bluuebunny/crossref_metadata_2025 huggingface dataset:
The anti-Fermi–Pasta–Ulam–Tsingou problem in one-dimensional diatomic lattices
Authors: Feng Sihan , Fu Weicheng , Zhang Yong , Zhao Hong
Published: May 2022

We study the thermalization dynamics of one-dimensional diatomic lattices (which represents the simplest system possessing multi-branch phonons), exemplified by the famous Fermi–Pasta–Ulam–Tsingou (FPUT)-β and the Toda models. Here we focus on how the system relaxes to the equilibrium state when part of highest-frequency optical modes are initially excited, which is called the anti-FPUT problem comparing with the original FPUT problem (low frequency excitations of the monatomic lattice). It is shown numerically that the final thermalization time T
eq of the diatomic FPUT-β chain depends on whether its acoustic modes are thermalized, whereas the T
eq of the diatomic Toda chain depends on the optical ones; in addition, the metastable state of both models have different energy distributions and lifetimes. Despite these differences, in the near-integrable region, the T
eq of both models still follows the same scaling law, i.e. T
eq is inversely proportional to the square of the perturbation strength. Finally, comparisons of the thermalization behavior between different models under various initial conditions are briefly summarized.
Intelligent Fault Diagnosis with Multi-scale Convolutional Dense Network
Authors: Li Xinyu , Lei Zihao , Wen Guangrui , Huang Xin , Chen Xuefeng , Cheng Changming , Peng Zhike
Published: May 2022

With the continuous development of artificial intelligence technology, intelligent fault diagnosis approaches have been successfully developed and achieved promising performance in recent years. However, in the existing methods, the time domain characteristics of the signal are first ignored in the process of network construction, and at the same time, it is less considered in the aspects of multi-scale feature extraction and feature fusion. In order to solve the above problems, a multi-scale convolutional dense network (MCDN) was established. Specifically, the proposed framework mainly includes three parts, among which the multi-scale feature pre-extraction module is used to extract multi-scale features, the dense connection module is used to achieve effective feature fusion, and the classification module realizes the recognition of different failure modes. To verify the performance of MCDN for fault diagnosis, rolling bearing data sets gathered from Xi’an Jiao Tong University (XJTU) are employed and analyzed. The analysis result confirms that the proposed method can achieve superior performance compared with other latest methods under varying degrees of noise.
Aerodynamic Study of Canard Parameter Configuration Principle for UAV
Authors: Jiang Feng , Tong Xiaoyan , Sun Jing , Zhang Suwen , Deng Jianzhi
Published: May 2022

This paper analyses the multi-objective design requirements of UAV with high timeliness, high manoeuvrability and long-endurance long-range flight capability. Then put forward an aerodynamic configuration conception of wide flight envelope that can perform multi-tasks, such as fast approach, long endurance patrol and critical maneuvering. By means of wind tunnel test, the aerodynamic characteristics regularities of this configuration changed by shape parameters, component combination and spatial relationships are studied. Base on analysing the flow coupling efficiency of canard vortex and wing vortex, proposed the principle of relative position matching between canard and wing. The results show that when the canard was higher than the wing, the canard vortex provided additional vortex lift on the upper surface of the wing, which could provide a favorable influence in the cruise phase. Further more, using the trapped vortex of variable curvature lip on nose which was similar to the influence mechanism of canard vortex, a stable favorable interference vortex system in a wide envelope could be obtained, and the components and controlling complexity of this aircraft configuration would be simplified.
Numerical Study on Infrared Radiation Characteristics of Dual-Engine Fighter Based on RMCM
Authors: Rui Wang , Qingzhen Yang , Kai Du
Published: May 2022

The study of the infrared radiation characteristics of dual-engine fighters provides theoretical support for the stealth design of future fighters. This paper takes a dual-engine fighter as the research object and uses the Reverse Monte Carlo Method (RMCM) to carry out the numerical simulation of its infrared radiation characteristics. The results show that: in the 3-5μm band, with the Mach number increasing, the peak infrared radiation intensity increases, and the solid radiation accounts for about 90% of the total radiation at a detection angle of 180°; in the 8-14μm band, the infrared radiation intensity is distributed in the shape of "8". When the Mach number increases, the infrared radiation intensity of the abdomen of the fuselage is higher than that of the back.
Model predictive control for automatic carrier landing considering ship motion
Authors: Ruiyang Zhou , Neusypin K. A.
Published: May 2022

This paper studies a control problem of UAV automatic landing on carrier considering carrier heave motion, which is given by an empirical model based on spectral density function. A linearized UAV dynamics model is applied as the predictive model, a MPC controller is then proposed for the flight dynamics control. Simulation is conducted with real parameters of the UAV “Silver Fox”, the results exhibit the great landing performance of MPC method.
Optimal Design of Wind Turbine Blades by Combination of Multi-airfoil Leaf Elements
Authors: Xi Lei , Zhao Lihua
Published: May 2022

