Articles de revues : « Nonlinear buffeting »

1

Wang, Hong Mei, Wei Zhang et Lan Hua Zhang. « Nonlinear Sliding-Mode Control for Induction Motors Based on Speed Sensorless ». Advanced Materials Research 580 (octobre 2012) : 105–9. http://dx.doi.org/10.4028/www.scientific.net/amr.580.105.

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In order to eliminate buffeting problems caused by the traditional sliding mode control algorithm of induction motors, this paper adopts a continuous control term. In the meanwhile, a simple observer is designed to estimate the rotor flux and rotor torque. Besides, the mechanical equation of induction motor is applied to calculate the motor speed. Finally, according to the results of simulation, the buffeting problems are basically eliminated and thus the method mentioned in this paper is proved feasible.

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Chen, Chern Hwa, Yuh Yi Lin, Cheng Hsin Chang, Shun Chin Yang, Yung Chang Cheng et Ming Chih Huang. « Aerodynamic Analysis in Time Domain of a Cable-Stayed Bridge ». Advanced Materials Research 479-481 (février 2012) : 1205–8. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1205.

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To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.

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Liang, Yan-Jun, Shi-Liang Wu, De-Xin Gao et Xiao-Rong Xue. « Feedforward and Feedback Vibration Control and Algorithm Design for Cable-Bridge Structure Nonlinear Systems ». Abstract and Applied Analysis 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/513530.

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Technique of feedforward and feedback optimal vibration control and simulation for long-span cable-bridge coupled systems is developed. Buffeting loading systems of long-span cable-bridge structure are constructed by weighted amplitude wave superposition method. Nonlinear model of cable-bridge coupled vibration control system is established and the corresponding system of state space form is described. In order to reduce buffeting loading influence of the wind-induced vibration for the structure and improve the robust performance of the vibration control, based on semiactive vibration control devices and optimal control approach, a feedforward and feedback optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results are presented to illustrate the effectiveness of the proposed technique.

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Kim, Ho-Kyung, Masanobu Shinozuka et Sung-Pil Chang. « Geometrically Nonlinear Buffeting Response of a Cable-Stayed Bridge ». Journal of Engineering Mechanics 130, n^o 7 (juillet 2004) : 848–57. http://dx.doi.org/10.1061/(asce)0733-9399(2004)130:7(848).

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Liu, Haosu, Junqing Lei et Li Zhu. « Identification and Application of the Aerodynamic Admittance Functions of a Double-Deck Truss Girder ». Applied Sciences 9, n^o 9 (1 mai 2019) : 1818. http://dx.doi.org/10.3390/app9091818.

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This paper presents the aerodynamic admittance functions (AAFs) of a double-deck truss girder (DDTG) under turbulent flows. The objective of the investigation is to identify AAFs using a segment model wind tunnel test. All of the wind tunnel tests were based on the force measurement method and conducted in a passive spire-generated turbulent flow. The segment model adopts a typical DDTG section and is tested in the service and construction stages under 0°, 3°, and 5° wind attack angles. Furthermore, a nonlinear expression is put forward to fit the identified AAFs. The buffeting responses of a long-span road-rail cable-stayed bridge are then calculated for both the service and construction stages using an equivalent ‘fish-bone’ finite element model of the DDTG. The unsteady effect of the buffeting force is considered based on quasi-steady buffeting theory using the identified AAFs. The calculated buffeting responses are finally compared with those for two other AAFs (AAF = 1.0 and the Sears function). The results indicate that the traditional AAFs overestimate vibrations in the vertical and torsional directions but underestimate vibrations in the lateral direction. The identified AAFs of the DDTG can be regarded as a reference for wind-resistant designs with similar girder sections.

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CROUCH, J. D., A. GARBARUK, D. MAGIDOV et A. TRAVIN. « Origin of transonic buffet on aerofoils ». Journal of Fluid Mechanics 628 (1 juin 2009) : 357–69. http://dx.doi.org/10.1017/s0022112009006673.

