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<title cf:type="text"><![CDATA[Editorial department of the Journal of National University of Defense Technology -->航天工程·材料科学与工程]]></title>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Area target search and payload parameters influence for UAV in uncertain environment]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004007]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[A real-time detecting and updating search strategy was presented for UAV area target search in uncertain environment, and an optimal configuration method of airborne photoelectric load parameters was proposed. An area target search model based on a two-dimensional discrete grid was established, and a probability map was used to describe the real-time acquisition and update of target information. A search objective function was built with the introducing of uncertainty index, revisiting of grid with target and controlling of grid detection times. The search route planning method based on particle swarm optimization was established. Through the estimation and analysis of average detection time and misjudgement probability of the task area, the optimal configuration strategy of airborne photoelectric load parameters was proposed. The Monte Carlo method was used to verify the effectiveness of the area target search method and the effect of photoelectric load parameter configuration on search efficiency and misjudgement probability.]]></description>
<pubDate>2020/8/8 11:01:28</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[WU Anping, GUO Zheng, HOU Zhongxi, LU Yafei]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WU Anping, GUO Zheng, HOU Zhongxi, LU Yafei</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004007]]></guid><cfi:id>25</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Precise relative orbit determination of LEO formation flying using BDS]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004008]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The PROD (precise relative orbit determination) for the LEO (low earth orbit) formation-flying satellites based on BDS (BeiDou satellite navigation system) was studied. Due to the lack of experimental data, the simulation method was used. Results show that the average number of visible BDS satellites at altitude of 500 km is about 9.7. Because of the GEO (geostationary earth orbit) satellites and IGSO (inclined geosynchronous earth orbit) satellites, the LEO satellites can observe more BDS satellites over the Asia-Pacific region. When only the observation noise is considered, the accuracy of PROD based on BDS is 0.74 mm. Furthermore, the influence of ephemeris errors is analyzed. For a few kilometres separation of the LEO satellites, the effect of ephemeris errors on PROD could be ignored. However, for a 200 km separation of the LEO satellites, the SD (single difference) ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and MEO satellites co-work with GEO satellites, the accuracy decreased from 1.09 mm to 0.96 mm, decreased by 13.54%. Finally, the conclusion is that the accuracy of PROD based on BDS can reach sub-millimeter level after the remaining errors are processed, the differences of the PROD results are not apparent between different regions. When relative position between satellites is only a few kilometres, the GEO satellites and IGSO satellites can improve the accuracy of PROD all over the world. In the future, BDS will be widely used in PROD of LEO satellites.]]></description>
<pubDate>2020/8/8 11:01:28</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[YI Bin, GU Defeng, SHAO Kai, YI Dongyun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YI Bin, GU Defeng, SHAO Kai, YI Dongyun</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004008]]></guid><cfi:id>24</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Parameter determination method for bolted flange′s finite element model]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004009]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Bolted flange joint is widely used in most kinds of industrial structures. In order to indicate the static or dynamic response accurately, an exact and efficient finite element model needs to be built. For the parameters are not certain when building the model, the numerical simulation and experiment were synthetically employed to study the determination of the model′s mesh parameters and contact parameters. After confirming the parameters, the finite element model of bolted flange not only has high computational accuracy, but also has ideal computational efficiency.]]></description>
<pubDate>2020/8/8 11:01:28</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[JIANG Guoqing, MA Bin, CHEN Wanhua]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>JIANG Guoqing, MA Bin, CHEN Wanhua</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004009]]></guid><cfi:id>23</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Creep test and numerical analysis for near space aerostat′s envelope material]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004010]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Creep is an important characteristic of near space aerostat′ s envelope material. A creep test bench was designed to test the creep characteristics of a typical envelope material for near space aerostat, and the creep data of the material at atmospheric temperature were obtained. Based on the creep model of general polymer materials and the creep data obtained from the test, the creep calculation model of aerostat materials was analyzed, and the relevant parameters were fixed. Also, the creep variables of aerostat materials were simulated with the method of finite element analysis. Furthermore, the veracity of the creep model and the simulation analysis for DPE-3 thin film was verified by comparing the creep variables calculated by the creep model, the creep variables analyzed by the finite element simulation and the actual creep variables were obtained by the creep test. The creep test method and the results of calculation and analysis can provide a reference for the design and analysis of aerostat in near space.]]></description>