This paper takes the blades of a large horizontal axis wind turbine as the research object, selects NACA series airfoil elements for combination, arranges and distributes them according to the thickness and curvature of each airfoil, and generates a new blade that is different from a single airfoil. The aerodynamic performance of the two blades was compared and analyzed by using Qblade software to verify the effectiveness of the method, and the wind energy utilization rate was improved while ensuring the strength of the blade roots.
A Numerical Simulation Study for A Dual Thrust Solid Propellant Rocket Motor Nozzle
Authors: AbdelGawad Alaa R , Guozhu Liang
Published: May 2022

CFD simulation through the rocket motor nozzle is an important issue as it gives a better understanding of the flow behavior and shows the evolution of the parameters along with the nozzle. CFD simulations using ANSYS FLUENT were conducted to model the flow through an experimental dual thrust solid rocket motor nozzle at two pressure values representing the two pressure levels. A two-dimensional axisymmetric numerical simulation was carried out using a pressure-based solver to solve the governing equation and the standard k-ε model to model the turbulence through the motor nozzle. The hot gas properties used in the simulation model were calculated using the CEA software (chemical equilibrium with applications). The parameters marched out from simulations were used to calculate the thrust values for each case. The results calculated through the numerical models compared with the experimental measurements and showed an acceptable level of accuracy.
The attitude control optimization of small rocket
Authors: Ni Runfeng , Wen Chunyu , Jia Linhai , Zhang Yao , Liu Shiyu
Published: May 2022

In this article, an optimization method for attitude calculation and vector control of small rocket is proposed, which reduces the performance requirements and costs of gyroscopes. Dynamic model parameters such as engine thrust curve and rocket body moment of inertia are added to the traditional filtering and control algorithm, which can reduce the hardware performance requirements of sensors and the cost of rocket control system. This method has achieved good results in the test, and is of great significance for the promotion of small rockets.
Analysis of orbit error effect on ultra-high space-ground two-way time comparison
Authors: Guo Yanming , Bai Yan , Gao Shuaihe , Zou Decai , Chen Xiaofeng , Wang Rong , Liu Yinhua , Gao Yuping , Lu Xiaochun
Published: May 2022

In view of the characteristics of the low-orbit spacecraft's orbit, the influence of the low-orbit spacecraft's orbit error on the time comparison method based on tri-frequency is theoretically analyzed. With the simulation and test, validing the effectiveness of the precise two-way time comparison method, and the accuracy of the method can reach the order of ps-level. Furthermore, with the simulated data, the influence of orbit error on the ultra-high precise space-ground time comparison is analyzed. The results show that the percentage of orbit noise in the total orbit error has a great influence on the accuracy of time comparison. In order to achieve a link accuracy better than ps, the percentage of orbit noise should be kept within 5%.
Application and development of MBSE in aerospace
Authors: Wenyue Wang , Junjie Hou , Yinxuan Mao , Jinjie  , Zhiang Lu
Published: May 2022

MBSE (Model-Based Systems Engineering), as the representation of digital technology, has achieved effective management of system complexity through model-centric means, and a state of coordination and matching with modern complex engineering systems. On the basis of introducing the background of MBSE and the overview of MBSE practice in the aerospace field, two typical application cases of MBSE in the domestic and foreign were analyzed. In order to provide reference for the application of MBSE in the aerospace field, suggestions and conclusions on the development of MBSE application in China were put forward: the integration of traditional development process and MBSE method, the consistency understanding of system model, and the integration ability of system model and domain model.
Energy Release Study of Reaction Fragment in Dynamic Loads
Authors: Wang Zhanlei , Xu Longtao
Published: May 2022

Al-W-KClO3 is a kind of metastable reactive composite material, which belongs to multi-functional energetic structure material. Its energy release characteristic under dynamic loading was studied in this paper. The Al-W-KClO3 powder of different components was first pressed to study their forming ability. The Al-W-KClO3 powders of four different molar ratios were moulded into approximate hemispherical liner on a basis of fine formability. The reaction energy releasing characteristics of reactive fragments were researched under the dynamic loads. The steel target was penetrated by the four kinds of reactive fragments, respectively in a high detonation velocitiy and low one, then the effect of penetrating was also analyzed. The result showed that the energetic materials of Al-W-KClO3 could maintain a fine formability and a fine reaction-energy release property at certain ratio of constituents.
Study on Vibration Damping Performance of Composite Crankshaft Torsional Vibration Damper
Authors: Zhao Xuesong , Fang Min , Gao Haowen
Published: May 2022

