor faults and reconstruct signal in speed closed-loop control. Then, the control plan of the acceleration process is optimized based on the target shooting method, aiming to simulate the variation of various variables in the engine acceleration process more accurately, so as to verify the feasibility of the sensor fault-tolerant control scheme. Finally, a hardware-in-loop simulation platform is built based on the idea of distributed control, and the fault-tolerant control scheme of the sensor proposed previously is verified based on this platform. The results show that the proposed scheme can accurately diagnose the sensor faults and reconstruct the signal within 0.2 s, and the actual speed can rise from 67.87% to 99.9% in 4 s, ensuring the safe and rapid completion of the acceleration process.
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Yin, Zhengyang, Yi Yang, Guoji Shen, Ling Chen, and Niaoqing Hu. "Eight-DOF Dynamic Modeling of EMA Mechanical Transmission and Spalling Fault Characteristic Analysis." Actuators 11, no. 8 (August 6, 2022): 226. http://dx.doi.org/10.3390/act11080226.
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Electromechanical actuators (EMAs), as the critical actuator system of next-generation aircraft, have attracted the attention of many institutions and enterprises around the world. However, due to harsh working conditions, their reliability cannot satisfy the requirements of widespread application in aircraft. Therefore, in order to conduct fault diagnosis on EMAs, in this paper, we establish a comprehensive dynamic model under numerous assumptions to study the fault characteristics that may occur in the displacement and acceleration responses of EMA systems. First, an eight-DOF dynamic model containing typical mechanical components of an EMA is established. Then, by obtaining the impact forces between balls and the spalling fault and the nonlinear relationship between the total elastic restoring forces and the change of ball deformation when the fault occurs, a faulty dynamic model is established. Comparison of the simulation results between the normal and faulty model reveals that the acceleration amplitude at the third harmonic of the ball passage frequency increases when fault occurs. Based on this phenomenon, a numerical calculation method of fault characteristics is proposed. Finally, the effectiveness of the established models and the identified phenomenon are verified by experiments conducted on an EMA test rig in a laboratory environment.
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Song, O. Y., and P. R. Menon. "Acceleration of trace-based fault simulation of combinational circuits." IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 12, no. 9 (1993): 1413–19. http://dx.doi.org/10.1109/43.240089.
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Rogers, A. M., and D. M. Perkins. "Monte Carlo simulation of peak-acceleration attenuation using a finite-fault uniform-patch model including isochrone and extremal characteristics." Bulletin of the Seismological Society of America 86, no. 1A (February 1, 1996): 79–92. http://dx.doi.org/10.1785/bssa08601a0079.
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Abstract A finite-fault statistical model of the earthquake source is used to confirm observed magnitude and distance saturation scaling in a large peak-acceleration data set. This model allows us to determine the form of peak-acceleration attenuation curves without a priori assumptions about their shape or scaling properties. The source is composed of patches having uniform size and statistical properties. The primary source parameters are the patch peak-acceleration distribution mean, the distribution standard deviation, the patch size, and patch-rupture duration. Although our model assumes no scaling of peak acceleration with magnitude at the patch, the peak-acceleration attenuation curves, nevertheless, strongly scale with magnitude (dap/dM) ≠ 0, and the scaling is distance dependent (dap/dM) ∝ f(r). The distance-dependent magnitude scaling arises from two principal sources in the model. For a propagating rupture, loci exist on the fault from which radiated energy arrives at a particular station at the same time. These loci are referred to as isochrones. As fault size increases, the length of the isochrones and, hence, the number of additive pulses increase. Thus, peak accelerations increase with magnitude. The second effect, which arises in a completely different manner, is due to extreme-value properties. That is, as the fault size increases, the number of patches on the fault and the number of peak values at the station increase. Because these attenuated pulses are produced by a statistical distribution at the patch, the largest value will depend on the total number of peak values available on the seismogram. We refer to this result as the extremal effect, because it is predicted by the theory of extreme values. Both the extremal and isochrone effects are moderated by attenuation and distance to the fault, leading to magnitude- and distance-dependent peak-acceleration scaling. Remarkably, the scaling produced by both effects is very similar, although the underlying mechanisms are completely different. Because this model approximates data characteristics we have observed in an earlier study, we adjusted the parameters of the model to fit a set of smoothed peak accelerations from earthquakes worldwide. These data have not been preselected for particular magnitude or distance ranges and contain earthquake records for magnitudes ranging from about M 3 to M 8 and distance ranging from a few kilometers to about 400 km. In fitting the data, we use a trial-and-error procedure, varying the mean and standard deviation of the patch peak-acceleration distribution, the patch size, and the pulse duration. The model explicitly includes triggering bias, and the triggering threshold is also a model parameter. The data can be approximated equally well by a model that includes the isochrone effect alone, the extremal effect alone, or both effects. Inclusion of both effects is likely to be closest to reality, but because both effects produce similar results, it is not possible to determine the relative contribution of each one. In any case, the model approximates the complex features of the observed data, including a decrease in magnitude scaling with increasing magnitude at short distances and increase in magnitude scaling with magnitude at large distances.
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Liu, Shulian, Ling Zhang, Likang Yang, Cunkai Gu, and Zaihua Wang. "The Identification Method of the Winding Vibration Faults of Dry-Type Transformers." Electronics 12, no. 1 (December 20, 2022): 3. http://dx.doi.org/10.3390/electronics12010003.
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To identify the four typical faults of dry-type transformer winding insulations, looseness, deformation and eccentricity, this study establishes the electric magnetic force multi-physical field simulation model of a dry-type transformer winding under the four typical faults with COMSOL software, based on the vibration mechanism of an SCB10-1000/10 dry-type transformer. Through the multi-physical field coupling calculation, the comparative relationship between the vibration acceleration of the winding under the four kinds of faults and the normal working state is obtained. The results show that the amplitude growth rate of the fundamental frequency or harmonic frequency of the acceleration signal under four kinds of faults is different from that under normal conditions. Therefore, the threshold value of the fundamental frequency or harmonic increment of the acceleration signal is introduced to describe the growth rate of the acceleration signal relative to normal conditions. Finally, four typical faults are identified with different threshold ranges of acceleration increment under faults, laying a foundation for the fault diagnosis of transformer winding vibrations.
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Zhang, Hehong, Yunde Xie, and Zhiqiang Long. "Fault Detection Based on Tracking Differentiator Applied on the Suspension System of Maglev Train." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/242431.
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A fault detection method based on the optimized tracking differentiator is introduced. It is applied on the acceleration sensor of the suspension system of maglev train. It detects the fault of the acceleration sensor by comparing the acceleration integral signal with the speed signal obtained by the optimized tracking differentiator. This paper optimizes the control variable when the states locate within or beyond the two-step reachable region to improve the performance of the approximate linear discrete tracking differentiator. Fault-tolerant control has been conducted by feedback based on the speed signal acquired from the optimized tracking differentiator when the acceleration sensor fails. The simulation and experiment results show the practical usefulness of the presented method.
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Du, Can Yi, and Fei Fei Yu. "Analysis of Engine Camshaft Bearing Loosening Fault Based-on Model Simulation and Vibration Signal." Advanced Materials Research 694-697 (May 2013): 896–900. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.896.
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Virtual technology is used for simulation analysis of engine camshaft bearing-loosening fault. Firstly, dynamic model of engine powertrain and its valve-train is established, and then the model parameters could be set to simulate the camshaft bearing loosening fault, so the vibration acceleration signals on engine cylinder head can be obtained by simulation calculation. Then by analyzing and comparing with the vibration signals in the normal state, camshaft bearing-loosening fault features are extracted. The analytical result based-on model simulation and vibration signal is used to guide the actual engine fault diagnosis.
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ISUMI, MASANORI, HIROSHI KATSUKURA, and YOUICHI HAGINO. "STUDY ON THE SIMULATION OF ACCELERATION ENVELOPES BY FAULT MODELS." Journal of Structural and Construction Engineering (Transactions of AIJ) 348 (1985): 26–32. http://dx.doi.org/10.3130/aijsx.348.0_26.