<pubDate>2020/8/8 11:01:28</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHANG Yuanping, JIANG Luhua, SONG Lin, LYU Jing, YANG Yanchu]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHANG Yuanping, JIANG Luhua, SONG Lin, LYU Jing, YANG Yanchu</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004010]]></guid><cfi:id>22</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Experimental study and finite element analysis on hygroscopic aging of adhesively bonded composite repaired metallic structures with cracks]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004011]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Due to serve under the environment of high temperature and high humidity, hygroscopic aging behaviors are commonly discovered in adhesively bonded composite repaired metallic aircraft structures, which results in the decrease in mechanical properties and server life. In order to investigate the effect of hygroscopic aging on adhesively bonded composite repaired structures, moisture absorption and aging test were performed on adhesively bonded composite repaired aluminum alloys plates containing double-sides cracks with single patch and E44/Polyamide epoxy resin, then the effect of hygroscopic aging on load carrying capability, crack propagation life, repaired effect and duration of fatigue load were analyzed by the experimental method and finite element method (including damage zone theory and J-integral ). Results show that hygroscopic aging lowers the load carrying capability and fatigue crack propagation life greatly, with the result that the average value of fatigue crack propagation life and ultimate load of repaired structure decreases by 29% and 10% respectively after immersing in water for 40 days, and the failing mode of adhesive changes into interfacial failure from cohesive failure. After immersing in water for 30 days, the adhesive specimens became completely plastic, whose elastic module decreases by 60%, and plastic deformation increases to 25%. The effect of hygroscopic aging on the damage zone was obvious, which results in the fast damage of adhesive, and the longer the crack is, the faster the damage is. The hygroscopic aging of repaired structure also increases the value of J-integral around the crack tips, which decreases the crack propagation life of repaired structures.]]></description>
<pubDate>2020/8/8 11:01:28</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[WANG Yue]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WANG Yue</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202004011]]></guid><cfi:id>21</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Model and validation of two-dimensional compressible bleed flow]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002009]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[According to the characteristics of supersonic and subsonic flow, the Prandtl-Meyer expansion wave theory, and the Mach number after expansion waves based on the back pressure and static pressure, the bleed mass flow rate was obtained, the conditions for the occurrence of choking were derived, and a two-dimensional supersonic bleed model was established. According to the impulse theorem, based on the assumption that the state change of gas from the main flow area to the bleed chamber was due to the impulse effect of the pressure difference, a subsonic bleed model was established and the mechanism of subsonic bleed chocking was revealed. CFD(computational fluid dynamics) verification shows that the deviation of the subsonic bleed impulse model is considerable, so the subsonic bleed flow was described by a numerical fitting model. This study provides a reference for three-dimensional bleed research.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHANG Baohu, ZHAO Yuxin, LIU Jun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHANG Baohu, ZHAO Yuxin, LIU Jun</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002009]]></guid><cfi:id>20</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Design and optimization of structure-thermal protection integrated for missile]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002010]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Based on traditional corrugated core structure,a structure-thermal protection integrated structure was designed for missile in severe aerodynamic and thermodynamic environment. The coupled thermo-mechanical numerical model was established to analyze the structural loading capacity and thermal protection performance of the integrated structure, and results show that the integrated structure has good loading capacity at high temperature and the thermal protection efficiency can be improved by increasing thickness of structural thermal insulating layer and inner wall. Aimed at maximum thermal protection efficiency and minimum structural mass, non-dominated sorting genetic algorithm-Ⅱmethod was adapted to achieve multi-objective optimization. The optimization results show that the thermal protection efficiency factor and structural mass of the integrated structure interact with each other, so it needs comprehensive consideration when designed.