bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonsmooth dynamic modeling and simulation of spatial mechanisms with frictional translational clearance joints
Authors: Du Yujie , Jiao Fangzheng , Wang Ping , Liu Fei , Li Long 
Published: May 2024

Abstract
This paper presents a nonsmooth dynamic approach of modeling and computation for spatial mechanism including spatial frictional translational joints (SFTJs) with small clearances. In this research, the dynamic formulation is derived in the Lie group setting, which leads to a coordinate-free and compact formulation. In the following, the normal contact interaction between the slider and guide is described by the complementarity relations between the constraint force in the normal direction. The tangent contact interaction in the SFTJ is characterized by the Coulomb’s friction law in the type of a set-valued map. Based on the horizontal linear complementarity problem (HLCP), the non-smooth dynamics can be established and calculated by combining the Lemke’s algorithm and the RK-MK time integration algorithm. Finally, A spatial crank-slider mechanism with SFTJs is shown as a numerical case. The simulation results demonstrate the correctness and effectiveness of the proposed method which can capture the nonsmooth dynamical behavior of the system.
Flow resistance enhancement for the leakage decrease of labyrinth seals using teeth tip winglets
Authors: Gu Qianlei , Yang Jiangang 
Published: May 2024

Abstract
A novel flow resistance enhancement technology is proposed to decrease the leakage flow for labyrinth seals adopting teeth tip winglets (TTW). The specially designed TTW is utilized to double the throttling effect at each teeth tip. In addition, the annular slots on the TTW can also generate teeth tip vertexes. These vertexes disrupt the direction of teeth tip leakage flow, enhancing the local flow resistance. To validate this concept, a three-dimension computational fluid dynamic model (CFD) is established. The flow field and leakage performance of the seal with TTWs are calculated with compassion to the baseline seal. Results show that the TTW seals increase flow resistance at the teeth tips, resulting in an extra dissipation effect. As a result, the maximum leakage decrease ratio reaches up to 15.1%
Estimation of the rope tension in trucklift slope hoisting system with varying profile of track
Authors: Han Tok Hyong , Kim Kwang Hyok , Han Un Chol 
Published: May 2024

Abstract
This paper focused on a study concerned with the estimation of the rope tension in Trucklift slope hoisting system with varying profile of track. In this system, the profile of track is not straight and there exists the segment where the sagged rope moves between the edges on the inclined track, and the rope tension always varies by the movement of platforms with empty and laden trucks. So co-simulation of ADAMS and MATLAB/Simulink was used to estimate the rope tension when the platforms move on the track, because there is a moving rope with sagged inclined segment in this system. From simulation results were analyzed the variation of the rope tension according to the position of platform and the influence of the angle of slope of track and the mass of platform when platforms move on the track. In the case of using Koepe winder, the simulation results could be used as more important reference data for the design and operation of Trucklift slope hoisting system with varying profile of track.
A novel method of internal ballistics identification and performance prediction for SRMs based on genetic algorithm
Authors: Zhang Ling , Wang Deyou , Zhang Beichen , Lu Yingying , Li Shipeng 
Published: May 2024

Abstract
Improving the identification accuracy of internal ballistic parameters in the solid rocket motor(SRM) is of great significance in guaranteeing that missiles fulfill their intended operational missions. In practice, the internal ballistic performance is according to the inverse calculation burning area obtained by the measured pressure data of the SRM and the measured burning rate, which still has ascending space for optimization in the prediction accuracy. Accordingly, a genetic algorithm-based method for the identification of internal ballistic parameters and performance prediction for SRMs was proposed. Based on the measured, data of limited test runs, the initial identification of the burning rate coefficient, pressure exponent and propellant density was carried out by GA (Genetic Algorithm). The model was updated on the basis of the inverse calculation burning area obtained by identification results. Then the secondary identification was carried out to modify the key parameters. The Φ50mm laboratory-scale test SRM was analyzed as an example. The internal ballistic performance in the SRM was predicted. The calculation results show that the prediction results obtained by the method are in high agreement with the measured pressure data, which verifies the effectiveness of the method in improving the prediction accuracy of the internal ballistic performance.
Numerical simulation on the dynamic cold extrusion of bolted single-lap Al/Al joint under interference-fit
Authors: Zuo Duquan , Jin Shaoqing , Liu Jie , Cao Yuejie , Zhang Minghao , Zheng Guo , Lin Binbin , Fu Yaoming 
Published: May 2024