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Chen, Jian, Robert Randall, Ningsheng Feng, Bart Peeters, and Herman Van der Auweraer. "Modelling and diagnosis of big-end bearing knock fault in internal combustion engines." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 16 (February 24, 2014): 2973–84. http://dx.doi.org/10.1177/0954406214524743.
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Big-end bearing knock is considered to be one of the common mechanical faults in internal combustion engines (IC engines). In this paper, a model has been built to simulate the effects of oversized clearance in the big-end bearing of an engine. In order to find a relationship between the acceleration response signal and the oversized clearance, the kinematic/kinetic and lubrication characteristics of the big ending bearing were studied. By adjusting the clearance, the impact forces with different levels of bearing knock fault can be simulated. The acceleration on the surface of the engine block was calculated by multiplying the simulated force spectrum by an experimentally measured frequency response function (FRF) in the frequency domain (and then inverse transforming to the time domain). As for experimentally measured vibration signals from bearing knock faults, the signal processing approach used involved calculating the squared envelopes of the simulated acceleration signals. The comparison to the experimental results demonstrated that the simulation model can correctly simulate vibration signals with different stages of bearing knock faults.
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H. Saffari, A. Roohafzayan, A. Mahdavian, and M. Yari. "Stochastic Finite Fault Modeling and Simulation of Strong Ground Motion of Mosha Fault in Iran." Electronic Journal of Structural Engineering 20 (June 1, 2020): 63–71. http://dx.doi.org/10.56748/ejse.20247.
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This study aims at predicting large earthquakes caused by Mosha fault in Tehran, the capital of Iran with population of more than 13 million people which located alongside active faults. This study uses the EXSIM program to do the finite fault modeling of simulation. Using Geopsy software and programming in MATLAB we evaluated the site effect of 13 station. Using other required parameters of Mosha fault in EXSIM, we gained the artificial strong motions of the stations. Finally, using SeismoSignal and MATLAB software, we depicted the Acceleration -time graph and the semi-logarithm frequency spectrum with “Fourier transform” of each station. we compared the results of the finite fault simulation with Ambraseys attenuation relationship, semi-logarithm frequency spectrum with Fourier transform and spectrum-response graphs of 2009 earthquake in Shahr-e Rey measuring Mw = 4.2. In both cases of comparing meaningful results were found. Finally, in order to generalize the results to the city of Tehran, we evaluated the seismicity using Arc GIS software. The results show that if Mosha fault is activated, east of Tehran is influenced the most. Consequently, it is of high importance to study different ways to reduce the risk of the possible earthquake caused by Mosha fault.
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Yang, Hongyi, Yanxin Li, and Qinfen Lu. "Performance Simulation of Long-Stator Linear Synchronous Motor for High-Speed Maglev Train under Three-Phase Short-Circuit Fault." World Electric Vehicle Journal 13, no. 11 (November 18, 2022): 216. http://dx.doi.org/10.3390/wevj13110216.
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The high-speed Maglev train is driven by long-stator linear synchronous motors (LLSM). During the long-time outdoor operation, the insulation material of the armature winding may be damaged, either due to aging or the movement of the windings. This may result in the three-phase short-circuit fault, which affects the traction performance and the operation of the train. In this paper, a simulation model of the high-speed Maglev train traction system with a three-phase short-circuit fault LLSM is established, including the converters at two ends, feeder cables, segmented LLSM and traction control system. The system adopts a double-end power supply mode. The model divides the fault segment LLSM into two parts. One part is connected to the converter, which is equivalent to a normal operating segment with shortened long-stator. The other part is equivalent to a three-phase short-circuit linear generator. Based on this model, the influence of running speed and fault segment length on the traction performance of the train is simulated. In addition, the stator current, acceleration and traction force of the Maglev train during fault segment are investigated in the acceleration phase, deceleration phase and constant speed phase, respectively. The results can provide a reference for three-phase short-circuit fault diagnosis.
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Guo, Junjun, Yitong Gu, Weihong Wu, Shihyu Chu, and Xinzhi Dang. "Seismic Fragility Assessment of Cable-Stayed Bridges Crossing Fault Rupture Zones." Buildings 12, no. 7 (July 19, 2022): 1045. http://dx.doi.org/10.3390/buildings12071045.
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Current studies lack probabilistic evaluations on the performance of fault-crossing bridges. This paper conducts seismic fragility analyses to evaluate the fragility of cable-stayed bridges with the effects of fault ruptures. Synthetic across-fault ground motions are generated using existing simulation methods for the low-frequency pulses and high-frequency residuals. Incremental dynamic analysis is utilized to generate the seismic responses of the bridge. The optimal intensity measure (IM) for a cable-stayed bridge that crosses a fault is identified based on the coefficient of determination (R2). Root-mean-square velocity (Vrms) is found to be the best IM for cable-stayed bridges traversed by fault ruptures, instead of the commonly used ones such as peak ground acceleration or velocity (PGA or PGV). Fragility curves for the critical components of fault-crossing cable-stayed bridges, including pylons, cables, and bearings, are developed using the IM of Vrms, and are subsequently compared with those for the cable-stayed bridge near faults. Results show that the bearings on transition piers are the most vulnerable component for fault-crossing cable-stayed bridges because of the rotation of their girder. Compared to cable-stayed bridges near faults, pylons and bearings are more vulnerable in the transverse direction for cable-stayed bridges crossing faults, whereas the vulnerability of cables is comparable.
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Zhong, Ju Fang, Long Wei Zhang, and Jun Wei Liang. "An Improved Source Model for Simulation Near-Field Strong Ground Motion Acceleration Time History." Applied Mechanics and Materials 438-439 (October 2013): 1474–80. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.1474.
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The key to near-field strong ground motion simulation based on stochastic finite fault method is to determine the spectrum of ground motion. We present an improved source spectrum model for simulation near-field strong ground motion acceleration time history. We combine Masudas source spectrum model with scaling factor Hij to keep radiation energy conservation and reflect the energy decrease with frequency at low to mid frequencies. We calculate the Fourier amplitude spectrum Fa, accelerate response spectrum Sa, velocity response spectrum Sv and displacement response spectrum Sd of simulation time histories. By comparative analysis of the laws of spectrum values (Fa, Sa, Sv, Sd) with the variation of frequency or period, we discusses the effects of sub-fault dividing scheme, the method of determining scale factor and source spectrum model on spectrum values (Fa, Sa, Sv, Sd). The results show that sub-fault dividing scheme has slightly effect on the model presented in this paper, and the model enable to reflect the sink laws of source spectrum value in mid-to-low frequencies well. We demonstrate that the improved model is superior to other commonly used models.
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Zyadat, Zaidan, Nadjim Horri, Mauro Innocente, and Thomas Statheros. "Observer-Based Optimal Control of a Quadplane with Active Wind Disturbance and Actuator Fault Rejection." Sensors 23, no. 4 (February 9, 2023): 1954. http://dx.doi.org/10.3390/s23041954.
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Hybrid aircraft configurations with combined cruise and vertical flight capabilities are increasingly being considered for unmanned aircraft and urban air mobility missions. To ensure the safety and autonomy of such missions, control challenges including fault tolerance and windy conditions must be addressed. This paper presents an observer-based optimal control approach for the active combined fault and wind disturbance rejection, with application to a quadplane unmanned aerial vehicle. The quadplane model is linearised for the longitudinal plane, vertical takeoff and landing and transition modes. Wind gusts are modelled using a Dryden turbulence model. An unknown input observer is first developed for the estimation of wind disturbance by defining an auxiliary variable that emulates body referenced accelerations. The approach is then extended to simultaneous rejection of intermittent elevator faults and wind disturbance velocities. Estimation error is mathematically proven to converge to zero, assuming a piecewise constant disturbance. A numerical simulation analysis demonstrates that for a typical quadplane flight profile at 100 m altitude, the observer-based wind gust and fault correction significantly enhances trajectory tracking accuracy compared to a linear quadratic regulator and to a H-infinity controller, which are both taken, without loss of generality, as benchmark controllers to be enhanced. This is done by adding wind and fault compensation terms to the controller with admissible control effort. The proposed observer is also shown to enhance accuracy and observer-based rejection of disturbances and faults compared to three alternative observers, based on output error integration, acceleration feedback and a sliding mode observer, respectively. The proposed approach is particularly efficient for the active rejection of actuator faults under windy conditions.