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[XU Shinan, WU Cuisheng]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>XU Shinan, WU Cuisheng</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002010]]></guid><cfi:id>19</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Real-time interpretation method for range image based on position prediction]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002011]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[When the shooting range′s optical theodolite tracks the target in real time, the camera will randomly jitter, causing the target large-scale motion in the image. In dealing with large-scale motion, the tracking method based on the search window is easy to lose the target, and the tracking method based on the full-image search is time-consuming. Considering these problems, an improved TLD(tracking-learning-detection) framework combining KCF(kernelized correlation filter) and target position prediction was proposed. An orthogonal polynomial optimal linear filter and camera angle information were utilized to predict the position of the next frame of the target, and KCF was used for fast-tracking in this area, which can improve the success rate and save the tracking time, and can detect when the tracking fails. Simulation experiments demonstrate that the optimal linear filter can accurately predict the target position and provide KCF with a more accurate search position. Besides, the algorithm consumes only 1.1ms per frame, and the positioning accuracy is better than that of TLD and KCF, which can effectively copes with camera′s jitter. The actual task verification proves that this method can improve the automatic interpretation level of the shooting range and reduce manual intervention.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHONG Lijun, YU Qifeng, ZHOU Jiexin, GUO Pengyu, HUANG Wei]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHONG Lijun, YU Qifeng, ZHOU Jiexin, GUO Pengyu, HUANG Wei</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002011]]></guid><cfi:id>18</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Quantitative analysis method of aviation unsafe events under mixed uncertain conditions]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002012]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to solve the problem of quantitative analysis of aviation unsafe events under uncertain conditions, based on the random and fuzzy theory, a mixed uncertain description of the subjective and objective variables that affect flight safety was proposed. To describe the subjective variables which were hard to be expressed by probability, the random variables that follow a uniform distribution in the λ-cut set of membership were introduced. Then, an aviation safety index and a numerical computational method under mixed uncertain conditions were proposed, which can reflect the aviation safety level concisely, intuitively and accurately. Through the Bow-tie model which is commonly used in the field of aviation safety, the relationship of the safety index and the membership of tire burst accident was obtained by simulation analysis. The quantitative results show that the aviation safety indices can be significantly improved with proper control of the membership degree.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[CUI Lijie, CHEN Haoran, REN Bo, ZHANG Jiakui]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>CUI Lijie, CHEN Haoran, REN Bo, ZHANG Jiakui</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002012]]></guid><cfi:id>17</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Attitude dynamic analysis of the end-bodies of space tether system in deployment]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002013]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to analyze the attitude motion of end-bodies in deployment of STS(space tether system), based on the Lagrangian equations of the second kind, the mathematical model of deployment of the system and the angular motion of end-bodies were developed, to analyze the attitude dynamics of end-bodies in deployment. Since the sizes of satellites are not negligible in actual space missions, the mother-satellite and sub-satellite connected by tether were regarded as rigid bodies with certain sizes, and the mass of the mother-satellite is much larger than the sub-satellite in modeling. Besides, the tether is regarded as a rigid rod with a certain mass. The mathematical model was used to analyze the deployment process of STS, and to analyze the main influence factors to the attitude motions of end-bodies including the initial disturbance of attitude angles, and the dynamic or static asymmetry of end-bodies. Simulation results demonstrate that either the initial disturbance or the dynamic and static asymmetry of end-bodies in deployment can cause the attitude angles instability, or even cause the tether enwinding satellites. The simulation results can provide reference for the attitude control of satellites in deployment.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[CHEN Shumin, WANG Changqing, Zabolotnov Yuriy, LI Aijun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>CHEN Shumin, WANG Changqing, Zabolotnov Yuriy, LI Aijun</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002013]]></guid><cfi:id>16</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Experimental and numerical prophetic study on the failure of the connection structure between stages of the missiles(rockets) under quasi-static load]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002014]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The interstage bolted flange connection is a common connection mode of the missiles (rockets), but it destroys the continuity of the whole missiles (rockets) structure and is of weak load bearing capacity that the whole missiles (rockets) structure is liable to fail so as to lose the strength under external load. Based on the bolted flange connection structure between stages of the actual missiles (rockets), multiple experimental specimens were simplified and manufactured, the quasi-static loading experimental system and the special bolt force signal acquisition sensor were designed, two quasi-static failure experiments were carried out, and the finite element simulation model was established by ABAQUS simultaneously. According to the experimental results and the measured data, the failure mechanism of the connection structure under quasi-static load was analyzed, and the numerical simulation results and precision of the finite element simulation model were proved good. The results in this research can be used as a reference for the loading bearing capacity and experimental design of connection structure between stages of missiles (rockets) under quasi-static load.]]></description>
