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<title cf:type="text"><![CDATA[Editorial department of the Journal of National University of Defense Technology -->航天工程·机械工程·材料科学与工程]]></title>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Review of RCS measurement and imaging methods of stealth aircraft]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203012]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Stealth aircraft has gradually become a great power, and will continue to play an important role, making stealth technology become the key technology of aircraft design. RCS(radar cross section) measurement of stealth aircraft is a necessary step to design, manufacture and maintain stealth aircraft. The basic process of RCS measurement of stealth aircraft was reviewed from three aspects:RCS test of scaled model, outdoor RCS test of full-scale aircraft and indoor near-field test of full-scale aircraft, the theoretical basis of RCS near-field measurement of stealth aircraft was summarized, and the near-field RCS measurement technology with imaging diagnosis function was analyzed intensively. The development trend and key technologies of stealth aircraft RCS measurement were prospected, which is helpful to have a general understanding of RCS measurement of stealth aircraft and grasp the development direction of RCS measurement.]]></description>
<pubDate>2022/6/2 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[JIA Gaowei, YIN Peng, SHAO Shuai, WANG Jianfeng]]></author>
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<atom:name>JIA Gaowei, YIN Peng, SHAO Shuai, WANG Jianfeng</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203012]]></guid><cfi:id>7</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Reliability analysis of flight vehicle stage separation under mixed uncertainties]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203013]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[To quantity the comprehensive influence of both random and epistemic uncertainties during the process of flight vehicle stage separation, combined with the characteristics of hybrid model based on random and interval theory, a new reliability assessment method of separation between flight vehicle stages based on the hybrid model of random and interval theory was proposed. According to the requirements of the hypersonic vehicle separation mission, the separation kinetic simulation model was constructed. According to the geometric characteristic of the separation structure between the stages, a new rapid collision detection method was proposed. And the hybrid reliability assessment model of flight vehicle separation mission was constructed. The hybrid reliability assessment model was converted to unconstrained optimization problem of random reliability assessment. Considering of the characteristic of highly nonlinearity of system performance function due to complex external force and moment during the process of flight vehicle stage separation, the unconstrained optimization problem was efficiently solved by efficient global optimization and active learning Kriging method. It is shown that the influence of mixed uncertainty factors on the flight vehicle separation process can be described exactly through this method and the interval of flight vehicle separation mission reliability can be given accurately, which can further support the detailed design of flight vehicle separation.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[NIE Zhaowei, WANG Hao, QIN Meng, ZHANG Hairui]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>NIE Zhaowei, WANG Hao, QIN Meng, ZHANG Hairui</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203013]]></guid><cfi:id>6</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Cohesive element method for "dewetting" damage research of propellant]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203014]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Cohesive element is an important means to investigate the "dewetting" damage of propellant. The high filling ratio geometric model of propellant was constructed by the molecular dynamics method, and the mesoscopic finite element analysis model of propellant was constructed by combining the periodic geometry and periodic boundary treatment methods. The "dewetting" behavior of the interface between the particle and the matrix was simulated by using the cohesion element and PPR cohesive zone model. The mechanical response of propellant mesoscopic structure was analyzed under the uniaxial tensile and pure shear tests, and the damage mechanism of "dewetting" of propellant was studied. According to different volume fraction ratio, strain rate and cohesive strength, the influence law of "dewetting" damage was analyzed. The research methods and conclusions can provide a useful reference for the formulation of a new generation of high-performance propellant.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[CUI Huiru, LYU Xuan, XU Yurong]]></author>
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<atom:name>CUI Huiru, LYU Xuan, XU Yurong</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203014]]></guid><cfi:id>5</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of the influence of canopy optimization design on aerodynamic characteristics of cluster parachute system]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203015]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Developing the cluster parachute deceleration landing system is a key to realize the requirements of efficient deceleration and lossless landing of heavy-duty spacecraft. Based on aerodynamic theory, simulation analysis was performed on aerodynamic performance of single parachute in the parachute system. Taking simulation results as a reference, the configuration design of large ring sail umbrella was optimized..Based on the correctness and convergence of the simulation method, the cluster parachute system with multiple single parachute configurations was regarded as a research object, the aerodynamic resistance performance and attitude stability of the parachute system when the canopy is full were studied Through the flow field analysis and data comparison of the simulation results, it is found that the parachute with window and gap can not only ensure the good resistance characteristics of the cluster parachute system, but also maintain the working stability of the parachute system. This design can avoid the collision between single parachute due to force.