bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delay segmented tristable stochastic resonance system driven by non-gaussian colored noise and its application in bearing fault detection
Authors: He Lifang , Cao Longmei , Zhang Junsheng 
Published: June 2024

Abstract
This study investigates the Delayed Segmented Tristable Stochastic Resonance (DSTSR) system under the influence of additive non-Gaussian colored noise. The research employs an improved segmented tristable potential function, wherein the equilibrium points and barrier heights can be independently controlled by parameters. Simultaneously, the segmented function on both sides reduces the restrictions of higher-order terms on the walls of the potential wells. The equivalent Langevin equation for the DSTSR system is obtained using the path integral method, the unified colored noise approximation method, and the small-delay approximation. Subsequently, the theoretical expressions for the steady-state probability density, mean first passage time (MFPT), and Signal-to-Noise Ratio (SNR) are derived from the resulting equations, and the impact of variations in system parameters on these performance metrics is discussed. Additionally, Monte Carlo simulations for MFPT are conducted to verify the accuracy of the theoretical derivations. Combining the results from the theoretical section and the impact of parameters on system performance, the article employs an adaptive genetic algorithm to optimize system parameters. This algorithm is then applied to simulation experiments and bearing fault detection. In the simulation experiments, the DSTSR system is compared with other systems. The results indicate that the DSTSR system exhibits the highest SNR improvement. Furthermore, in bearing fault detection under non-Gaussian colored noise, the DSTSR system shows higher spectral amplitude and SNR at the fault frequency compared to the tristable stochastic resonance system and the segmented tristable stochastic resonance system without time delay feedback. This suggests that stochastic resonance can effectively detect weak signals in non-Gaussian non-white noise scenarios, and the introduction of time delay contributes to the occurrence of stochastic resonance to a certain extent.
Design and analysis of the C6H6-filled circular photonic crystal fiber with ultra-flat dispersion for broadband supercontinuum generation with peak power of 130 W and 250 W
Authors: Trong Duc Hoang , Van Lanh Chu , Thi Thuy Nguyen 
Published: June 2024

Abstract
This article introduces a new model of a circular silica-based photonic crystal fiber with a hollow core filled with C6H6. The difference in the air hole size and the distance between them in the first ring around the core has a profound effect on the dispersion, leading to ultra-flat dispersion with values as low as ±0.996 ps nm−1· km in wavelength range 0.74 µm. The high nonlinear coefficient of several 1000 W−1 · km−1 and the low confinement loss of a few tens of dB m−1 suggest proposing three fibers with dispersion and nonlinear properties suitable for broadband supercontinuum generation at low peak power. The influence of peak power on the broadening of the supercontinuum spectrum is also investigated. Fibers with a flat all-normal dispersion profile provide a smooth spectrum with bandwidths of 1.215 and 1.626 µm at 30 dB with a peak power of 250 W. A fiber with an anomalous dispersion regime generates a supercontinuous spectrum, broadening to 3.868 µm in the mid-infrared region (2.467 µm bandwidth at 30 dB) under laser pulse excitation with 130 W peak power. Our results provide further insights into the generation of broadband mid-infrared supercontinuum using liquid-core silica-fibers, which have great potential for applications in the fields of optical communications and optical sensing.
Connection strength analysis for composite fuselage gate structures of civil aircraft
Authors: Wu Yang , Qiu Xudong , Bai Chunyu , Liu Hu 
Published: June 2024

