bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on Risk Assessment with Uncontrollable High Thrust for Civil Airplane
Authors: Candong Zou , Nanbo Xu 
Published: February 2020

Abstract
Not all single failures and probable combinations of failures that can cause UHT malfunction can be eliminated for the civil airplanes, a petition for a partial exemption from FAR25.901(c)/CCAR25.901(c) related to UHT is usually requested. The risks associated with exempting the UHT from FAR25.901(c)/CCAR25.901(c) should not be greater than those currently known and accepted for comparable existing transport category airplanes. Based on the development of a high horizontal tail airplane with 2 rear-mounted engines, this paper proposes a method for UHT malfunction risk assessment from handling qualities aspect by simulation analysis and simulator tests.
Experimental Study of Hybrid Deicing System
Authors: Jun Shu , Dongguang Xu , Lin Ye , dongyu Zhu 
Published: February 2020

Abstract
The hybrid deicing system combines the traditional electrothermal deicing system with the electro impulse deicing system. Firstly, the prototype design of the ice wind tunnel hybrid deicing system is carried out, and the electrothermal deicing system and the electro impulse deicing system are integrated in the airfoil model. Then, through the laboratory plate deicing experiment to study the deicing effect of different heating and excitation combinations, explore the work control law of the hybrid deicing system, and finally verify the effect of the hybrid deicing system through the ice wind tunnel test. The plate panel test found that with the increase of the surface temperature of the skin, there is a minimum binding force between the ice and the skin. In the ice wind tunnel deicing experiment, the prototype of the hybrid deicing system shows a good deicing effect with less energy consumption.
Electrochemical Kinetic Property Determination of MIECs by Comprehensive Multi-physical Coupling Model
Authors: Wang Jianhua , Khalid Salman , He Fei , Wu Wanfan 
Published: February 2020

Abstract
Surface exchange and bulk diffusion coefficients are important electrochemical kinetic properties of mixed ionic-electronic conductors (MIECs), which are usually obtained through electrical conductivity relaxation (ECR) experiments. However, the extensively employed method is built upon the ideal diffusion described by Fick’s second law with linear absorbing boundary, which is almost impossible to achieve in actual experiments. To simulate the actual experiment system and improve the estiamtion accuracy, a comprehensive mathematical model is established to describe the coupled multi-physical processes involved, such as convection-diffusion in the surrounding atmosphere, surface exchange, bulk diffusion of MIECs, and heat transfer. A comparison between different models is carried out, and the results show that the new model established is more accurate and compatible with more complex conductivity curves.
Energy and Exergy Analysis of Steam Source Optimization for Boiler Soot Blowing System
Authors: Wu Wanfan , Ran Fangyuan , He Fei , Wang Jianhua 
Published: February 2020

Abstract
In order to improve the economy of boiler soot blowing system, the steam source position of boiler soot blowing system should be optimized. For a 1000MW ultra-supercritical coal-fired unit, the thermodynamic process of soot blowing steam in temperature and pressure reducing station was studied through energy analysis and exergy analysis in this paper, and it was revealed that the annual water and energy consumption of boiler soot blowing system was independent of the steam source position, the change of steam source position only affected the annual exergy loss of soot blowing system. The comparion results indicated that the annual exergy loss of soot blowing system with cryogenic reheater outlet as steam source was minimal. After adopting cryogenic reheater outlet as the steam source position of soot blowing system, it would be more economical than the original soot blowing system with platen superheater outlet as steam source. The annual exergy loss would be reduced by about 2.183×1010kJ, and it was equivalent to an annual increase of power generation revenue by about 2486000CNY.
The Calculation of Friction Heat and Thermal Analysis of Spur Gears Based on Thermal Elastohydrodynamic Lubrication Theory
Authors: Liu Shuyi , Qi Chen 
Published: February 2020

Abstract
In order to predict the temperature distribution of gears more accurately, the influence of oil film on frictional heat generation should be taken into account in computational model. In this paper, based on the theory of thermal elastohydrodynamic lubrication, the calculation of frictional heat flux in the meshing process and the steady thermal analysis of spur gears is completed. The reliability of the model is verified by comparing the calculated results with the value of empirical formulas and experimental data. This paper provides an effective analysis method for gluing prediction, failure analysis and lubrication state analysis of aero-engine transmission gears.
Application of Weak Signal Denoising Based on Improved Wavelet Threshold
Authors: Zhang Ning , Lin Pengfei , Xu Lei 
Published: February 2020