In order to reduce the crankshaft vibration’s impact on the performance and working life of the vehicle engines, using silicone oil and damping properties of rubber, designed a silicone, rubber compound crankshaft vibration damper that required the actual demand. Determined the silicone oil shock absorber and rubber vibration isolator in the main performance parameters of the design process; completed the main structure size design; calculated the silicone oil shock absorber in the motor rated power as 92 kw, the rated speed as 2200 r/min, the torque value and excitation frequency and crankshaft maximum amplitude under the condition that the crankshaft excitation frequency as 1927.2 r/s. Determined the damping value of the optimum damping point during working time was Cd=93.66 Nms/rad, drew the crankshaft resonance curve of silicone oil shock absorber, calculated torque value frequency and the maximum crankshaft amplitude of the rubber vibration isolator under specific working condition, determined the optimum damping point and damping value as Cr=0.3158 Nms/rad while vibration isolator was working, mapped crankshaft resonance curve of the rubber vibration isolator; calculated the optimum damping points of the combined crankshaft torsional vibration, constructed the resonance frequency test bed of the compound torsion damper, inspected resonance frequency value and its corresponding swing value. It has been proved that after installing the compound torsion damper, the amplitude value of the crankshaft reduced about 81%, much lower than that before installation, which had significant effect, and meeted the design requirements.
Design of Vibrating Screen Separation Equipment for Powder Materials
Authors: Wei Yanbiao , Tao Chong , Zheng Lei , Huang Mingyu
Published: May 2022

The vibrating screen has absolute advantages in the sorting equipment due to its simple structure, reliable operation and large processing capacity. Therefore, the vibrating screen is widely used in powder material sorting equipment. Because powder materials usually contain a certain amount of moisture, high-frequency vibration can effectively separate materials with different particle sizes, and together with the feeding and unloading of the belt conveyor, it forms a sorting device. This article mainly includes the calculation of the feeding conveyor mechanism, the calculation of the sieve plate size selection, the calculation of the entire vibration screening mechanism and the calculation of the unloading conveyor mechanism. In addition, the strength and fatigue strength of the key parts of the equipment are checked, and the installation and use of the equipment are explained in detail.
Design and Analysis of a New Column Vane Hydraulic Pump Based on Computer Aided Design
Authors: Cheng YiQi , Wang XinHua , Chen YingChun
Published: May 2022

A new model of column vane hydraulic pump is discussed. Firstly, taking the stator surface as the research object, the equation of the stator surface is established based on the applied triangular space theory. MATLAB and Pro/E software were used to establish the three-dimensional model of column vane hydraulic pump.In the second part, the structural characteristics of the pump are described in detail, the working principle of the pump is analyzed, and the correctness of the stator equation is verified. Secondly, on the basis of describing the structural characteristics of the cylinder pump, the working principle of the new cylinder pump is analyzed. Finally, COMSOL Multiphysics is used to visualize the flow field and analyze the fluid-structure interaction. The results show that the working principle of the new hydraulic pump is reasonable, the flow field diagram of the pump is relatively uniform and the deformation is small under the design condition.
Research and Implementation of Multi Axis System with Macro Instruction
Authors: Chen Longcan , Chao Xiaojie
Published: May 2022

In the current industrial field control, most of the servo control systems communicate with the motion controller and the servo driver, and if the industrial site needs to modify the parameters of the servo system in time according to the requirements of the processing technology, the modification of the parameters becomes very inconvenient, and you need to enter the system to change the parameter values. In order to solve this problem, a kind of macro instruction based on touch screen is introduced to realize the multi axis servo in the industrial field. The system reads and sets, uses the communication mode of Modbus RTU protocol and RS-485, thus realizes the simultaneous reading and writing of the multi axis system, introduces the Modbus RTU communication function of the Weinview touch screen and the communication function with the Panasonic servo driver in more detail, and gives a kind of macro instruction based on the Weinview touch screen. The implementation of a multi axis control system. The detailed design plan and process of the system are introduced, which can also provide reference and reference for the design and application of similar systems.
Study on Creep Damage Analysis of Composite Rotor
Authors: Bi Shiying
Published: May 2022

This paper studied the creep damage of the combined rotor, the creep damage model of the parts is used to analyze the combustion chamber and the pull rod of the turbine, and then the nonlinear relationship between the creep damage of the combined rotor and the parts is revealed by combining the whole damage model.
Design of Airborne Hyperspectral Automatic Filling Device for Liquid Nitrogen Refrigeration
Authors: Han Yachao , Li Jing , Gao Zihong , Chen Jie , Nie Zhiyang
Published: May 2022

To maintain sensitivity of the sensor, especially the infrared band sensor, liquid nitrogen is needed for cooling during the imaging process of airborne hyperspectrometer. However, traditional filling process requires a lot of manual intervention, which is not only time-consuming and labor-intensive, but also creates great potential safe hazard during aviation operations. In view of this, this paper designs an airborne hyperspectral automatic filling device for liquid nitrogen using time-delay electromagnetic switch, pressure sensing detector and electromechanical device, which achieves the purpose of automatic liquid nitrogen filling, increases operation efficiency of airborne hyperspectral equipment, reduces air stage operation steps, and guarantees personal safety of air operators, thus playing a good demonstration role in further standardizing and optimizing the technical process of air-borne hyperspectral remote sensing data.
Numerical Simulation of Flow Field Structure of Flashboard Distortion Generator
Authors: Wu Zheng-gang , Zhang Tao , Cai Wen-xiang , Chen Xiong
Published: May 2022