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Inoue, Tomohiro, and Takashi Miyatake. "3D simulation of near-field strong ground motion based on dynamic modeling." Bulletin of the Seismological Society of America 88, no. 6 (December 1, 1998): 1445–56. http://dx.doi.org/10.1785/bssa0880061445.
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Abstract We simulate the strong ground motion generated from the earthquake rupture process on a shallow strike-slip fault using a 3D finite-difference method. The faulting process is modeled using a crack model with fixed rupture velocity. The variability of peak ground velocity patterns, correlated with fault location and source parameters such as stress drop or rupture velocity, is investigated. Our findings suggest that these patterns are strongly affected by rupture directivity and the uppermost depth of the fault or that of the asperity. When a fault breaks the ground surface, the peak ground velocity and the peak ground acceleration show a narrow region of strong motion. When a fault is buried under the ground, the high peak ground velocity zone of the fault-parallel component is apart from the fault trace by a distance comparable to the fault depth. On the other hand, the fault-normal peak ground velocity is a maximum along the fault trace. The fault length (or asperity length) is not so effective for peak ground velocities. The effect of heterogeneity in stress drop and rupture velocity on strong ground motion is also investigated. When stress drop is not uniform but increases linearly with depth from zero at the uppermost depth, the peak ground velocity is reduced. These results help better predict the strong ground motion generated from a potential fault.
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Refani, A. N., Yuyun Tajunnisa, K. Yudoprasetyo, F. Ghifari, and D. I. Wahyudi. "Evaluation of Structure Performance under Seismic Load with Non-Liner Time History on High-Rise Building Affected by Kendeng Fault Earthquake Simulation." Key Engineering Materials 879 (March 2021): 232–42. http://dx.doi.org/10.4028/www.scientific.net/kem.879.232.
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Indonesia is a country located in the convergence of small plates and large plates. Furthermore, this causes Indonesia to be high potentially to earthquake hazards. The newest geological research published by Geophysical Research Letter (2016) shows the existence of Fault Kendeng, a fault stretches along 300 km from South Semarang, Central Java, to East Java with a movement of 0,05 millimeter per year [1]. As a result of its research, an evaluation using a non-linear time history analysis for structural buildings is necessary. The objective of this study is to evaluate structural buildings using a non-linear time history analysis. This study applies DSHA (Deterministic Seismic Hazard Analysis) method to obtain acceleration time history on bedrocks. Since the record of ground movement in Indonesia is limited, the attenuation function equation used to scale and match other country’s time acceleration history data. SSA (Site-Specific Analysis) is used to propagate earthquake acceleration from bedrocks to the surface. The earthquake acceleration on the surface generates as the earthquake load on the buildings. The results of Kendeng fault earthquake simulation using non-linear time history analysis shows that column members capacity is more robust than beam members capacity which the beam collapse mechanism occurs initially. From the maximum total drift ratio result, when the Kendeng fault earthquake occurs, the building structure performance level is at collapse prevention level Based on ATC-40 [2]. This research result shows that 96,7% of plastic hinge has not yielded. However, some elements are already damaged. Since most damage members are column, then it may require column strengthening to enhance maximum performance level at life safety condition category.
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Shi, Baoping, Abdolrasool Anooshehpoor, James N. Brune, and Yuehua Zeng. "Dynamics of thrust faulting: 2D lattice model." Bulletin of the Seismological Society of America 88, no. 6 (December 1, 1998): 1484–94. http://dx.doi.org/10.1785/bssa0880061484.
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Abstract Particle motions in a foam rubber model of shallow-angle thrust faulting show many features different from those commonly assumed in dislocation models of subduction thrusts (Brune, 1996). As a complement to a physical foam rubber experiment, we have carried out dynamic simulation using a 2D lattice numerical model. The model is constructed as a triangular block sliding over a rectangular elastic block. It consists of a 2D set of particles interacting with each other by nonlinear Hooke's forces and obeying Newton's equations of motion. Rough surfaces are introduced on the contact plane of the two blocks to simulate realistic friction. The numerical simulations demonstrate several key features of thrust faulting, including stick slip, fault opening, and strong breakout and shaking at the hanging-wall toe (the wedge-shaped tip of the outcropping hanging-wall block) of the thrust fault, all consistent with the foam rubber experiments. The stick-slip motion shows an approximate time and slip repeatable behavior. Each slip event is characterized by a self-healing pulse associated with fault opening and frictional locking. The rupture pulse propagates steadily along the fault. When rupture reaches the toe of the fault outcrop, the hanging wall breaks away from the foot wall and creates a large opening vibration of the hanging wall. The peak acceleration observed at the hanging-wall toe of the fault outcrop is about 3 to 4 times the peak acceleration in the center part of the fault, and about 2 to 3 times the motion of the foot wall. Such a large increase in peak acceleration at the toe is caused mainly by multiply reflecting stress waves trapped in the wedge-shaped hanging wall of the fault. The strong asymmetry of the particle velocity between the hanging wall and foot wall is an important feature of the results consistent with the foam rubber model but different from standard dislocation models. This dynamic result illustrates the important effects of thrust faulting geometry on fault slip and ground motion.
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Hung, Truong Ngoc. "Methods for Fault Location in High Voltage Power Transmission Lines: A Comparative Analysis." International Journal of Renewable Energy Development 11, no. 4 (August 15, 2022): 1134–41. http://dx.doi.org/10.14710/ijred.2022.46501.
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Power transmission system stability can be significantly affected due to faults. The fault location accuracy in the transmission lines can make many benefits such as acceleration of the line restoration, reduction in cost, breakdown time, maintenance, and time searching. The methods based on the impedance, including the simple reactance, Takagi, modified Takagi, and double-end, are very much appreciated for locating the fault in transmission lines and especially by estimating the fault distance. This study proposes a comparative case study between these methods. The theoretical basis and the analysis, calculation, and estimation of each method are specifically re-established. To observe the performance of each method, a practical 220kV Quy Nhon - Tuy Hoa transmission line in Vietnam is used to simulate, calculate, evaluate, and compare under the various fault types and resistances. The power system is modeled and simulated in the MATLAB/Simulink software via the time domain. The voltage and current measurements at two ends of the line are used to determine the fault location on the Quy Nhon - Tuy Hoa transmission line. The simulation results show clearly the effectiveness of each fault location method.
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Wang, Shi Ming, Xian Zhu Ai, and Li Na Ma. "Failure Analysis in Hydraulic System of the Polar Expedition Buoy which is Based on Virtual Prototype." Advanced Materials Research 718-720 (July 2013): 1559–63. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.1559.
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Introduced the particulIarity circumstances of polar exploration buoy in contrast to normal buoy., raised the important academic value and practical meaning of the research of failure of the polar ocean observing buoys. This paper is based on ,a pair of gear pieces in hydraulic system of polar buoy, and made the virtual prototype simulation experiment on the fault gear pieces. By comparing of the normal meshing with broken teeth meshing which drew the presence of failures, and then analysis the CM acceleration both in time-domain and frequency-domain of fault gear in different rotating speeds, which verify the correctness of the simulation.
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Song, Jia, Weize Shang, Shaojie Ai, and Kai Zhao. "Model and Data-Driven Combination: A Fault Diagnosis and Localization Method for Unknown Fault Size of Quadrotor UAV Actuator Based on Extended State Observer and Deep Forest." Sensors 22, no. 19 (September 28, 2022): 7355. http://dx.doi.org/10.3390/s22197355.
