Table of contents

It is our great pleasure to welcome you to the 2020 11^th Asia Conference on Mechanical and Aerospace Engineering (ACMAE) on December 25-27^th, 2020, which is planned to held in Chengdu, China. However, due to the spread of COVID-19, many countries have strict restrictions to travel aboard; Meanwhile, the safety of the participants is always the priority. We made a hard decision to hold the conference online. ACMAE 2020 is dedicated to issues related to the advancement of all Mechanical and Aerospace Engineering topics.

Following the successful conference in Bangkok, Thailand, last year in 2019, the conference focus is still on Asia's research, achievements, markets, industry, etc. The technological innovation advances at an ever dramatic pace, we believe that face-to-face communication is of great essential, and virtually we expect that to be maintained even if we cannot socialize outside of sessions. With a solid reputation, ACMAE is where you will meet and network with engineering leaders, business innovators, researchers, academics and policy makers from across the globe. Do not miss the chance; hope to see you at ACMAE 2021.

ACMAE conference was held online by Zoom tools, after getting familiar with the functions of the Zoon on the first day, 3 speakers-Prof. Konstantin Lukin, Prof. Antonio De Maio and Prof. Ramesh K. Agarwal showed up to give a 45 mins keynote speeches, and then 8 parallel sessions were held to share and discuss the research of all the participants in specific field. Each presenter has 15 minutes for presentation, including 12 minutes presentation and 3 minutes for Q&A part. More than 60 participants from China, Italy, Ukraine, Russia, and Thailand joined the conference.

The proceedings present a selection from papers submitted to the conference from universities, research institutes and industries. 59 papers were finally selected from the submitted papers. As always, competition and acceptance rates are not high, all authors should be very satisfied with their success. The papers selected depended on their quality and their relevancy to the conference. The volume tends to present to the readers the recent advances in the field of Aerospace Mechatronics and Avionics Systems, Mechanical Engineering in Aerospace and various related areas, such as Aerospace Communications, Aerospace Engineering and Management and Electronic Systems, etc.

We would like to thank all the authors who have contributed to this volume and also to reviewers, speakers, chairpersons, sponsors and all the conference participants for their support to ACMAE 2020. Wish to see all of you in next year conference.

Professor Ian R. McAndrew PhD FRAeS

Conference Chair

ACMAE 2020

List of Conference Committee, Advisory Chairs, Conference Chairs, Program Co-Chairs, Steering Co-chairs, Publication Chair, International Publicity Co-chairs, Technical Committee Members are available in the pdf.

2020 The 11th Asia Conference on Mechanical and Aerospace Engineering (ACMAE 2020) was held online successfully by using "ZOOM" during December 25-27, 2020

Due to the spread of COVID-19 around the world, the epidemic situation in various countries is complicated, especially in winter. The number of infected people in many cities is growing rapidly and the world was dealing with different confinement and mobility restrictions when ACMAE 2020 was due to be held. Although a few people might be able to attend, most of people found it difficult to come to attend the conference in Chengdu. And most authors chose to make online presentation. Considering the safety of the authors, the Organizing Committee of the ACMAE 2020 make a hard decision that organize this year's conference fully online for better communication. The good news is that in terms of contents, there continues to be the same depth as before, with a wide range of excellent keynote speakers and many contributing scholars.

Many researchers, engineers, academicians as well as professionals in Mechanical and Aerospace Engineering field from all over the world have presented their latest research results and development activities. Each author had 12 minutes for presentation and 3 minutes for question and answer. During the question time, the author and audience can use the "Raise Hand" function or "chat" function to ask questions. There were eight sessions for all the oral presentations: Material design and performance analysis; Control Theory and Control Engineering; Mechanical Design Manufacturing and Automation; Power Machinery Engineering; Unmanned driving system and key technology; Aircraft design and modeling; Satellite System and Aerospace Engineering; Fluid mechanics and calculation. These topics are the most of main researches in the Mechanical and Aerospace Engineering field and also the conference can promote the development of the field. With the rapid technology advancements around us, it requires a lot of multi-disciplinary insight to first grasp and then capitalizes on the opportunities. ACMAE 2020 will always provide the professional stage to share the latest opinions and researches.

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Double-blind

• Conference submission management system: iConf conference system

• Number of submissions received: 106

• Number of submissions sent for review: 106

• Number of submissions accepted: 59

• Acceptance Rate (Number of Submissions Accepted/Number of Submissions Received X 100): 55.66%

• Average number of reviews per paper: 2

• Total number of reviewers involved: 42

• Any additional info on review process: All submitted articles should report original, previously unpublished research results, experimental or theoretical, and will be peer-reviewed by the technical committees from the specific field. And the accepted papers need to revise according to the review comments and the template should follow the IOP template

• Contact person for queries: Ms. Ashily (secretary_acmae@icmae.org)

Please submit this form along with the rest of your files on the submission date written in your publishing agreement.

The information you provide will be published as part of your proceedings.

In this process, the processing flow of fiber Bragg grating (FBG) embedded carbon fiber reinforced composites are prepared by means of pressurized film forming and end-surface elicitation. Firstly, the development of composites in aerospace field is introduced. Then, according to the principle of FBG sensor, a scheme for embedding fiber grating into carbon fiber composites is designed. There are three key steps involved in this process, namely, laying the bare fiber parallel to the carbon fiber cleavage direction, applying the end-surface elicitation method with the use of stainless steel thin tubes and Teflon fine tubes for protection, and pasting the rubber strip tile on the end to prevent the curing of the fiber break. After processing, a 260x60x3mm surface intact product is made according to the design scheme. There is no deformation in Carbon fiber surface and the end-surface is intact. Experimental tests show that this product has good temperature and strain response.