In order to accurately analyze the characteristics of flashboard distortion generator, flow field with different structure and aerodynamic parameters was studied by numerical simulation.Then distribiton of Mach on the AIP interface behind the flashboard was analyzed, so as to guide the experiment design of the flashboard distortion generator. The results show that Mach distribution on the AIP interface is basically divided into three obvious regions. Mach transitions from high Mach to low Mach is in a small area. The average Mach of AIP interface increases slowly with the total pressure increasing, and decreases sharply with the increase of inserted depth. The angular vortex structure formed in the corner area where the flashboard meets the shell would extend downstream, so it is necessary to study the influence of angular vortex on compressor stability boundary.
Study on the Side Effects of Hall Effect Based on Phase Change Method
Authors: Zheng Wenying , Lai Jiatong , Xie Feng
Published: May 2022

The basic principle of some side effects in measuring electromagnetic induction intensity of Hall element is briefly introduced, and the effect of these side effects on the measurement results is discussed. It is preliminary that the effects of Nernst effect and Righi-Leduc effect on the experimental results are not significant and can be ignored, and the unequal potential difference contributes the most to the experimental results. In other experiments with Hall element as measuring instrument, it can also provide a reference for reducing system error.
Distortion model of star tracker on-orbit calibration algorithms based on interstar angles
Authors: Chen Zhanglei , Zheng Yong , Zhan Yinhu , Li Chonghui , Chen Bing , Zhang Houtian
Published: May 2022

On-orbit calibration techniques for star trackers are critical for precise attitude determination in artificial satellites. As calibration algorithms based on interstar angles do not require a priori information about the satellite attitude, they are a focal point for studies in this area. In these algorithms, the distance between each ideal star point and the principal point on the focal plane is required to model lens distortions. These distances are typically approximated using the distances between observed star points and the principal point, named the simplified approximation method. We propose an embedded iteration method and perform numerical simulations and ground-based night-sky experiments to compare the results of star tracker calibrations based on the two proposed methods. The results indicate that the simplified approximation calibration model has systematic model errors, which are predominantly manifested in the principal point estimates. Nevertheless, the simplified approximation converges more rapidly and easily than embedded iteration. Therefore, embedded iteration should only be used if the calibration accuracy is critical, large lens distortions are present, and ample computational resources are available. Otherwise, simplified approximation should be used to model lens distortions.
Autonomous positioning and navigation method of individual soldier combining multi-source data based on stellar vector
Authors: jie Shen , Jian Xing , Yuan Gao , Zhilong Ye , Chiyu Zhang
Published: May 2022

This article introduces a fully autonomous navigation method for individual soldiers performing missions in the field, which can be used in conjunction with the existing satellite navigation such as GPS and Beidou and inertial integrated navigation methods to make up for the deficiencies of traditional navigation methods. The existing satellite navigation methods such as GPS/Beidou are susceptible to electromagnetic interference, and may fail due to enemy interference during war. Inertial navigation cannot get rid of its own "zero drift" shortcomings. The navigation method based on stellar vector calculation is one This is a purely passive navigation method that does not receive external interference and can navigate autonomously under extreme conditions. This article introduces the principle of the navigation method based on stellar vector calculation, and conducts simulation and field experiments. The accuracy of the navigation method is up to 300m after verification.
CanSat payload with Autogyro for descent in experimental rocket flights: Development, CFD analysis, and preliminary test on free-fall
Authors: Ventura Alejandro , Nuñez-Quispe Johan , Sanchez Godo , Santivañez Jafet
Published: May 2022

This research work develops the design of a CanSat payload assisted with an Autogyro system for a controlled descent in experimental rocket flights. The design, development, Computational fluid dynamics (CFD) analysis, and a preliminary test on free-fall had been carried out. The data obtained from this study and test allowed us to determine the relationship between the drag coefficient and the projected geometry of the CanSat by using CFD simulation and data such as speed and acceleration from the free-fall test. The results allowed us to propose an estimation for the drag coefficient behavior on the speed range studied.
Topological design and kinematic analysis of a novel hybrid space control mechanism
Authors: Qi Yang , Wang Yu , Liu Jie , Wang Hong , Wu Wenxuan , Lu Enli
Published: May 2022

In order to meet the demand of space mechanism for Chinese space station, a novel hybrid space control mechanism is designed. The hybrid space control mechanism is made up of a serial mechanism and a parallel mechanism. The serial mechanism realizes large workspace and the parallel mechanism provides excellent position accuracy. The physical prototype of the novel hybrid space control mechanism is built up, and the mobility and foldability of the serial mechanism are exhibited. Its kinematic and workspace analysis are carried out, which correctness is verified through comparison with simulation results. The aforementioned research laid a solid foundation for future study about the hybrid space control mechanism.
Response analysis of solid missile grain in UAV-borne environment
Authors: Peng Li , Hong-wei Xu , Xuan Wang , Jie Zhang
Published: May 2022