<pubDate>2020/4/29 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[YUAN Jiehong, TIAN Tonghui, GUAN Zhenqun, WANG Qingwen, CHEN Baisheng]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YUAN Jiehong, TIAN Tonghui, GUAN Zhenqun, WANG Qingwen, CHEN Baisheng</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002014]]></guid><cfi:id>15</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Method to detect satellite historical orbit maneuver based on fitting of prediction error distribution]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002015]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Orbit maneuvers can cause satellite orbital anomalies and are one of the key concerns of the space situational awareness. A method to detect historical orbital maneuvers from satellite TLE(two line element) data was proposed. By analyzing the prediction errors, the abnormal cataloging values of the selected orbital parameter were detected, and then the corresponding historical maneuvering information was obtained. Firstly, a large number of sample data of prediction errors were obtained from the historical TLE data, and the probability distribution model of the prediction errors expressed by the Gaussian mixture model was fitted from these sample data by the EM(expectation maximization) algorithm. Then, based on the fitted distribution model, the threshold of detecting abnormal cataloging values of orbital parameter through prediction errors was determined. Finally, taking into account the relationship between orbital maneuvers and abnormal cataloging values of the orbital parameter, the method to detect orbital maneuver from the cataloging sequence of the orbital parameter was determined. The results of maneuver detection on typical active satellites show that the proposed method can detect historical maneuvers accurately while maintaining a low false detection rate.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[LI Tao, HUANG Hao, CHEN Lei]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LI Tao, HUANG Hao, CHEN Lei</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002015]]></guid><cfi:id>14</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Prediction method for booster rocket′s debris safety control zone based on infill-sampling Kriging model]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002016]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Dynamics model of the rocket and its debris were established, and the quaternion algorithm was used to compute the carrier attitude. A prediction method of safety control zone based on infill-sampling Kriging model was proposed, which combined the characteristics of Monte Carlo and Kriging surrogate models. Then a flow chart of prediction was provided furthermore, and one booster rocket′s debris safety control zone was simulated. Simulation results show that, compared with the Monte Carlo method without losing computational accuracy, the proposed method has equivalent computational accuracy and higher computational efficiency:it can meet the rapid iteration requirement for engineering design. While compared with the conventional extreme deviation overlying method, it can reduce the area of safety control zone dramatically and has relatively good engineering application value.]]></description>
<pubDate>2020/4/29 11:02:03</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHU Xuejun, BU Kuichen, WANG Hao, GAO Feng, ZHAO Changjian]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHU Xuejun, BU Kuichen, WANG Hao, GAO Feng, ZHAO Changjian</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202002016]]></guid><cfi:id>13</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis and experimental evaluation of helium inflation calculation methods on the ground of high-altitude balloon]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106001]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The amount of helium used in a balloon is an important issue, which directly affects balloon′s ascent velocity and altitude, and then affects the reliability and stability of the platform. Therefore, the study of accurate calculation method of helium is requested. Vertical dynamic model of balloons was established and the theoretical values of initial ascent velocity were calculated. It can be used to compare with the actual initial ascent velocity and provide a basis for evaluating helium inflation calculation methods. Three helium inflation calculation methods of high-altitude balloon were summarized, the accuracy and error range of the three methods were analyzed and compared according to the flight experiments. The buoyancy compensation law was put forward, and three methods have been evaluated. Through the study, it shows that the existing helium inflation calculation methods can be modified effectively, and then it can provide guidance for future flight experiments.]]></description>
<pubDate>2021/12/4 21:09:55</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[YANG Yanchu, DU Qianqian, ZENG Dandan, WANG Fan, ZHANG Hangyue]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YANG Yanchu, DU Qianqian, ZENG Dandan, WANG Fan, ZHANG Hangyue</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106001]]></guid><cfi:id>12</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Vibration characteristics analysis of flexoelectric Timoshenko nano-beam in viscoelastic medium]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106002]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Based on the Hamiltonian principle and taking nonlocal effect, piezoelectric effect and flexoelectric effect into consideration, the vibration governing equation and boundary conditions of the Timoshenko nano-beam in the viscoelastic medium were established, and the method of solving the governing equation of flexoelectric nano-beam with simply supported boundary conditions was adopted. The effects of nonlocal parameters, flexoelectric effect and viscoelastic medium on the vibration characteristics of the flexoelectric nano-beam were systematically studied. The results show that the transverse flexoelectric coefficient can significantly increase the structural stiffness of the flexoelectric nano-beam, while the nonlocal parameters and the tangential flexoelectric coefficient can reduce the structural stiffness of the system. In addition, the critical damping coefficient of the viscoelastic medium, in which the flexoelectric nanobeam no longer reciprocating vibration, can be obtained by studying the effects of viscoelastic medium. Research results can provide a theoretical basis for the extension and application of flexoelectric nano-beam in energy harvester.]]></description>