Through the composite creep solid propellant creep experiment, the composite solid propellant curve is obtained. The power rate constitutive model, linear viscoelastic model and Schapery nonlinear constitutive model are used to describe the creep process. The study shows that Schapery modified nonlinear constitutive model can better describe the creep properties of composite solid propellants. Through the ABAQUS user subroutine, the finite element application of Schapery's creep-type nonlinear constitutive model is studied. The research results in this paper can provide a reference for the analysis of the creep effect of the grain during the vertical storage of the solid rocket motor.

Based on the higher-order sandwich beam theory, the Chebyshev quadrature sandwich beam element is established for the bending analysis of the simply-supported sandwich beam. Gauss Lobatto sampling is adopted as element nodes. The discrete governing equation of the sandwich beam is obtained by the principle of minimum potential energy. A series of numerical examples are carried out on simply-supported sandwich beams under sinusoidal loading. The results are compared with the finite element method, showing that the proposed method can yield very accurate displacements and stresses. This method is suitable for the static analysis of simply-supported sandwich beams with different materials and different geometric parameters.

The rigorous thermal environment brought by long-time high-speed flight is imposed severe requirements on the structural bearing capacity and structural thermal safety of the aircraft. The integrated non-ablative thermal protection system based on continuous fiber-reinforced ceramic matrix composites is becoming a hot spot on the design of aircraft structures. However, the multi-scale, non-linear, non-uniform features of such materials, as well as complex thermal and mechanical characteristics, pose serious challenges to structural design and evaluation. Under the aero heating environment, the non-uniform temperature rising and thermal matching between different components in the continuous fiber-reinforced ceramic matrix composites are extremely complicated, which has a significant influence on the thermal safety performance of the structure. In this paper, based on the commonly used 3D orthogonal weaving process and the thermal characteristics prediction method of fiber bundles considering the effect of PyC interface layer, the fluid-structural strong thermal coupling characteristics of different woven parameters in typical aircraft structure is carried out. Quantitatively characterizing the heat transfer characteristics of this new material under the actual flight condition of the aircraft can further to improve the accuracy of the thermal property parameters obtained based on the ground test. The analysis results show that increasing the proportion of fiber bundles in a certain direction is the most effective method to increase the thermal conductivity in this direction. At the same time, the arrangement of the coupling yarns will also have a greatly influence on the thermal conductivity of the material. These results is of great significance for the design of the materials.

Though there are still disputes on whether the threading dislocation density (TDD), to produce high quality Gallium Nitride ( GaN ) with low TDD is needed. In this passage, we would first show the impact of dislocation and review the latest methods to reduce dislocation on Si, GaN, and sapphire. The Si substrating with serpentine channels could produce GaN by using Si substrate with low density dislocations. The method that use the markless-3D provides a new way to reduce the dislocation from big off-angle. The multiple-step growth technique controls the conditions of crystallization and use two steps of crystallizing to grow with both low dislocation density and 2D growth shape. The last method is to use the Na-flux method to exclude cracks with sapphire in crystal.

Based on the ultrasonic phased array technology, the time delay law of ultrasonic deflection and focusing at the water-aluminium alloy interface is studied in this paper. By changing the delay time applied on each array element, the immersion ultrasonic phased array technology can realize the preset deflection angle and focusing depth, so as to detect different angles and depth positions of the work piece. The principles of ultrasonic phased array deflection and focusing are studied based on Huygens principle, and the time delay law is obtained when the sound beam is deflected and focused. When ultrasonic waves deflect and focus at the water-aluminium alloy interface, the Matlab software is used to simulate the time delay law and sound field distribution, which verifies the correctness of the design and calculation of the time delay law.

Nowadays, the expansion of existing electric cables has been a crucial limiting factor in the development of urban electricity power. Compared with traditional power cables, superconducting cables have advantages of large current carrying capacity, low energy consumption, and high current density. Superconducting wires and tapes, which are the main compositions of cable cores, are the basis of superconducting high-voltage applications. Among them, the 122-type iron-based superconducting wires and tapes show excellent comprehensive performance. In this paper, the development history of superconducting materials, wires and tapes and preparation method are briefly introduced, and influencing factors of critical current density of iron-based superconducting wires and tapes are summarized. Furthermore, future research direction for superconducting wires and tapes is prospected.

Supersonic micro nozzles are widely used in aerospace propulsion, supersonic gas assisted processing and other fields. In this paper, combining numerical analysis and computational fluid dynamics (CFD) simulation methods, using a fast parameter optimization method, the design of experiment response surface method (DOE_RSM) to optimize the design of a micro solenoid valve Laval nozzle about single element cold air propulsion. Simulate the flow characteristics of the nozzle under different configurations and working conditions. Using the three-dimensional model to draw the structure grid and analyse the influence of the micro solenoid valve nozzle configuration on the thrust, effective specific impulse, outlet flow rate, mass flow rate, and outlet cross-sectional pressure difference under different environmental conditions. Determine the significant influencing factors and carry out parameter optimization. Different from the traditional rocket or air assisted processing nozzles, the satellite micro-thrust nozzles need to consider frequent switching actions. In this paper, we finally obtained the optimized configuration and size of the solenoid valve nozzle. Based on the calculation results, a cold-air propeller which include replaceable nozzles and can be used under normal pressure was designed, to provide a reference for cold air propulsion in the space station cabin and ground supersonic gas assisted processing.