Abstract
Civil aircraft boarding gate is an important channel for passengers to enter and exit the aircraft, and is also an important part of the aircraft structure, with the function of maintaining cockpit pressure. Traditional boarding doors are made of metal, and with the large number of composite materials used in the bearing structure of civil aircraft, composite boarding doors are also used in new civil aircraft. The strength of the connection inside the new composite boarding gate is related to the safety of passengers and crew. This paper focuses on the connection problem of the internal structure of composite boarding gate, aiming to analyze its connection strength under working conditions. This paper establishes a real finite element model of the boarding gate according to the loading condition and force transmission characteristics of the civil aircraft door and analyzes the connection strength of the structure such as the skin and the transverse and longitudinal beams, the skin and the side frame, the transverse and longitudinal beams connection, and the stop block in turn. The study shows that the strength of the connecting structures of the boarding gate designed by using composite materials is reasonable and can meet the service requirements of the boarding gate, thus demonstrating the rationality of the boarding gate structure designed with composite materials.
On modelling strain gradient viscoelasticity of polymer nanocomposites
Authors: Jiang Yiyuan , Li Li , Hu Yujin 
Published: June 2024

Abstract
Theories of generalized continuum mechanics have found great success in the analysis of nanostructures. However, there exists no work on analysing composites whose constituents are generalized continua. The present work fills this gap and studies the strain gradient viscoelasticity of polymeric nanocomposites. The key problem is to assign the nonclassical boundary condition of the representative volume element (RVE). To resolve it, a perturbation field is superposed on the homogeneous displacement boundary condition. The wavelength of perturbation is comparable to the strain gradient characteristic length. Simulations to obtain the macroscopic effective mechanical properties are performed, which agree well with the experimental data. The frequency dependence of the perturbation field is revealed, and it has a clear physical interpretation in terms of the segmental motions of polymer chains.
Study on the corrosion fatigue properties of ultrasonic surface strengthened axle steel
Authors: Liu Yu , Zhao Xiaocan 
Published: June 2024

Abstract
Owing to fatigue damage and environmental erosion, locomotive axles are prone to premature failure during service. It is therefore very important to improve the corrosion fatigue properties of axles. In this paper, the fatigue behavior of ultrasonic surface strengthened axle steel under corrosive environment was studied. The surface integrity of ultrasonic strengthened axle steel was characterized by microscopic analysis and hardness test. The fatigue data and fatigue fracture of axle steel under corrosion environment were compared. Also, the mechanism of the corrosion environment on fatigue crack initiation and propagation was analyzed. Results show that serious plastic deformation is generated in the surface of axle steel after ultrasonic strengthening. The grains in surface layer are obviously refined and get coarse gradually as deep into the matrix. The hardness of surface layer is greatly improved as well. The maximum value is located on the outermost surface, about 2 times of the matrix. Under the same fatigue load, the fatigue cycle number for ultrasonic strengthened axle steel is more than that of original sample. This is due to grain refinement, work hardening, and residual compressive stress induced by ultrasonic strengthening, which inhibits fatigue crack initiation in corrosion environment.
Analysis of crack propagation of annular butt weld and distribution of weld-induced residual stress
Authors: Zhu Jin , Xia Jie , Jin Hui 
Published: June 2024

Abstract
The circumferential surface crack propagation and the effect of weld-induced residual stress were analyzed to comprehensively understand the mechanical behavior and fracture resistance of dissimilar girth welded joints of steel castings. The evaluation of stress intensity factors is conducted for circumferential cracks on internal surfaces, aiming to predict the fracture toughness of dissimilar welded joints. The distribution of weld-induced residual stress is obtained by thermal elastic-plastic finite element methods. The impact of residual stress on the propagation of cracks is investigated through the application of extended finite element theory. The high-stress intensity factors were found in such dissimilar welded joints due to the local bending and distortion caused by the asymmetrical weld geometry. The tensile residual stress and distortion were applied to the weld root area and its vicinity. Both the asymmetrical weld geometry and tensile residual stress contribute to the tensile distortion of the inner surface around the weld root, and enable the growth of internal surface cracks in the circumferential direction and radially from inside out of the welded joint. The fracture resistance decreases with the simultaneous influence of residual stress and welds’ asymmetry.
Highly elastic polymer substrates with local strain management for stretchable electronic applications
Authors: Chen Sujie , Li Ming , Han Lei 
Published: June 2024