<pubDate>2021/12/4 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHANG Dapeng, WU Dong, LEI Yongjun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHANG Dapeng, WU Dong, LEI Yongjun</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106002]]></guid><cfi:id>11</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Application of Vondrak-Cepek combined filtering in the fusion of BeiDou CV and TWSTFT]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106003]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to reduce the diurnal in TWSTFT (two-way satellite time and frequency transfer), based on the fact that there is no diurnal in BeiDou common view link, the Vondrak-Cepek combined filtering was applied to combine BeiDou common view and SATRE (satellite time and ranging equipment) TWSTFT or SDR (software-defined radio) TWSTFT among NTSC (national time service center), Chinese Academy of Sciences, PTB (physikalisch-technische bundesanstalt) and NIM (national institute of metrology). Two indexes, namely time deviation and amplitude spectrum, were used to evaluate the gain factors in reducing the diurnal of the fusion results, and the agreement of the two types of links was revealed by taking GPS PPP (precise point positioning) time comparison as reference. Results show that the diurnal of the fusion results is greatly improved after Vondrak-Cepek combined filtering, and the absolute value of the differences between the fusion solutions and GPS PPP solutions is kept within the calibration uncertainty of time link. For the baseline of NTSC-PTB, the gain factors of 1-day time deviation(TDEV) of fusion results versus SATRE TWSTFT and SDR TWSTFT are 1.85 and 1.81, respectively. For the baseline of NTSC-NIM, the gain factors are 1.69 for SATRE TWSTFT and 1.59 for SDR TWSTFT. The short-term stability of fusion results is significantly improved.]]></description>
<pubDate>2021/12/4 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[WANG Weixiong, DONG Shaowu, WU Wenjun, GUO Dong, WANG Xiang, GAO Zhe]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WANG Weixiong, DONG Shaowu, WU Wenjun, GUO Dong, WANG Xiang, GAO Zhe</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106003]]></guid><cfi:id>10</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Test of mechanical properties of C/SiC composites at elevated temperature air]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106004]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The compression, bending and tensile properties of C/SiC composites at elevated temperature air were tested. The microstructures of fractures at room temperature and elevated temperature were analyzed by scanning electron microscope, respectively. Results show that, when the test temperature varies from room temperature to 1 000 ℃, the compressive strength, flexural strength and tensile strength of C/SiC composites decreases from 247 MPa to 78 MPa, 480 MPa to 277 MPa and 247 MPa to 152 MPa, respectively. The performance of these three mechanical parameters of C/SiC composites is reduced by 68%, 42% and 38%, respectively. High temperature oxidation leads to interface degradation and carbon fiber structural damage, which aggravates the degree of fiber breakage, and changes the state of fiber-matrix bonding. As a result, the fiber toughening mechanism gradually disappears, and composite properties decays.]]></description>
<pubDate>2021/12/4 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[CHEN Weihua, WANG Liyan, ZHANG Hanyi, JI Nizhi, LI Guanshu, MA Jing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>CHEN Weihua, WANG Liyan, ZHANG Hanyi, JI Nizhi, LI Guanshu, MA Jing</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106004]]></guid><cfi:id>9</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Ensemble learning for state recognition of payload from telemetry data]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106005]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to deal with various complex telemetry problems, such as high dimensionality, huge volume, unbalanced categories and failure to intuitively make sense about states of payload, and considering the requirement of interpretability in space mission, a general method for fast identification of payload based on information gain and integrated learning method was proposed. Sample statistics and information gain was used to select features and reduce the dimension of the telemetry data; meanwhile, the integrated learning algorithm was used to complete the adaptive recognition and classification about payload states. The proposed method combined the advantages of the parameter classification information evaluation criteria of the information gain and strong modeling, high accuracy and strong anti-noise ability under unbalanced category samples. Furthermore, the model had to possess the property of being explanatory and able to find the key parameters. The method was verified by experiments using actual mission data, which was tested using the payload telemetry data on operational scientific satellite mission. Following that, an state-of-art result, of which the overall recognition accuracy is higher than 90 percent and a few samples can also be identified, covered mission requirement in all and proved the effectiveness and practicability.]]></description>