Considering the difficulty of large computation and the characteristic of helicon plasma, a modified collisional-radiative model was proposed for the diagnosis of low-temperature helicon argon plasma. A simplified 47-level is proposed due to the lack of experimental support of transition data at high levels as well as heavy computation to obtain macroscopic parameters of helicon argon plasma, e.g., electron number density ne and electron temperature Te. A creative twice-matching method is proposed in the model because the current double-line intensity ratio method shows significant sensitivity in diagnosing low-temperature electrons. Calculations based on this model shows the spectrum intensity depends on the electron temperature as well as density for low-temperature plasma, especially when it's below 6eV. The twice matching process based on the priori knowledge chooses 15 spectrums cognizable within the wavelength from 680nm to 860nm, adopting the absolute values of the lines to match with the results calculated by the collisional-radiative model. This method greatly reduces the average error to 13.7%. The result indicates that the precision of the electron temperature and density has been improved a lot and the relative errors are 25% and 40%, respectively. Within the accuracy range above, the research shows when RF power is 500-800W and the pressure is 0.5-1.3Pa, the electron number density rises with the increasing RF power and decreases with the increasing magnetic field strength (450-900G) and gas pressure. Moreover, comparing to the number density of electrons, the electron temperature changes less and rises with the decreasing pressure.

The steering gear is an important part of the guided missile control system and the actuator of the flight control system. The torque motor is one of the key components of the steering gear. Its performance directly affects the performance of the steering gear and directly determines the dynamic quality of the guided missile during flight. According to the composition and working principle of the torque motor, to judge its performance, the no-load angular displacement characteristics and pressure characteristics of the torque motor should be tested. In order to accurately and quickly measure the performance of the torque motor under working conditions, the design of the torque motor test system is realized based on the virtual instrument development software. The test system mainly includes two parts: a hardware platform and a human-computer interaction interface. The hardware platform mainly includes an industrial computer, a torque motor test bench, a control box and a data acquisition card. The human-computer interaction interface has the functions of test parameter setting, data acquisition, data processing, data storage and form printing. The torque motor test system has the advantages of small prototype size, convenient operation and accurate test results. The test results show that the test method of the test system is reasonable, the test system runs reliably, the test efficiency is high, it can carry out stable and real-time data collection and processing, is easy to operate and maintain, and meets the key requirements of torque motor testing.

In the aviation framework, the workload evaluation is influenced by human factors effects both for pilots and ground operators. Nevertheless, the measurement of workload is of great importance to prevent human errors due to fatigue. In the present work, correlation analysis has been carried out to investigates the relationship between subjective and objective workload measurements. An experimental campaign was conducted using a full flight business aircraft simulator. Particular attention has been paid to the NASA-TLX subscales contribute. In terms of objective measurements, three different indexes gathered from heart rate variability have been considered. As the main result, the frequency-domain index reveals a large correlation effect with the workload subscale for the maneuvers taken into account.

As a significant tool of transportation widely used in the logistics field, a well-performed parachute is highly required for this demand, especially for the sake of higher cost performance. The current study aims to investigate the internal relationship amidst various parameters of the parachute, conducting error analysis and accordingly providing an optimal experimental scheme. The objective of this experiment is to determine reference area and the resistance coincident, which are primarily parameters to estimate the weight of the designed parachute. Because the reference area is hard to determine using regular geometry method, a new parameter area ratio is redefined as the ratio of the original area of parachute surface to the reference area so that the reference area can be calculated by solving geometry problem. A simplified assumption that the parachute can be seen as a quasi-rigid body was previously made in order to approach the ideal parachute. Despite several limitations of the experiment, the final results perfectly aligned with the pre-experiment expectation. By following the similar procedures and after several trials, the ratio of the original area of parachute surface to the reference area was determined to be 3.90 and the resistance coincident to fall in the range of 2.00-3.00.

Plug seedlings are the main way of modern seedling cultivation in China. Aiming at the problems of low efficiency, high labor intensity and poor work quality for manual transplanting or semi-automatic transplanting of plug seedlings, a stable and efficient seedling picking device is designed for the automatic transplanting machine. It is based on the gear-cam-link composite mechanism to realize the seedling trajectory in accordance with the agronomic requirements. The mathematical model of the seedling picking device is established, and the theoretical profile equation of the cam groove and the actual picking trajectory equation are deduced. The 3D model and the virtual prototype model of the picking seedling device are constructed, and the simulation trajectory is obtained, using SolidWorks and ADAMS software. The simulation results show that the simulation working trajectory has good consistency with the theoretical trajectory.

In this paper, by designing the overall idea of the pipeline steam dryness control measurement system, designing and implementing the pipeline steam dryness control measurement system, constructing the pipeline steam dryness control measurement test platform, integrating the pipe steam dryness control measurement system and the effect verification, studying and establishing the steam dryness detection method to improve the application effect of steam in the tobacco processing process.

Finite element analysis (FEA) provides numerical modeling and testing methods of stress analysis for products. The time of products development cycle can be shorten and the cost for products physical testing can be reduced with FEA. Drop test is one of the important tools uses for the impact behaviour study of cell phones, which identifies weak design points during the impact behaviour of cell phone. With the development of technology and growing of people's demand, the screen of cell phone is getting bigger and bigger. Full-screen smartphones have become a trend. It is necessary that modeling and analyzing for full-screen smartphones are considered. This study conducts free-drop simulation and analysis on full-screen smartphones based on ABAQUS/CAE.

In order to analyse the influence of gear parameters on the internal pressure pulsation of the aviation gear pump, the flow field analysis software PumpLinx is used to calculate the internal flow field of the aviation gear pump. By setting monitoring points inside the gear pump under different gear parameters, the pressure pulsation results at different positions under different gear parameters are obtained and analysed. The results show that the larger the modulus, the greater the pressure pulsation in the oil inlet area, oil trapped area and the oil outlet area; the greater the number of teeth, the greater the pressure pulsation in the oil trapped area, and the smaller the impact on the oil inlet area and oil outlet area; the larger the index circle pressure angle, the smaller the pressure pulsation in the trapped oil area, and the smaller the impact on the oil inlet area and the oil outlet area. The analysis results provide a reference for further optimizing the internal pulsation and oil trapping problems of aviation gear pumps.