Abstract
In this Study, the application of wavelet threshold denoising in weak signal detection of underwater targets under complex sea conditions is discussed. Firstly, the basic principle and steps of wavelet threshold denoising method based on Mallat decomposition are analyzed. Then a new threshold function is proposed to overcome the shortcomings of traditional Donoho hard and soft thresholds. The denoising effects of wavelet and wavelet packet threshold denoising methods under hard threshold, soft threshold and new threshold functions are simulated, and the signal-to-noise ratio (SNR) and mean square error (MSE) after denoising are taken as evaluation indexes. The results show that the improved threshold denoising method outperforms the traditional threshold denoising methods.
Design of Image Recognition Algorithm for Critical Flight Parameters in Civil Aircraft Display System
Authors: Zhang Maodi , Zhou Yuanhui , Gu Qingfan 
Published: February 2020

Abstract
In the current civil aircraft display system design, complex COTS devices such as CPU and GPU have been widely used. While improving product performance, it also greatly increases the difficulty of airworthiness certification. Taking the display system as an example, the data integrity of the critical flight parameters which is displayed on the display unit must reach 1.0E-7 or higher, and the development assurance level of each software and hardware module must reach level B or higher. However, according to industry experience, the data integrity of CPU and GPU can only reach the level of 1.0E-6. Therefore, for the critical flight parameters in the display system, it must be monitored to cover the entire data path from data processing to image generation to prove the data validity. Aiming at the numeric critical flight parameters of civil aircraft display system, this paper proposes a numeric image recognition technology realized by FPGA image processing function, which can be used to monitor the integrity of numeric critical flight parameters, and this technology has been performed and verified in real display unit.
Improving Clamping Accuracy of Thin-walled Workpiece in Turning Operation
Authors: Elsheikh Ammar H. , Guo Jiajie , Bai Kun , Lee Kok-Meng 
Published: February 2020

Abstract
This study presents theoretical and experimental error analysis and avoidance which results from the fixation of a thin-walled metal disk workpiece on a duplex turning machine. The distance between the rotating workpiece surface and a fixed datum point is measured using a laser displacement sensor (LDS). The measured data are analyzed numerically to get the error in the fixation system in terms of Euler angles. Then the workpiece clamping points are axially adjusted according to the calculated angles. Moreover, the problem formulation and the solution procedures are presented in details. Finally, a case study has been used to verify the proposed approach. The results indicate that the proposed technique can be used to decrease the fixation error to a reasonable range.
Experimental Evaluation for the Interference-fit Electromagnetic Rveting Joint with Headless Rivet
Authors: Song Danlong , Zhang Xiangyang , Liu Kai , Zhang Yanchao , Yang Zhenchao 
Published: February 2020

Abstract
Electromagnetic riveting (EMR) technology as a relatively new mechanical joining process has many advantages compared to traditional riveting methods. However, it needs to be investigated whether the traditional pressing riveting can be replaced by EMR process in aerospace manufacturing engineering. Therefore, in this paper, the differences of riveting quality between automatic riveting and handheld EMR were compared by riveting and mechanical experiments including the uniformity of interference fit, shear and pull-off strength and fatigue life of the joints respectively. It was observed that the interference fit of the riveting joint using EMR is more uniform along the axial direction of rivet than that of automatic riveting. In addition, the overhang of the rivet was difficult to control by handheld EMR, so the quality of rivets for EMR was poorer than that of automatic riveting. Thus, the shear and pull-off strength and fatigue life of EMR joints were affected by the quality of rivets, and a longer rivet is needed for the EMR.
Research on Hull Assembly Process Planning Based on Rule Reasoning
Authors: Lei Li , Di Liu , Pengyu Wang , Honggen Zhou 
Published: February 2020

Abstract
Currently, hull assembly process is mainly dependent on experience, and lack of normative standard. In this paper, hull structure for assembly features is systematically studied, and an assembly sequence planning method based on Rule Reasoning is proposed. Firstly, assembly feature and sequence expression of hull structure is analyzed and the constraint relation of connection information is described. Secondly, the relationship between established structures and the constraint function is designed. Setting the double bottom of the ship as an example, hull assembly sequence is obtained based on geometric constraints and optimized by the fuzzy evaluation method and finally realized the computer aided evaluation of the hull assembly sequence.
Improvement of Microstructural and Mechanical Characteristics of Friction Stir Welded AA6061 Aluminium Alloy Joint
Authors: Shehabeldeen Taher A. , Mahmoud T. S. , Nemat-Alla Mahmoud , Elkady E.Y. , Yin Yajun , Ji Xiaoyuan , Shen Xu , Zhou Jianxin 
Published: February 2020

