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Reducing aerodynamic vibration of rigid rotors with retreating side active control avoidance

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Chinese Journal of Aeronautics 2025年第1期38卷 353-364页

作者： Weiliang LYU School of mechanics and aerospace engineering Dalian University of TechnologyDalian 116024China

This paper proposes a new approach to eliminate aerodynamic lift oscillation,called the Dominant Sector Individual Blade Control(DS-IBC)method for rigid rotor *** Advancing Blade Concept(ABC)rotor model for aerodynamic analysis based on the free-wake method is ***-IBC avoids applying active control on the rotor's retreating side by employing and restricting active control inputs to a sector area of the rotor *** this sector,only primary collective and cyclic pitch control are *** blade takes turns entering the sector,creating a“relay”active control form to ensure continuous control *** method also includes outer-trim and inner-trim iteration *** show that DS-IBC can eliminate aerodynamic lift oscillation using much smaller control inputs than the sine-trim *** focusing active control on the rotor's advancing side,DS-IBC improves the effective lift-to-drag ratio and reduces the implementation difficulty of active rotor control for aerodynamic oscillation elimination,especially at a large lift-offset.

关键词： Advancing blade concept Lift-offset Rigid rotor Aerodynamic lift oscillation Dominant Sector Individual Blade Control(DS-IBC)

A data-based inverse problem-solving method for predicting structural orderings

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Frontiers of Structural and Civil engineering 2025年第1期19卷 22-33页

作者： Yiwen LI Jianlong CHEN Guangyan LIU Zhanli LIU Kai ZHANG School of aerospace engineering Beijing Institute of TechnologyBeijing 100081China Applied mechanics Laboratory Department of Engineering MechanicsSchool of AerospaceTsinghua UniversityBeijing 100084China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063000China

Inverse problem-solving methods have found applications in various fields,such as structural mechanics,acoustics,and non-destructive ***,accurately solving inverse problems becomes challenging when observed data are ***,advancements in computer science have paved the way for data-based methods,enabling the discovery of nonlinear relationships within diverse data *** this paper,a step-by-step completion method of displacement information is introduced and a data-driven approach for predicting structural parameters is *** accuracy of the proposed approach is 23.83%higher than that of the Genetic Algorithm,demonstrating the outstanding accuracy and efficiency of the data-driven *** work establishes a framework for solving mechanical inverse problems by leveraging a data-based method,and proposes a promising avenue for extending the application of the data-driven approach to structural health monitoring.

关键词： mechanical inverse problem displacement information completion digital structural orderings data-based method genetic algorithm

mechanics of twisted and coiled tube-based artificial muscles driven by hydraulic pressure

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Science China Technological Sciences 2025年第4期68卷 76-85页

作者： Hao LIU Zhiya ZHANG Lei LIU Dabiao LIU department of engineering mechanics School of Aerospace Engineering Huazhong University of Science and Technology Hubei Key Laboratory of engineering Structural Analysis and Safety Assessment

The twisted and coiled polymer(TCP) artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density. The relation between geometry, mechanics, and actuation performance for this kind of muscle is crucial. In this study, we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment, theory, and finite element simulation. Accounting for the helical geometry and transverse isotropy of the TCP muscles, we develop a phenomenological model to predict the actuation performance of TCP tube-based *** torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are characterized. It is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube, resulting in an improved actuation performance of the twisted and TCP muscles. The torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure, while the tensile actuation in TCP muscles increases with the coil diameter. The theoretical predictions and simulations are in good agreement with experimental results. This study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.

