20 resultados para 171-1051A
Resumo:
利用奇异摄动理论的两时间变量展开法,研究了垂直强迫激励圆柱形容器中的单一水表面驻波模式.假设流体是无粘、不可压且运动是无旋的,在忽略了表面张力的影响下,得到一个具有立方项以及底部驱动项影响的非线性振幅方程.对上述方程进行了数值计算,并研究了特定(3,4)模式的表面驻波结构和特性,如驻波的节点分布及随某些参数的变化规律等,从计算的等高线的图象来看,和以往的实验结果相当吻合.
Resumo:
Hydrophobic surface benefits for drag reduction. Min and Kim[1] do the first Direct Numerical Simulation on drag reduction in turbulent channel flow. And Fukagata and Kasagi[2] make some theoretical analysis based on Dean[3]'s formula and some observations in the DNS results. Using their theory, they conclude that drag reduction is possible in large Reynolds number. Both Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) are performed in our research. How the LES behaving in the turbulent channel flow with hydrophobic surface is examined. Original Smagorinsky model and its Dynamical model are used in LES. The slip velocities predicted by LES using Dynamical model are in good agreement with DNS as shown in the Figure. Although the percentage of drag reduction predicted by LES shows some discrepancies, it is in the error limit for industrial flow. First order and second order moments of LES are also examined and compared with DNS's results. The first-order moments is calculated well by LES. But there are some discrepancies of second-order moments between LES and DNS. [GRAPHICS]
Resumo:
本书阐明了板壳断裂理论的基础。论证了Reissner型板壳断裂理论的科学性、经典板壳断裂理论的缺陷及在一定范围内仍具有的实用价值；介绍了作者所创意的研究Reissner型板壳断裂纹尖端场的方法等。
目录
- §1．1 板壳弯曲断裂问题
- §1．2 Kirchhoff经典板壳弯曲断裂理论
- §1．3 Reissner型板壳弯曲断裂理论
- §1．4 Kirchhoff与Reissner型板壳弯曲断裂理论的比较
- §1．5 含裂纹有限尺寸板壳断裂分析的局部-整体法
- §1．6 含表面裂纹板壳
- §2．1 Kirchhoff板的基本概念和基本假定
- §2．2 基本公式与弹性曲面微分方程
- §2．3 边界条件
- §2．4 弹性薄板的应变能
- §2．5 极坐标下的挠曲面微分方程与内力公式
- §2．6 裂纹尖端场特征展开式通项公式
- §2．7 Kirchhoff板弯曲应力强度因子
- §3．1 基本方程和公式的复变函数表示
- §3．2 所引入函数的确定程度与一般形式
- §3．3 坐标变换与边界条件
- §3．4 运用保角变换方法求解孔口问题
- §3．5 应力强度因子与函数Φ(z)的关系
- §3．6 复变-主部分析法之应用简例
- §3．7 共直线裂纹问题的一般解答
- §3．8 典型弯曲裂纹问题的解答及弯曲应力强度因子公式
- §3．9 共圆曲线裂纹问题的解答及弯曲应力强度因子公式
- §4．1 裂纹尖端奇异元的位移模式与弯曲应力强度因子
- §4．2 裂纹尖端奇异元的刚度矩阵
- §4．3 裂纹尖端奇异元与常规单元的连接
- §4．4 解析法与数值法的结果比较与讨论
- §4．5 两共线半无限裂纹问题的定解条件及解的实用价值
- §5．1 Reissner型板的基本假定
- §5．2 Reissner型板的基本公式与平衡微分方程
- §5．3 基本方程的简化
- §5．4 边界条件
- §5．5 极坐标下的基本公式与平衡微分方程
- §5．6 两种平板理论用于无裂纹板时的比较
- §5．7 两种乎板理论用于含裂纹板时的比较
- §6．1 基本方程和一般求解方法
- §9．1 局部-整体法与其它解析和数值法的结果比较
- §9．2 边界对应力强度因子的影响
- §9．3 板的支承条件及长宽比的影响
- §9．5 计算Reissner型板应力强度因子的一组近似方程与近似解法
- §9．4 Reissner型板理论与Kirchhoff板理论所得应力强度因子的比较
- §9．6 关于数值计算的几点讨论
Resumo:
Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the first detailed study of the mechanics and modes of adiabatic shear localization in solids, and provides a systematic description of a number of aspects of adiabatic shear banding. The inclusion of the appendices which provide a quick reference section and a comprehensive collection of thermomechanical data allows rapid access and understanding of the subject and its phenomena. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. This reference book has come about in response to the pressing demand of mechanical and metallurgical engineers for a high quality summary of the knowledge gained over the last twenty years. While fulfilling this requirement, the book is also of great interest to academics and researchers into materials performance.Table of Contents
| 1 | Introduction | 1 |
| 1.1 | What is an Adiabatic Shear Band? | 1 |
| 1.2 | The Importance of Adiabatic Shear Bands | 6 |
| 1.3 | Where Adiabatic Shear Bands Occur | 10 |
| 1.4 | Historical Aspects of Shear Bands | 11 |
| 1.5 | Adiabatic Shear Bands and Fracture Maps | 14 |
| 1.6 | Scope of the Book | 20 |
| 2 | Characteristic Aspects of Adiabatic Shear Bands | 24 |
| 2.1 | General Features | 24 |
| 2.2 | Deformed Bands | 27 |
| 2.3 | Transformed Bands | 28 |
| 2.4 | Variables Relevant to Adiabatic Shear Banding | 35 |
| 2.5 | Adiabatic Shear Bands in Non-Metals | 44 |
| 3 | Fracture and Damage Related to Adiabatic Shear Bands | 54 |
| 3.1 | Adiabatic Shear Band Induced Fracture | 54 |
| 3.2 | Microscopic Damage in Adiabatic Shear Bands | 57 |
| 3.3 | Metallurgical Implications | 69 |
| 3.4 | Effects of Stress State | 73 |
| 4 | Testing Methods | 76 |
| 4.1 | General Requirements and Remarks | 76 |
| 4.2 | Dynamic Torsion Tests | 80 |
| 4.3 | Dynamic Compression Tests | 91 |
| 4.4 | Contained Cylinder Tests | 95 |
| 4.5 | Transient Measurements | 98 |
| 5 | Constitutive Equations | 104 |
| 5.1 | Effect of Strain Rate on Stress-Strain Behaviour | 104 |
| 5.2 | Strain-Rate History Effects | 110 |
| 5.3 | Effect of Temperature on Stress-Strain Behaviour | 114 |
| 5.4 | Constitutive Equations for Non-Metals | 124 |
| 6 | Occurrence of Adiabatic Shear Bands | 125 |
| 6.1 | Empirical Criteria | 125 |
| 6.2 | One-Dimensional Equations and Linear Instability Analysis | 134 |
| 6.3 | Localization Analysis | 140 |
| 6.4 | Experimental Verification | 146 |
| 7 | Formation and Evolution of Shear Bands | 155 |
| 7.1 | Post-Instability Phenomena | 156 |
| 7.2 | Scaling and Approximations | 162 |
| 7.3 | Wave Trapping and Viscous Dissipation | 167 |