Abstract
To improve mechanical characteristics of friction stir welded joint made of AA6061-T6, AA2024 was used as a filler material due to its high strength and compatibility with AA6061 aluminium alloy. Different filler strip thickness (1, 1.5, and 2 mm) were investigated. Homogenous plastic deformation of the mixture with soft and refined grains was observed in the stir zone due to dynamic recrystallization of the grains. Friction stir welded joints with filler strip showed high hardness and tensile strength compared with filler-free joints. Welded joint with 1 mm filler strip has the highest tensile strength among other joints due to the dynamic recrystallization of the refined grains as a result of heat concentration. In addition, using greater thickness of filler strips makes the joining process more difficult, causes joint defects and reduces the tensile strength of welded joints.
Temperature Field Measurement in a Cutting Tool by Laser Interferometry
Authors: Efimovich I A , Zolotukhin I S 
Published: February 2020

Abstract
To increase machining efficiency, in addition to determining the temperature distribution on the tool surface, it is also necessary to determine the internal temperature distribution. The existing methods for determining the cutting tool temperature distribution and temperature field measurement have significant disadvantages, which limit their applicability and accuracy. The purpose of this study is to develop and test a novel cutting tool temperature field measurement method. The method involves recording the cutting tool thermal expansion fields by laser interferometry and calculating the tool material temperatures with its coefficient of thermal expansion (CTE). Compared with the methods employing infrared thermometry, the method developed in the present study has a higher spatial resolution and a lower achievable field of view due to its usage of light in the visible region. In addition, since the oxidation film has a higher reflection coefficient for visible light, the present method is less sensitive to the thin-film interference on an oxidized tool surface than those using infrared thermometry, eliminating the false shift of the measured temperature. Moreover, by utilizing cheaper optical components and equipment for interference fringe pattern registration, this method is more affordable. Unlike the emissivity coefficient in infrared thermometry, CTE is independent of changes in the surface quality and can be measured with high accuracy by modern dilatometry. Therefore, the developed method, which employs CTE to calculate the temperature, has a higher reliability. In the present study, the efficiency of this method is tested by the orthogonal turning of difficult-to-cut martensitic heat-treated steel with a cemented tungsten carbide tool. Through the experiment, the temperature distributions along the rake face and flank of the tool, as well as the temperature field inside the tool, were obtained. The results can improve the temperature field measurement in machining cutting tools.
Boundary element analysis of dynamic interaction of anisotropic elastic half-space and structure under impact load
Authors: Markov I P , Igumnov L A 
Published: February 2020

Abstract
In this paper, a direct boundary element formulation for numerical modelling of threedimensional dynamic soil-structure interaction is briefly described. Formulation is applicable to problems involving isotropic and anisotropic elastic materials. It is based on the Laplace domain regularized boundary integral equations for the displacements under assumption of vanishing initial conditions and zero body forces. Mixed boundary elements are employed for the spatial discretization of the boundary integral equations. Subdomain technique is used to tackle problems involving piecewise homogeneous material properties. The described formulation is employed for the boundary element analysis of dynamic soil-structure interaction problem involving a structure which contains a cavity with a complex geometrical form. Soil is represented by a transversely isotropic elastic half-space. Effect of material anisotropy of half-space on the transient response of the embedded structure is assessed. It is observed that the shear modulus anisotropy have substantial impact on the displacements response. Influence of the Young’s modulus in the plane of isotropy is lesser but still pronounced.
Research of surface microstructure of the steel 40CrNiMo after EDM
Authors: Grisharin A , Ablyaz T , Muratov K , Shlykov E , Morozov E , Shafranov A , Matigullina E , Sirotenko L 
Published: February 2020

Abstract
The aim of the work is to study the influence of modes of electrical discharge machining, on the microstructure and microhardness of the treated surface of thermally hardened steel 40CrNiMo. To fulfill the task, a sample was made of hardened steel 40CrNiMo. The sample was processed in various modes of electrical discharge machining. Microsections were made from the obtained sample. Metallographic and microdurometric analysis was carried out. The study of the microstructure showed that no clearly defined altered layer was detected in all processing modes. The study of microhardness showed that near the surface of the studied samples there is a drop in the level of microhardness. This phenomenon is caused by tempering during the surface heating during processing. The heat-affected zone does not exceed 1.2 mm, and is minimal under high-performance modes.
Design of tools with the cutting part of the original profile for high-speed milling
Authors: Vakulin M S , Gordeev Yu I , Yasinsky V B 
Published: February 2020

Abstract
This paper considers and justifies the design of the cutting part of multi-edge contour mills with the increased performance and surface quality. The numerical experiments using the finite element method (FEM) allow determining stresses and deformations in the layer of the material being cut when processed by multi-edge mills of a new type, i.e. they allow evaluating indirectly unit loads during milling. The required shape and dimensions of the cutting wedge were determined taking into account various values of the geometric parameters of the cutting part, the properties of the workpiece material and cutting conditions. All the above resulted in a 3D model of the end mill, which had got a trapeze-shaped tooth located along two intersecting helical lines with tilt angles of 22 and 85 degrees. Along with improving the quality of the processed surface, the experimental studies also showed a change of chip shape. The chip has a finely crushed structure; the sizes of its elements are about 2 μm, which agrees nicely with the results of the FEM preliminary estimates.
Experimental analysis of the EDM process of dissimilar materials
Authors: Ablyaz T , Shlykov E , Muratov K , Oglezneva S , Karmanov V , Osinnikov I , Sarabjeet S S , Sahil D 
Published: February 2020