In order to solve the problem of the result delay in the real-time calculation of engine inlet total pressure distortion index in flight test, the multi-step prediction of engine inlet total pressure distortion index in flight test is carried out. The average prediction error of traditional cascade forward neural network prediction model is higher than traditional autoregressive integrated moving average model. An improved algorithm is proposed. By establishing a time series dynamic level model, the time series of engine inlet total pressure distortion index is divided into low dynamic series and high dynamic series by using particle swarm optimization algorithm. The cascade forward neural network prediction model is used for training and prediction respectively. The results show that the average prediction error and maximum prediction error of the improved algorithm are reduced by 3.90%, 10.66% and 3.29% and 1.38% respectively compared with autoregressive integrated moving average model and traditional cascaded feedforward neural network.

Currently, more and more spacecrafts are being designed, to explore the planets of the solar system. One of the very important stages in the execution of such missions is the movement from the moment of deorbiting until the moment of approaching the surface. The entire descent trajectory from the moment of separation to contact with the surface is a very important stage and a very important object of research particularly in the field of Computational Fluid Dynamics (CFD). It is to this process that a series of articles by the authors is devoted. This article is devoted to the movement of the descent vehicle in the lower atmosphere. Some parameters of the descent vehicle movement at this stage of movement are analyzed. The importance of such research and the possibility of using inflatable braking devices are shown.

Jet impingement is widely used in anti-icing and de-icing of aeroengines. To improve the efficiency of anti-icing and de-icing, heat transfer in jet impingement flow should be further enhanced. By using large eddy simulation (LES) method, jet impingement flow was analysed in time-domain and spatial-domain. It was revealed that the jet flow has quasi-periodic characteristics in time, and heat transfer is dominated by vortex structure. In addition, the impinged surface curvature has a certain influence on the spatial distribution of Nusselt number. Better heat transfer effect can be achieved by inducing more vortices and applying proper surface curvature.

Low-thrust control technologies display advantages in space missions. In this study, a linearization method for constant-thrust control is proposed. Based on elliptic integrals, the constant-thrust linear equations are introduced. Furthermore, an analytical two-section linear equations are derived. In addition, for considering J₂ perturbation, semi-analytical linear equations are also presented. Numerical simulations are conducted to demonstrate the validation of the proposed method, which proves to be a practical choice for engineering.

In the paper we briefly describe conceptual design of Ukrainian reusable single-stage rocket demonstrator. The main objective consists in design, development and trials of a series of 'Grasshopper' demonstrators equipped with both the jet propulsion engine set and microwave/optical vision and measurement systems for the performing and control of its soft landing at the starting point. The greatest advantages of our design consist in availability of the results of previous developments of rocket engines and guiding systems for 'Yuzhmash' space ships, as well as advanced technique for real-time microwave 3D imaging using random/noise signals and MIMO¹ radar operation mode with FPGA²-based signal processing.

The shape of hypersonic aircrafts represented by the waveriders is becoming more slender and flatter, thereby greatly reducing the structural rigidity of the aircrafts. This innovation is applied to satisfy the demand of long-range flight. In this paper, the effect of elastic deformation on the trimming and dynamic stability of the waverider was analysed through Computational Fluid Dynamics(CFD)/Computational Structural Dynamics(CSD)/Rigid Body Dynamics(RBD) coupling. The results show that as the decline of structural stiffness, the angle of attack increases and the lift-drag ratio deteriorates when the waverider is trimmed. The elastic deformation makes the dynamic center get forward, and the static stability of waverider becomes poorer. What's more, the dynamic stability of pitching motion is reduced due to the coupling of rigid-body motion and elastic vibration.

Certification of modern aircraft requires the manufacturers to demonstrate flight safety within the flight envelope, including icing conditions. Icing wind tunnel test is an important way for flight safety and certification. However, the size of aircraft models that can be tested in icing wind tunnels is limited by the dimensions of the facilities. It is an effective method to replace the large model with a hybrid airfoil to carry out the experiment. If properly designed, these hybrid airfoil models can generate the full-scale ice accretion on the leading edge and reduce blockage. Based on the similarity of flow field in the leading edge, a multi-objective genetic optimization algorithm is proposed to design the hybrid airfoil under different conditions. The pressure tests are carried out and compared with the leading edge pressure coefficient of the corresponding full-scale airfoils. The design and experimental results show that the pressure coefficient deviation between the hybrid airfoils designed and the corresponding full-scale airfoil in the 15% chord length range of the leading edge is within 3%. Finally, icing wind tunnel test is used to inspect the ice shape of full-scale and hybrid airfoils, and the results shows that ice accretion process have good agreement of hybrid and full-scale airfoils.

The aerodynamic shape optimization design of the aircraft is to combine the aerodynamic performance analysis of the aircraft with the optimization method, by constantly changing the design shape of the aircraft, its aerodynamic performance is improved to achieve optimal aerodynamic performance under certain constraints. Aircraft aerodynamic shape optimization is a comprehensive design platform that integrates geometric parameterization, moving grid, CFD calculation and optimization algorithms. With the development of computational fluid dynamics (CFD) and the maturity of calculation methods, the role of aerodynamic shape optimization in modern aircraft design becomes more and more important. To this end, an aerodynamic shape optimization design platform based on non-uniform rational B-spline (NURBS) was established. In the optimization process, a mesh deformation method based on radial basis functions is used, and an arbitrary Lagrangian Eulerian method (ALE) is used to describe the unsteady process of the wing. The optimization analysis of the large aspect ratio wing under subsonic conditions has certain reference value for the deformation problem in the aerodynamic shape optimization design.

