Table of contents

Preface

It is our great pleasure to welcome you to 2018 The 9th Asia Conference on Mechanical and Aerospace Engineering (ACMAE 2018) which will be held in Singapore during December 29-31, 2018. ACMAE 2018 is dedicated to issues related to Mechanical and Aerospace Engineering topics.

Following the successful conference in Yokohama, Japan last year, the conference focus on Asia's research, achivements, markets, industy, etc. The technological innovation advances at an ever-dramatic pace, we believe that face-to-face communication is essential. 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. Don't miss the chance, hope to see you at ACMAE 2018.

The proceedings present a selection from papers submitted to the conference from universities, research institutes and industries. 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 2018.

ACMAE 2018 Organizing Committee

December 14^th, 2018

List of Conference Chairs, Conference Advisory Chair, Conference Program Co-Chairs, Steering Co-chairs, Publication Chair, International Publicity Co-chairs, Conference Technical Committees available in this PDF.

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

The internal carriage of stores on an aircraft's merit is especially importance for attack aircraft. For the safe carriage and separation of stores, it is important to know the flow field environment the store experiences during flight. A CFD investigation was conducted to determine cavity flow characteristics. M-SST DES Method are used as numerical simulate method. Compared with the wind tunnel test results, the open cavity flows are studied. The numerical simulation results are in good agreement with the wind tunnel test results, thus verifying the credibleness of the M-SST DES Method. As a typical research model, AEDC's 'Wing-Pylon-Finned Store' wind tunnel test model is computed in this paper. Last, this paper investigates the store's separation characteristic, which is internal carriage on and release from aircraft. Those results are also indicated that the DES method of numerical simulation flow-filed can embody the unsteady aerodynamic random factors of the store separation from internal weapons bay.

This paper introduces a topology optimization design method for flexible mechanism of composite wing leading edge based on discrete material optimization (DMO) with composite material. The DMO method is combined with the topology optimization to select the deviation of the actual displacement and the target displacement of the 10 coordinate points on the initial curve of the leading edge as the objective function, and the volume fraction of each phase material is used as the constraint to establish the composite material optimization model, which is solved by the OC optimization criterion method. The MATLAB codes are compiled to calculate the optimization problem and a distinct result image is obtained. The CATIA software is used to model the topology image in three dimensions, and the model is imported into Hyperworks software for simulation analysis. The results show that this complaint mechanism can achieve a maximum deflection of 9.1 degrees, which verifies the feasibility of the method.

With the rapid development of the global air transport industry, airport surface traffic is increasingly busy. The safety hazards of taxiing conflict still exist during the airport operation for the initially planned taxiing path about aircraft, which directly affects the operational safety and efficiency of the airport surface. Using the correlation and dependence between the position sequences of aircraft glide motion, a method based on Long Short Term Memory networks (LSTM) is used. Combining the change of the motion state of the surface aircraft, the attenuation memory window is introduced to improve the hidden layer structure to further enhance the prediction accuracy in the LSTM model, and it is compared and verified under different parameters. The method realizes the target of surface position prediction for the aircraft in future period, lays the foundation for aircraft surface taxiing conflict detecting, and avoids taxiing conflict.

Gurney flap (GF) is well-known that one of the most attractive plain flaps because of the simple configuration and actually effective in improving lift of the airfoil. Many studies were conducted but the effects of GF on the various airfoil types need to be further investigated. This study aimed to clarify the effect of GF in case of the Supercritical airfoil, SC-0414 airfoil. The Ansys Fluent software is used to perform the flow simulations. The result in airfoil baseline is compared with the experiment result obtaining from wind tunnel testing. The flow simulations focus on analyzing the lift coefficient when increasing the height of Gurney flaps. The velocity of the simulations, as well as the experiment is U = 12 m/s and the Reynolds number Re is 1.6 × 10⁵. In the smoke wind tunnel, the flow field are clearly observed by smoke lines. The lift coefficient results of the flow simulations show the similar qualitative trend as the conventional airfoil model with Gurney flap.

In this paper, based on the genetic algorithm, a 4-section optimization airfoil structure is designed, which can change entire camber of the airfoil. For this new type of integral changeable camber airfoil, its first structure cam be deflected downward by 30 degrees, the second section is fixed, the third stage be capable of deflect downward by 30 degrees, and the fourth section be able to bend up and down by 30 degrees. In addition, the computational fluid dynamics method is adopted to numerically simulate the aerodynamic performance of variable camber airfoils. The numerical results observe that the used of varying camber airfoil has better been stalling characteristics and larger lift coefficient comparison with the Clark Y airfoil and NACA114 airfoil.

