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

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

穿爆弹撞靶效应数值分析

利用流体弹塑性模型和欧拉算法对穿爆弹撞击有限尺度模拟靶的力学效应进行了数值分析。给出了撞靶过程中各物理量的变化，分析了靶板尺度、撞靶速度对撞靶效应的影响

Dynamic Deformation of Clamped Circular Plates Subjected to Confined Blast Loading

In this paper, the dynamic deformation of thin metal circular plates subjected to confined blast loading was studied using high-speed three-dimensional Digital Image Correlation (3D DIC). A small-scale confined cylinder vessel was designed for applying blast loading, in which an explosive charge was ignited to generate blast loading acting on a thin metal circular plate clamped on the end of the vessel by a cover flange. The images of the metal plates during the dynamic response were recorded by two high-speed cameras. The 3D transient displacement fields, velocity fields, strain fields and residual deformation profiles were calculated by using 3D DIC. Some feature deformation parameters including maximum out-of-plane displacement, final deflection, maximum principal strain and residual principal strain were extracted, and the result was in good agreement with that simulated by AUTODYN. A dimensionless displacement was introduced to analyse the effects of plate thickness, material types and charge mass on the deflection of metal plates. DIC is also proven to be a powerful technique to measure dynamic deformation under blast loading

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

拉断后射流对钢靶的随机侵彻

聚能破甲弹的金属射流断裂后发生径向随机发散,导致破甲深度显著下降。本文分析了径向随机发散的规律,得出描述拉断后射流对钢靶随机侵彻深度的一阶非线性常微分方程,并给出了大炸高条件下的简化解

“忘年友”活动启事

年轻的朋友们: 　我们是力学所的一群离退休职工，中科院老科协工程力学分会的成员，愿意与你们相识并希望结成忘年至交。 　我们熟悉力学所的园地和房屋，熟悉力学所的事业和历

读郑哲敏先生63年报告有感

读郑哲敏：关于二室研究方向和任务的报告有感 　这是1963年8月19日郑哲敏先生送交杨刚毅副所长的一份报告，力学所文书档案1963－03－004－02。土力学部分另由钱