Abstract
The installation process for the dynamic cold extrusion of Al/Al interference-fit bolted joint applied by electromagnetic force was investigated by numerical simulation. The simulation results show that the deformation distribution of the bore wall at joint installed by the electromagnetic force is more uniform than that of the traditional installation technologies. And in the axial direction of bore wall without pin, the maximum stress region occurs at its outlet regardless of the values of interference-fit. Additionally found that the critical interference-fit value for a joint to reach yield strength is about 1 %, and when the amount of interference-fit is less than 1%, the joint mainly exhibits elastic deformation, and when the interference is more than 1 %, the plastic deformation is its main manifestation.
Improved differential optimization algorithm for multi-satellite joint earth observation scheduling
Authors: Liu Yan , Zhang Shengyu , Cai Jingying , Wen Zhijiang , Hu Haiying 
Published: May 2024

Abstract
The mission completion rate is an important evaluation criterion in the multi-satellite joint observation scheduling problem. This paper proposes a model to address this issue to maximize the mission completion rate. The task requirements and constraints were analyzed with the constellation’s ocean surveillance task as the background. According to the characteristics of the solution space, an improved differential teaching-learning-based optimization is proposed. The proposed algorithm employs a probability-based discretization method and a difference-based individual updating strategy. Simulation experiments demonstrate the effectiveness of the method by improving the task completion rate and convergence speed compared to the benchmark algorithm in the given test case.
Influence of emissivity on infrared radiation characteristics of the two-dimensional nozzle
Authors: Deng H W , Yang Q Z , Yang B X , Xiao C X 
Published: May 2024

Abstract
In the case of the same outlet area, the two-dimensional (2-D) nozzle has a large aspect ratio compared to the axisymmetric circline nozzle, which enables it to reduce the visible area of high-temperature components such as the center cone and the flame stabilizer inside the nozzle. It can also strengthen the mixing effect of wake flow and outflow to achieve the effect of cooling. In this work, based on the calculation of the flow field of the 2-D convergent-divergent nozzle, the infrared radiation characteristics of its with different emissivity coatings and the coating under high-temperature coming off are calculated in the 3∼5um waveband. The results show that with the increase of emissivity, the mean value of infrared radiation intensity of the nozzle in the range of detection angle 0°-70° decreases to 68.80%, while the mean value of infrared radiation intensity in the range of detection angle 80°-90° rises to 136.55%. The nozzle coating coming off is caused by excessive temperature and its infrared radiation intensity even exceeds the infrared radiation intensity of the uncoated state when the coating comes off.
An approximate optimal control method for 6-DOF spacecraft
Authors: Mao Renhao , Sun Shujian , Lei Jiakun 
Published: May 2024

Abstract
In this paper, an approximate optimal control method based on adaptive dynamic programming (ADP) is proposed for the proximity operations with six degrees of freedom (6-DOF) relative motion control of spacecraft. Firstly, the dynamic model is normalized and dimension-reduced to avoid the excessive gradient change of the neural network. Then, a nonlinear disturbance observer is designed to deal with the disturbance. Finally, using ADP ‘s reinforcement learning idea, a single-critic neural network is constructed to solve the approximate optimal control strategy and minimize the cost function. The simulation results show that the designed controller can achieve the attitude and orbit maneuvering targets, and the overall energy consumption is approximately optimal.
Gas rudder 2DOF FOPID position control based on CSFLA optimisation
Authors: Qi Yingjian , Deng Hanyu , Shen Haijun , Yu Zai 
Published: May 2024