Abstract
Stretchable electronic devices have been extensively investigated in healthcare and wearable electronics. The stretchable substrate with strain control is paramount to integrating rigid devices into stretchable electronic systems for high mechanical strain. The common approach utilizes rigid strain control islands integrated on the surface of the soft stretchable matrix, but strain concentration effect and poor adhesion at the interface between the rigid islands and the elastic substrate are challenges. In this work, a stretchable substrate is developed by embedding the bottom strain control islands into the interior of an elastic substrate and the top strain control islands on the substrate surface to minimize strain concentration and improve the adhesion of the interface. The simulation results show that the strain concentration at the interface of the top island is suppressed and the maximum strain on the substrate surface is reduced by more than 30%. The interface between strain control islands of PI film and elastic substrate of Ecoflex can maintain more than 3000 stretch cycles under repeated strain of 100%. A stretchable inverter is fabricated based on this stretchable substrate with stretchable conductive wire. It is shown that the voltage transfer characteristics of the stretchable inverter have no significant change under strain of 100% for more than 3000 stretch cycles, demonstrating the capability of this stretchable substrate to integrate rigid devices for reliable stretchable electronic systems.
Effects of T6 treatment on the microstructure and mechanical properties of az80 magnesium alloy
Authors: Jiang Rui , Wang Ruolan , Ding Boyuan , Zhang Zhenwei 
Published: June 2024

Abstract
The mechanical and microstructure properties of the AZ80 magnesium alloy in deformed and T6 states were evaluated and analyzed by tensile testing and metallographic analysis. The results showed that the grain size of the magnesium alloy increased after T6 treatment, whereas the number of deformed grains decreased considerably. These changes were accompanied by a transformation of the β-Mg17Al12 phase from a discontinuous point-like morphology to a continuous lath-like morphology. After T6 treatment, the tensile strength and yield strength of the material were significantly improved. These findings indicated that the microstructure of the AZ80 magnesium alloy was altered through T6 treatment, and its mechanical properties were markedly enhanced.
Experimental study of scaled-down model ejection water ballistics and two-phase flow of gas and water
Authors: Diao Zhenting , Fang Dengjian , Zhou Yuan 
Published: June 2024

Abstract
There are many factors affecting the hydrodynamic and water ballistic trajectory of vehicles launched underwater, among which the ejection gas pressure, initial motion parameters of the submarine launch platform and the launching water depth have a particularly significant influence. Since it is costly and too long time to carry out a real-size study on the influence of underwater launching parameters, this paper adopts a scaled-down model ejection test to study the evolution characteristics of the flow field of vehicle launched underwater with different ejection pressures and initial ejection angles to reveal the influence of the above parameters on the characteristics of the water ballistics.
Study on the influence of vibration characteristics of ship’s stern structure
Authors: Zhou Quan , Gu Ruizhao , Liao Shuting , Wang Hongfu , Lv Yang , Chen Lin 
Published: June 2024

Abstract
The stern structure of the ship, as the primary source of vibration and noise, has always been widely studied. Conducting an analysis of the vibration characteristics of the stern and determining the impact of local structures on the complex coupled vibration in the stern section are particularly important aspects of research. This paper employs the structural-acoustic coupling methodology to investigate the vibration features of the stern of a ship. The study explores the influence of variations in parameters such as the rudder, stern frame, and shaft system on the vibration response of the stern. The results provide valuable insights into controlling vibration and noise in the stern section of ships, as well as informing the design of related structures.
Three-point support analysis and optimization design under the change of gravity center of diamond lathe
Authors: Hu Jiongfeng , Xia Huiheng , Zhang De , Li Jingtong 
Published: June 2024