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The rotor is an essential actuator of quadrotor UAV, and is prone to failure due to high speed rotation and environmental disturbances. It is difficult to diagnose rotor faults and identify the fault localization simultaneously. In this paper, we propose a fault diagnosis and localization scheme based on the Extended State Observer (ESO) and Deep Forest (DF). This scheme can accurately complete the fault diagnosis and localization for the quadrotor UAV actuator without knowing the fault size by combining the model-based and the data-driven methods. First, we obtain the angular acceleration residual signal of the quadrotor UAV by using ESO. The residual signal is the difference between the observed state of ESO and the true fault state. Then, we design the residual feature analysis method by considering the position distribution of the quadrotor UAV actuator. This method can embed the actuator fault localization information into the fault data by simultaneously considering pitch and roll of the quadrotor UAV. Finally, we complete the fault diagnosis and localization of the quadrotor UAV actuator by processing the fault data by using DF. This scheme has the advantages of straightforward observer modeling, strong generalization ability, adaptability to small sample data, and few hyperparameters. Our simulation results indicate that the accuracy of the proposed scheme reaches more than 99% for the unknown size of the quadrotor UAV actuator fault.
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Zhou, Lijian, Tian Xu, Zhaohong Lu, and Dong Zhang. "A Study on the Sloshing Problem of Vertical Storage Tanks under the Action of Near-Fault Earthquakes." Advances in Civil Engineering 2020 (January 22, 2020): 1–10. http://dx.doi.org/10.1155/2020/1097696.
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In this study, through a vibration table test, finite element simulation, and research on the rationality of the wave-height fortification of national storage tank specifications, the sloshing response of vertical storage tanks under the action of near-fault ground motion was analyzed. The test results showed that the sloshing wave height of a vertical storage tank was larger under near-fault or long-period ground motions, and the relationship between the sloshing wave height and the peak acceleration of input ground motions was approximately linear. The numerical simulations of the model tank showed that the simulation wave height and the test wave-height data were well fitted. Therefore, it was feasible to simulate the sloshing of large vertical storage tanks using ADINA software. In addition, a large number of sloshing simulations of near-fault ground motions on 10,000 m3 vertical storage tanks were performed. The simulated wave height had a high correlation with the predominant period or pulse period of near-fault ground motions. Under the calculation with similar parameters, the wave height of the tank standard in several countries had a lower fortification of the near-fault excitation wave height. Through the root mean-square method using a small sample size, a wave-height correction under a near-fault effect was applied to the wave-height formula for the Chinese tank seismic specification. Finally, the problem of a double-damping correction was addressed by adjusting China’s GB50341 wave-height formula. This work provides a reference value for practical engineering applications.
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Shao, Ningning, Xiaoqiang Chen, and Ying Wang. "Research on IPSO-RBF transformer fault diagnosis based on Adam optimization." Journal of Physics: Conference Series 2290, no. 1 (June 1, 2022): 012117. http://dx.doi.org/10.1088/1742-6596/2290/1/012117.
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Abstract As the lifeblood element of the power system, the transformer plays a pivotal role in power transmission and voltage conversion. The fault prediction of the transformer can not only realize the early warning before the fault but also provide theoretical support for the formulation of a transformer maintenance scheme, which can improve the safety and reliability of the power system. In this paper, a new method of transformer fault diagnosis based on dissolved gas in oil is proposed by combining the Adam optimization algorithm based on the classical momentum concept with the PSO algorithm. Firstly, a PSO-RBF transformer fault diagnosis model is constructed. Through the simulation experiment of nonlinear collocation of acceleration factors, the nonlinear exponential decreasing collocation is used to improve the optimization ability of particle swarm optimization. The simulation analysis is carried out based on the transformer fault data within the jurisdiction of Lanzhou electric power company. The diagnosis results verify that the diagnosis rate and stability of the IPSO-RBF-Adam transformer fault diagnosis model are better than the PSO-RBF model.
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Park, Gwangmin, Byeongjeom Son, Daehyun Kum, Seonghun Lee, and Sangshin Kwak. "Dynamic Modeling and Simulation for Battery Electric Vehicles under Inverter Fault Conditions." Applied Mechanics and Materials 110-116 (October 2011): 3007–15. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3007.
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This paper presents a dynamic modeling, simulation, and analysis of a Battery Electric Vehicle (BEV) according to vehicle dynamic characteristics. Mathematical model variants for the components of BEVs can be modeled and investigated using the Matlab/Simulink software. In order to compare the dynamic performance of BEVs under inverter fault and normal conditions, the CarSim co-simulation platform is configured with real vehicle calibration data. Using this approach, it was possible to quickly check for dynamic performance issues of an electric vehicle without incurring the time delay and cost. The simulation results such as motor output, vehicle speed/acceleration, and propulsion forces are discussed and compared for each drive mode.
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Wang, Haifei, and Junjie Gong. "Dynamic analysis of coupling misalignment and unbalance coupled faults." Journal of Low Frequency Noise, Vibration and Active Control 38, no. 2 (January 8, 2019): 363–76. http://dx.doi.org/10.1177/1461348418821582.
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Misalignment is a common fault occurring in the rotor system. However, the response characteristics have not been understood comprehensively, especially the relation between forces or torques and displacements, accelerations, or moments. First, misalignment modeling is investigated in this paper. Two coupled rotor system is modeled by six degrees of freedom. Misalignment effects are considered at coupling location using nodal force vectors and moment vectors. Second, Newmark- β method is used to solve the nonlinear equations. Acceleration, displacement, and force or moment response characteristics are discussed. Some results are obtained as follows: (1) 2× will appear in the parallel misalignment forces spectrum, and 0× will appear in the vertical force spectrum; 2×, 4×, 6× will appear in the angular misalignment moment spectrum. (2) In parallel misalignment simulation, it is found that multifrequency components are more obvious, static components are showed in vertical forces and displacements, 1× is dominated and 2× is weak in the displacement spectrum, and 2× is obvious in the force spectrum; acceleration is periodic impulse signal and 1× and 2× are dominated in its spectrum; vertical displacement is truncated and its values are positive, the orbit looks like an inverted triangle. (3) In angular misalignment simulation, it is found that multifrequency components of response are more obvious, 2× is obvious in the vertical displacement spectrum, and 2× is dominated in the moment spectrum; acceleration is periodic impulse signal, horizontal and vertical displacements are periodic, the orbit looks like a moon or an eight shape, and 2× is obvious in the moment spectrum.
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Ikutama, Shinya, Takeshi Kawasato, Yosuke Kawakami, Masahiro Nosho, Atsuko Oana, Kazuo Dan, Haruhiko Torita, and Yasuo Okada. "Source Modeling for Predicting Ground Motions and Permanent Displacements Very Close to the Fault Trace." Journal of Earthquake and Tsunami 12, no. 04 (October 2018): 1841005. http://dx.doi.org/10.1142/s1793431118410051.
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A conventional “recipe” for strong ground motion prediction has been applied to the seismic fault (deep fault; located within seismogenic layer). In order to perform assessments of strong ground motions and permanent displacements at sites very close to the fault trace, we proposed the method of modeling that takes the entire ruptured fault from the ground surface to the seismic fault into account. Our approach was validated by the simulation of observed records obtained at stations very close to the fault trace of the mainshock of the 2016 Kumamoto Japan, earthquake (Mw7.1). Also, through the ground motion assessment performed for a hypothetical strike-slip fault with a 90[Formula: see text] dip angle, we found that adding the shallow fault had virtually no effect on acceleration time history, but it had a clear effect on the fault-parallel component of velocity and displacement time histories in the area close to the fault trace.
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Wang, JiaQing, Han Xiao, Yong Lv, Tao Wang, and Zengbing Xu. "Detrended Fluctuation Analysis and Hough Transform Based Self-Adaptation Double-Scale Feature Extraction of Gear Vibration Signals." Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/3409897.
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This paper presents the analysis of the vibration time series of a gear system acquired by piezoelectric acceleration transducer using the detrended fluctuation analysis (DFA). The experimental results show that gear vibration signals behave as double-scale characteristics, which means that the signals exhibit the self-similarity characteristics in two different time scales. For further understanding, the simulation analysis is performed to investigate the reasons for double-scale of gear’s fault vibration signal. According to the analysis results, a DFA double logarithmic plot based feature vector combined with scale exponent and intercept of the small time scale is utilized to achieve a better performance of fault identification. Furthermore, to detect the crossover point of two time scales automatically, a new approach based on the Hough transform is proposed and validated by a group of experimental tests. The results indicate that, comparing with the traditional DFA, the faulty gear conditions can be identified better by analyzing the double-scale characteristics of DFA. In addition, the influence of trend order of DFA on recognition rate of fault gears is discussed.