Abstract
Aiming at the problems of parameter variety, rigid-flexible coupling and external unknown factors interference in the process of spacecraft propulsion, a two-degree-of-freedom fractional-order PID (2DOF FOPID) controller based on a coevolutionary shuffled frog leaping algorithm (CSFLA) is designed for the high-precision control of the gas rudder servo control system. The anti-interference and target tracking capabilities of 2DOF PID is combined with the advantage of FOPID, which is insensitive to the parameters of the controlled object, to improve the performance of the control system as a whole. CSFLA is formed by integrating the self-learning evolution of elite populations and the interactive learning strategy among populations into the SFLA to enhance the global searching ability and searching accuracy of SFLA, and CSFLA is used to optimize the parameters of the 2DOF FOPID controller. The simulation results show that the designed CSFLA-2DOF FOPID controller has the advantages of fast response speed, small overshoot, strong tracking performance and strong anti-disturbance ability, which improves the dynamic and static performance and anti-disturbance ability of the gas rudder servo control system.
Study on the influence of pendulum convex plate on the partial value of quartz flexible accelerometer
Authors: Jiayue Zhang , Hong Liu , Yuchao Hao 
Published: May 2024

Abstract
The partial value is an essential performance index for assessing the stability of quartz flexible accelerometers. By analyzing the structure of the quartz flexural accelerometer and the impact of the pendulum convex plate, the influence of the convex plate on the partial value of the accelerometer is studied by theoretical derivation and modeling simulation methods. The results show that the barycentric coordinate shifts by approximately 10.7678 × 10-12
µm with the change of the coplanarity of the convex plate, which causes mechanical zero position errors, increases the partial value, and affects the stability of the quartz flexural accelerometer. Therefore, the coplanarity of the convex plate should be maintained at ≤0.3 µm and the partial value should be within the error range of ≤ |±2| mg and provide improvement measures to establish a basis for further improving the stability of the quartz flexible accelerometer.
Analysis of aerodynamic and stealth characteristics of aircraft under the action of microwave plasma
Authors: Wu Xinyi , Zhang Yujian , Tian Deyang , Wu Changju , Zhou Jie , Zhu Yunliang 
Published: May 2024

Abstract
This paper investigates the impact of plasma on the aerodynamic and stealth characteristics of hypersonic aircraft. Utilizing the finite volume method, the governing equations of the fluid mechanics were discretized, and the seven-element air chemical reaction model was employed for computations. A technique involving the alteration of the chemical reaction source term rate was employed to replicate the actual plasma concentration distortion phenomena induced by microwaves around hypersonic vehicles, enabling an analysis of the influence of plasma density distortion on the aerodynamic characteristics of these vehicles. In addition, the method of Piecewise Linear JE Recursive Convolution Finite-difference Time-domain (PLJERC-FDTD) is used to calculate the radar scattering cross-section of the target within both the initial and distorted flow fields. This allowed an examination of the variation in the aircraft’s stealth characteristics when exposed to distortion in an ionized environment.
Active control and prediction model for the dynamic shape of laminated plate/shell structures with piezoelectric actuators
Authors: Zheng Hao , Wang Hongfu , Zhou Qiang , Li Jingjing , Huang Junsong , Wang Baichuan , Liu Xiaorang , Yin Guochuan 
Published: May 2024

Abstract
This study establishes an active control and prediction model for the dynamic shape of laminated plates/shells with piezoelectric actuators. Firstly, transient responses of shell structures are numerically calculated by adopting the finite element method (FEM) and the Newmark formulae, then the Kuhn-Tucker equation is utilized to get the time-varying voltage values with a minimum shape control error. Subsequently, a backpropagation neural network (BPNN) is constructed to predict the control precision for cases with different piezoelectric actuator layouts. Finally, the proposed control model is demonstrated through numerical examples with a maximum relative control error of only 0.023% for a given desired shape and the average error of the prediction model with 98 input neurons is 18%, thereby satisfying the application requirements. Furthermore, for a model with 3870 degrees of freedom and 21 discrete time points, the computational time is reduced significantly from 8.24 s to 0.002 s through the prediction model, making it highly suitable for optimization problems by utilizing heuristic algorithms.
Design and verification of controller for a small coaxial dual-rotor aircraft
Authors: Gao Botao , Wu Zhilin , Wu Mingjian , Li Shuang 
Published: May 2024