Abstract
The aim of the present study is to investigate the surface roughness of Electrical Discharged Machined (EDM) samples with Electrode Tool (ET) materials. For the experiments, three different types of ETs were considered which are made of different materials viz. composite, copper, and graphite. Aluminium, low alloy 35GS steel and OT4 titanium alloy were selected as the workpiece materials. Machining parameters used were: current (I) 8 A, voltage (U) 100 V, and pulse duration (Ton) as 150 μs. It was found that the ET made of composite material performs best in EDM of 35GS steel and OT4 titanium alloy. Specifically it was concluded that in the first case, the performance of composite ET is higher than graphite ET by 59 %. Similarly, in the second case, its productivity was found to be 74% and 95% higher when machined with graphite and copper ET respectively. Moreover, the surface roughness values of 35GS steel machined with composite ET was found to be 15% higher when machined with copper and graphite ET. While processing titanium alloy with composite ET, surface roughness values were observed as high as 44% and 25% when machined with copper and graphite ET respectively.
Experience of forming combined low-energy electron-ion beams in plasma sources of charged particles
Authors: Antonovich D A , Gruzdev V A 
Published: February 2020

Abstract
The paper shows the possibility of forming combined electron-ion beams in a single multi-discharge structure that does not contain incandescent elements. A design of the electrode structure of an electron-ion source is proposed, which consists of two «Penning type» discharge cells connected in series (along the axis). It is shown that the interconnection of separately controlled discharges in the structure increases the degree of gas ionization at reduced pressure, as well as the formation of double electric layers in the plasma, which ensure the formation of combined ion-electron flows in a single structure. This is ensured by creating conditions for the drift of the electron beam through the entire part of the electrode structure, which ensures the formation of the ion current of the source, and helps to increase the degree of ionization of the gas in this region. In addition, the deceleration of the electron beam in the ion acceleration gap ensures the return of electrons, which have lost part of their energy to gas ionization, into the region of the formation of the plasma emitting ions. This contributes to an increase in the density of the ion emission current. Some experimental parameters of the beams formed by the developed structure are presented.
Evaluation of influence of technological parameters on width of strengthened layer in plasma surface hardening of structural steels
Authors: Balanovsky A E , Gozbenko V E , Kargapol’tsev S K , Karlina A I , Karlina Yu I 
Published: February 2020

Abstract
The article presents the results of the studies of the influence of technological parameters of plasma hardening on the geometric dimensions of the hardening track using modern research methods. The visualization of the heating spot on the metal surface according to the methodology made it possible to further evaluate the role of anode and cathode spots on the formation of a common heating spot in the process of plasma hardening of metals. It was established that, depending on the effective thermal power of the plasma arc, there are several modes of combustion of the plasma arc. For example, at an arc current of 20 A, there are several characteristic anode spots on the surface in the form of regular circles, which, with an increase in the arc current, contract to the center of the common heating spot. It has been established that the speed and distance of hardening affects the width of the hardened zone during plasma surface hardening of metals. The region of existence of several regimes of plasma hardening in a common heating spot was revealed, for which both single and group anode spots are characteristic.
Beam diagnostics on the electron beam welding installation at Budker Institute of Nuclear Physics
Authors: Blokhina K A , Devyataykina T A , Medvedev A M , Semenov Yu I , Sizov M M , Starostenko A A , Tsyganov A S 
Published: February 2020

Abstract
This paper describes the equipment and methods of the beam diagnostics, namely, the beam current density distribution measuring and the beam position and inclines angle determination. Such a diagnosis is aimed at applying on the electron-beam technological installations, in particular, on the electron-beam welding installations. The paper presents the results of the beam current density distribution measurement, describes the design of the beam position and inclines angle measurement system, and presents the results of preliminary tests of the prototype of this system.
Electron-beam welding of large thickness parts in a narrow gap
Authors: Chulkov I S , Goncharov A L , Chulkova A V 
Published: February 2020

Abstract
The paper presents a method of large thickness parts welding in a narrow gap with filler wire. A modernized deflection magnet is proposed, which allows deflecting an electron beam directly in the zone of weld pool. The distribution of magnetic induction in a local magnetic field along the axis of electron beam guide was measured and the results obtained were compared to the calculated ones. A photographic recording of electron beam deviation in a local magnetic field created by the presented deflection magnet was carried out. The angle of electron beam deviation about electron beam guide axis is estimated.