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[DONG Haibo, SUI Rong, HUANG Mingxing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>DONG Haibo, SUI Rong, HUANG Mingxing</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203015]]></guid><cfi:id>4</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of charging effect on spacecraft surface under solar wind]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203016]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Aiming at the charging process of the spacecraft in the solar wind plasma, based on the spacecraft surface charging simulation software developed by the European Space Agency, a numerical calculation model of the spacecraft was established. The interaction between the solar wind plasma and the spacecraft was simulated, and different surface materials were simulated. The calculation and analysis of the surface potential of the spacecraft and the structure of the wake were realized, and the spatial potential structure and plasma density distribution around the spacecraft in the near-day environment were given. The research results show that the choice of surface material will affect the depth of the space barrier and the structure of the wake, and the surface material whose surface is charged to a lower potential has a smaller wake area; the potential distribution of the spacecraft towards the sun is mainly dominated by photoelectrons and secondary electrons, while the back of the potential distribution of the positive side is mainly affected by the wake effect. The above results have certain theoretical reference value for related work such as detection and evaluation of solar wind environment spacecraft and engineering research.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[HAO Jianhong, HUANG Sai, ZHAO Qiang, FAN Jieqing, ZHANG Fang, DONG Zhiwei]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HAO Jianhong, HUANG Sai, ZHAO Qiang, FAN Jieqing, ZHANG Fang, DONG Zhiwei</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203016]]></guid><cfi:id>3</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Effect of fuel injection advance angle on diesel engine performanceunder the condition of adjustable fuel injection law]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203017]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to obtain the effect law and genesis mechanism of fuel injection advance angle on the performance of diesel engine under the adjustable fuel injection law conditions, on the basis of the realization of adjustable fuel injection law injection, the working process calculation model of diesel engine was established by Fire software, and the main parameters of model were calibrated through experiments, then the performance of diesel engine with the fuel injection advance angle under saddle-shaped fuel injection law was analyzed with the model. The results show that with the delay of pressurization time, the fuel injection law changes from rectangle to slope and then to saddle-shaped, which realizes the flexible and adjustable fuel injection law. Under the condition of saddle-shaped fuel injection law, there is an optimal fuel injection advance angle to optimize the power and economy of diesel engine. At the same time, with the increase of fuel injection advance angle, the in-cylinder pressure, in-cylinder temperature and heat release rate of diesel engine increase gradually, and the time of reaching their peak values all move forward, while the NO<sub>x</sub> emissions and soot emissions show an increasing and decreasing trend respectively.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[YANG Kun, ZHOU Lei, ZHAO Jianhua, NIE Tao, LIU Nan]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YANG Kun, ZHOU Lei, ZHAO Jianhua, NIE Tao, LIU Nan</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203017]]></guid><cfi:id>2</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Influence of different galvanic corrosion protection methods of TA2-B10 pipe on the corrosion characteristics of B10 pipe]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202203018]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to study the influence of TA2-B10 alloy tube on the corrosion characteristics of B10 tube under different galvanic corrosion protection methods, the direct connection, electrical insulation connection and electrical insulation + coating of TA2-B10 tube with a diameter of DN80 were set up in Qingdao Maidao seawater test site. After connect three groups of control pipelines with different galvanic corrosion protection methods, flowing seawater and immersion alternate corrosion tests of 1 m/s, 3 m/s, and 4 m/s were conducted in sequence.After test, three sets of B10 pipelines were cut. Through the pipeline inner surface potential distribution test, the corrosion type of the B10 pipeline under different galvanic corrosion protection methods were analyzed; the potential polarization curve, electrochemical impedance spectroscopy and microscopic characterization were used to analyze the corrosion characteristics of the B10 at a distance of 250 mm from the flange joint under different galvanic corrosion protection methods. Results show that the directly connected TA2-B10 tube is in a galvanic corrosion state, the potential in the B10 terminal is positively shifted and the corrosion is accelerated, and the electrical insulation connection and the insulation+coating connection TA2-B10 tube are in a self-corrosive state. The electrical insulation+coating connection has better insulation effect; the B10 sample under electrical insulation+coating connection protection has the smallest corrosion current density and the most negative self-corrosion potential; the impedance spectra of the three groups of B10 samples all show the characteristics of single capacitive impedance arc, the B10 sample of electrical insulation+coating under the protection of layer connection has greater transmission resistance and film layer resistance; electrical insulation+coating connection can effectively slow down the three corrosion tendencies of pitting, pointed and intergranular corrosion. The above results comprehensively show that the insulation+coating protection method has a better galvanic corrosion protection effect.]]></description>
<pubDate>2022/6/2 10:28:11</pubDate>
<category><![CDATA[航天工程·机械工程·材料科学与工程]]></category>
<author><![CDATA[XIA Jiangmin, LI Zhuying, LIN Yufeng, CHEN Yexing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>XIA Jiangmin, LI Zhuying, LIN Yufeng, CHEN Yexing</atom:name>
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