Radiative properties of alumina/aluminum particles and influence on radiative heat transfer in solid rocket motor

The thermal radiation of micron-sized condensed phase particles plays a dominant role during the heat transfer process in aluminized Solid Rocket Motors（SRMs）. Open research mainly focuses on the radiative properties of alumina particles while the study considering the presence of aluminum is lacking. In addition, the thermal radiation inside the SRM with consideration of the participating particles is seldom studied. In this work, the multiscale method of predicting the thermal environment insi...     

淬火制度对16NiCo钢组织性能的影响

研究了淬火温度及冷却方式对１６ＮｉＣｏ钢微观组织和性能的影响，结果表明：该钢不同温度淬火风冷与油冷后，随淬火温度的提高，性能变化趋势相近，强度至８００℃～８３０℃达最大值，而后开始降低，８６０℃淬火冲击韧性为最高。８６０℃油淬与８３０℃风冷相比，强度下降不多，冲击韧性提高幅度比较大，并且随淬火温度的增加，两个强度指标之间的差别越来越大。     

双层钙钛矿(Sr2-xBax)FeMoO6的结构和电磁性能研究

利用X射线粉末衍射、Rietveld结构精修技术及电、磁测试等手段分别对（Sr2-xBax）FeMoO6（0≤x≤2）的晶体结构及电磁性质进行了研究。研究结果表明：对于掺杂含量x≤1．6的（Sr2-xBax）FeMoO6样品,其电阻率温度关系呈金属性,而对于掺杂含量x≥1．7的样品,其电阻率温度关系呈半导体性。居里温度Tc在x=0．4处出现极大值。     

叠层穿刺CF/Al复合材料准静态拉伸力学行为与失效机制

针对新型的叠层穿刺碳纤维织物增强铝基复合材料（CF/Al复合材料）,通过细观力学数值模拟与实验结合的方法研究了其在准静态拉伸载荷作用下的渐进损伤与断裂力学行为。复合材料经向拉伸弹性模量、极限强度与断裂应变的实验结果分别为129.61 GPa、630.14 MPa和0.75%,细观力学模型预测误差分别为-9.41%、7.57%和1.33%,均匀化计算的宏观应力-应变曲线与实验曲线总体上相符。经向拉伸变形初期首先出现经/纬纱交织处基体合金的局部损伤,随着拉伸应变量的增大依次发生纬纱和穿刺纱的横向开裂,拉伸变形后期基体合金与经纱失效引起宏观应力-应变曲线的急剧下降,复合材料拉伸断口表现为经纱轴向断裂及纬纱和穿刺纱横向开裂共存的形貌特征,纤维拔出和基体断裂导致的经纱轴向断裂是诱发复合材料最终失效的主要机制。     

Precipitation behavior and properties of extruded 7136 aluminum alloy under different aging treatments

In this work, the mechanical properties and electrical conductivity of the extruded 7136 aluminum alloy treated by single-stage aging treatment (T6), retrogression and re-aging treatment (RRA), and multiple retrogression and re-aging treatment have been investigated by means of hardness measurements, electrical conductivity tests and tensile tests. The results have shown that the properties of the 7136 alloy such as hardness, tensile strength and electrical conductivity were sensitive to retrogression time (within 90 min). With prolonging the retrogression time, the tensile strength was enhanced first and then decreased, yet the electrical conductivity was continuously increased. The 60 min-treated alloy performed the highest tensile strength (716 MPa), whereas the 90 min-treated alloy possessed the highest electrical conductivity (33.95%IACS). Compared with the T6-treated alloy, the tensile strength and electrical conductivity were improved by 3.3% and 18.9%, respectively. The electrical conductivity showed an obvious increase with repetitious times of the RRA treatment. After 3RRA60 treatment, a good combination of tensile strength (705 MPa) and electrical conductivity (33.20%IACS) can be obtained. Compared with the T6 condition, the tensile strength and electrical conductivity were improved by 1.7% and 16.3%, respectively. The mechanism of microstructure evolution under different aging treatments has been discussed in detail.     

NEPE推进剂/衬层结构-性能MD模拟（Ⅱ）--复杂体系组分分子迁移和配方设计示例

用分子动力学( MD)方法,对( PEG/NG/BTTN)/NPBA/HMX/AP/PEG/N-100//HTPB/TDI复杂的推进剂/衬层模型体系进行295 K-NVT模拟研究,展示了组分分子的浓度分布和迁移状况,发现HMX和NPBA分子有向界面层迁移趋势,而AP则呈平均分布态势。以RDX等量取代HMX后所得新配方的MD模拟研究表明,前者拉伸模量( E)、体模量( K)和剪切模量( G)、柯西压( C12-C44)和K/G值均有明显下降,表明新配方的刚性、强度和延展性均有下降;新配方中引发键(N—NO2)最大键长(1.528?)明显大于原配方中相应值(1.503?),预示新配方感度增大、安全性将下降;比较RDX、HMX与其他组分之间的结合能,前者小于后者,预示新配方的相容性较差。     

高硅氧纤维增强苯并噁嗪树脂复合材料的制备及性能

以苯并噁嗪为基体树脂,短切高硅氧纤维为增强材料,制备了一种模压用复合材料。研究了该树脂的热性能、固化动力学性能及力学性能。结果表明,苯并噁嗪增强高硅氧纤维混合物随固化温度升高工艺窗口未发生显著变化,利用Kissinger、Crane法得到固化反应活化能为69.619 kJ/mol,反应级数为0.95。复合材料拉伸强度为35.5 MPa,,压缩强度为196 MPa,线烧蚀率为0.14 mm /s.     

虚拟仿真技术在机械装调实训教学中的应用研究

分析了虚拟仿真技术应用于机械装调实训教学的必要性及其功能要求,介绍了机械装调仿真实训平台的构建和教学应用策略,提出了仿真技术应用中需注意的问题和解决思路。     

空间相机支撑结构选型动力学分析

在航天遥感领域,离轴三反射镜消像散光学系统(TMA)以大视场、无遮拦等特点被广泛运用。由于离轴TMA系统的特点以及空间相机在发射过程中经历的恶劣的力学环境,相机支撑结构的力学特性对于相机成像品质的保证具有至关重要的意义。文章用Solidworks建立了支撑结构的实体模型,并在此基础上建立了有限元模型。通过对4种结构构型方案的力学特性的分析比较,为相机光机结构设计打下了基础,对三反离轴相机支撑结构的工程设计具有一定的指导作用。     

流体动压集装式机械密封的选型及应用

介绍了流体动压集装式机械密封的原理及应用,针对输油泵的工作环境和技术特点,设计出符合要求的流体动压型集装式机械密封,对端面动力槽进行了对比、选型,并进行了多种摩擦副材料配对试验验证,分析认为采用圆弧深槽方案可以有效地改善密封端面的润滑情况,使密封具有高的可靠性和好的密封性能。