Solid rocket motor of UAV-borne missile experiences the effect of cyclic temperature. For the single chamber double thrust rocket motor, the finite element model of the solid motor grain is established. Temperature field and stress-strain field under a mounted flight cycle are studied. The research results can provide reference for the structural integrity evaluation of the single chamber double thrust rocket motor and UAV flight system.
Numerical investigation on fluid characteristics of supersonic mixing layers with splitter plate in a confined space
Authors: Li Chunlei , Li Yingkun , Li Weixuan , Zhu Liang , Chen Xiong , Yang Shuifeng , Wu Yan
Published: May 2022

High-speed airbreathing engines has been going on for more than a century, since French engineer Reina Lauren first developed the concept of the ramjet. Kelvin-Helmholtz (K-H) instability and compressibility effects on the evolution of supersonic mixing layer growing rate have been widely investigated in experimental and computational ways. The present study proposed a quasi-DNS solver which is written in Fortran 90, the mixing process of the supersonic planar mixing layers is analyzed in detail, especially, the process of the vortex rolling up, stretching, pairing and merging are also reported in present study. It is noteworthy that the mechanisms of K-H instability are analysed in detail, and the baroclinic term has a great influence on the growth of the supersonic mixing layer in confined space.
Flow Mechanism and Feasibility Investigation of Hypersonic Jet Control Surface
Authors: Ji Yi-min , Yang Hua , Li Zheng , Gao Zheng-hong , Chen Shu-sheng
Published: May 2022

Hypersonic vehicle is a kind of vehicle that can fly at more than Mach 5 in the atmosphere. To solve the control problem of hypersonic vehicle, this work investigates the feasibility of hypersonic jet control surface. The numerical simulation method based on compressible Reynolds averaged Navier-Stokes equations with SST turbulence model is adopted. Firstly, the mechanism of hypersonic flow around airfoil with different deflection angles of aerodynamic control surface, which is arranged at the rear 30% of the airfoil behand a 2% chord gap, is analyzed and studied in detail. Then, a jet nozzle is set on the trailing edge of the airfoil to calculate and analyse the jet control effect of different total pressure ratio with 1.5mm gap (Mach 5, total pressure ratio from 1 to 300, altitude 40km). Thus, the flow mechanism, aerodynamic characteristics and control efficiency of the jet control surface is obtained. The results demonstrate that the aerodynamic control surface is effective in the hypersonic flow, and the control effect is proportional to the deflection angle of the control surface. Besides, the jet control surface also has control efficiency, which changes linearly with the total pressure ratio of the jet. And with the increase of jet total pressure ratio, the jet control surface can achieve the same control ability as the aerodynamic control surface. It reveals that the jet control surface is potentially a good control technique for hypersonic vehicle.
Study on the influence of baffles on the aerodynamic coefficients of long-span flexible bridge section
Authors: Chi Xiaoling , Chen Changping , Qian Changzhao
Published: May 2022

In the study of wind resistance performance of Bridges, the study of aerodynamic coefficients directly affects the accuracy of wind resistance performance of bridges. In this paper, the aerodynamic coefficients of main girder section of single-tower single-side suspension curve suspension cable footpath bridge are studied by numerical simulation and wind tunnel test. In order to improve the wind resistance performance of the bridge, the aerodynamic performance of the bridge section was improved by optimizing the bridge section and adding baffles, and the aerodynamic coefficient was obtained by wind tunnel test. The first section in your paper
Estimation of vehicle dynamics by fusion image and radar based on subtraction convolutional neural network
Authors: Kao I-Hsi , Chan Ching-Yao
Published: May 2022

The main goal of this paper is to estimate the vehicle dynamic by image and radar fusion through a deep learning model. In the designed deep learning model, multiple convolutional neural networks are used. In addition, tensor subtraction is added in the model to express the time-series features. In addition to the fusion of images and radar, the accuracy of using a single sensor to estimate vehicle dynamics is also tested. The result shows that the performance of using the fusion of radar and image is better than using a single sensor. Finally, by using both signals in the deep learning structure, the mean square errors of estimation angular x, angular y, angular z, and linear velocity obtained from our model have values of 2.86e-6, 4.72e-6, 6.19e-5, and 2.41e-2, respectively.
Dynamic simulation of complex multi-hinge space flap mechanism
Authors: Feng Yunwen , He Zhiyu , Xue Xiaofeng , Dong Meng
Published: May 2022