A numerical simulation around a compound airfoil was performed using the vortex method. The compound airfoil consists of a front airfoil, a fixed wing, and a rear airfoil, and it assumes the rudder of a submarine. As for the shape of the front airfoil and the rear airfoil, NACA0012 was used. Reynolds number was Re = 3.8×10⁵. In the numerical simulation, the angle of attack of a front airfoil and a rear airfoil was changed, and the magnitude of the gap between these movable airfoils and the fixed wing was changed. The time history of the fluid force of acting on an airfoil, and the flow pattern were investigated. The total lift was greatly produced, when the front airfoil and rear airfoil attached the same attack angle as the same direction. It was found that the total lift with the large one where the gap between these movable airfoils and the fixed wing is larger can be obtained. It was found that the rear airfoil governs the flow of the compound airfoil.

Aiming at the inefficiency of tool distribution in CNC workshop of aircraft equipment manufacturing, and adapting to the particularity of distribution without large network environment, The solution of intelligent tool delivery using AGV based on machine vision and QR Code navigation is proposed. Image processing of AGV path ribbon, path navigation error analysis and QR Code position calibration are studied in the planned path to achieve machine vision plus QR Code redundant navigation positioning. The AGV can complete the accurate loading and unloading tool of the robot library through the QR Code interaction mode with the machine tool. To realize automatic distribution of tool in CNC workshop of aircraft equipment manufacturing.

Different from the traditional helicopter, there would be a severe interaction between rotor and fuselage with canard and horizontal tail during hovering for canard rotor wing (CRW) aircraft. The un-steady RANS (URANS) equations discretized on overset grid are solved in this paper to simulate this kind of aerodynamic interaction. A UH60-A rotor hovering case is used to validate the numerical method. Subsequently, the numerical method is employed on two configurations, i.e., Isolated rotor configuration and Full CRW configuration under numerous collective pitch angle. The force and moment coefficients for different parts with respect to different collective pitch angles are obtained. The result shows that downwash of rotor has a stronger impact on fuselage than canard wing and horizontal tail. Compared with isolated rotor, fuselage with canard wing and horizontal tail has a slight impact on the trust and torque of the rotor in full CRW aircraft configuration.

The nonlinear aeroelastic response of a folding wing with the hinge free-play nonlinearity is investigated. A nonlinear structural dynamic model is established based on the modal synthesis of free-substructures by modification of the connected relationships, and is unnecessary to re-establish it if the stiffness changes. The nonlinear aeroelastic equation is obtained by rational function approximation of the unsteady aerodynamic force, and solved by Runge-Kutta method to predict the aeroelastic response of the folding wing. The results show that the free-play at hinges changes the aeroelastic characteristic of the folding wing, leading to the occurrence of the limit cycle oscillation within a certain velocity range. Moreover, the sensitivity to the free-play is different for the inboard and outboard hinges. If the free-play is controlled within a certain value, the motion of nonlinear aeroelastic system of the folding wing can be considered linear approximately.

This paper focuses on the calibration of aircraft airdata system to obtain online accurate Angle of Attack(AOA) and Angle of Sideslip (AOSS) from measured quantities contain error. For this purpose, an adaptive version of the extended Kalman filter (EKF) is employed to estimate accurately flight path trajectories of an aircraft. The investigations are made with flight simulated data with turbulence effects. Results are analyzed and found that adaptive EKF provides more accurate results over EKF.

In the present study, a kind of blunt trailing edge airfoil with its flap is designed for the purpose of reducing drags of blunt leading and trailing edge airfoils which are used for rotor/wing of CRW. The aerodynamic characteristics of designed flaps and elliptic airfoil which has the same thickness are numerically investigated based on the Reynolds-averaged Navier–Stokes equations and the SST k-ω two-equation turbulence model. The comparisons of aerodynamic force and moment coefficients show that, the lift characteristic is improved for designed flaps, but the drag will not be reduced if the flap has great bending trailing edge, and small bending trailing edge design is suitable for this kind of flap, and it will reduce the drag and improve the longitudinal stability characteristics.