In this work, the cracks of HB4-49-14CdD swivel nut in aircraft were found and analyzed by macroscopic observation, morphology testing and metallographic examination. In order to figure out the cause of cracks, manufacturing and assembling process were investigated, and finite element method was used to simulate the tightening process. The results showed that overload tightening torque lead to the fracture and failure of swivel nut.

Surfing Aircraft Vortices for Energy (SAVE) refers to the behavior that an aircraft "rides" on the vortex of the front aircraft just like the formation flying of migratory birds and it can also provide guidance for the aircraft that is difficult to avoid entering the front vortex, reduce the incidence of flight accidents caused by the vortex, and improve the safe operation ability of civil aviation. The technology has the advantages of saving energy and increasing range, which is a hot issue in the field of aviation research. Firstly, this paper analyzes the main research contents, technological developments and applications in the field of SAVE at home and abroad. Then discusses the key technologies of SAVE such as aerodynamic principles, control of SAVE, safety guarantee, path planning, and related experimental verification technologies. Finally, the development and application trend of SAVE technology in military and civil aviation fields and its corresponding benefits brought by it will be pointed out.

Customer manufacturing supervision of civil aircraft refers to the operator of the aircraft or its authorized entity's supervision and inspection process during aircraft's manufacturing and final assembly, through which the operator (airline company) ensures that the delivered aircrafts meet the requirements of approved technical standards, process specifications, and engineering documents, as well as confirming that optional components and aircraft's layout comply with technical standards required by the purchase contract. Manufacturing supervision brings forward aircraft delivery inspection, qualitative improvement of which enables the improvement of efficiency in single aircraft airworthiness inspection, ensuring aircraft's continued airworthiness. From the manufacture's perspective, analyzing customer's needs and preference on manufacture supervision in advance, taking advantage of the relatively long production cycle, disposing proper engineering solutions for manufacture deviations, reducing the business negotiation items due to deviations not only helps reach the goal of customer supervision, but also helps optimize engineering dispositions.

Hypersonic aircrafts and aero-engine combustion chambers both generate non-equilibrium and high-enthalpy flows and bring complex material-relied heat convection performance. The convective heating prediction is difficult due to unknown surface thermal state, leading to poor usability of wall temperature correlation method (WTCM). This paper aims at improving WTCM for convective heating prediction in chemically reacting flows through coupling computation of catalysis on thermal protection materials. Modified WTCM for chemically reacting flows accounts for two distinct physical events driven by temperature gradient and species reaction, which follow the Fourier's and Fick's laws, respectively. Preliminary validation testing demonstrates the feasibility of the modified WTCM to rapidly evaluate aerodynamic heating with limited deviation. The current research provides essential technical support for the evaluation and design of hypersonic aircrafts and aero-engine combustion chambers.

Under the current production mode of multiple varieties and small batches, the traditional post-event quality assessment method is still used in the manufacture of rocket body structure in China. In order to solve the problem that this method can not fully reflect the quality of each step in each process, a quality assessment method for rocket body structure based on product quality DNA is proposed in this paper, which converts the assessment of product quality into the analysis of product quality DNA. This method comprehensively assesses the quality of each process and each step in each process by searching the assessment knowledge base based on product quality DNA. Based on the principle of biological DNA, this paper combines the idea of product gene with product quality, and constructs a model of product quality DNA from three structural levels(basic structure, double helix structure and superhelix structure). This paper takes a weld of a rocket body structure as an example and assesses the quality of this weld by using the quality assessment method for rocket body structure based on product quality DNA. The results show that the quality of the weld is assessed as "good".

In order to study the thermal lubrication characteristics of aero-gear pump journal bearing (APJB) under certain load and low medium viscosity, a APJB numerical model was established based on the combination of Reynolds and adiabatic flow energy equations. The hydrodynamic lubrication and temperature effects on the viscosity are considered and the finite difference method is adopted. The results show that with the increase of APJB width parameters, the eccentricity decreases monotonically, the minimum oil film thickness increases, the friction resistance increases and the end discharge decreases. In addition, the eccentricity of bearing, maximum oil film pressure, end discharge flow and oil film thickness increase with the APJB radial clearance, while the friction and temperature inside the APJB decrease. When the APJB width changes from 21 to 27mm, the maximum oil film temperature and pressure increases by 2.16% and –35.23%, respectively; when the radial clearance changes from 0.0315 to 0.0413mm, the maximum oil film temperature and thickness decrease by 3.03% and 8.99%, respectively.

A Fluid Structure Interaction framework developed at CIRA to deal with multi-physics problems in a partitioned approach is presented. The CIRA multi-block structured flow solver for unsteady Navier-Stokes equations UZEN was updated and tightly coupled with an open-source solver for non-linear structural dynamics in a modular approach. The solvers are glued in space and time through an open source library, able to control the executing processes and to deliver exchanging data by specific adapters. The validity of the framework is tested on vortex-induced vibration effects of a cantilevered beam in low Reynolds flow and on as three-dimensional wing flutter in transonic turbulent flow.

By studying the classification and use characteristics of navigable airspace, studying the methods and standards of all kinds of navigable airspace planning, determining all kinds of key parameters of navigable airspace, constructing the navigable airspace planning and management system based on Ge, providing corresponding technical reference and effective management means for the planning of navigable airspace, and solving the problems of airspace planning, efficient use of airspace and low altitude supervision Question.