Dynamics simulation of large civil aircraft complex multi-hinge space flap mechanism was studied, and a set of dynamics simulation modeling method of complex multi-hinge space flap mechanism based on Motionview was proposed. Firstly, a moving digital prototype of the complex multi-hinge space mechanism was constructed. The multi-point constraint RBE3 element was used to associate the intersection points of the rigid multi-hinge mechanism to the body of the flap surface considering flexibility, and the rigid-flexible coupling dynamic model of the flap mechanism was formed. The dynamics simulation of the mechanism was carried out under the aerodynamic load conditions of cruise, take-off and landing, the driving torque and hinge point load dynamics indexes of the complex multi-hinge space flap mechanism were obtained. The simulation results show that the driving arm of the inner mechanism bears most of the lateral load from the flap wing surface, the radial direction of the joints bearing at each hinge bears the aerodynamic pulling force from the flap wing surface. And the inner mechanism of the flap is the main bearing part, the load capacity of the inner rocker arm is almost four times that of the outer rocker arm. The dynamic simulation research can provide a certain reference for the design and improvement of the complex multi-hinge space flap mechanism.
Model order reduction for structural nonlinear dynamic analysis based on Isogeometric analysis
Authors: Li Wei , Chen Zhaolin , Guo Yujie
Published: May 2022

Model order reduction approach generates lower dimensional approximations to the original system while preserving model’s essential information and computational accuracy. For nonlinear structural dynamic problems, where the stiffness matrix is configuration dependent, an iterative solution procedure is inevitable and a revisit to all the elements is essential for updating the stiffness matrix. In this paper, the nonlinear dynamics of the planar curved beams and 3D cylindrical shells are studied based on the isogeometric analysis and their model order reductions are investigated based on the proper orthogonal decomposition and discrete empirical interpolation method (POD-DEIM). Numerical results show that IGA-based POD-DEIM method significantly improves the computational efficiency of the nonlinear dynamic analysis of the beam and shell structures.
A New Normalization Form Based on a General Unified Normalization Computing for the Gravitational Potential Tensor of Arbitrary Orders
Authors: Han Chao , Dong Tianshan , Cheng Ming , Wang Yu , Liu Shenggang
Published: May 2022

Taking a general unified recursive algorithm for computing the normalized gravitational potential based on Cunningham's formula into account, the numerical stability of both the recursion for spherical harmonic series and the pre-processing for the spherical harmonic coefficients are discussed. Then a new method of normalizing the associated Legendre polynomial is proposed.
Design of opposed piston 2-stroke internal combustion engine test platform
Authors: Pei Tianyou , Qiu Shuheng , Chen Feixue , Gao Weiwei , Li Zheng , Zhang Chi
Published: May 2022

Opposed piston two-stroke engine, due to its characteristics of fast expansion, high power density and indicate efficiency, and dynamic balancing, attracts many researchers’ attention. In order to explore its combustion performance, a novel test platform consisting of a drive system and combustion control system is proposed in this paper. The drive system mainly contains a 75-kW induction motor, a synchronous gearbox, and two crankshaft mechanisms. The displacement of the piston and chamber pressure is acquired and used to control combustion parameters. Using this mechanical device, the rotary motion can be converted to the opposite movement of the two pistons precisely. All the designed functions of the platform are verified by the combustion experiments of an opposed-piston two-stroke prototype. Furthermore, the experimental data is used to verify a one-dimension simulation model to evaluate the combustion characteristics of the prototype.
Scenario demand-based design of new energy vehicles from the inside out and its practices
Authors: Li Yong , Liu Fuyong , Hao Ruimin
Published: May 2022

Based on the related theories of scenario study and pure electric vehicle interior design, this paper constructs scenario demand-based interior design process framework and method for pure electric vehicles. After completing construction of the design process framework and method, corresponding design practice is carried out to complete theoretical verification. The demands are sorted through KANO model. Then, a design framework is built according to the demand sorting result. Finally, specific program is designed based on the design framework. This paper perfects the theoretical system for interior design of pure electric vehicles. The interior design program for future pure electric vehicles will provide design references for interior designers.
Steering Trapezoid Optimized Design of the Off-road Racing Car
Authors: Chen Jing , Shen Xinyi , Wang Aoqi
Published: May 2022

The parametric analysis model of the suspension and steering system of racing car has been established. Two design principle for Splitting Point of steering trapezium has been expounded. Taking minimum deviation between actual wheel turning angle from the angle and theoretical turning angle, the minimum variation of the toe angle as the optimal object, Optimization Design of Splitting Point has been studied. The results indicated that, the wheeled vehicle steering characteristics and the correspond between steering system and suspension has been improved by Optimization Design of Splitting Point. A set of AWD racing steering system design steps and optimization methods are summarized, which provides a clear idea for solving related problems.
Lightweight Design of Gearbox Housing of Baja Racing Car Based on Topology Optimization
Authors: Zeng Zhiyuan , Zhang Yijun , Tang Dingyong
Published: May 2022

In view of the National Undergraduate Baja Contest, an initial model is established for the reducer. According to the calculated force of the transmission part, the reinforcing ribs of the bearing hole are optimized and the initial model is optimized and checked several times using the topology optimization module of ANSYS. The safe and reliable housing model with a weight reduction of 35.82% makes full use of the material properties, thus contributing to lightweight of the whole vehicle under the premise of sufficient strength.
Forming simulation and process optimization of inflatable strut reinforcement plate for automobile back door
Authors: Zhang Haibo , Wang Tianwu
Published: May 2022