In this paper, nonlinear satellite system with actuator faults is considered. To solve the problem of attitude stabilization of satellite under external disturbances and actuator faults, an observer is designed firstly. And the output of the observer is proved to be uniformly ultimately bounded. By using the estimated information of the observer, a backstepping fault-tolerant controller is derived. The proposed controller could achieve attitude stabilization in the presence of actuator faults. Finally, a simulation of attitude stabilization is carried out to illustrate effective of the fault-tolerant controller

Due to the limitation of target indication error and steady-state tracking error, it is difficult for the existing beam-riding guidance weapon system to attack long-range and high-maneuvering targets accurately. In order to solve this problem, this paper proposes a high precision guidance and control method for beam-riding guidance multi missile coordination: through sharing error information between multiple missiles in the same guiding beam, correcting the center line of guided beam and eliminating the steady-state error in the process of missile tracking target, thus the strike capability of the guided missile for long distance and high maneuvering target is enhanced. The six degree of freedom controlled trajectory simulation is used to verify this method. The simulation results show that the guidance and control method is correct and effective. Compared with the existing beam-riding guidance system, it has a higher hit precision and better application prospect.

The control of attitude of a satellite is difficult to verify since several subsystems of different disciplines, e.g., flexible multibody dynamics, machines, electronics and control, are involved and strongly coupled. A traditional method is to model each single discipline subsystem with a domain specific software, and combine them through interfaces. However, the problems are that lots of interfaces between software have to be developed, and manual decoupling of systems should be considered during modelling process. In this Paper, models of the dynamics and the control system are established in a unified modelling software, MWorks, which is an Integrated Development Environment of Modelica. The model can be used to verify the satellite control strategy, and also provide an effective means for satellite attitude control system design. Moreover, on this basis, the whole satellite was modelled to access state parameters changes under the coupling of the dynamic subsystem, the attitude control subsystem, the power supply subsystem, the propulsion subsystem and the integrated electronic subsystem can be synthetically considered.

The occurrence of system failure or of external disturbances are problem that must be considered in the design of safe flight control systems. Adaptive control schemes show the ability to handle such issues without any a priori knowledge about the fault or disturbance. The main condition for obtaining a stable adaptive controller is the passivity of the plant but most real system do not satisfy this condition. The use of properly defined Parallel Feedforward Compensator (PFC) can allow the augmented system to meet the passivity requirements. An alternative design approach for tuning the PFC and the invariant gains of the Simple Adaptive Controller (SAC) is presented in this work. The tuning procedures is a modification of the PSO and is called Population Decline Swarm Optimization (PDSO) since it takes into account a decline demographic model to speed up the tuning steps. The method is applied to adaptively control the pitch response of an aeroplane during level flight. Tuning results are presented along with flight mechanics simulation taking into account different command laws.

A scheme of piece-wise linearization PID control of aero-engine software defined control system based on wireless network is proposed in this paper. The characteristic of the system is that the PID controller is separated and distributed among the nodes of the wireless network, each node has the function of computing, memory and wireless communication, no core control unit in the system and the whole wireless network acts as a distributed PID controller. The linearization model and corresponding tuning parameters at different working points in flight envelope of the aero-engine are established offline using the memory resource of each node to make the node task parameters switch when the aero-engine working at different points. Finally, MATLAB/Simulink software tool is used to conduct the digital simulation analysis, the result shows that the proposed scheme achieves good dynamic and steady-state performance, and achieves good control effect.

A distributed aero-engine PID controller implementation scheme based on nocenter and peer to peer wireless network is proposed in this paper. The basic method is to make the PID controller virtualized and then distribute them in the nodes of the wireless network, the control task of the system is the synthesis of node tasks of multiple wireless network, and there is no special controller node in the system. In order to deal with the potential faults of nodes in the wireless network, tasks have the ability to migrate among nodes. Based on the analysis of complex frequency domain theory, task migration has less impact on the system response, Finally, the influence of task migration on the system is simulated and analyzed in the MATLAB/Simulink environment, simulation results are consistent with the theoretical analysis, the availability of the designed control system is proved.

This paper studied the optimal formation control of quadrotor UAV based on the dynamic model, and the collision avoidance between quadrotors is considered. By constructing the problem into a standard convex quadratic programming problem, we hope to improve the solving efficiency of the formation control problem. Firstly, the nonlinear dynamic model of quadrotor is linearized and the prediction model is established. Then, the safety zone constraints are transformed from a circular zone to a half-plane zone, making the optimization problem be a standard convex quadratic programming problem. Finally, the quadratic programming problem is solved using distributed receding horizon optimization. Numerical simulations in three-dimensional space show that this method can obtain the optimal formation trajectory with collision avoidance, and can improve the solving efficiency.

