炸药装药撞击起爆低速气炮模拟实验系统

本文建立的低速气炮模拟实验系统可以实现炸药装药撞击起爆基本现象的定性、定量观测。延长载荷作用时间是用低速气炮模拟炸药装药发射安全性的技术关键。本文用高压气垫式缓冲器能延长载荷作用时间,模拟膛压波形。低速气炮实验结果证实,炸药装药撞击时发生了变形、剪胀、局部破坏、气体压缩等一系列力学变化;这些力学变化在一定条件下导致炸药局部爆炸。载荷与缺陷是影响含缺陷装药撞击起爆的基本特征量

Factors affecting urban renewal in high-density city : case study of Hong Kong

2010-2011 > Academic research: not refereed > Publication in policy or professional journalVersion of RecordPublishe

SiO2对Al2O3凝胶纤维相变的影响

以尿素催化 硅 酸 乙 酯 水 解 制 得SiO2溶胶。29SiNMR、27AlNMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成Al—O—Si键而有效地将其包裹,从而阻止了过渡态Al2O3微晶的相互接触,抑制了α-Al2O3的成核和生长

煤与瓦斯突出的二维模拟实验研究

介绍了自行设计、加工的模拟煤与瓦斯突出的二维实验装置及配套的压力数据自动采集处理系统。在二维模拟实验装置上做了一系列的实验。实验发现,煤样的破坏存在"开裂"和"突出", 两类典型的破坏形式, 破坏阵面的前沿以拉伸强间断的形式向外传播。煤体破坏的初期是轴对称的, 而后则只在某一方向上向外扩展, 而且破坏阵面的扩散速度是逐渐衰减的, 不存在恒稳推进。在煤体破坏过程中, 应力重新分布, 并有4种不同的应力转移形式。这些结论对于认识煤与瓦斯突出的机理是十分有益的。F8T1R5

Numerical simulation of the fracture process in ceramic FPD frameworks caused by oblique loading

Using a newly developed three-dimensional (3D) numerical modeling code, an analysis was performed of the fracture behavior in a three-unit ceramic-based fixed partial denture (FPD) framework subjected to oblique loading. All the materials in the study were treated heterogeneously; Weibull's distribution law was applied to the description of the heterogeneity. The Mohr-Coulomb failure criterion with tensile strength cut-off was utilized in judging whether the material was in an elastic or failed state. The simulated loading area was placed either on the buccal or the lingual cusp of a premolar-shaped pantie with the loading direction at 30 degrees, 45 degrees, 60 degrees, 75 degrees or 90 degrees angles to the occlusal surface. The stress distribution, fracture initiation and propagation in the framework during the loading and fracture process were analyzed. This numerical simulation allowed the cause of the framework fracture to be identified as tensile stress failure. The decisive fracture was initiated in the gingival embrasure of the pontic, regardless of whether the buccal or lingual cusp of the pontic was loaded. The stress distribution and fracture propagation process of the framework could be followed step by step from beginning to end. The bearing capacity and the rigidity of the framework vary with the loading position and direction. The framework loaded with 90 towards the occlusal surface has the highest bearing capacity and the greatest rigidity. The framework loaded with 30 towards the occlusal surface has the least rigidity indicating that oblique loading has a major impact on the fracture of ceramic frameworks. (C) 2015 Elsevier Ltd. All rights reserved

A 3D numerical simulation of stress distribution and fracture process in a zirconia-based FPD framework

In this study, a numerical approach to the fracture behavior in a three-unit zirconia-based fixed partial denture (FPD) framework was made under mechanical loading using a newly developed three-dimensional (3D) numerical modeling code. All the materials studied were treated heterogeneously and Weibull distribution law was applied to describe the heterogeneity. The Mohr-Coulomb failure criterion with tensile strength cut-off was utilized to judge whether the material was in an elastic or failed state. For validation, the fracture pattern obtained from the numerical modeling was compared with a laboratory test; they largely correlated with each other. Similar fracture initiation sites were detected both in the numerical simulation and in an earlier fractographic analysis. The numerical simulation applied in this study clearly described the stress distribution and fracture process of zirconia-based FPD frameworks, information that could not be gained from the laboratory tests alone. Thus, the newly developed 3D numerical modeling code seems to be an efficient tool for prediction of the fracture process in ceramic FPD frameworks. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 96B: 376-385, 2011

A model for Impact Ignition of Charges with Gas Gaps

炸药装药发射安全性模拟实验表明，炮弹炸药装药底隙是诱发膛炸的最危险因素，证实“快速压缩间隙气体加热炸药”是炸药装药撞击起爆的最重要机制。本文分析炸药装药撞击起爆模拟实验，在忽略化学反应的条件下，建立了含气体间隙炸药装药撞击起爆一维模型，给出了描述低速气炮实验中气隙温度分布的方程及参数，即炸药最高温度的控制方程及参数。这些控制参数为气体的比热比、初始相对温度、气体压缩比、气体散热与输入功率比、界面传热系数比

民航客机防爆箱的研制

本文简介研制民航客舱防爆箱遇到的困难,指出这是爆炸火球区内抗爆容器的设计问题。在实验和理论分析基础上,就爆炸火球区内抗爆措施提出了建议并得到验证

A Statistics Method of Data Processing with Similarity Numbers for Simulation Tests of Impact Ignition of Explosive Charges

用相似准数构造刺激量，根据不同撞击条件起爆的实验结果，用最大似然法在正态假设下估计刺激量的期望和方差，并对处理结果进行讨论。把炸药装药撞击起爆实验数据视同刺激量不重复的感度试验数据，用最大似然法处理炸药实验数据。结果表明炸药装药撞击起爆模拟实验相似律存在；用相似准数统计方法可以处理实验数据

Progress in the study of damage and mechanical properties of energetic materials

研究含能材料的损伤和力学性能对于指导含能材料配方和结构件设计，以及对含能材料进行安全性评估和寿命预测等都具有重要的意义。损伤一方面使含能材料的力学性能劣化，另一方面还影响含能材料的感度、燃烧甚至爆炸性能。本文对含能材料损伤和力学性能的研究现状进行了综述和归纳。对含能材料损伤的产生、实验模拟、主要损伤模式，损伤对含能材料的感度和燃烧性能等的影响，炸药单相材料的性质，影响含能材料力学性能的因素以及损伤本构关系等进行了介绍。对其中的一些关键问题和热点问题进行了分析，并对今后需要开展的工作发表了一些看法