Taking a new energy SUV back door inflatable strut reinforcement plate as an example, three key process areas are set on the surface of the plate, and the structural characteristics and forming characteristics of each area are analyzed. On this basis, a finite element model is established. Preliminarily select the process parameters that meet the actual production requirements, use AutoForm to perform numerical simulation analysis of stamping forming, compare the forming quality of the product under the forming process and the drawing process, to achieve the purpose of process optimization, and then determine the final stamping process plan. Taking the maximum springback as the evaluation index, an orthogonal test with 4 factors and 3 levels is designed, and the parameter scheme with the best forming quality through the range analysis method provides a reference for the subsequent actual production of the part.
Optimal Design of Suspension System of Four-wheel Drive Baja Racing
Authors: Wang Aoqi , Chen Jing , Shen Xinyi
Published: May 2022

In order to match the four-wheel drive system of Baja racing, improve the handling stability and driving comfort of the car, and optimize the parameter design of the suspension. Establish a suspension system model in ADAMS, conduct motion simulation, analyze important suspension parameters, modify the suspension hard points according to the analysis results, and optimize the suspension parameters. Finally, a set of excellent suspension parameters is obtained, and the performance of the suspension system can be improved. The suspension parameters of the simulated racing car have been determined, and other performance parameters have also been improved through hard-point modification. Using ADAMS to perform motion simulation of the suspension system saves time and can efficiently realize the optimal design of the suspension system.
Hyperelastic Model with Energy Limiter for EPDM and Its Numerical Application
Authors: Xing-gui Fan , Jin-sheng Xu , Xiong Chen , Hui Li , Bing-dong Tan
Published: May 2022

To simulate the working process of EPDM PSD of dual-pulse solid rocket motor from beginning to failure, we use a hyperelastic model with erergy limiter to model this working process. In traditional practice, the consistent tangent moduli of mechanical model is derived by analytic method, however, the analytic method is tedious and fallible. To solve this problem, we introduce numerical approximate method (complex-step derivative, which is proved to be of second-order for suitably small perturbation and does not suffer from inherent subtractive cancellations ) to derive the consistent tangent moduli, which is simple, robust, and efficient, and can be easily implemented into commercial finite element software. Finally, we simulate a case of unixial tension of a dumbbell-shape and compare the simulation results with the analytic results, a good agreement between the two kinds of results is observed.
Improvement of the model by preprocessing big data of tapping temperature prediction industry
Authors: Dong Huwei
Published: May 2022

The quality of steel is highly related to the tapping temperature. At present, many models can predict the tapping temperature to a certain extent. However, after in-depth exploration of the model, it was found that most of the models have a better performance for the tapping temperature prediction of common steel, while the special steel was ignored. It is because that most models are rough in the data processing. The neglect of incomplete data, uneven distribution problems have caused models to over-emphasize some types of steel, while it does not agree with the production demand of steel mills. This paper proposes Bayes neural network model with the improved filling method based on K-Means algorithm and data homogenization method based on K-Means algorithm. The statistical results show that the model has a better performance at error within ±5°C ratio, mean absolute error, root means square error, etc. than the traditional ones.
Multi-objective flexible job-shop scheduling problem researching based on improved adaptive NSGA-II
Authors: Zhang Lei
Published: May 2022

To solve the scheduling problem of products manufacturing in the military electronic equipment enterprises, a multi-objective flexible job-shop scheduling model was established with the objective of minimum the make span, production costs and equipment load. According to the characteristics of flexible job-shop scheduling problem, an adaptive NSGA-II algorithm was proposed in this paper, which could change the probabilities of crossover and mutation operation at different stages of genetic processes. To improve the diversity of population, the algorithm performed independent crossover and mutation operations on the working processes and equipment. Besides, a population independent elite retention strategy was adopted to avoid the loss of optimum solutions. At last, the feasibility and validity of the improved adaptive NSGA-II are verified by a flexible job-shop example.
Design rationale representation approach based on intent-driven ontology and MBD model in design change
Authors: Huang Zhengxiong , Chen Yazhou , Xu Songqing
Published: May 2022

Aiming at the problem that the design rationale (DR) in design change has a wide range of sources and various forms, which makes designers difficult to reuse them, this paper proposes a DR representation approach for design change. Firstly, the overall three-layer structure of the approach is introduced; Use OWL to express the concepts related to the designer and product model in design change, and use SWRL and SQWRL to mine and extract useful DR information; A DR representation tool is developed based on CAD software to export the low semantic level information to the ontology as well as import the high semantic level information back to the Model Based Definition (MBD) model. The approach combines the expressing ability of ontology and visuality of 3D annotation to capture, represent and reuse DR information, which promotes the design change under the MBD environment. Finally, a stamping part is taken as an example, and designers can refer to the experience of the predecessors related to the changed parameter through using the tool.
Study of flow characteristics affected by some blade structure elements based on a liquid hydrogen turbopump
Authors: Wu Bu-ming , Xia Chen
Published: May 2022