As an important component to provide satellite energy, the power subsystem in-service operation state is of great significance to satellite safety. In this paper, the power subsystem reliability evaluation is carried out on the basis of the actual telemetry data from satellites. Firstly, the influence factors of the power subsystem telemetry data are analyzed, and the modified method to calculate the output parameters is established; Furthermore, the degradation trajectory of the power subsystem output power is analyzed under different in-service time, and then the difference between the global and the local degradation is discussed. Finally, using the performance degradation model, the reliability evaluation method for the power subsystem is set up. The result shows that the local degradation trajectory in the end of lifetime is critical for the remaining useful life prediction, and the method can provide references for the in-service reliability analysis of the on-orbit satellites.

Acoustic-vibration prediction at early stage of satellite development can contribute to their structural and layout design. In this paper, numerical models of a practical satellite subjected to acoustic excitation at launch stage were established. Then, the effect of acoustic condition was further analyzed. The results demonstrate that it is difficult to predict all-frequency-band acoustic response of complex satellites by an individual method, so a combined method was proposed in this paper. The damping loss factor model of panels with equipment was introduced to resolve the issue of on-board equipment modelling in the statistical energy analysis model. The service modules are extremely sensitive to acoustic excitation of about 354∼2828Hz, which should be highlighted when carrying a rocket with a high sound pressure level at this frequency band.

In this paper we will study the effects of an increasingly complex Kalman filter state transition matrix on the accuracy of the estimation of a non-linear relative navigation system. The propagation model will be constant in all the cases. The measurements are generated using Xu-Wang model and then noise is added. Whereas the process non-linear vector function/propagation matrix of the Kalman filter will be modified. In the first scenario the Clohessy-Wiltshire equations are considered as the basic propagation model of the Kalman Filter. In the second scenario the eccentricity of the chief satellite's orbit is included in the model of the Kalman Filter. In the 3rd case we are using the model presented by Xu-Wang which incorporates the oblateness of Earth into the Tschauner-Hempel model. The divergence of the Kalman Filter is studied and provides a guideline to design engineers.

In response to the needs of positioning and navigation in lunar exploration projects such as manned landing on the moon, and the initial positioning of the lunar lander, this paper proposes a lunar positioning and navigation method based on stellar vector measurement and inclination information fusion, and demonstrates the correctness of the algorithm. A semi-physical simulation platform was built and the experimental method verified that the accuracy reached the positioning accuracy index of 30 arc seconds. Lunar surface positioning is different from ground positioning and cannot be positioned by satellites. This method solves the problems of low timeliness and low accuracy of ground measurement and control methods, greatly improving the timeliness and accuracy of lunar surface positioning, and has positive significance for lunar exploration projects.

In the process of hypersonic boundary layer transition, the leading edge receptivity due to free-stream acoustic disturbance provides unstable perturbations in boundary layer with initial amplitudes, which is one of hot issues in the study about transition mechanism. The receptivity of leading edge is influenced by many factors, involving geometry parameters, disturbance types, etc., among which the bluntness plays a key role for generating disturbances. In order to reveal the mechanism of bluntness influence on the boundary layer transition, investigations into the acoustic receptivity on flat plates with sharp and blunt leading edge are carried out. The flow conditions are as follows: Mach number 6, Reynolds number 1e7/m, adiabatic wall. By introducing two-dimensional plane fast and slow acoustic waves into the free-stream, the whole receptivity process of free-stream disturbances passing through shock wave into boundary layer is simulated with high-order accuracy DNS method. With sharp leading edge as a reference, the generation mechanism of the perturbations near blunt leading edge and its influence on the boundary layer downstream are analyzed. Some conclusions are obtained: for acoustic disturbances in hypersonic free-streams, the receptivity mechanism of blunt leading edge is different from that of sharp leading edge; both the fast and the slow mode can be produced respectively near the sharp leading edge by the fast and the slow acoustic wave, while only fast mode appears near the blunt leading edge; the receptivity of blunt leading edge due to the fast acoustic is stronger than that due to slow acoustic, and is also stronger than that of the sharp leading edge in a certain region of boundary layer downstream.

When the Rapidly-exploring Random Tree (RRT) algorithm in the global path planning algorithm is used for autonomous online path planning of UAVs, there is a problem that the optimal path cannot be obtained. An improved RRT algorithm is proposed, including The dynamic constraints, heuristic search strategy, dynamic step fusion strategy, and the improvement of the selection method of changing new nodes under specific conditions. The simulation results show that the improved RRT algorithm can meet the premise of UAV dynamic constraints. Next, the optimal path planning for multiple goals is realized, especially in reducing the nodes in the random tree.

Unmanned Aerial Vehicles are widely used in aerial photography, exploration, logistics and other fields for their low cost, low take-off and landing requirements and many other advantages. With the deep application of UAVs, their safety problems have become increasingly prominent. The frequent occurrences of collision events have attracted the public attention. This paper reviews the UAVs weight threshold estimation test, UAVs impact aircraft windshield test and aircraft horizontal stabilizer test, and compares the results with bird collision results, discusses the impact safety challenges of light and small UAVs. This paper puts forward what should focus on about UAVs designing.

Plasma stealth is a new concept and principle of stealth technology. Firstly, WKB analysis method is used to analyse the attenuation of electromagnetic wave under the action of plasma. Then, a certain UAV inlet was selected to establish a model, and the inner wall was covered with a ring of closed cavity. Plasma was generated by discharge, and the stealth performance of the inlet was numerically simulated for the L-band electromagnetic wave and its stealth effect was analyzed. This method verifies the feasibility of applying plasma stealth technology to the l-band radar wave for inlet stealth.