<pubDate>2021/12/4 21:09:56</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[LI Hu, GUO Guohang, HU Tai, YANG Jiasen, DONG Zhenxing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LI Hu, GUO Guohang, HU Tai, YANG Jiasen, DONG Zhenxing</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106005]]></guid><cfi:id>8</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Experimental analysis on combustion characteristics of gaseous oxygen and methane splash platelet injector]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106006]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The combustion characteristics of single-element and multi-elements splash platelet injector were studied by experimental methods, the heat load of injector faceplate under different working conditions were investigated, and the effects of different mixing ratios and different structural parameters on combustion chamber pressure and combustion efficiency were obtained. Results show that the mixing ratio of the multi-elements injector has little effect on the chamber pressure, but has a greater effect on combustion efficiency. For single-element injectors, the combustion efficiency improves with the increase of the mixing ratio. Under the same conditions, increasing the expanding angle and the length of the trapezoidal orifice is beneficial to improve the combustion efficiency, but will cause the increase of the thermal load of injector faceplate. The injector faceplate of each injectors has different degrees of deformation or failure. These results are of significance for guiding the design of the platelet injector and screening the structure of the injector.]]></description>
<pubDate>2021/12/4 21:09:56</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[YIN Liang, LIU Weiqiang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YIN Liang, LIU Weiqiang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106006]]></guid><cfi:id>7</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Evaluation method of the uncertainty of the temperaturemeasurement for meteorological sounding rocket]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106007]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Based on the temperature correction model of meteorological sounding rocket, through error analysis theory, research on the method of temperature correction and uncertainty evaluation was conducted. According to the law of atmospheric density change during the falling process of rocketsonde, the mathematical model of temperature correction was established, and the formula of temperature correction was deduced. According to the error theory, eight error factors which affect the temperature correction were analyzed, and the expression of error in temperature correction was given one by one. Taking measured data as an example, using the above formula, the uncertainty of temperature inversion of sounding rocket was analyzed and calculated. The results show that the uncertainty of temperature inversion is larger in 50~60 km, and the maximum is 3.6 K; uncertainty in 40~50 km is 0.3~0.9 K; uncertainty in less than 40 km is no more than 0.3 K.The main factors that affect the uncertainty of temperature are aerodynamic heating correction, lag effect correction, structural heat conduction correction, and sensor correction for environmental heat radiation. It is not enough to use the reference atmosphere or the standard atmosphere for only single correction in data processing. Iterative correction is needed, and the maximum difference between iterative correction results and single correction results is 5.6 K.]]></description>
<pubDate>2021/12/4 21:09:56</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[SUN Yu, CHEN Shuchi, WAN Li, JIN Bo, SHENG Zheng, WANG Xin]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>SUN Yu, CHEN Shuchi, WAN Li, JIN Bo, SHENG Zheng, WANG Xin</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202106007]]></guid><cfi:id>6</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Research and development method of software on spacecraft]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102009]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Construction of autonomic capability on spacecraft faces such developing problems as requirements increasing, variability, more complexity, and unknowingness of trend. It is needed to alter development method and architecture design to suit these trends. Based on the research of current four methods, a fifth method, a development mode which is model-based and data-oriented, was proposed. A service model with plug-and-play capability was given, and the electronic data sheet technology was used to construct the bottom-up plug-and-play capability from device level to functional service level. An intelligent planning service instance using this service model was designed and described. The purpose of the fifth method is to provide a persistent development base for the construction of the autonomic capability on spacecraft and the intelligence management and control ability between space and ground.]]></description>
<pubDate>2021/4/1 15:04:09</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[LYU Liangqing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LYU Liangqing</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102009]]></guid><cfi:id>5</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of UAV multi-frame fusion location and error convergence characteristic for ground target]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102010]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[High-precision positioning of the ground target is an important premise for the UAV (unmanned aerial vehicle) to carry out target reconnaissance, firepower guidance, effectiveness evaluation, etc. However, the accuracy of the UAV′ s target positioning is limited by factors such as many error factors and long transmission chain. The method of multi-frame image registration method based on Kalman filter for ground target location was studied. By combining the multi-frame target image acquired by UAV, the high-precision fusion positioning of UAV to ground target was studied based on Kalman filter. Monte Carlo method was introduced to simulate the error convergence, value and distribution of multi-frame fusion location method based on Kalman filter. The influence of observation interval and line-of-sight elevation angle on error convergence was analyzed. Several suggestions for improving the positioning accuracy were proposed.]]></description>