关键词： artificial muscles hydraulic pressure actuation characteristics anisotropy

Disentangling electronic and phononic thermal transport across two-dimensional interfaces

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Chinese Physics B 2025年第2期34卷 401-406页

作者： Linxin Zhai Zhiping Xu Applied mechanics Laboratory Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

Electrical and thermal transport at two-dimensional(2D) interfaces is critical for semiconductor technology, yet their interplay remains unclear. We report a theoretical proposal to separate electronic and phononic contributions to thermal conductance at 2D interfaces with graphene, which is validated by non-equilibrium Green's function calculations and molecular dynamics simulations for graphene–gold contacts. Our results reveal that while metal–graphene interfaces are transparent for both electrons and phonons, non-covalent graphene interfaces block electronic tunneling beyond two layers but not phonon transport. This suggests that the Wiedemann–Franz law can be experimentally tested by measuring transport across interfaces with varying graphene layers.

关键词： electrical and thermal transport 2D interfaces Wiedemann–Franz law theoretical proposal

Surface Quality Improvement of aerospace Material of Inconel 718 by GOV(Flow Peening)Process

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Chinese Journal of Mechanical engineering 2025年第1期38卷 273-294页

作者： BurakŞahin İbrahim Göv Mustafa Sait Koca Murat Kalak Kürşad Göv Faculty of Aeronautics and aerospace Aerospace Engineering DepartmentGaziantep University27310 GaziantepTurkey

Inconel 718 superalloy has extensive applications in a variety of industries such as the moulding,aerospace and medical due to its excellent mechanical features such as poor thermal conductivity,high strength at high temperatures and corrosion ***,it is very difficult to process by traditional machining and finishing *** based finishing process is one of non-traditional finishing method applied to complex *** peening process is one of the surface treatment processes mostly applied to improve the surface *** superior advantages of these two processes are combined into one *** newly developed and patented process is called as GOV *** this study,the effects of GOV process parameters(number of cycles,steel ball size,media concentration)on the surface quality of Inconel 718 already pre-processed by wire electric discharge machining are *** performance parameters are identified as surface roughness,material removal and white layer *** finishing with the GOV process improves the surface roughness,Ra value by decreasing from 2.63μm to 0.46μm by removing micro-level chips up to 10.7 mg which is supported by SEM *** layer formed due to nature of EDM process is completely removed from specimen surface.

关键词： Flow peening(GOV)process Surface finishing Abrasive flow machining Inconel 718

The mechanical and water absorption properties of carbon fiber buoyancy materials under hydrostatic pressure

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Science China(Technological Sciences) 2025年第1期68卷 247-261页

作者： Fanglin CONG Zihan LI Guocai YU Yang JIN Zixu ZHU Linzhi WU College of aerospace and Civil engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of Advanced Ship Materials and mechanics Harbin Engineering UniversityHarbin 150001China department of Basic Courses Naval University of EngineeringWuhan 430033China

Buoyancy material technology is of paramount importance for the development of marine *** this study,a novel carbon fiber buoyancy material(CFBM)is designed and prepared by utilizing composite circular tubes with light weight and high *** reveal the failure mechanism under hydrostatic pressure,a finite element model(FEM)based on the three-dimensional Hashin and Yeh failure criterion is developed and validated *** the simulated and experimental results indicate that the hydrostatic strength of the CFBM is mainly determined by the buckling of carbon fiber tubes located at the edges of the *** analysis is conducted to investigate the effect of the number of unit-cells,length,and wall thickness of carbon fiber tubes on the mechanical properties of the *** addition,a 60-day water absorption test of the CFBM at 12.5 MPa is conducted to characterize its *** results indicate that the maximum water absorption rate of the CFBM is 0.59%and the hydrostatic strength is reduced by only 7.97%during the 60-day test ***,the designed CFBM is used at the water depth of 1000 m as buoyancy *** with traditional buoyancy materials,the proposed CFBM has significant advantages in both hydrostatic strength and *** work has broad engineering application prospects and is of high significance for promoting the implementation of carbon fiber composites in the ocean engineering field.