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Liu, Bo Yan, Wen Hao Shen, and Bao Ping Shi. "Seismic Hazard Assessment of Hengshui Area by the Modified Stochastic Finite Fault Modeling." Applied Mechanics and Materials 744-746 (March 2015): 894–97. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.894.
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In recent years, numerical simulation of strong ground motion has been well developed with the progress of earthquake science, and it has become an important approach to estimate strong ground motion. In this research, we improve the original program of EXSIM and the modified program named MEXSIM to calculate the Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) which is essential for seismic hazard assessment of Hengshui area. Considering the impact of V30(the average shear-velocity down to 30 m) we calculate the impact of two scenario earthquakes from the rupture processes of Hengshui fault and Qianmotou fault. Comparing to Qianmotou scenario earthquake, if the instability fault is Hengshui fault, the PGA and PGV could be 200-360gal and 20-35cm/s respectively in Hengshui city.
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Tariq, Muhammad Ahsan, Muhammad Usman, Syed Hassan Farooq, Imran Ullah, and Asad Hanif. "Investigation of the Structural Response of the MRE-Based MDOF Isolated Structure under Historic Near- and Far-Fault Earthquake Loadings." Applied Sciences 11, no. 6 (March 23, 2021): 2876. http://dx.doi.org/10.3390/app11062876.
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Fixed base structures subjected to earthquake forces are prone to various issues, such as the attraction of greater forces to structure, amplified accelerations to non-structural components, expensive design for better seismic performance, and so forth. Base isolation applied at the foundation of vulnerable structures is a radical bypass from the conventional approaches utilized by structural engineers. However, the practical implementation of passive base isolation is constrained by factors such as large displacements at isolation level, uplifting forces at isolators, and vulnerability to unpredictable and versatile earthquakes. This study is focused on the evaluation of the smart base isolation system under various harmonic and earthquake loadings. The proposed system employs a magnetorheological elastomer (MRE)—a class of smart materials, based on an adaptive isolation layer under the building structure for its vibration control. The building is idealized as a five-degree-of-freedom (DOF) structure with the mass lumped at each storey. The stiffness of the MRE isolation layer is adjusted using the linear quadratic regulator (LQR) optimal feedback control algorithm. A total of 18 simulations have been performed for the fixed base, passively isolated, and MRE-based isolated structures under a series of earthquake loadings of both a near-fault and far-fault nature for analyzing a total of 306 responses of the structures. The simulation results indicate that MRE-based isolation has significantly reduced all the responses compared to the passively isolated structure for both the near-fault and far-fault earthquake loadings. For harmonic loading, however, the passively isolated structure outperformed the MRE isolated structure in terms of storey drift and acceleration responses.
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Meng, Rui, Xin Cai, and Xingwen Guo. "A New Resultant Vibration Acceleration Model of a Planetary Gear Train and Fault Response Analysis." Shock and Vibration 2022 (February 27, 2022): 1–20. http://dx.doi.org/10.1155/2022/5243204.
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A new resultant vibration acceleration model is proposed to reveal its signal characteristics more accurately in the healthy and faulty state. First, an analytical lateral-torsional coupled dynamic model is developed with consideration of time-varying mesh stiffness and damping, static transmission error, and gear backlash. Then, the effect of gear backlash and damping on the system is analyzed, and a numerical velocity signal in the healthy and faulty state is carried out. Considering the effects of transmission paths, the resultant acceleration signal along the vertical direction is constructed as the weighted vibration summation. This signal includes a vertical component of the vibration along the meshing lines of both sun-planet and ring-planet pairs. Moreover, it also contains the vertical component of the planet gears, sun gear, and planet carrier acceleration relative to their own supporting bearings. Finally, the simulation results from the resultant signal model are experimentally validated and analyzed in both time and frequency domains.
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Иншаков, Александр, Aleksandr Inshakov, Иван Курбаков, Ivan Kurbakov, Мария Курбакова, and Mariya Kurbakova. "USING OF ACCELERATION CHARACTERISTICS OF THE ENGINE AND THE TURBOCHARGER FOR SUPERCHARGING SYSTEM DIAGNOSING." Bulletin Samara State Agricultural Academy 2, no. 3 (July 27, 2017): 34–39. http://dx.doi.org/10.12737/17451.
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The purpose of the research is to identify the peculiarities of interconnection of dynamic characteristics of the turbocharger TKR 6.1 and the engine D-245-35 in the presence of a fault in the pressurization system. In the practice of fault finding in the system of supercharging of automotive engine widely used method of diagnosis, OS-nated steak subs on the measurement of the boost pressure in the nominal modes. In terms of the service companies due to the lack of brake stands to estimate the load mode is often not possible. For acceleration of the turbocharger and engine at the department of mobile power tools, national research of Mordovsky State University named after N. P. Ogarev created diagnostic complex consisting of forming unit of the source signals, the optical sensor shaft speed of the turbocharger, sensor of frequency of rotation of the motor shaft, the linear displacement transducer arm balancing machines, analog-to-digital Converter, software and a personal computer. The tests were carried out on the engine MMZ D-245-35, with an installed turbocharger TKR-6.1, simulation of the working regimes was carried out on the roller-brake stand. The test results obtained a series of characteristics of the acceleration of the turbocharger engine D-245-35 and TKR-6.1 with a step input exposure. Analysis of the data showed that the presence of a malfunction of the boost «leak turbine inlet», «air filter clogged» leads to an increase in the transient time and reducing the frequency of rotation of the rotor TKR in all modes. Spaced- out characteristic obtained in idling mode in the fault conditions «loss of gases after the compressor» is accompanied by the growth of the amplitude value of the shaft speed TCR and the reduction of time of transition. This feature of the waveform of the acceleration allows us to identify faults of this kind in the diagnosis of the supercharging system.
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Luo, Wei Bing, Ji Ming Fan, Ji Lv, Li Ya Zhang, and Cui Cui Wu. "Seismic Response Analysis of the Numerical Simulation Method on Cable-Stayed Bridge Tower which Considers the Rigid Foundation." Advanced Materials Research 875-877 (February 2014): 998–1002. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.998.
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The seismic responses under the action of far-fault and near-fault ground motions of the bridge tower structure of the long-span cable-stayed bridge are numerically discussed by means of the model of the bottom consolidation of the column. The results show that the responses of tower of the cable-stayed bridge correlate well with the properties of the ground motions. The seismic responses of the model have much larger values under the near-fault velocity pulse-like ground motions than those of the counterpart. The frequency of system reduces as the flexibility of structure decreases because of the rigid foundation; The displace response of tower shows that the rigid foundation has little influence on the seismic response of the cable-stayed bridge, while the acceleration response of the tower implies that rigid foundation has adverse effect. Thus, consideration of the soil-pile-superstructure interaction can be meaningful both in theory and reality during the seismic design of long-span cable-stayed bridge structure.
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Lin, Tzu-Kang, Tappiti Chandrasekhara, Zheng-Jia Liu, and Ko-Yi Chen. "Verification of a Stiffness-Variable Control System with Feed-Forward Predictive Earthquake Energy Analysis." Sensors 21, no. 22 (November 22, 2021): 7764. http://dx.doi.org/10.3390/s21227764.
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Semi-active isolation systems with controllable stiffness have been widely developed in the field of seismic mitigation. Most systems with controllable stiffness perform more robustly and effectively for far-field earthquakes than for near-fault earthquakes. Consequently, a comprehensive system that provides comparable reductions in seismic responses to both near-fault and far-field excitations is required. In this regard, a new algorithm called Feed-Forward Predictive Earthquake Energy Analysis (FPEEA) is proposed to identify the ground motion characteristics of and reduce the structural responses to earthquakes. The energy distribution of the seismic velocity spectrum is considered, and the balance between the kinetic energy and potential energy is optimized to reduce the seismic energy. To demonstrate the performance of the FPEEA algorithm, a two-degree-of-freedom structure was used as the benchmark in the numerical simulation. The peak structural responses under two near-fault and far-field earthquakes of different earthquake intensities were simulated. The isolation layer displacement was suppressed most by the FPEEA, which outperformed the other three control methods. Moreover, superior control on superstructure acceleration was also supported by the FPEEA. Experimental verification was then conducted with shaking table test, and the satisfactory performance of the FPEEA on both isolation layer displacement and superstructure acceleration was demonstrated again. In summary, the proposed FPEEA has potential for practical application to unexpected near-fault and far-field earthquakes.
