压力容器裂纹寿命预测的概率分析方法

本文在文献的基础上,进一步考虑材料性能分散性和使用环境随机性的影响,用概率分析方法对有裂纹的压力容器进行安全性分析,阐述了其可靠度指标和失效概率的分析计算步骤。并用Monte-Carlo方法预测裂纹扩展寿命,从而为正确确定压力容器的运行方式及合理的修理间隔期提供了重要的技术依据。算例证明了该方法的合理性、可行性。     

超动态变化的压力测量

本文介绍了采用MS-1215A/D板与IBM兼容机等组成的压力信号采集处理系统。该系统能对模拟压水堆大破口失水事故时超动态变化的压力进行高速采集,并能及时进行数据处理;根据需要还可打印有关参数和图表。此外,本文还介绍了为确保输入计算机的信号可信而采取的有效措施。     

可压缩流动压力修正方程分析

依据Ｐａｔａｎｋａｒ提出的差分方程稳定性判断的４项基本法则,对可压缩流动的压力修正方程进行了分析,得出压力修正方程系数为正的条件．指出在每一次求解压力修正方程时必须提高解的收敛程度,以保证下一次迭代的差分方程矩阵接近主对角占优．分析了速度离散方程的欠松驰因子对可压缩流压力修正方程的影响．     

The surface activation of boron to improve ignition and combustion characteristic

Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low combustion efficiency. Herein, nano-Al and graphene fluoride (GF) as surface activated materials are employed to coat boron (B) particles to improve ignition and combustion performance. The reaction heat of nano-Al coated B/KNO₃ and GF coated B/KNO₃ are 1116.83 J/g and 862.69 J/g, respectively, which are higher than that of pure B/KNO₃ (823.39 J/g). The ignition delay time of B/KNO₃ could be reduced through nano-Al coating. The shortest ignition delay time is only 75 ms for B coated with nano-Al of 8 wt%, which is much shorter than that of pure B/KNO₃ (109 ms). However, the ignition delay time of B/KNO₃ coated with GF has been increased from 109 to 187 ms. B coated with GF and nano-Al shown significantly influence on the pressure output and flame structure of B/KNO₃. Furthermore, the effects of B/O ratios on the pressure output and ignition delay time have been further fully studied. For B/KNO₃ coated with nano-Al and GF, the highest pressures are 88 KPa and 59 KPa for B/O ratio of 4:6, and the minimum ignition delay time are 94 ms and 148 ms for B/O ratio of 7:3. Based on the above results, the reaction process of boron coated with GF and nano-Al has been proposed to understand combustion mechanism.     

高能硝胺推进剂的压强指数分析

从高能硝胺推进剂配方组成入手 ,深入研究了各组分参数的变化对该推进剂燃烧性能的影响 ,认为 :高硝胺 ( HMX或 RDX)含量和高硝酸酯增塑剂含量是高能硝胺推进剂 ( NEPE)高压强指数的根本原因。同时指出该类推进剂的燃烧性能的调节将不再仅仅局限于硝胺的催化 ,而应针对硝胺和硝酸酯及 AP的特殊作用进行综合调节     

动载荷轴承滑油管内压力波研究初探

作者通过分析计算动载荷轴承油膜区间的变化规律,发现轴承滑油进口处油膜压力随时间变化。由于轴承进口处油膜压力变化,导致滑油进口处存在压力波。进一步分析滑油进口处压力波在滑油管内的传播及试验研究,首次发现,滑油管内压力波是由轴心运动引起的,它与轴承滑油压力、温度、轴承负荷及轴承几何尺寸等因素有关。作者认为,滑油管内压力波的发现,必将推动轴承润滑理论的发展。     

Response of masonry systems against blast loading

In this paper eight successive experimental blast tests with an increasing TNT equivalent charge weights ranging from 0.56 kg to 17.78 kg were conducted on unreinforced, ferrocemented overlay masonry and confined masonry walls. The pressure-time history caused by the blast was recorded by pressure sensors installed on the test specimen. The resulting damage pattern was observed during each test. Weak zones in the three systems of masonry were identified. Scaled distances for different damage levels in the three masonry systems were experimentally obtained. The results provide a basis for determining the response of each masonry system against blast loading. Consequently, efficiency of ferrocemented overlay ma-sonry and confined masonry was found established in mitigation against blast loads.     

潜艇耐压结构可靠性研究进展

本文从基本随机变量及其对可靠性的影响、可靠性计算、可靠性设计与分析、可靠性安全标准等几方面介绍了潜艇耐压结构可靠性研究的结果,并对今后的研究方向提出了看法。     

圆柱壳承受水下爆炸作用时的动响应

本文提出了有限水域内水下爆炸实验设计的一般考虑方法,结合实验结果得到了各种条件(λ/D)下圆柱壳受水下爆炸作用时的壁压分布规律,采用塑性动力学中绝对最小原理对结构响应进行了数值计算,给出了冲击波作用下圆柱壳响应的一种偏安全估算方法。     

焊接接头的 TIG 熔修对潜艇耐压壳体抗爆性的影响

本文初步探讨了 TIG 熔修工艺对潜艇耐压壳体抗爆性的影响。试验结果表明,TIG 熔修可以有效地延缓在爆炸载荷作用下焊接接头裂纹的发生和发展。本文的工作为深入、系统地研究熔修工艺对潜艇耐压壳体抗爆性的影响作了有益的尝试,并为提高潜艇耐压壳体抗爆性指出了新的途径。