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Buffeting flow on transonic aerofoils serves as a model problem for the more complex three-dimensional flows responsible for aeroplane buffet. The origins of transonic aerofoil buffet are linked to a global instability, which leads to shock oscillations and dramatic lift fluctuations. The problem is analysed using the Reynolds-averaged Navier–Stokes equations, which for the foreseeable future are a necessary approximation to cover the high Reynolds numbers at which transonic buffet occurs. These equations have been shown to reproduce the key physics of transonic aerofoil flows. Results from global-stability analysis are shown to be in good agreement with experiments and numerical simulations. The stability boundary, as a function of the Mach number and angle of attack, consists of an upper and a lower branch – the lower branch shows features consistent with a supercritical bifurcation. The unstable modes provide insight into the basic character of buffeting flow at near-critical conditions and are consistent with fully nonlinear simulations. The results provide further evidence linking the transonic buffet onset to a global instability.

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CHEN, C. H., et C. I. OU. « EXPERIMENTAL MODAL TEST AND TIME-DOMAIN AERODYNAMIC ANALYSIS OF A CABLE-STAYED BRIDGE ». International Journal of Structural Stability and Dynamics 11, n^o 01 (février 2011) : 101–25. http://dx.doi.org/10.1142/s0219455411004002.

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To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The dynamic characteristics of the bridge identified by a continuous wavelet transform algorithm are compared with those obtained by the finite element analysis. The finite element model was then modified and refined based on the field test results. The results obtained from the updated finite element model were shown to agree well with the field identified results for the first few modes in the vertical, transverse, and torsional directions. This has the indication that a rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.

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Wang, Dahai, Xinzhong Chen et Jie Li. « Prediction of wind-induced buffeting response of overhead conductor : Comparison of linear and nonlinear analysis approaches ». Journal of Wind Engineering and Industrial Aerodynamics 167 (août 2017) : 23–40. http://dx.doi.org/10.1016/j.jweia.2017.04.008.

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Solari, G., et G. Piccardo. « Probabilistic 3-D turbulence modeling for gust buffeting of structures ». Probabilistic Engineering Mechanics 16, n^o 1 (janvier 2001) : 73–86. http://dx.doi.org/10.1016/s0266-8920(00)00010-2.

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Ali, Khawaja, Hiroshi Katsuchi et Hitoshi Yamada. « Development of nonlinear framework for simulation of Typhoon-induced buffeting response of Long-span bridges using Volterra series ». Engineering Structures 244 (octobre 2021) : 112721. http://dx.doi.org/10.1016/j.engstruct.2021.112721.

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Li, Hui, Yue Quan Bao, Shun Long Li, Wen Li Chen, Shu Jin Laima et Jin Ping Ou. « Monitoring, Evaluation and Control for Life-Cycle Performance of Intelligent Civil Structures ». Advances in Science and Technology 83 (septembre 2012) : 105–14. http://dx.doi.org/10.4028/www.scientific.net/ast.83.105.

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This paper includes five parts. The first is the sensing technology, in which ultrasonic-based sensing technology for scour monitoring of bridge piers, electro-chemistry-based distributed concrete cracks and automobile wireless sensors are introduced. The second is the application of compressive sensing technology in structural health monitoring, in which the recovery of lose data for wireless senor networks, spatial distribution of vehicles on the bridge and localization of acoustic emission source by using compressive technique are included. The third is damage monitoring and identification of seismically excited structures, in which data-driven seismic localization approach and nonlinear hysteretic model identification approach are proposed. The fourth is the monitoring for wind and wind effects of long-span bridges, the vortex-induced vibration of deck, suspended cables and stay cables is observed and the buffeting of bridge under Typhoon is also measured. The last one is the data analysis, modeling and safety evaluation of bridges based on structural health monitoring techniques.

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Sparling, B. F., et A. G. Davenport. « Three-dimensional dynamic response of guyed towers to wind turbulence ». Canadian Journal of Civil Engineering 25, n^o 3 (1 juin 1998) : 512–25. http://dx.doi.org/10.1139/l97-113.