In view of the single curved deformation characteristics of zero Poisson's ratio (ZPR) honeycomb, Arrow honeycomb with ZPR is applied to the reflecting surface of the spatial parabolic cylinder antenna in this paper. First of all, the loading method for cylinder formation of honeycomb with ZPR is analysed. Then, Abaqus analysis, surface fitting and precision calculation are integrated into the objective function. Antlion Optimization (ALO) algorithm is used to optimize the RMS error of the deformed surface. The analysis results show that it is feasible to apply the honeycomb with ZPR to the reflector of cylindrical antenna, and the accuracy of deformed profile is improved by 45.5% through the ALO algorithm, which proves the effectiveness and efficiency of the ALO algorithm to solve the problem with unknown initial value. The research results are certainly significant for the optimization design of honeycomb with ZPR and the application of ALO algorithm.

With the popularity of smart mobile terminals and Wi-Fi signals, people's demand for indoor location services has also increased. However, in the indoor space, GPS positioning is inaccurate, and the Wi-Fi signal may also have signal instability even no signal in some areas. This paper proposes a prediction method based on improved HMM model combined with historical trajectory clustering. The experimental results on UJIIndoorLoc data set show that the predicting trajectories can greatly improve the real-time performance of location services and the proposed method has great improvement in accuracy and scalability comparing with another model.

Schlieren and shadowgraph photography has been widely used to offer insight into the flow field in aerospace engineering due to their ease of application. The high-speed schlieren and shadowgraph techniques are typically applied to investigation of unsteady shock wave structure including shock reflection patterns and shock wave/boundary layer interactions, etc. Generally, qualitative analysis is performed based on the schlieren and shadowgraph image sequences. To process and analyze the large data set of the high-speed schlieren and shadowgraph images quantitatively, especially for the shock wave detection and tracking, a software was developed based on MATLAB GUI and its image processing toolbox. In this study, the image processing techniques exploited in the software, such as background subtraction, filter, threshold, edge detection, and shock tracking are presented. A case study on the phenomena of shock wave reflection from a solid surface was conducted. The results show that the proper filter method and the background image subtraction can effectively eliminate the image noises in frequency domain, which makes it easier to analyze the flow structure. Moreover, the instantaneous locations of shock waves are detected accurately, and the shock wave propagation speed calculated using the developed software are consistent with those of previous studies.

The development of the technology for UVAs (Unmanned Aerial Vehicle) autonomous landing on mobile platform is introduced in this article. And the existing problems of UAVs autonomous landing on mobile platforms are also analysed. In order to solve these problems, a guidance method of UAV autonomous landing on mobile platform based on prediction of intersection points is proposed in this paper. In this method, the intersection point of the trajectory of UAV and the trajectory of the mobile platform is predicted based on the speed plan for UAV and the motion state of mobile platform. Then, the UAV will be guided to the intersection point by proportional guidance law. And at each time of the landing of the UAV, the location of the intersection point will be corrected in real time. In order to verify this method, a mathematical simulation experiment was designed. The result of this experiment shows that UAVs are able to land more accurately on the mobile platform with less overload using this method.

Hazard detection is the key technique for autonomous landing during a planetary exploration mission. This paper proposed an end-to-end spatiotemporal network to detect all hazards in the image sequences captured by optical camera. The spatial stream processes the colour image sequences and the temporal one learns features from optical flow image sequences. The spatial features and temporal features are fused by the proposed metric fusion method, and then the spatiotemporal features become more discriminative through triplet loss. A hazard map can ultimately be obtained in the testing phase after processing on the full-size image sequences. The evaluation results prove the effectiveness of the proposed network, and the testing results show the feasibility of practical application.

Unmanned aerial vehicle (UAV) relay communication is an important means to realize long-range wireless communication, where the lowest power loss could prolong the air residence time and increase the duration of the relay communication of UAV. In this paper, we present a UAV relay communication path planning based on the minimum encircling circle algorithm for the UAV working at the lowest power loss. We acquired the minimum radius of UAV relay communication based on for moving platform positions, and then determined the 3D position and flight path of UAV. Compared with the centroid enclosing circle algorithm, our simulation can reduce the signal transmitting power, realize the path planning of UAV relay communication under the lowest power loss.