In the dynamic mechanics analysis of light and small unmanned aerial systems (UAS), The importance of the high-precision modelling of UAS is unquestionable. Modelling can be classified into 3D geometric model modelling and finite element model modelling, of which the finite element model modelling is mainly divided into four parts: discretization, connection modelling, contact modelling and material attribute definition. This review summarizes the existing modelling methods of light and small UAS, and provides the basic methods and modelling methods for the simulation calculation of light and small UAS. Implications for practice and future research are provided.

A compound control method with aerodynamic canard and reaction jet is proposed for anti-Unmanned Aerial Vehicle (UAV) vertical launch missile. The purpose of this method is to solve the problem of vertical launch with high angle of attack and low dynamic pressure. This paper first introduces the actuator layout and ignition strategy of reaction jet. Then the model of compound control system is established and compared with aerodynamic control in detail. Simulation studies demonstrate the effectiveness of the proposed method.

Aimed at decreasing the numerical dissipation of weighted non-oscillatory and non-free-parameter dissipation (WNND) scheme, we present an improved counterpart for shock-capturing. The new algorithm is based on the framework of Z-type weighting procedure with new local and global smoothness indicators. The performances of the proposed scheme are evaluated on several numerical tests governed by one-dimensional Euler equations. Numerical results indicate that the improved WNND scheme has advantages over the original WNND and third-order WENO-JS and WENO-Z schemes.

Polar navigation ships, offshore platforms, and amphibious aircraft sometimes need to work in low temperature environments, which will inevitably form varying degrees of icing on the surface of structures such as cabin doors. In order to ensure their normal working conditions, it is advisable to choose reasonable anti-icing and deicing methods to prevent icing or effectively remove icing. Therefore, it is necessary to study the mechanical properties of ice to provide a reference for the selection of anti-deicing methods. This article summarizes the common methods for measuring the shear strength and tensile strength of ice, which can provide some guidance for the freezing strength test of fresh water and sea water.

The effect of wall temperature on the three-dimensional rotating detonation wave in an annular chamber is investigated by utilizing premixed hydrogen/air as the reactant and the improved delayed detached-eddy simulation method to evaluate the turbulent transportation. Four cases are set with different wall temperature, i.e. adiabatic wall, isothermal wall with 400K, 800K and 1200K. When using isothermal wall, there is no reactant deficit zone which appearing in the case with adiabatic wall. As the wall temperature increasing, the leading oblique shock will form at both side of the detonation front. When comparing the specific impulse with the adiabatic case, all the three isothermal cases have a better performance. And the lowest wall temperature case shows the highest specific impulse.

Polynomial chaos expansion (PCE) method is a common tool for uncertainty quantification (UQ) in fluid mechanics. However, there exists 'Dimensional Curse' when the parameters dimension is very high, and large samples are required to solve the PCE function. This would hinder the application of PCE in high dimensions. An intelligent PCE method based on the idea of features selection in machine learning is proposed in this paper. Therefore, only several important features will be selected to construct the PCE function, then fewer samples will be needed to solve the model, and it will be more efficient. Several benchmark functions and an RAE2822 airfoil flow case are utilized to verify the UQ capability of the intelligent PCE. It is proved to be more efficient than the original PCE, with nearly same accuracy.

The noise generation mechanism of an open cavity flow is investigated using Lagrangian coherent structures (LCS) together with dynamic mode decomposition and Helmholtz decomposition methods. The flow field of an open cavity with the length-depth ratio L/D = 2, Mach number Ma = 0.8 and Reynolds number Re = 2500 is first obtained through direct numerical simulation with 5-th order weighted essentially non-oscillatory (WENO) scheme. LCSs are then obtained from flow field reconstructed by the mean velocity field and the decomposed modes. The interactions between LCSs inside the shear layer and the squeezing zone are found to be important sound sources. The method efficiently isolates the structures responsible for the noise generation.

The Reynolds averaged Navier-Stokes models are still the workhorse in current engineering applications due to its high efficiency and robustness. However, the closure coefficients (also known as model parameters) of turbulence models are calibrated by model builders according to some fundamental flows, and the values suggested by the model builders may not be applicable to all flow types. In this work, the Bayesian method is applied to recalibrate the closure coefficients of SA turbulence model to improve its performance in backward-facing step problem. The results show that the four parameters C_b1, C_w3, C_v1 and κ are well informed by the experimental data of skin friction coefficient. The recalibrated model parameters show better performance than the nominal values in the prediction of skin fiction coefficient.

For studying the complex flow structure of a high speed cavity, including shear layer, separation, reattachment and vortex, the single-color fluorescent oil flow visualization system in the 0.6m×0.6m trisonic wind tunnel of China Aerodynamic Research Development Centre was enhanced. Different portions of the cavity such as its bottom wall, left and right side walls, front and rear walls and area outside the cavity utilized different oil films with different fluorescent particles to visualize the flow mixing more effectively in the cavity. Specialized ultraviolet light sources are used to enhance the oil flow image contrast. Additionally, to ensure the oil film follows the surface streamlines and indicates the skin friction lines more accurately, the thickness and viscosity of the oil film are well controlled. A high-speed cavity wind tunnel test was conducted to validate the improved oil flow visualization system at Mach number ranging from 0.6 to 2.0. The experimental result shows that the improved oil flow system can effectively visualize complex flow patterns of the cavity flow at all Mach numbers. Colour fluorescent oil flow visualization system established in the present study provides a capability to visualize the flow mixing phenomenon in cavity flows with a high image contrast.