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The three-dimensional dynamic response of a guyed tower subjected to turbulent buffeting was investigated analytically in this study. Nonlinear dynamic response was determined in the time domain using Newmark's method to perform a step-by-step integration of the governing equations of motion. A simulated windstorm containing both alongwind and acrosswind turbulences was generated using a second-order autoregressive process. It was found that the fluctuating response in the acrosswind direction was similar in magnitude to that in the alongwind direction, with the relative size of the alongwind and acrosswind components depending on wind direction. Resultant bending moments in the mast were increased significantly by the acrosswind motion, leading to larger peak leg loads. Peak mast displacements and shear forces, on the other hand, appeared to be less sensitive. Dynamic guy fluctuations and axial forces in the mast were also investigated.Key words: guyed tower, dynamic response, wind loading, wind simulation, structural analysis, finite element analysis.

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Song, Yang, Zhigang Liu, Huajiang Ouyang, Hongrui Wang et Xiaobing Lu. « Sliding Mode Control with PD Sliding Surface for High-Speed Railway Pantograph-Catenary Contact Force under Strong Stochastic Wind Field ». Shock and Vibration 2017 (2017) : 1–16. http://dx.doi.org/10.1155/2017/4895321.

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As is well known, the external disturbance (especially the stochastic wind load) has nonnegligible effect on the operation of pantograph-catenary system, which may cause the strong fluctuation in contact force as well as the increased occurrence of contact loss. In order to improve the current collection quality of a high-speed railway pantograph-catenary system under a strong stochastic wind field, a sliding mode controller with a proportional-derivative (PD) sliding surface for a high-speed active pantograph is proposed. The nonlinear finite element procedure is employed to establish the catenary model. The fluctuating wind speeds along catenary are simulated using empirical spectrums. The buffeting forces exerted on contact and messenger wires are derived to construct the stochastic wind field along the catenary. A PD sliding surface is properly determined to guarantee that the mechanical impedance of pantograph head at the dominant frequencies of contact force decreases when the sliding surface approaches zero. Through several numerical simulations with different wind velocities and wind angles, the control performance of two popular control laws (proportional switching law and constant switching law) is evaluated.

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Hu, Liang, et You-Lin Xu. « Extreme value of typhoon-induced non-stationary buffeting response of long-span bridges ». Probabilistic Engineering Mechanics 36 (avril 2014) : 19–27. http://dx.doi.org/10.1016/j.probengmech.2014.02.002.

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Hao, Wei, et Qingshan Yang. « Reformative translation model for probability density functions of amplitude processes of crosswind-excited super-tall buildings ». Advances in Structural Engineering 23, n^o 5 (1 novembre 2019) : 847–56. http://dx.doi.org/10.1177/1369433219886086.

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At the vicinity of vortex lock-in wind speed, the nonlinear aerodynamic damping effect of super-tall buildings is significant, which can greatly promote the surge of vortex-induced vibration in the crosswind direction, where the crosswind response characterized by harmonic amplitude shows narrow-band hardening non-Gaussian characteristic with the kurtosis well below 3, and the corresponding probability distribution of amplitude process distinctly differs from that of typical random buffeting response. Although the moment-based Hermite translation model has been widely used for estimating the extreme value distribution of non-Gaussian process, it fails to represent the probability distribution of hardening non-Gaussian amplitude process, notably for the response with a kurtosis close to 1.5. In this study, a new translation model based on orthogonal expansion of random processes is developed for obtaining the non-Gaussian amplitude process from an underlying Gaussian amplitude process, and the probability density function of the non-Gaussian amplitude process is derived by mapping the cumulative distribution function. The coefficients of translation model are determined by minimizing the errors between the estimated probability density functions and target values through nonlinear optimization, and the closed-form semi-empirical formulations, which connect the model coefficients with response kurtosis, are also proposed using least-square curve fitting. Moreover, the effectiveness and monotonicity of the proposed translation model are examined. This model can be readily incorporated into the extreme value analysis of crosswind response and facilitate the evaluation of wind-induced fatigue of super-tall buildings.

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Wu, Yanchi, Xinzhong Chen et Yunfei Wang. « Identification of linear and nonlinear flutter derivatives of bridge decks by unscented Kalman filter approach from free vibration or stochastic buffeting response ». Journal of Wind Engineering and Industrial Aerodynamics 214 (juillet 2021) : 104650. http://dx.doi.org/10.1016/j.jweia.2021.104650.

