双轴应力下含裂纹加筋曲板剩余强度的弹塑性有限元计算

 采用考虑了大应变的弹塑性有限元方法,以裂纹尖端张开角为断裂准则,实现了双向受载条件下加筋曲板中裂纹起裂到失稳整个扩展过程的数值模拟计算;还对与加筋曲板有同样尺寸的加筋平板进行了分析和计算。结果表明,所提出的分析方法和所采用的断裂准则适用于对含裂纹加筋结构所进行的剩余强度分析。     

A lightning swept stroke model: A valuable tool to investigate the lightning strike to aircraft

In the context of lightning strike on the Dassault Falcon family of aircraft, the standard zoning of Falcon 50, 900 and 2000, inferred from FAA and EUROCAE WG31 documents [US Department of Transportation, Federal Aviation Administration, Advisory Circular AC 20-53A, 1985; US Department of Transportation, Federal Aviation Administration, Advisory Circular AC 20-53B, Draft, 1991; EUROCAE WG 31, Aircraft Lightning Zoning Standard, ED-91, 1998], has been presented. Zoning proves to be quite similar between the three types of aircraft. Thanks to the feed-back on lightning strikes to Falcon, lightning traces have been observed on the fuselage for different flight conditions and aircraft. Observations are compared with the zoning performed by Dassault. A physical model, developed by ONERA, was used to simulate the sweeping of lightning on the fuselage of a Falcon 900. The results are in good agreement with the lightning traces observed on the fuselages.     

现代模拟电路故障诊断方法发展综述

模拟电路故障诊断技术近年来得到了迅速发展,取得了许多可喜的成果。该文探讨了这一领域中一些重要的热门研究问题,主要包括:基于专家系统、神经网络、模糊理论、小波变换等理论发展起来的模拟电路故障诊断的新理论和新方法;重点介绍了作者总结的上述各种方法的基本原理、优缺点及其发展现状;对其他一些智能方法也进行了简要介绍;最后指出了模拟电路故障诊断技术的发展趋势。     

含多处损伤结构的剩余强度研究

系统地回顾了含多处损伤MSD结构的损伤连通准则,指出采用Dugdale的片状塑性区尺寸的Swift韧带屈服准则对一般工程材料最为合适.对具有潜在危险性的典型的广泛MSD结构作了剩余强度分析,分析结果表明:广泛MSD大大地降低了结构的剩余强度.     

固体火箭发动机喷喉结构设计准则的研究

提出了固体火箭发动机喷管喉衬结构综合设计准则──间隙临界值δｋ的概念，详细介绍了该设计准则δｋ的计算公式推导过程及其应用。并通过某固体火箭发动机四种不同技术状态喷喉结构的地面试车得到试验验证。     

焊后热处理对高温运行10CrMo910钢管接头持久寿命的影响

本文通过１０ＣｒＭｏ９１０钢大口径厚壁管道高温模拟试验证实，焊后热处理是一个短时超高温运行过程，它使１０ＣｒＭｏ９１０钢管接头组织提前老化，显著降低了接头的持久寿命。试验结果表明，传统的焊后热处理工序应当取消。     

火箭弹气动弹性发散计算研究

本文对火箭弹气动弹性发散计算进行了较详细的研究，包括与气动弹性发散计算方法有关的结构质量一刚度模型、气动升力模型和安全裕度要求等。     

超声爬波无损检测方法的研究

本文介绍了超声无损检测中一种具有较好应用前景的波型──超声爬波。试验研究了爬波检测时缺陷定位、定性评定的方法，并给出了主要结论。     

A Thermodynamic Approach to the Magnetospheric Complexity: The Role of Fluctuations

Recent studies evidenced that the magnetotail dynamics looks like the one of an avalanching system. This fact has been related with a near criticality dynamics and modelled by singular diffusion and transport equations. Here, we discuss some features of the Earth’s magnetotail dynamics using a thermodynamic approach. In detail we discuss the role played by fluctuations in singular diffusion and relaxation processes from a non-equilibrium thermodynamics point of view. Moreover, the emergence of non-Gaussian statistics is discussed in the framework of the thermodynamics of composite systems.     

美国低空风切变危险性评估的研究概况

对美国在低空风切变的危险性评估及其准则、风切变模型及地面系统仿真等方面的研究概况作一介绍,最后找出我国在这方面研究的差距,并提出努力的方向。