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Jiang, Hong-Chun, Yu-Ling He, Gui-Ji Tang, and Xing-Hua Yuan. "Electromagnetic Force and Mechanical Response of Turbo-Generator End Winding under Electromechanical Faults." Mathematical Problems in Engineering 2021 (December 23, 2021): 1–19. http://dx.doi.org/10.1155/2021/9064254.
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This paper comparatively studies the electromagnetic force and mechanical response of the end winding before and after 3 kinds of typical electromechanical faults in turbo-generator. The analytical expression of electromagnetic force of end winding is derived under the composite fault of static eccentricity and rotor interturn short circuit. Meanwhile, the three-dimensional transient finite element simulation is carried on, and the frequency composition and amplitude variation characteristics of the radial, axial, and tangential electromagnetic force are analyzed for the end windings under static eccentricity, rotor interturn short circuit, and composite fault. Therefore, it provides a reference for the vibration wear detection and electromagnetic force control of the end winding. Moreover, the maximum stress and deformation of different positions on the end involute are obtained. And the three-directional vibration acceleration characteristics of the end winding are further analyzed. Finally, the distribution law of winding fatigue failure and vibration wear is acquired, which lays a foundation for the reverse suppression of end winding fatigue failure and insulation wear.
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Yuan, Jie, Jinting Wang, and Shoubiao Zhu. "Effects of Barriers on Fault Rupture Process and Strong Ground Motion Based on Various Friction Laws." Applied Sciences 10, no. 5 (March 2, 2020): 1687. http://dx.doi.org/10.3390/app10051687.
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A barrier may induce a supershear rupture on a fault. This paper focuses on two questions: One is whether the existence of a barrier accelerates the propagation speed of a whole fault rupture, and the other is what are the effects of friction laws and strength of a barrier on the rupture propagation process. For these purposes, classical slip-weakening, rate-state, and modified slip-weakening friction laws are employed to simulate the effect of a barrier on the fault rupture process. The simulation results showed that the rupture speed of the fault obviously decreases when the rupture front propagates to the barriers, and the rupture speed obviously increases when the rupture front leaves barriers. It was also found that a barrier on a fault may induce a supershear rupture via the rate-state friction law. The simulation results also showed that with the increase of barrier strength, the rupture speed near barriers fluctuates more and more; when the barrier strength exceeds a certain level, a supershear rupture area appears on the fault; with the increase of barrier strength, the propagation distance of the rupture at supershear wave velocity correspondingly increases. In addition, with the increase of barrier strength, the overall rupture duration of the fault slightly increases. This indicates that a barrier cannot shorten the total duration of a fault rupture. Though a barrier will lead to a supershear rupture, it just regulates the distribution of the rupture speed on the fault surface. Moreover, with the increase of barrier strength, the peak ground acceleration caused by rupture through the barrier also increases, indicating that the existence of a barrier may lead to the intensification of seismic hazards.
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Yang, Zeng Zeng, Ji Gang Wu, Bin Qin, and Yao Zhou Li. "ADAMS Dynamics Simulating and Analysis of Vibration Signal for Deep-Groove Ball Bearings." Applied Mechanics and Materials 312 (February 2013): 254–57. http://dx.doi.org/10.4028/www.scientific.net/amm.312.254.
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This paper presents the dynamics-simulation and research of vibration characteristic on deep-groove ball bearing. It introduces an analysis of the vibration frequency in different damage of bearing and spectrum analysis of the fault signal on bearing to draw response on vibration characteristics in bearing, so as to provide a simple method on research of dynamic fault characteristic of bearing. This work shows some kind, characteristics signal and frequency of fault on bearing. The normal model and other two models which have raceway crack in inside track and out ring are set up by using ADAMS software to analyse the dynamic of them, the test program that vibration signal of three models are obtained by acceleration sensors to instead of that of real condition is simulated. In addition, the test signal of vibration is given in time domain respectively, and the vibration characteristic is identification by using spectrum analysis method, so that it can provides technical support for diagnosis of fault bearing. In the study of fault diagnosis, several experimental results provide that the uncertainty of fault diagnosis and interference of other complicated factors are avoided effectively in real environment. The result of simulated analysis is consistent with the theory calculation. This method is more effective, convenient and expansibility than a research of practical fault-diagnosis.
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Wang, Shi Ming, Xian Zhu Ai, Chao Lv, and Li Na Ma. "Study on Fault Diagnosis of Gear Transmission which is Based on ADAMS." Applied Mechanics and Materials 215-216 (November 2012): 812–16. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.812.
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Introduced a transmission system of a new oscillation buoy ocean wave energy generation device, the system can transform the mechanical energy into electric energy. A pair of gear model was built by SOLIDWORKS, the parameter is just the same as the real data, then imported the model into ADAMS. Under the same simulation parameters, two experiments were done, one engaged without failure, the other engaged with one broken tooth of drive wheels. Calculated TIME and STEPS by Shannon sampling theorem, simulated the marker point’s acceleration of the drive gear, then obtain image data of time domain and frequency domain, after analyzed, found this method has a significant meaning to practice.
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Li, Jun, Jing Ren, Chong Ren, Xiaodong Zhang, and Haotian Xu. "Algorithm Research on Minimum Inertia Demand of New Energy Sending Grid Generating Units Considering System Transient Stability." Journal of Physics: Conference Series 2401, no. 1 (December 1, 2022): 012090. http://dx.doi.org/10.1088/1742-6596/2401/1/012090.
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Abstract After a lot of conventional power-generating units at the local end-to-end power grid have been replaced, the new energy-generating units do not participate in the active response of the system through the grid connection of the converter, which reduces transient stability due to the reduction of the inertia of the local grid. Firstly, based on the principle of transient energy, the mechanism of the moment of inertia of the local power grid is established by affecting the fault removal angle, and then the acceleration energy during the fault and the deceleration energy after the fault is removed is revealed. Based on the equal area rule, the relationship between the inertia and the transient stability limit, and the static stability limit before and after the fault is deduced, and the minimum engineering moment of inertia required to ensure the transient stability of the system at a certain output power level at the transmitting-end grid is given. The algorithm and simulation example analysis verify the effectiveness and practicability of the proposed method.
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Kkallas, Ch, C. B. Papazachos, B. N. Margaris, D. Boore, Ch Ventouzi, and A. Skarlatoudis. "Stochastic Strong Ground Motion Simulation of the Southern Aegean Sea Benioff Zone Intermediate‐Depth Earthquakes." Bulletin of the Seismological Society of America 108, no. 2 (January 16, 2018): 946–65. http://dx.doi.org/10.1785/0120170047.