Abstract
The position of three-point support has an important impact on the stiffness and accuracy of the diamond lathe. To determine the position of the support, this paper commences by conducting static and dynamic analysis on the large-size platform machine tool whose base is 2340×1540 mm under the two support schemes. It determines the basic layout scheme of the support points of the machine tool under the change of gravity center. Subsequently, by combining the least squares fitting and particle swarm optimization algorithm with the optimization goal of minimum deformation of the machine tool base working surface, the position of the support points is optimized under the influence of the Change of Gravity center. The results indicate that the optimal solution of the design variable within the design interval can be obtained through limited sampling points and optimization iterations. The average and maximum deformation of the base working surface are 0.867 μm and 1.45 μm. They decreased by 11.17% and 26.02% compared with before optimization.
Numerical investigation of the vortical structures in the near wake of a model wind turbine
Authors: Weislein Tobias , Seel Ferdinand , Lutz Thorsten , Krämer Ewald 
Published: June 2024

AbstractIt is well known that the vortex system in a horizontal axis wind turbine wake is highly relevant in terms of fatigue loads and performance of wind turbines located in the wake of other wind turbines. The breakdown process of tip vortices particularly influences the mixing process of the low-speed wake region with the undisturbed flow outside the wake. As a collaboration with the Technische Universität Berlin (TUB), a major goal in a joint research is to study the effects involved in tip vortex breakdown. TUB designed a model turbine that will be towed through a large water tank to analyse and to control the tip vortex decay. To accommodate the measurement equipment, the ratio of blade length to nacelle length is unconventionally small, leading to uncertainty regarding the effect on the breakdown of the tip vortex. Due to the dimensions of the model wind turbine the root vortex system and the nacelle wake are not comparable to former studies and should therefore be investigated in detail. To do so computational fluid dynamics, in particular delayed detached eddy simulations, are conducted for the model turbine with the compressible flow solver FLOWer and the two-equation Menter-SST turbulence model. Two simulations are conducted with and without the nacelle. The results indicate that the root vortices propagate downstream and interact with each other. Additionally, these vortical structures are also influenced by the geometry of the turbine nacelle which causes faster decay of the root vortices compared to a configuration without the nacelle. However, the root vortex breakdown does not influence the tip vortices as the turbulent intensity matches for the area where tip vortices are present. In short, this investigation shows that the influence of the nacelle geometry and root vortex system on the tip vortices is negligible. Thus, the model wind turbine designed by TUB is suitable for the investigation of tip vortices.
Numerical prediction of aerodynamic loads acting on a blade section-model oscillating in stall
Authors: Cortes N , Amandolese X , Pfister JL , Blondel F , Boisard R , Schotté JS , Mauffrey Y 
Published: June 2024

Abstract
For blades operating close to stall angle of attack, one of the potential instabilities is known as stall flutter. It is a dynamic instability in torsion for which the mechanism of energy transfer relies on a dynamic stall process where the flow separates partially or completely during each cycle of oscillation. It leads to dynamic loops in lift, drag and moment that affect the aerodynamic performance of the blade, create unsteady stresses in the blades and can lead to fatigue damage. In the present study, dynamic loops of a NACA 634421 airfoil in forced pitch oscillations have been simulated with the FastS CFD solver based on a URANS modelling approach and compared to benchmark experiments as well as results obtained with the ONERA semi-empirical dynamic stall model using a unique set of dynamic parameters that best fit the experimental dynamic loops. The dynamic tests have been conducted for a mean angle of attack of 13.5°, an amplitude of oscillation of 8° and three reduced frequencies k
1 = 0.0183, k
2 = 0.0785 and k
3 = 0.183. This study has shown that the CFD FastS solver can satisfactorily reproduce the unsteady lift and moment coefficients experienced by a section model oscillating in stall.
Performance improvement of a Vestas V52 850kW wind turbine by retrofitting passive flow control devices
Authors: Manolesos M , Celik Y , Ramsay H , Karande R , Wood B , Dinwoodie I , Masters I , Harrold M , Papadakis G 
Published: June 2024