This paper focuses on the application of neural partial differentiation (NPD) approach to estimate the longitudinal parameters of an aircraft HFB 320 from noisy flight data. By exciting both short period and phugoid modes of an aircraft with thrust variation, the aircraft system dynamics becomes highly nonlinear and aerodynamic parameters appears nonlinear to the state trajectories of velocity, AOA, pitch rate and pitch angle. This paper highlights the application of NPD for such a class of nonlinear dynamics; previously it was used only for the estimation of parameter appearing linear to the states. The extracted the nonlinear longitudinal parameters of HFB 320 aircraft are compared with the parameters estimated by using adaptive Unscented Kalman Filter (UKF) approach. Finally, the estimation results are validated by comparing with flight data and the responses obtained from the estimates by adaptive UKF.

The large and complex interior space of multi-cabin space station makes the astronauts easily happened to navigational disorder during the travel.With the need to enhance the navigation ability of the astronauts,based on a method study on space station intra-vehicular navigation simulation including both VR visual simulation and physiological HDBR simulation,multiple different sets of sample scenes are designed for the orientation cues numbers reflected by the whole visual orientation cues that has similar form,and the specific form of the whole visual orientation cues that reflects same orientation numbers.Through the experimental data analysis, the influence law of the whole station's interior orientation cues on the navigation task performance and associated physiological effects in the cabin are obtained.

The visual characteristics are important factors influencing the cognition and memory of the icon. In order to study the process of memory coding of feature binding in working memory of icon, the experiment requires 20 subjects to remember whether the icon features or feature binding are consistent and response quickly by pressing buttons, and the behaviour data and ERP data of the subjects are recorded. The experiment results show that compared with single feature memory of an icon, the accuracy under the icon-color feature binding memory condition is lower and the reaction time is longer while the P300 brain electric component with larger amplitude can be triggered. Studies have shown that the binding of visual features in icon memory requires additional cognitive resources. Compared with the other three memory conditions, the latency of the P300 under icon semantic-color feature binding is more significant, indicating that the task of semantic coding of icon is more difficult to complete and the cognitive load is greater.

In order to study the influence of microburst on the ballistic characteristics of rockets, an engineering model was established by using the vortex ring method based on the basic principle of hydrodynamics and the theory of the exterior ballistic. The wind field model is combined with the six-degree-of-freedom rigid-body ballistic model of rockets. This study examined a kind of empennage-rocket whose flight process was influenced by a microburst. The simulation results show that the microburst model based on the vortex method is simple and the three-dimensional characteristics are good, which can describe the main wind field characteristics of the microburst in a certain extent. Meanwhile, the microburst affects the ballistic characteristics of rockets such as the trajectory, velocity and angular motion. The extent of the effect is concerned with the vertical wind velocity along the central axis and the vortex ring radius of the microburst model.

Modern aviation product needs to meet the reliability requirements during the development process. In this paper, a comprehensive assurance system of reliability requirements completion is established and a method to evaluate the assurance system capabilities of reliability requirements completion based on CMM (Capability Maturity Model) is proposed. The evaluate index system in each level is described and AHP method is applied to determine the weight of each index factor in maturity. The evaluation results can comprehensively and effectively direct the aviation product reliability work during the development process and ultimately ensure the reliability of aviation product meets the requirements.

In this paper, the approach and application of semi-blind source separation (SBSS) in aero-engine vibration signal is studied. Firstly, the features of aero-engine vibration signal and difficulties for blind source separation (BSS) are summarized, and the SBSS incorporated the available prior knowledge is match to the goal of signal processing. Then, the ICA with reference (ICA-R) algorithm based on classical FastICA is introduced, with Newton iteration and gradient descent iteration approach to obtain optimal solution. The unique parameters in ICA-R for aero-engine vibration signal are also provided. Finally, the efficacy and the accuracy of the ICA-R algorithm are verified by numerical simulations and real engine vibration signals. The approach of SBSS in this paper perfectly suited to handle aero-engine vibration source separation and it lead to efficient implementation in fault diagnosis.

The problem of accumulation of space debris in near-Earth space is very relevant now. More than 15,000 debris have been recorded, and this represents a danger for current and future missions to space. A solution to this issue is to remove these spacecrafts from orbit. One of the ways to do it is to use inflatable device. These inflatable braking device can be installed on the landing vehicles on Earth, before their launch, or after they have been labelled as space debris. Studies have already been conducted about inflatable device. Using inflatable device instead of rigid device has advantages, such as a small mass and a great compacity, which is convenient to respect the required launching volume. This paper is dedicated to use of various inflatable brake devices and they are compared with each other.