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Abstract We employ the stochastic finite‐fault modeling approach of Motazedian and Atkinson (2005), as adapted by Boore (2009), for the simulation of Fourier amplitude spectra (FAS) of intermediate‐depth earthquakes in the southern Aegean Sea subduction (southern Greece). To calibrate the necessary model parameters of the stochastic finite‐fault method, we used waveform data from both acceleration and broadband‐velocity sensor instruments for intermediate‐depth earthquakes (depths ∼45–140 km) with M 4.5–6.7 that occurred along the southern Aegean Sea Wadati–Benioff zone. The anelastic attenuation parameters employed for the simulations were adapted from recent studies, suggesting large back‐arc to fore‐arc attenuation differences. High‐frequency spectral slopes (kappa values) were constrained from the analysis of a large number of earthquakes from the high‐density EGELADOS (Exploring the Geodynamics of Subducted Lithosphere Using an Amphibian Deployment of Seismographs) temporary network. Because of the lack of site‐specific information, generic site amplification functions available for the Aegean Sea region were adopted. Using the previous source, path, and site‐effect constraints, we solved for the stress‐parameter values by a trial‐and‐error approach, in an attempt to fit the FAS of the available intermediate‐depth earthquake waveforms. Despite the fact that most source, path, and site model parameters are based on independent studies and a single source parameter (stress parameter) is optimized, an excellent comparison between observations and simulations is found for both peak ground acceleration (PGA) and peak ground velocity (PGV), as well as for FAS values. The final stress‐parameter values increase with moment magnitude, reaching large values (>300 bars) for events M≥6.0. Blind tests for an event not used for the model calibration verify the good agreement of the simulated and observed ground motions for both back‐arc and along‐arc stations. The results suggest that the employed approach can be efficiently used for the modeling of large historical intermediate‐depth earthquakes, as well as for seismic hazard assessment for similar intermediate‐depth events in the southern Aegean Sea area.
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Karastathis, V. K., G. A. Papadopoulos, T. Novikova, Z. Roumelioti, P. Karmis, and P. Tsombos. "Prediction and evaluation of nonlinear site response with potentially liquefiable layers in the area of Nafplion (Peloponnesus, Greece) for a repeat of historical earthquakes." Natural Hazards and Earth System Sciences 10, no. 11 (November 17, 2010): 2281–304. http://dx.doi.org/10.5194/nhess-10-2281-2010.
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Abstract. We examine the possible non-linear behaviour of potentially liquefiable layers at selected sites located within the expansion area of the town of Nafplion, East Peloponnese, Greece. Input motion is computed for three scenario earthquakes, selected on the basis of historical seismicity data, using a stochastic strong ground motion simulation technique, which takes into account the finite dimensions of the earthquake sources. Site-specific ground acceleration synthetics and soil profiles are then used to evaluate the liquefaction potential at the sites of interest. The activation scenario of the Iria fault, which is the closest one to Nafplion (M=6.4), is found to be the most hazardous in terms of liquefaction initiation. In this scenario almost all the examined sites exhibit liquefaction features at depths of 6–12 m. For scenario earthquakes at two more distant seismic sources (Epidaurus fault – M6.3; Xylokastro fault – M6.7) strong ground motion amplification phenomena by the shallow soft soil layer are expected to be observed.
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Wang, Wei, and Jingwen Wang. "Dynamic Response Enhancement and Fault Protection of Boost Converter-Fed Brushless DC Motor in Aerospace Applications." Applied Sciences 9, no. 10 (May 23, 2019): 2113. http://dx.doi.org/10.3390/app9102113.
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The permanent magnet (PM) brushless DC (BLDC) machine has been widely used in various applications due to its high reliability and simplicity. In aerospace applications, the requirements of its dynamic acceleration characteristic and fault protection capability have further increased. This paper proposes an optimized inverter topology composed of a boost converter, two protective power switches, and a three-phase full bridge for the dynamic response improvement and fault protection capability enhancement of PM BLDC machines. The corresponding drive logic, control method, and protection strategy are designed to develop a drive system for an aeronautical fuel pump. The response performance is significantly improved in handling under-voltage and over-rated conditions by utilizing the boost converter during different processes, and the protection capability is enhanced to deal with over-voltage and over-current fault isolation. A boost converter-fed BLDC pump system prototype is built and tested. It is concluded that the simulation and experiment results verify the rationality and validity of the proposed method.
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Cui, Xi Zhong, Yong Xu Liu, and Han Ping Hong. "A Stochastic Model for Simulating Vertical Pulseless Near-Fault Seismic Ground Motions." Bulletin of the Seismological Society of America 112, no. 2 (December 7, 2021): 961–77. http://dx.doi.org/10.1785/0120210114.
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ABSTRACT The vertical near-fault seismic ground-motion component can cause significant structural deformation and damage, which can be evaluated from time history analysis using actual or synthetic ground-motion records. In this study, we propose a new stochastic model for the vertical pulseless near-fault ground motions that depends on earthquake magnitude, rupture distance, and site condition. The proposed model is developed based on the time–frequency characteristics of 606 selected actual vertical record components in strike-slip earthquakes. The use and validation of the model are presented using simulated records obtained by two simulation techniques. For the validation, the statistics of time–frequency-dependent power spectral acceleration estimated from the simulated records using the proposed stochastic model are compared with those from the actual records and the ground-motion models available in the literature.
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Kou, Farong, Jianghao Wu, Jian Gao, Dapeng Wu, and Ruochen Chen. "Active Fault-Tolerant Control Based on the Fault of Electromagnetic Hybrid Active Suspension." Shock and Vibration 2021 (November 1, 2021): 1–16. http://dx.doi.org/10.1155/2021/4273698.
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In order to improve the ride comfort and handling stability of the vehicle and realize the recovery of vibration energy, an electromagnetic linear hybrid suspension actuator composed of linear motor and solenoid valve shock absorber is proposed. At the same time, a fault diagnosis and fault-tolerant control strategy is designed to solve the system instability caused by the fault of electromagnetic hybrid active suspension. The 1/4 vehicle two-degree-of freedom suspension model, the linear motor mathematical model, and the solenoid valve shock absorber test model are established. In this paper, the fuzzy sliding mode controller is used as the controller and the unknown input observer is used to estimate the state of the suspension. According to the residual obtained from the unknown input observer and compared with the residual threshold, the suspension fault is determined. In the case of fault, the fuzzy sliding mode controller is used to compensate the force and realize the suspension fault-tolerant control. The performance of the suspension is simulated on random road and bumped road, respectively. The simulation results show that the fault-tolerant control effect of the three performance indexes of the suspension is good, and the ride comfort and safety of the suspension are improved. Finally, the bench test is carried out, and the test results show that in the fault-tolerant control state, the root mean square value of the sprung mass acceleration is reduced by 31.69% compared with the fault state and the dynamic performance of the suspension is improved.
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YANG, DIXIONG, PIXIN YANG, and CHANGGENG ZHANG. "CHAOTIC CHARACTERISTIC ANALYSIS OF STRONG EARTHQUAKE GROUND MOTIONS." International Journal of Bifurcation and Chaos 22, no. 03 (March 2012): 1250045. http://dx.doi.org/10.1142/s0218127412500459.
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This paper aims to analyze and understand the irregularity and complexity of earthquake ground motions from the perspective of nonlinear dynamics. Chaotic dynamics theory and chaotic time series analysis are suggested to examine the nonlinear dynamical characteristic of strong earthquake ground motions. Based on the power spectral analysis, principal component analysis and modified false nearest neighbors method, it is illustrated qualitatively that the acceleration time series of earthquake ground motions exhibit chaotic property. Next, the chaotic time series analysis is proposed to calculate quantitatively the nonlinear characteristic parameters of acceleration time histories of near-fault ground motions. Numerical results show that the correlation dimension of these ground motions is fractal dimension. Their Kolmogorov entropy is a limited positive value, and their maximal Lyapunov exponent is larger than 0. It is demonstrated that the strong earthquake ground motions present the chaotic property rather than the pure random signals, and the severe irregularity and complexity of ground motions are the reflection of high nonlinearity of earthquake physical process.
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Cheloni, Daniele, and Aybige Akinci. "Source modelling and strong ground motion simulations for the 24 January 2020, Mw 6.8 Elazığ earthquake, Turkey." Geophysical Journal International 223, no. 2 (July 21, 2020): 1054–68. http://dx.doi.org/10.1093/gji/ggaa350.