Abstract
This study presents the results of a collaborative effort between academia and industry aimed at further enhancing the benefits provided by Vortex Generators and Gurney Flaps. To achieve this objective, an integrated approach was employed, involving wind tunnel experiments, on-site measurements, and computational simulations to design devices tailored for an onshore (Vestas V52, 850 kW) turbine and assess their influence on turbine performance. Device selection was based on wind tunnel measurements, while their positioning on the blade was based on infrared thermography images from the field. A Reynolds Averaged Navier Stokes solver was used to predict the performance of the devices on both airfoil and blade level. The final assessment of the upgrade pack was based on SCADA data and Lidar measurements. The results show that an Annual Energy Production uplift of 5.77% is measured for this turbine.
Validation of a BEM correction model for swept blades using experimental data
Authors: Fritz Erik , Boorsma Koen , Ferreira Carlos 
Published: June 2024

Abstract
This study validates a correction model, which extends standard blade element momentum theory to swept blades and, by doing so, enhances wind turbine simulation predictability for these advanced geometries. This correction model addresses limitations in BEM algorithms, accommodating the complexities of swept blades by considering the sweep-induced tip vortex displacement and curved bound vortex self-induction. The validation is based on previously published results from wind tunnel experiments on a horizontal axis wind turbine with straight and swept blades, providing blade-level aerodynamic data for comprehensive numerical comparisons. In both blade configurations (straight and swept), good agreement is found between experimental and numerical results, validating the numerical approach. For the swept blade case, an additional comparison to a BEM algorithm assuming a straight blade and to one accounting for crossflow is drawn, underscoring the former’s inadequacy for swept blades. Comparably minor differences between the fully-corrected and only crossflow-corrected algorithms render the assessment of the proposed BEM correction model’s added benefit uncertain. Using the validated BEM algorithm, the experimental results are corrected for twist deformations of individual blades, enabling a direct comparison of the campaigns with straight and swept blades. Results align with expectations, indicating sweep-induced reductions in axial induction and blade loads in the swept blade section.
Validating low- and high-fidelity simulations of a yawed 8 MW wind turbine against measurements
Authors: Höning L , Meyer P J , Huhn M L , Theron J N , Thomas P , Wegner A , Mechler S , Gottschall J , Stoevesandt B 
Published: June 2024

Abstract
This paper presents a comparison study of the aerodynamic behavior of an 8 MW wind turbine operating under yawed conditions using field measurements, Blade Element Momentum (BEM) theory and Computational Fluid Dynamics (CFD). Turbulent inflow wind field measurements are used to generate an IEC-compliant turbulence box upstream of the wind turbine that is used within the BEM tool MoWiT and the CFD tool chain by IWES in OpenFOAM. Both simulation approaches take into account blade flexibility using modal reduced, anisotropic beam elements in BEM and Geometrically Exact Beam Therory (GEBT) in CFD. While the focus is being set towards the CFD approach, turbine power output, blade root bending moments and blade tip deflections are analyzed. It is shown that both modeling approaches react differently towards the generated wind field.
Design of an efficient experiment for identification-based stability analysis of operating wind turbines
Authors: Hermes Armin , Riva Riccardo , Zahle Frederik , Madsen Jesper , Bergami Leonardo , Skovby Casper 
Published: June 2024

Abstract
This paper proposes a new approach to calculate aeroelastic stability of operating wind turbines using system identification, and explores how an efficient numerical experiment can be designed. The data-driven method is based on time series including induced motion of the blades, which can stem from any fidelity simulation. While this study utilises HAWC2, the findings enable the usage of e.g. computational fluid dynamics in a fluid-structure-interaction simulation. Different forcing sequences are suitable to excite the blade, but especially the doublet and chirp show favourable characteristics and results for an application of no more than five seconds. System identification, the Multivariable Output-Error State sPace (MOESP) algorithm in particular, is used to find an algebraic equivalent of the simulated turbine. Using the output-only version, about 20 seconds of simulated time are sufficient to identify the system such that the predicted response matches the input with an R
2-score of > 99.8 %. A comparison with HAWCStab2 shows frequency differences of < 0.5% across the wind speed range, matching mode shapes but some bigger deviations in aeroelastic damping.