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Zhao, Lei, Changqing Yuan, Xiaoming Li et Jingjiu He. « Multiple Spacecraft Formation Flying Control around Artificial Equilibrium Point Using Propellantless Approach ». International Journal of Aerospace Engineering 2022 (2 mai 2022) : 1–26. http://dx.doi.org/10.1155/2022/8719645.

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This paper demonstrates a detailed analysis of the feasibility for compact formation system around an L2-type artificial equilibrium point by means of continuous low-thrust propulsion in the hybrid form of solar sail and Coulomb force propulsion. Firstly, in view of non-ideal solar sail, the position of L2-type artificial equilibrium point and numerical periodic orbits around L2 utilized as leader’s nominal trajectory are given. Secondly, considering the external disturbances in the deep space environment, the nonlinear dynamic model of the spacecraft formation system based on the circular restricted three-body problem (CRTBP) is derived, under the assumption that the leader covers the nominal trajectory and each follower adjusts its propulsive acceleration vector (that is, both its sail attitude and electrostatic charge) in order to track a desired relative trajectory. Thirdly, based on a new double power combination function reaching law, a fast integral terminal sliding mode control methodology (MFITSM) is ameliorated to achieve orbital tracking rapidly, which has better robustness against external disturbances and the buffeting effect during spacecraft propulsion simultaneously. To properly allocate control inputs, a novel optimal allocation scheme is designed to calculate the charge product of the spacecrafts and sail attitude angles, which can make the magnitude of the acceleration required from the Coulomb propulsion system minimum and avoid formation geometry instabilities by balancing electrostatic interaction between adjacent spacecraft. Finally, several numerical examples are conducted to validate the superiority of the proposed control algorithm.

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Guangming, Xiong, Long Teng, Zhu Yong, Tian Ce, Guo Kai et Tan Wei. « Experimental and Numerical Study on Flow-Induced Vibration of PWR Steam Generator U-Tubes ». International Journal of Acoustics and Vibration 27, n^o 3 (30 septembre 2022) : 221–32. http://dx.doi.org/10.20855/ijav.2022.27.31864.

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The flow-induced vibration (FIV) of steam generators (SGs) in pressurized water reactors (PWRs) is a significant problem in the design process. This problem contains issues such as two-phase flow, nonlinear dynamics and fretting wear. In this paper, an experimental setup was established to study the FIV of a newly designed U-tube SG. Numerical simulations, including computational fluid dynamics (CFD) and vibration studies were performed to reveal the detailed mechanisms of FIV. To study the U-bend region of the tube bundles, the experiments were carried out under 23 experimental conditions containing void fractions of 70%, 80%, 90 and 95%. The flow fields of the tested model in each condition were calculated to reveal the causes of the vibration phenomenon, and the vibration results were calculated through structure dynamics. The experimental results showed that the vibration amplitudes of the U-tube increased with increasing inlet velocity, flow rate and bending radius. It decreased with increasing void fraction under the same inlet velocity, while it increased with increasing void fraction under the same flow rate. Along with the out-of-plane vibration, the in-plane vibration also featured high amplitude vibration of the U-tubes due to lack of support by the anti-vibration bars (AVBs). The simulation results show the same variation trends of the vibration responses as the above experiments. The prototype SG can be fluid-elastic stable in given working conditions, and the main vibration mechanism of this model is turbulence buffeting. The experiment and simulation methods and data can be used in the design process of new SGs similar to this prototype.

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Zuo, Leibin, Qinfeng Li, Cunming Ma, Li Yadong et Chuanchuan Hu. « Analysis of Span-Directional Coherence Function and Buffeting Response of a Long-Span Natural Gas Pipeline Suspension Bridge under a Turbulent Wind Field ». Journal of Sensors 2022 (19 septembre 2022) : 1–17. http://dx.doi.org/10.1155/2022/5381511.