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SUMMARY On 24 January 2020 an Mw 6.8 earthquake occurred at 20:55 local time (17:55 UTC) in eastern Turkey, close to the town of Sivrice in the Elazığ province, causing widespread considerable seismic damage in buildings. In this study, we analyse the main features of the rupture process and the seismic ground shaking during the Elazığ earthquake. We first use Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1 satellites) to constrain the fault geometry and the coseismic slip distribution of the causative fault segment. Then, we utilize this information to analyse the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations. The absence of seismic registrations in near-field for this earthquake imposes major constraints on the computation of seismic ground motion estimations in the study area. To do this, we have used a stochastic finite-fault simulation method to generate high-frequency ground motions synthetics for the Mw 6.8 Elazığ 2020 earthquake. Finally, we evaluate the potential state of stress of the unruptured portions of the causative fault segment as well as of adjacent segments, using the Coulomb stress failure function variations. Modelling of geodetic data shows that the 2020 Elazığ earthquake ruptured two major slip patches (for a total length of about 40 km) located along the Pütürge segment of the well-known left-lateral strike-slip East Anatolian Fault Zone (EAFZ), with up to 2.3 m of slip and an estimated geodetic moment of 1.70 $\,\, \times $ 1019 Nm (equivalent to a Mw 6.8). The position of the hypocentre supports the evidence of marked WSW rupture directivity during the main shock. In terms of ground motion characteristics, we observe that the high-frequency stochastic ground motion simulations have a good capability to reproduce the source complexity and capture the ground motion attenuation decay as a function of distance, up to the 200 km. We also demonstrate that the design spectra corresponding to 475 yr return period, provided by the new Turkish building code is not exceeded by the simulated seismograms in the epicentral area where there are no strong motion stations and no recordings available. Finally, based on the Coulomb stress distribution computation, we find that the Elazığ main shock increased the stress level of the westernmost part of the Pütürge fault and of the adjacent Palu segment and as a result of an off-fault lobe.
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Kaviris, George, Angelos Zymvragakis, Pavlos Bonatis, Vasilis Kapetanidis, and Nicholas Voulgaris. "Probabilistic and Scenario-Based Seismic Hazard Assessment on the Western Gulf of Corinth (Central Greece)." Applied Sciences 12, no. 21 (November 3, 2022): 11152. http://dx.doi.org/10.3390/app122111152.
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The Gulf of Corinth (Central Greece) is one of the most rapidly extending rifts worldwide, with its western part being the most seismically active, hosting numerous strong (M ≥ 6.0) earthquakes that have caused significant damage. The main objective of this study was the evaluation of seismic hazard through a probabilistic and stochastic methodology. The implementation of three seismotectonic models in the form of area source zones via a logic tree framework revealed the expected level of peak ground acceleration and velocity for return periods of 475 and 950 years. Moreover, PGA values were obtained through the stochastic simulation of strong ground motion by adopting worst-case seismic scenarios of potential earthquake occurrences for known active faults in the area. Site-specific analysis of the most populated urban areas (Patras, Aigion, Nafpaktos) was performed by constructing uniform hazard spectra in terms of spectral acceleration. The relative contribution of each selected fault segment to the seismic hazard characterizing each site was evaluated through response spectra obtained for the adopted scenarios. Almost all parts of the study area were found to exceed the reference value proposed by the current Greek National Building Code; however, the three urban areas are covered by the Eurocode 8 regulations.
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Xu, Yonggang, Kun Zhang, Chaoyong Ma, Xiaoqing Li, and Jianyu Zhang. "An Improved Empirical Wavelet Transform and Its Applications in Rolling Bearing Fault Diagnosis." Applied Sciences 8, no. 12 (November 22, 2018): 2352. http://dx.doi.org/10.3390/app8122352.
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As essential but easily damaged parts of rotating machinery, rolling bearings have been deeply researched and widely used in mechanical processes. The real-time detection of bearing state and simple, rapid, and accurate diagnosis of bearing fault are indispensable to the industrial system. The bearing’s inner ring and outer ring vibration acceleration can be measured by high-precision sensors, and the running state of the bearing can be effectively extracted. The empirical wavelet transform (EWT) can adaptively decompose the vibration acceleration signal into a series of empirical modes. However, this method not only runs slowly, but also causes inexplicable empirical modes due to the unreasonable boundaries of the frequency domain division. In this paper, a new method is proposed to improve the empirical wavelet transform by dividing the boundaries from the spectrum, named the fast empirical wavelet transform (FEWT). The proposed method chooses different points in the Fourier transform of the spectrum (key function) to reconstruct the trend component of the spectrum. The minimum points in the trend component divide the spectrum into a series of bands. A more reasonable set of boundaries can be found by choosing appropriate trend components to obtain effective empirical modes. The simulation results show that the proposed method is effective and that the acquired empirical mode is more reasonable than the EWT method. Combining kurtosis with fault feature extraction of inner and outer rings of bearings, the method is successfully applied to the fault diagnosis of rolling bearings.
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Chu, Jianxiong, Zhenyu Li, Lipeng Huang, Xueying Huang, and Kunming Wang. "Fault Diagnosis of Transformer Winding Based on VMD-SVM." Journal of Physics: Conference Series 2355, no. 1 (October 1, 2022): 012024. http://dx.doi.org/10.1088/1742-6596/2355/1/012024.
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Abstract Considering the nonlinear and non-stationary characteristics of the transformer vibration acceleration signal obtained from the surface of the transformer tank, the variational mode decomposition (VMD) theory is introduced. Simulation analysis shows that the VMD decomposition has obvious advantages over EMD when the needle frequency is similar to the signal. It effectively avoids two types of modal aliasing and over-decomposition, and accurately reflects the characteristics of the source signal. Aiming at the problem that the two core parameters of the support vector machine are difficult to determine, the Pareto particle swarm method is used to perform multi-objective parallel optimization of the two core parameters of the support vector machine to obtain the optimal parameters. The VMD-SVM fault diagnosis model is tested using the transformer instance fault data, and compared with the other two methods. The instance test results show that the VMD-SVM proposed in this paper has the highest diagnostic accuracy and realizes the latent fault of the power transformer winding. accurate diagnosis.
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Ye, Yunguang, Ping Huang, and Yongxiang Zhang. "Deep learning-based fault diagnostic network of high-speed train secondary suspension systems for immunity to track irregularities and wheel wear." Railway Engineering Science 30, no. 1 (October 20, 2021): 96–116. http://dx.doi.org/10.1007/s40534-021-00252-z.
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AbstractFault detection and isolation of high-speed train suspension systems is of critical importance to guarantee train running safety. Firstly, the existing methods concerning fault detection or isolation of train suspension systems are briefly reviewed and divided into two categories, i.e., model-based and data-driven approaches. The advantages and disadvantages of these two categories of approaches are briefly summarized. Secondly, a 1D convolution network-based fault diagnostic method for high-speed train suspension systems is designed. To improve the robustness of the method, a Gaussian white noise strategy (GWN-strategy) for immunity to track irregularities and an edge sample training strategy (EST-strategy) for immunity to wheel wear are proposed. The whole network is called GWN-EST-1DCNN method. Thirdly, to show the performance of this method, a multibody dynamics simulation model of a high-speed train is built to generate the lateral acceleration of a bogie frame corresponding to different track irregularities, wheel profiles, and secondary suspension faults. The simulated signals are then inputted into the diagnostic network, and the results show the correctness and superiority of the GWN-EST-1DCNN method. Finally, the 1DCNN method is further validated using tracking data of a CRH3 train running on a high-speed railway line.
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Li, Xiao Cong, Tao Zheng, Zhi Jian Liang, and Jun Hua Xu. "Multi-Index Nonlinear Coordinated Control of TCBR and Hydro-Generator Excitation." Applied Mechanics and Materials 704 (December 2014): 199–203. http://dx.doi.org/10.4028/www.scientific.net/amm.704.199.
Full textAbstract:
As a new FACTS device, thyristor controlled braking resistor (TCBR) is one of the effective devices to enhance transient stability of generator. In this paper, a coordinated controller for TCBR and hydro-generator excitation system with the multi-index nonlinear coordinate control method based differential geometry theory is proposed. By means of Hartman-Grobman theorem, differential geometry multi-index nonlinear control (DGMINC) design method can reassign the closed-loop system eigenvalues of linear approximate system to the nonlinear system via appropriately selecting output function parameter matrix. Therefore, the system can get good control performance. The simulation results show that TCBR and generator excitation system controlled by this coordinate control strategy can decrease the generator acceleration area rapidly when the severe fault occurred and increase deceleration area significantly after the fault is cleared. So that, power system transient stability limitation improved significantly.