Abstract
In recent years, coaxial dual-rotor aircraft has attracted much attention due to its unique aerodynamic layout. However, it is difficult to miniaturize the coaxial dual-rotor aircraft that relies on the principle of periodic pitch variation due to complex structure and control difficulties. This study proposes a small cylindrical coaxial dual-rotor aircraft based on a vector motor seat. For the control problems of such coaxial dual-rotor aircraft, a position and attitude controller based on neural networks and adaptive cascaded PID control is designed. A control system model was established and tested using MATLAB/Simulink. The proposed control scheme’s soundness and efficiency were confirmed by creating a prototype and performing flight trials. The results show that compared with the classic PID controller, the control effect of the controller has improved by 36.3% to 54.6%. In the centripetal rotation flight simulation experiment, the displacement error does not exceed 0.2 m, the speed error does not exceed 0.05 m/s, and the attitude angle error does not exceed 0.01 rad. This validates the effectiveness of the designed controller, indicating that the controller can enhance the stability of the system and achieve stable hovering and flight.
Analysis of aerodynamic characteristics of flexible flapping wings mimicking hummingbirds
Authors: Xia Meng 
Published: May 2024

Abstract
Over hundreds of millions of years of natural selection, hummingbirds have evolved excellent flight characteristics. This ingenious wing structure provides a new inspiration for the design of bionic flapping wings. In this paper, a kind of bionic flexible flapping wing is designed with a hummingbird as the prototype, its parametric aerodynamic characteristics are analyzed, and its feasibility is verified by simulation. Combined with the simulation results, the aerodynamic parameters such as lift, drag, and lift-drag ratio are comprehensively considered, and the optimal parameter combination is 5 m/s-20 Hz. Under this parameter combination, the aerodynamic performance is the best, and the lift-drag ratio is as high as 13.3. This paper can provide a theoretical basis and technical reference for further development of bionic flapping wing MAV design.
Design optimization of a low-cost three-stage launch vehicle with modular hybrid rocket motors
Authors: Wenzhi Hao , Hao Zhu , Wei He , Zhiguo Zhang 
Published: May 2024

Abstract
This article investigates the impact of modular propulsion system design on the performance and cost of a three-stage hybrid rocket. Furthermore, it conducts a multi-objective optimization of unit payload cost, take-off mass, and payload mass ratio, considering factors such as the number of motors and layout considerations. The optimization design scheme for the three-stage hybrid rocket is divided into four cases. In the first case, each stage is equipped with a fixed single motor, and each stage is independently optimized without modular design. The second case considers the use of multiple motors in the first and second stages, still without modular design. The third case also involves multiple motors in the first and second stages, but all motors in each stage have identical parameters except for the nozzle expansion ratio, implementing a modular design. In the fourth case, the number and layout of the motor design method are the same as those in the third case, with independent optimization in the third stage using partial modular design. The results indicate that the unit payload cost of the multi-motor non-modular design case can be reduced by 13.12% compared to the single-motor non-modular design case. Within the modular case, the full modular design case is slightly inferior to the partial modular design case. Based on the above data, it can be concluded that the first and second stages of modular rockets offer the best performance and the lowest cost.
Sensitivity analysis of aircraft structural fatigue reliability under mixed uncertainty
Authors: Liu Shiyu 
Published: May 2024

