舰载导弹垂直发射系统的综合测控系统

通过对舰载导弹垂直发射系统中贮运发射箱内环境监控、导弹综合测试、发射过程控制、射击参数装定以及应急状态自动处理等需求分析,提出建立综合测控系统方案,并探讨了以LONworks总线为核心的综合测控系统基本结构、组成和功用.     

火场中A3钢的晶粒度与燃烧时间和温度关系的研究

本文模拟典型火灾温度－时间曲线,对热轧成的Ａ３钢进行受热处理,测定在不同燃烧时间和温度下Ａ３钢的晶粒度,给出了Ａ３钢的晶粒度与燃烧时问和温度之间的定量关系,提出了通过测定Ａ３钢晶粒度的大小来鉴定火场中不同部位的燃烧时间和温度的科学方法     

长杆射弹对钢纤维混凝土靶开坑特性的实验研究

为考察射弹对钢纤维混凝土靶的侵彻特性,采用57mm轻气炮,进行了小尺寸模拟射弹对钢纤维混凝土靶(钢纤维的体积分数为2%)的侵彻实验。实验中观察了钢纤维混凝土靶的开坑形状,测量了射弹的击靶速度,并且采用注沙法测出靶体的开坑体积,计算出射弹对靶体的侵彻体积,得到了长杆射弹的动能与侵彻体积的关系。引入射弹单位面积的冲击动能和靶体单位侵彻体积的冲击动能,结合钢纤维混凝土靶的实验数据,考察了两者之间的关系。     

Phenomenological modelling of flow behaviour of 20MnMoNi55 reactor pressure vessel steel at cryogenic temperature with different strain rates

In the present study a phenomenological constitutive model is developed to describe the flow behaviour of 20MnMoNi55 low carbon reactor pressure vessel (RPV) steel at sub-zero temperature under different strain rates. A set of uniaxial tensile tests is done with the variation of strain rates and temperature ranging from 10⁻⁴ s⁻¹ to 10⁻¹ s⁻¹ and -80 °C to −140 °C respectively. From the experimental data, family of flow curves at different temperatures and strain rates are generated and fitted exponentially. The strain rate and temperature dependence of the coefficients of the exponential flow curves are extracted from these curves and characterised through a general phenomenological constitutive coupled equation. The coefficients of this coupled equation are optimised using genetic algorithm. Finite element simulation of tensile tests at different strain rates and temperatures are done using this coupled equation in material model of Abaqus FEA software and validated with experimental results. The novelties of proposed model are: (a) it can predict precisely the flow behaviour of tensile tests (b) it is a simple form of equation where fitting parameters are both function of strain rate ratio and temperature ratio, (c) it has ability to characterize flow behaviour with decreasing subzero temperatures and increasing strain rates.     

Optimization of resistance spot brazing process parameters in AHSS and AISI 304 stainless steel joint using filler metal

The aim of this research study was to determine optimal resistance spot brazing parameters for joining between AHSS and AISI 304 stainless steel by using filler metal. The key parameters investigated in this study consist of the brazing current, electrode pressure and brazing time. The Taguchi method was applied to the design of experiments. Signal-to-Noise ratio was introduced in the study to identify optimal levels from the process where input parameters yield increased shear strength. Brazing was thus implemented with 5,000A brazing current, 0.70 MPa electrode pressure, and 1.50s brazing time. The maximum shear strength obtained was 54.31 N·mm⁻² in accordance with input parameter settings. In addition, Cu-rich phase and Ag_0.4Fe_0.6 intermetallic phases were found at the interface zone.     

对接组合体初始姿态影响的建模研究

建立了对接过程对组合体初始姿态影响的解析与数值模型。解析模型采用相对于整体质心的动量矩定理,给出了对接完成后组合体姿态角速度计算的解析表达式。结合追踪器的绝对运动方程和目标器的相对运动方程,建立了基于对接动力学的数值模型。通过单一偏差和组合偏差两种算例,对解析和数值模型得到的组合体初始姿态角速度进行了对比分析。计算结果表明,两种模型绝对偏差在0.07°/s以内,相对偏差在10%以内,另外给出了两种模型在工程任务中各自的适用阶段。     

大空间钢结构建筑消防安全评估研究

大空间钢结构建筑发生火灾时,火焰及火灾产生的高温羽流可能对钢构件构成一定威胁。采用经验公式计算和FDS模拟分析两种方法计算火灾环境中大空间建筑钢构件的温度,评估钢构件是否达到或超过其失效温度。     

917低磁钢与铝合金爆炸焊接复合实验研究

采用异种金属爆炸焊接复合技术 ,研制了 91 7低磁钢与LF5、LF2 1、LF1 1等铝合金的爆炸焊接复合板 ,并对该铝—钢复合板力学性能进行了实验研究 ,对复合界面进行了金相分析 .实验结果表明 ,该铝—钢复合板复合界面物理结合良好 ,其抗剪和抗弯强度满足实船使用要求     

基于高速数字逻辑器件的超宽带脉冲设计和应用

在对现有几种典型的超宽带脉冲产生方法分析的基础上, 采用组合高速数字逻辑器件实现了一种简单的产生超宽带纳秒级窄脉冲的电路,并对产生的窄脉冲进行时域叠加合成高阶波形.实验电路测试结果与理论分析和仿真吻合良好.实验表明,该窄脉冲产生电路能得到重复频率100 MHz、幅度达446 mV的窄脉冲.最后,结合UWB调制技术对该发射机的信息传输速率进行了分析.     

拉伸载荷作用下基体表层激光离散预处理对铬镀层／45钢基开裂行为的影响

采用激光离散预处理钢基体再电镀铬层技术得到了一种新型复合结构,研究了这种新型复合结构在拉伸载荷作用下的开裂行为特征,并与无激光处理钢基体的试样在同样试验条件下的开裂特征进行了对比分析。结果表明：有激光离散预处理钢基体试样的承载能力要高于无激光预处理钢基体试样的承载能力,且有激光处理的试样开裂区域在两个激光带之间（无激光处理区）,主裂纹呈现明显的周期性特征。本研究结果可归结为激光预处理钢基体不仅改善了基体表层的应力状态和力学性能,而且还改善了后续铬镀层的力学性能。