By analyzing flight environments and HUD key information of fighter combat mission, based on the theory of color psychology and the regulation of the avionics system, this study simplified 10 kinds of typical flight environments and combined with 7 types of key information colors into 70 color schemes. Taking reaction accuracy and reaction time as performance indicators and testing participants' subjective feelings, to evaluate pilots' recognition ability of key information and general information with different color schemes in different flight environments, so as to provide the scientific basis for information coding design of flight HUD. The experimental results showed that the cognitive performance of the bicolor coding is significantly better than that of the monochrome coding by comparing the mean reaction time in various environments, and the cognitive performance of color schemes with the hue of 320 or 340 was better than that of other color schemes in most environments.

In the present study, the effect of fillet surface on the performance of the ducted propeller using Reynolds-Average Navier Stokes (RANS) method is applied. The numerical simulations compare the propeller model with fillet on the surface and without fillet. OpenFOAM is used to simulate the performances and solve the problems in the open water propeller simulation. MRF approach is applied for this simulation. Kaplan model with the 19A nozzle is investigated by comparing the results with experimental data. The effect of fillet surface on the ducted propeller are presented and discussed in this study.

The PDE monitoring equipment being applied is large in size, harsh in working conditions, unable to carry out outdoor experiments, limiting the flexibility of PDE's original rational experiment. An online monitoring system was designed to meet needs of mobility, real-time, portability, none effect on PDE thrust test and so on. The paper introduces the whole scheme of the online monitoring system, the hardware design of each function module and the software design of the whole scheme. The experimental results show that the on-line monitoring system can realize the measurement of working parameters in the principle experiment of pulse detonation engine in time and accurately and improve the flexibility of operation

An improved static friction model is developed for elastic-plastic contacting surfaces. Two random variables of asperity height and curvature for Gaussian isotropic contacting surfaces are assumed to govern asperities distribution and they satisfy a joint probability distribution function. Based on the contact parametric representation of the KE model proposed by Kogut and Etsion, the expected macroscopic values of normal stress and shear stress are obtained by using statistically homogenized technique. Then the effect of roughness, the energy of adhesion and material properties on static friction coefficients are studied and the results show similar trend with literatures. A comparison of the present model with the SV friction model proposed by Sista and Vemaganti shows that the adhesion force has a more significant effect for smoother surface and SV model is more suitable for heavily loaded contacts. The static friction coefficient is related to the ratio of hardness to elastic modulus H/E. At the same roughness and normal load, lower H/E leads to lower critical interference ω_c, higher plasticity index ψ, and smaller static friction coefficient.

The measurement of the configuration parameters for the large balloon is an important content, including volume, surface area and specific size under a certain internal pressure. Non-contact measurement techniques using laser scanning have the advantage of fast acquiring large numbers of points. However, compared to their contact-based counterparts, these techniques are known to be less accurate. Furthermore, this accuracy depends on different parameters such as materials properties, surface texture, product color, etc. The large balloon is made by aluminum coated F-12 aramid plain weave fabric pieces. The digitizing errors for high-speed 3D digital laser scanning data based on the surface of F12 fabric material are analyzed and characterized in this paper. With error characterisation, an empirical model is obtained relating the errors to the influencing factor. Establishing a reasonable test scheme and using the technology of laser scanning, the spatial information of the surface for large balloon can be obtained quickly. The empirical formula is used to compensate for 3D laser scanning data of large balloon. The problem of compensation for 3D laser scanning data for improved test accuracy is addressed. The more accurate parameters of the configuration for large balloon are quickly obtained. This provides a method for the rapid, high-efficiency and high-precision test of configuration for large balloon.

In this paper for the first time we have constructed the exact solutions of two boundary value problems of the theory of elasticity for an infinite strip with a central transverse crack on which a constant normal stress is given (even-symmetric deformation). In the first problem the sides of the strip are free, while in the second they are rigidly clamped. The solution is represented in the form of series in Papkovich–Fadle eigenfunctions. The expansion coefficients (Lagrange coefficients) have the form of simple Fourier integrals. The final formulas are simple and can easily be used in engineering.