Abstract
Fatigue is the main failure mode of the structure. The aircraft structure is subject to multi-level cyclic loading, which is prone to fatigue damage, reduces reliability, and affects flight safety. Various uncertainties are inevitably associated with the factors related to the fatigue performance of the structure. In particular, for the variables with insufficient information, their uncertainties are hard to describe by the probability density function. In this paper, these variables are treated as interval variables. The sensitivity analysis of the aircraft structure fatigue reliability model under mixed uncertainties is studied. On the basis of the definition of the distance between interval numbers, the interval distance indexes are proposed as a global sensitivity measure for a mixed random-interval model system. To reduce the computational cost, the method combining the space partition with unscented transformation (SP-UT) is used to calculate the proposed indexes. Lastly, the proposed indexes and method are applied to solve the aircraft structure fatigue problem. Compared with the traditional MCS method, the proposed method has proved to be more conducive and efficient.
Research on high power and heat flux aerospace electronic products of integrated thermal conduction technology
Authors: Wang Minghe , Guo Qingyuan , Wang Xinghai , Zhu Qixing , Zhu Yufeng , Tang Wei 
Published: May 2024

Abstract
In response to the increasing demand for enhanced computational capabilities within satellite systems, there has been a simultaneous rise in the heat flux density of onboard electronic components. The thermal output of these components has significantly increased compared to traditional satellite processing electronics, leading to a concurrent elevation in the heat flux density related to processing chips and the surfaces accommodating equipment installations. This paper establishes a model for conduction heat dissipation in aviation electronic products. The outlined calculation methodology facilitates a preliminary assessment of the system’s heat dissipation capacity. The article further examines the inherent heat dissipation capabilities in two commonly employed structural configurations. Additionally, it introduces an integrated design approach for structural heat dissipation, including experimental considerations and validation outcomes. The assessment methodologies and design principles detailed in this article are particularly relevant and applicable to the thermal design imperatives associated with high-power electronic products deployed for the extended operational durations typical of spacecraft.
Experimental research on blowing-rain intensity and uniformity of rain tunnel for aircraft rain removal testing
Authors: Liu Qianqian , Zhao Yi , Liu Caixia 
Published: May 2024

Abstract
The objective of the present study is to characterize a rain tunnel that is used for performance testing of aircraft windshield rain removal systems. The rain tunnel in the present study is an open jet wind tunnel with six full cone pressure swirl nozzles arranged at its outlet. Experiments are conducted with water at room temperature as the working medium. The influence of total water supply flow rate and air velocity on the blowing-rain intensity and uniformity is studied. The total water supply flow rate varies from 0.57 m3/h to 1.03 m3/h, while the pressure at the inlet of the nozzle ranges from 1.44 bar to 6.52 bar. The air velocity of 30 m/s, 40 m/s, and 50 m/s is studied. A special test setup has been designed for measurements of the blowing-rain intensity and uniformity. Experimental results indicate that the blowing-rain intensity and uniformity both increase with the increasing total water supply flow rate and decrease with the increasing air velocity.
Rotating heat pipe model based on lumped parameter method
Authors: Wu Chang , Zeng Yu , Sun Hai , Yang Gang 
Published: May 2024

Abstract
On the basis of many theoretical studies about rotating heat pipes, a simplified mathematical model is established based on the lumped parameter method, ignoring the temperature difference inside each section of the heat pipe is ignored, and comparing the calculated results with the experimental data. It is identified that this model has a good applicability at high speeds and low liquid filling rates, and effectively reduces the amount of calculation, which is of practical significance to the engineering application of rotating heat pipes.
A composite planning method considering avoidance of multiple no-fly zones
Authors: He Mingyong , Nan Ying 
Published: May 2024

Abstract
Aiming at the problem that multiple no-fly zones need to be avoided in the reentry process of aircraft, a composite programming method combining conjugate gradient and dynamic programming is proposed. The method divides the reentry flight trajectory into two parts: the longitudinal plane and the transverse plane. The longitudinal plane uses the conjugate gradient method to guide the aircraft to meet the minimum mass of the thermal protection system during the whole flight. The horizontal plane mainly uses the dynamic programming method to obtain a reasonable obstacle avoidance route and inversely calculates the change law of the heading angle. The simulation results show that the three-dimensional reentry trajectory can reasonably solve the problem of avoiding multiple no-fly zones and meeting the aerodynamic constraints of the flight process.