关键词： carbon fiber buoyancy materials hydrostatic strength water absorption failure mechanism

Targets capture by distributed active swarms via bio-inspired reinforcement learning

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Science China(Physics,mechanics & Astronomy) 2025年第1期68卷 206-217页

作者： Kun Xu Yue Li Jun Sun Shuyuan Du Xinpeng Di Yuguang Yang Bo Li Institute of Biomechanics and Medical engineering Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Shanghai aerospace Control Technology Institute Shanghai 201109China Shanghai Key Laboratory of aerospace Intelligent Control Technology Shanghai 201109China College of Automation engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Natural swarms arranged from cells to herds are usually decentralized but display intriguing collective intelligence in coordinating individuals across large scales to efficiently achieve their common *** from nature may provide new strategies for controlling collective dynamics of synthetic swarms to accomplish specific ***,we present a bioinspired computational framework that steers distributed active swarms to collectively capture and merge targets via reinforcement *** exploit collective milling structures of natural herds to cage the targets,and adopt a switching control policy inspired by sperms’chiral dynamics to optimize the trajectories of individuals,through which the active swarms can selforganize to enclose single or multiple distant targets in a dynamical,adaptive and scalable *** exists a critical swarm size,beyond which the excessive competition between agents would generate large mechanical forces,leading to capture instability but enabling the transition from short-distance to long-distance merging capture of multiple *** work provides physical insights into distributed active swarms and could offer a multilevel,decentralized strategy toward controlling swarm robotics in wide applications such as bio-medical devices,machine immunity,and target clearance.

关键词： swarm intelligence robotics multi-tasks artificial intelligence bionics

State of Charge Prediction of Lithium-Ion Batteries for Electric Aircraft With Swin Transformer

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IEEE/CAA Journal of Automatica Sinica 2025年第3期12卷 645-647页

作者： Wei Zhang Hongshen Hao Yewei Zhang the School of aerospace engineering Shenyang Aerospace University

Dear Editor,As an important energy storage device, lithium-ion battery plays a vital role in electric aircrafts, which are new and promising equipment of transportation in the future with low carbon emissions. Accurate prediction of the state of charge (SOC) of lithium-ion batteries is of great importance in reducing the probability of abnormal accidents and ensuring flight safety.

关键词： Lithium-ion batteries

Effective diffusivity of a Janus sphere in an external field

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Applied Mathematics and mechanics(English Edition) 2025年第3期46卷 539-554页

作者： Tianyu YUAN L.P.LIU Jianxiang WANG Institute for Advanced Study Chengdu UniversityChengdu 610106China department of Mechanical and aerospace engineering Rutgers UniversityNew Jersey 08854U.S.A. department of Mathematics Rutgers UniversityNew Jersey 08854U.S.A. department of mechanics and engineering Science College of EngineeringPeking UniversityBeijing 100871China

During nearly 200 years of development in the knowledge of Brownian motion,the Janus sphere,as a typical Brownian particle with special surface properties,has been widely studied in the past few decades.A standard Janus sphere possesses two distinct *** two surfaces elicit different hydrodynamic interactions with ambient fluids or other interactions in response to environmental stimuli,such as chemical gradients,magnetic fields,and even *** diffusion of Janus spheres,particularly when controlled by a remotely applied field,has inspired various applications,ranging from the design of micro-swimmers and novel procedures for probing the mechanical properties of suspensions to the fabrication of composites with enhanced *** this work,we report a systematic analysis of field-controlled diffusion of Janus *** with stochastic differential equations of motion at the microscale,we derive a coarse-grained Fokker-Planck equation at the macroscale,describing the evolution of the probability distribution function of the Janus sphere in terms of its position and *** the concept of the hydrodynamic center,we derive,for the first time,explicit generalized Stokes-Einstein relations for long-time effective diffusivity,incorporating the effects of both the surface discontinuity of the Janus sphere and the external *** formulae enable predictions of the effective diffusivity as it varies with the slip length and characteristic angle of Janus spheres,and reveal the impact of an aligning potential field on the diffusion coefficients both parallel and perpendicular to the direction of the *** work not only deepens the understanding of field-controlled diffusion of Janus particles,but also holds a meaningful impact on the future applications in microfluidics and related fields.

关键词： Brownian motion effective diffusivity Janus sphere hydrodynamic center