Shock vector control (SVC) is one typical fluidic thrust vectoring technology. It has simple working principle and wide working range, but not high enough vector efficiency. In the paper, a bypass injection concept was proposed on the SVC technology to improve the vector efficiency and vector angle. The flow mechanism of SVC nozzle with bypass injection was investigated numerically after the turbulence model was validated by experimental data. The enhanced performance of SVC nozzle was estimated and the influence of critical affecting parameters, bypass injection angle ( θ.ad.) and bypass injection position (Xj.ad.) on vector performance were studied. Results show that, the vector efficiency was increased from 1.21 °/%-ω to 1.93 °/%-ω by adopting bypass injection, and the vector angle has an increase by about 58.9%. The vector performance increased with the increase of bypass injection angle when induced shock wave did not interacted with the opposite wall. The better vector performance was achieved with the configuration of the bypass injection slot was upstream of secondary injection slot when SPR is less than 1.0. In wide working ranges, a vector angle of 16°-20°, a vector efficiency larger than 2.0 ° / %-ω were obtained while thrust coefficient of a SVC nozzle kept larger than 0.90.

This article presents the results of the experimental researches on nanostructured carbon-containing PVD coatings based on titanium and chromium (Cr/C; CrN/CNx, Ti/C; TiN/CNx) deposited on a disk Ø 20 × 5 mm made of steel ShKh15 (MX15). Coatings were obtained on the UNICOAT 600SL installation (Russia). In the course of the research, such parameters as coatings adhesion to the substrate, their hardness and elastic modulus, as well as friction coefficients were determined by using the indentation, scratch testing and tribological testing methods, respectively, on the CSM equipment (Switzerland). The low values of the friction coefficient (Cr/C − 0,02, Ti/C − 0,07; CrN/CNx - 0,15; TiN/CNx − 0,13) suggest that they are promising to be used in the friction pairs of the drive actuating mechanism, and the high hardness values (from 3,000 to 3,700 units on the HV scale) are promising in highly loaded drives under extreme operating conditions.

In order to improve the interlaminar delamination resistance of the carbon-fiber/epoxy composite laminates, short fibers were applied between layers. The effects of length, density, type of short fiber on mode I fracture toughness(G_IC) and mode II fracture toughness (G_IIC) were investigated by three-factor and four-level orthogonal test combined with range analysis and scanning electron microscope observation. Finally, parameter optimization and test verification. The results show that the order of factors influencing G_IC and G_IIC within the selected parameters are: fiber type, fiber density and fiber length. When Kevlar fibers with a length of 11mm and a density of 20g·m^-2 were laid between layers, the G_IC was 451.4J·m^-2, which was 82.2% higher than that of the specimens without short fibers in the layers. Kevlar fibers with a length of 11 mm and a density of 5g·m^-2 were layered with a G_IIC of 2034.3 J·m^-2, which was increased by 240.5% compared with the specimens without short fibers in the interlayer.

Ejection seat is a complex system that can be both one-time-used and continuous-used, in which the supportability analysis technology plays an essential role. Supportability analysis includes Reliability-Centered Maintenance Analysis (RCMA, for short), Corrective Maintenance Analysis, Level of Repair Analysis (LORA, for short), Operation and Maintenance Task Analysis (O&MTA, for short), Support Equipment Requirement Analysis and Spare Parts Requirement Analysis (shortened as "6A"). Firstly, in this paper, the concept of "6A" technology and their relationship are introduced. The general "6A" working process of a certain type of ejection seat is then studied. In the end, the "6A" work is carried out on a certain type of ejection seat according to the analytical steps and requirements to "6A".

Chained decomposition will take place in terms of overheat of high concentration hydrogen peroxide, which will further cause explosion, in the electric pump pressurized liquid propellant rocket engine, which takes hydrogen peroxide of high concentration as oxidizing agent, the design of oxidant pump should consider safety factor for temperature rising of hydrogen peroxide and the influence of pump efficiency on quality control of motor system simultaneously. It's very important to know the effect of sealing ring gap at the bottom of impeller on temperature rising of bearing chamber and pump efficiency. So, this paper firstly establishes mathematical modal about the effect of sealing ring gap on temperature rising of bearing chamber and pump efficiency loss, to gain influencing curve, and then it analyzes parameters of cooling flow and mechanism of temperature rising, and give reasonable gap values, which take both safety and efficiency into account. Finally, 3D simulation calculation is carried out through pumplinx to verify the accuracy of this influence model.