The work develops the multi-dimensional dissipation strategy within advection upstream splitting methods (AUSM) in hypersonic flows based on the affordable shock-stable item by Chen et al. (J. Comput. Phys. 373 (2018) 662-672). This strategy is related to the sear velocity difference and the pressure-based sensing function. It strengthens the robustness of AUSM-family schemes against shock anomalies and meantime preserves shear layer. A series of numerical cases illuminate its potential capability for hypersonic flows, particularly in the extreme situations such as the large aspect ratio of cells, skewed non-orthogonal grid, and unstructured grid.

The work develops a localized hypersonic cross-flow transition criterion considering the influence of cross-flow intensity and surface roughness. A cross-flow extension of hypersonic modified γ-Re _θ transition model based on Chant2.0 computing platform is implemented. The extended transition model is used to predict the cross-flow transition on the elliptic cone (HIFiRE-5) in multiple states, and the predicted results are in good accordance with the experimental results.

To visualize the flow in the test section of an indraft supersonic wind tunnel in the University of Glasgow as long as possible, a background-oriented schlieren system was built up preliminarily. A MATLAB program based on a random dot algorithm developed in this study provides a fully customizable tool to generate background patterns with different sizes and dot densities. Background patterns produced by the in-house developed program then can be printed by a common ink-jet printer. To enhance the signal-noise ratio of the measurement system, white reflective film sheets, or semi-transparent paper can be employed. The correlation algorithm base on fast Fourier transform that is also applicable for PIV was chosen to process background oriented schlieren images. A validation test was performed to visualize the flow structure around a Pitot tube at M = 2.0. The experimental result proves that the BOS system established in this study is capable of visualizing the supersonic flow structure around the Pitot tube and sensitive enough to reveal weak density changes produced by the boundary layer, expansion waves, and weak oblique shock waves. Next, the current BOS system will be improved further by increasing the intensity of light sources to shorten the exposure time, using new cameras with better spatial resolution, and optimizing the background pattern.

The transition of the hypersonic boundary layer and the corresponding control have been extensively interested since the strong engineer background. In the present work, a hypersonic boundary layer over a flat plate of Mach 6 is computed using the high-order finite-difference scheme. The influences of the two-dimensional micro-grooves on the evolution of the second-mode instability wave are investigated. The comparison is carried out between different depths of the micro-groove. The results indicate that the actual control effect does not significantly vary with the depths under the condition with large grooves. The DNS prediction show different results with the theoretical model for the acoustic reflection coefficient. It is suggested that new model should be derived to guide the design and optimize of the parameters of the micro-groove.

In this paper, we report an automatic system which combines machine design and machine vision to promote the automatic lead sheet roll production. In terms of the key problem identifying and locating millimetre-level slit in motion, the rotating module and the slit recognition module are designed based on the geometric characteristics of the lead sheet roll hub, and machine vision technology is used to extract the features of slit images. The automatic system enhances the production efficiency of lead sheet roll by nearly 8 times and lowers the production cost.

Low-thrust propulsion technology is widely used in space missions. However, traditional methods are not appropriate for the general case. In this study, a linearization Lyapunov method for constant thrust control is proposed. Based on relative orbit elements (ROEs), analytical constant-thrust linear equations are introduced. Moreover, via Lyapunov method, the linear constant-thrust control strategy is obtained. Numerical simulations are conducted to demonstrate the validation of the proposed method. Given different thrust magnitudes, the accuracy meets the requirement in these cases. Thus, it proves to be a practical choice for engineering applications.

In view of the problem that the controller parameters of the servo system of launch vehicle cannot be adjusted after installation, the parameter adjustment method of the servo system controller parameters is designed by the optimization method based on the genetic algorithm. Set the scale, the notch frequency and the damping coefficient as the variable to be adjusted. The adjusted ITAE guideline module is the error criterion, and the notch filter parameters are adjusted. The experimental verification results of servo system simulation test bench show that the method of this paper can effectively optimize the parameters of servo system controller and improve the quality of servo system.

Finite-thrust control technology is widely applied to space missions such as orbital transfer and rendezvous. However, traditional low-thrust method requires time-varying acceleration for achieving transfer and rendezvous. In this study, a newly piecewise constant thrust method is proposed for orbital transfer problems considering J₂ perturbation. To rapidly obtain the solution, UKF parameter estimation method is adopted, which transform the original problem into a parameter estimation problem. Numerical simulations are conducted to demonstrate the validation of the proposed method. It proves to be a practical choice for engineering applications.

We consider a landing on an aircraft carrier. We propose a scheme for calculating the probability of go-around due to disengaging the arresting gear and a scheme for calculating the maximum descent of the aircraft trajectory with respect to the deck level immediately after leaving the deck. The main control parameter is the moment of increase in aircraft's thrust before touching the deck. The requirements imposed on the probability of go-around and the maximum descent of the aircraft trajectory determine the possible range for the moment of increase in aircraft's thrust. Proposing the scheme for calculating the probability of go-around, we use our previously obtained results related to finding the probability of a successful aircraft landing. We present the numerical results for the real aircraft when landing on the real aircraft carrier.

This work studied on the feasibility to produce agricultural bush parts using cold forging followed by machining to replace existing processes of piercing operation followed by shaving had been studied. Short tool life of the shaving punch is a major problem for existing processes. From this work, it was found that the maximum force required for cold forging operation is similar to that used on the existing process. Therefore same facility can be employed for a proposed method. A proper selection of billet size was necessary not only to obtain specific shape of final part, but also to yield maximum rate of material utilization. Another factor influencing the process was material flow constraint by cold forging die design. The design with highly constrained would lead to high stress introduced to the part. It is recommended to use forging die design with allow more of free material flow which is expected to improve tool life.