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A long-span natural gas pipeline suspension bridge is prone to buffeting under the action of a turbulent wind field. In order to accurately calculate the buffeting response of the structure under a turbulent wind field, the 1 : 15 segment model wind tunnel test is used to obtain the aerodynamic coefficient and flutter derivative of the bridge deck structure. According to the test results, the buffeting force coherence functions under five different span-directional spacing are fitted. The results show that the buffeting force coherence function corresponding to different wind attack angles has a peak at the corresponding wing grid vibration frequency in the low-frequency region; when the spacing increases to r = 0.51 m or above, the amplitude of coherence function decreases significantly; for the spacing of r = 0.17 m , the buffeting force coherence functions in different directions are obviously different but the corresponding coherence functions of resistance, lift, and torque show a similar curve trend between different wind attack angles. Based on the Scanlan buffeting force correction model, the buffeting response under the reference wind speed of 30.1 m/s is analyzed in the frequency domain and compared with the wind tunnel test results of the whole bridge. The results show that the buffeting response calculated in this paper is in good agreement with the wind tunnel test results of the whole bridge and the buffeting response law is consistent. The maximum value of vertical buffeting response is located near the 1/4 span, and the maximum values of lateral and torsional response are located in the middle of the span. The lateral buffeting displacement response is significantly greater than the vertical buffeting displacement response. Under different wind attack angles, the vertical, lateral, and torsional buffeting displacement responses of the bridge deck structure increase nonlinearly with the increase of wind speed.

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Jiang, Hongsheng, Yaojun Ge, Ke Li et Shiyi Liu. « A Novel Nonlinear Aerodynamic Model of Flutter and Buffeting Based on Condensed DOFs Technology ». International Journal of Structural Stability and Dynamics, 4 mai 2021, 2150112. http://dx.doi.org/10.1142/s0219455421501121.

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This paper proposes a novel Inertial Coordinates Independent (ICI) aerodynamic model using the condensed degrees of freedom (DOFs) technology. Through a management of the ICI inputs, the aerodynamic forces will not be restricted by the selection of inertial coordinates and will have the same prediction effect for different coordinates. In addition, by including the self-excited force and the buffeting force, and by reducing the appropriate number of aerodynamic DOF, the ability of the proposed model to describe the nonlinear aerodynamic characteristics such as memory effect is enhanced. It can be directly applied to any non-stationary inputs in the time domain, and improve its applicability to structures with large deformations. With the self-developed computational fluid dynamics (CFD) software, the aerodynamic to-be-identified parameters can be identified by a data-driven method, and the correctness of each term of this model has been verified. Finally, the overall accuracy of the proposed method is examined by comparing both the self-excited force and the hysteresis patterns of ICI model with those results based on a series of CFD simulations of a streamlined bridge deck section.

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Yang, Yi, et Ledian Zheng. « Wind-buffeting noise characteristics of simple cavity model based on nonlinear LRN/DES turbulence model ». Numerical Heat Transfer, Part A : Applications, 3 août 2022, 1–19. http://dx.doi.org/10.1080/10407782.2022.2102400.

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« A Novel Sliding Mode Controller for Underactuated Vertical Takeoff and Landing Aircraft ». International Journal of Circuits, Systems and Signal Processing 14 (30 avril 2020). http://dx.doi.org/10.46300/9106.2020.14.6.

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Compared with other control methods, the biggest advantage of using sliding mode variable structure control method lies in its strong robustness which could be used to directly handle the strong nonlinear flight control system. However, this control method requires switching between different switching surfaces, which will inevitably cause buffeting problems, so that the energy consumption increases. Therefore, how to overcome this disadvantage to achieve the superior performance of sliding mode variable structure control method is the current research focus. This paper studies the trajectory tracking of under-actuated VTOL aircraft with three degrees of freedom and two control inputs under various coupling effects. By the input and coordinate transformation, the dynamic equation of the system is transformed into decoupled standard under-actuated form and the sliding mode controller is designed. Then Lyapunov stability theorem is used to derive sliding mode control law which could ensure that the system asymptotically converges to the given trajectory. The simulation has demonstrated the effectiveness of this method

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Lei, Simian, Wei Cui, Luca Patruno, Stefano de Miranda, Lin Zhao et Yaojun Ge. « Improved state augmentation method for buffeting analysis of structures subjected to non-stationary wind ». Probabilistic Engineering Mechanics, juin 2022, 103309. http://dx.doi.org/10.1016/j.probengmech.2022.103309.

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Articles de revues sur le sujet « Nonlinear buffeting »

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