In this paper, a simulation study on liquid hydrogen turbopump was carried out to obtain the basic flow characteristics of the inducer and impeller with and without cavitation phenomenon considered. The influence of pump structure was analyzed, and the influence of circumferential position, inlet inlet angle and other parameters on flow field and aerodynamic performance was explored. The results show that the influence of boundary layer can be reduced and blade performance can be improved by increasing the blade wrap angle of the centrifugal blade or using a smaller inlet inlet angle near the shroud. In addition, increasing the blade wrap angle can also increase the pressure on the inlet leading edge of the blade, thus reducing the possibility of cavitation. A higher flow rate of the pump may reduce the possibility of cavitation. Cavitation is likely to reduce when the blade leading edge has a slightly slant stacking line of the impeller. Based on these research results, some opinions are given to improve the design method of liquid hydrogen turbopump.
Study of convergence speed enhancement for topology optimization
Authors: Nguyen Van-Tinh , Tao Ngoc-Linh , Nguyen Thanh-Trung , Bui Ngoc-Tam
Published: May 2022

The target of this research is to enhance of convergence speed of proportional topology optimization process since it usually spends much computational cost to reach the achievement. Conventionally, proportional topology optimization (PTO) is a non-sensitivity technique, in which, the material distribution is gradually optimized by certain amount of material at each iteration through the relationship between current maximum stress and allowable stress. This is a reason that PTO method took a long time to reach the optimal layout. This paper deploys an adaptive material amount to improve this point. The cantilever with fixed hole is used to validate the effectiveness of the new method. The result shows that the proposed technique provided a significant improvement on the performance of proportional optimization algorithm.
Star Sensor Simulation with Application of the k-NN Method in Star Identification Problem
Authors: Chen Danhe , Kudlak Vitaliya V. , Maslennikov Andrey L.
Published: May 2022

Simulation of the navigation systems is required to develop efficient, reliable, and accurate algorithms for orientation problems. In this paper the astronavigation system is considered, and the star sensor simulation based on algorithmic mathematical model is discussed. The algorithms include the starry sky image obtaining, data processing, and stars identification. Two modifications of the known stars identification algorithm are proposed and related to the use of k-NN method in identification and stars selection criteria for increasing computational efficiency. Simulation of the described approach for star sensor is performed in MathWorks MATLAB. The simulation results show adequate results.
Guidance law based on deep Q network algorithm
Authors: He Xianjun , Wu Mingyu , Chen Zhihua , Wu Wei-Tao , Zheng Chun
Published: May 2022

In this paper, an intelligent guidance law based on Deep Q Network (DQN) algorithm is proposed, for enabling the missile to intercept different maneuvering targets following the idea of the parallel-approach method. In specific, we propose the inverse ratio of the absolute value of line-of-sight (LOS) angle rate as the shaping reward function which guarantees the successful finding of the control strategy and the speeding up of the training process of the reinforcement learning (RL) model. Furthermore, to avoid rapid chattering caused by directly choosing missile acceleration as an action, we introduce the change rate of the acceleration as the action in the DQN algorithm and integrate it to obtain the acceleration command. Therefore, in our algorithm only LOS angle, LOS angle rate, and missile overload information are used in the established RL model to generate the guidance command, which is easy to implement. The simulation results and comparative experiments demonstrate that the proposed RL based guidance method achieves better guidance accuracy and higher success rate. The great performance of the proposed method suggests that the RL based guidance method is promising for the maneuvering target, and deserve further investigations in future.
The fuzzy-based systems in the communication between a human and a humanoid robot
Authors: Mogos E
Published: May 2022

The communication between a human and a humanoid robot is a real challenge for the researchers in the field of the robotics. Despite of the progress in the acoustic modelling and in the natural languages the humanoid robots are overtaken by the humans when the humanoid robots are engaged in the real life because the speech and the human emotions are extremely ambiguous due to the noises and the external audio events from the robot’s environment. The humans assign a correct interpretation to the perceived ambiguous signal, but the humanoids robots cannot interpret the ambiguous signal. The most common software used in the interpretation of the ambiguous signal is a fuzzy based software. The artificial neuro-fuzzy inference system, shortly known as ANFIS is the emotion recognition system based on the fuzzy sets which acts as the thalamus of the human brain and it is responsible for the sensorial perception of the humanoid robot. Our goal in this work is to create the fuzzy-based sound signals software and the fuzzy-based genetic algorithm with high performance in the communication between the human and the humanoid robots which help the humanoid robots to think, to understand the human speech and the human emotions and all the ambiguous signals from the robot’s environment in a way that it is distinguishable for every humanoid robot as the human.