<pubDate>2021/4/1 15:04:09</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[LU Yafei, WU Anping, CHEN Qingyang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LU Yafei, WU Anping, CHEN Qingyang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102010]]></guid><cfi:id>4</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Time-slot allocation algorithm of quality of service for SpaceFibre]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102011]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to achieve the deterministic transmission of the massive real-time data streams in a short time on the SpaceFibre onboard data network, the time-slot allocation algorithm of QoS (quality of service) for SpaceFibre was proposed. Formally the QoS of SpaceFibre network was described and the definitions of scheduling matrix were given; the queuing model of QoS was created and the impact of time-slot allocation on delay performance was quantitatively analyzed; From the perspective of network compatibility and robustness of algorithm, an improved binary sequence scheduling sub-algorithm was derived; the improved hybrid partheno-genetic scheduling sub-algorithm with the highly evolved initial population and more genetic operators was given; the SpaceFibre communication model was established by using the Opnet network simulation platform to compare with the delay performance under different algorithms. Simulation results show that the time-slot allocation algorithm has lower average latency compared with other algorithms. The performance of the network is optimized. The research results can provide a reference for building a low-latency SpaceFibre network.]]></description>
<pubDate>2021/4/1 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[ZHENG Jingya, AN Junshe]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHENG Jingya, AN Junshe</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102011]]></guid><cfi:id>3</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Nonsingular sliding mode guidance law for impact time control in three-dimensional space]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102012]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[To study the problem of impact time control for missiles in three-dimensional space with field-of-view constraint, a three-dimensional nonlinear sliding mode guidance law was proposed. The sliding mode surface was designed by using the impact time error and then the acceleration commands in pitch and yaw were derived. By making a simple correction to the proposed guidance, the singular issue driven by zero-initial-heading-error was overcome. The stability and convergence of the proposed guidance law was proved in a rigorous mathematical manner. The value range of some certain parameters and the relationship with the pure proportional navigation guidance law and the decoupled three-dimensional guidance law were analyzed. Simulation results indicate that control of the increasing or reducing impact time can be achieved effectively with the field-of-view constraint by using the proposed guidance law. The stronger the degree of coupling between the pitch and yaw planes is, the more advantageous the proposed guidance law in control energy is.]]></description>
<pubDate>2021/4/1 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[CHANG Sijiang, WU Fang, CHEN Shengfu]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>CHANG Sijiang, WU Fang, CHEN Shengfu</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102012]]></guid><cfi:id>2</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Stress concentration effect analysis of new aviation aluminum alloy pitting corrosion damage with complex morphology]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102013]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Based on simulation accelerated pitting corrosion test results of 7B04 aluminum alloy specimen, which combined with the pitting corrosion mechanization and microstructure of aluminum alloy and stochastic process essence of pitting corrosion, two typical damage models with complex morphology which were composed of many micro-ellipsoid corrosion pits were erected through finite element method, two models were named wedging model and encircling model respectively. The stress concentration effect which was embodied by stress concentration factor and stress nephogram was calculated and analyzed through ANSYS software and linear elastic fracture mechanics. The results show that the stress concentration effect of wedging model and encircling model is very different from the results of simplified ellipsoid corrosion pits model. The stress concentration factor value of wedging model and encircling model is almost the same, and may increase because of interference and influence and superposition of each single micro-ellipsoid corrosion pits. The obvious area or location of stress concentration effect of wedging model and encircling model almost locates at the intersection region between each micro-ellipsoidal corrosion pit, the intersection regions almost are on the side of the macro corrosion pits. The size range of wedging model and encircling model stress concentration effect are well matched with the microscopic grain size and small crack size of aluminum alloy.]]></description>
<pubDate>2021/4/1 0:00:00</pubDate>
<category><![CDATA[航天工程·材料科学与工程]]></category>
<author><![CDATA[LIU Zhiguo, LI Xudong, CHEN Chuan]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LIU Zhiguo, LI Xudong, CHEN Chuan</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202102013]]></guid><cfi:id>1</cfi:id><cfi:read>true</cfi:read></item>
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