| 7.4 | The Intermediate Stage and the Formation of Adiabatic Shear Bands | 171 |
| 7.5 | Late Stage Behaviour and Post-Mortem Morphology | 179 |
| 7.6 | Adiabatic Shear Bands in Multi-Dimensional Stress States | 187 |
| 8 | Numerical Studies of Adiabatic Shear Bands | 194 |
| 8.1 | Objects, Problems and Techniques Involved in Numerical Simulations | 194 |
| 8.2 | One-Dimensional Simulation of Adiabatic Shear Banding | 199 |
| 8.3 | Simulation with Adaptive Finite Element Methods | 213 |
| 8.4 | Adiabatic Shear Bands in the Plane Strain Stress State | 218 |
| 9 | Selected Topics in Impact Dynamics | 229 |
| 9.1 | Planar Impact | 230 |
| 9.2 | Fragmentation | 237 |
| 9.3 | Penetration | 244 |
| 9.4 | Erosion | 255 |
| 9.5 | Ignition of Explosives | 261 |
| 9.6 | Explosive Welding | 268 |
| 10 | Selected Topics in Metalworking | 273 |
| 10.1 | Classification of Processes | 273 |
| 10.2 | Upsetting | 276 |
| 10.3 | Metalcutting | 286 |
| 10.4 | Blanking | 293 |
| Appendices | 297 | |
| A | Quick Reference | 298 |
| B | Specific Heat and Thermal Conductivity | 301 |
| C | Thermal Softening and Related Temperature Dependence | 312 |
| D | Materials Showing Adiabatic Shear Bands | 335 |
| E | Specification of Selected Materials Showing Adiabatic Shear Bands | 341 |
| F | Conversion Factors | 357 |
| References | 358 | |
| Author Index | 369 | |
| Subject Index | 375 |
Resumo:
目录
- 访罗湖 忆当年［李佩］
- 怀念同窗益友郭永怀教授［钱伟长］
- 郭永怀追求科学、为国献身的一生［洪友士］
- 深深怀念为核盾牌献身的著名科学家--郭永怀先生 中国工程物理研究院
- 深切怀念郭永怀教授的奠基性贡献 中国空气动力研究与发展中心
- 胸怀长江长城 心系国家安危--纪念我国核防护工程奠基人郭永怀先生［周丰峻］
- 缅怀我们的首任系主任--郭永怀教授［辛厚文 马兴孝 俞书勤 何天敬］
- 科学和技术结合的典范--纪念郭永怀先生诞辰九十周年［郑哲敏 李家春］
- 怀念与感激［俞鸿儒］
- 继承先师遗愿，谈我所冲击动力学的发展--纪念郭永怀副院长诞辰九十周年［陈裕泽］
- 英名长存--纪念郭永怀副院长诞辰九十周年［沈中毅］
- 郭永怀与我国导弹弹头再入气动物理研究［魏叔如］
- 科研工作引路人--纪念郭永怀九十诞辰［胡在军］
- 科技楷模，引路良师--怀念敬爱的郭永怀副院长［朱竟洪 郑百瑛］
- 七律 永怀永怀郭老师［董务民］
- 留得春晖映核魂--怀念我们的好领导好老师郭永怀同志［孙德纶 张克才］
- 难以忘怀--忆郭永怀副院长事迹点滴［孙天雄］
- 研究工作与工程技术工作之间的关系［谈庆明］
- 忆敬爱的郭永怀老师［张兆顺 呼和敖德］
- 根深叶茂 厚积薄发--追忆恩师郭永怀先生教诲我打好基础［严宗毅］
- 力学前辈，科德风范［徐友钜］
- 领导的楷模 学者的典范 青年的导师--怀念郭永怀副院长［于长勤］
- 怀念郭永怀副院长［陈裕泽］
- 关于郭永怀事迹的回顾［张长富］
- 严谨的导师，可亲的长者--忆著名的空气动力学家郭永怀先生［吴兰春］
- 严谨细致 实事求是--纪念郭永怀九十诞辰［李启廉］
- 纪念核武器环境试验技术的奠基人--郭永怀副院长诞辰九十周年［李荣林］
- 郭老精神激励着材料科学研究的不断深入［周维宣 谭云］
- 郭永怀副院长的关怀与我所有机材料研究的发展［陈晓丽］
- 忆与郭永怀副院长的一次谈话［孙德纶］
- 缅怀郭永怀院士［陈家镛］
- 记郭永怀先生二三事［屠善澄］
- Remembering Yunghuai Kuo[C.C.Lin]
- Recall with love and respect[William R.Sears]
- Y.H.Kuo:An appreciation[Frank E.Marble]
- A commemorative tribute to Professor Guo Yonghuai[T.Y.Wu]
- Y.H.Kuo:A great scientist,revered teacher and good friend[Alfred Ritter]
- 氢氧燃烧及爆轰驱动激波管［俞鸿儒］
- 颗粒材料中致密波结构研究［孙锦山 朱建士 贾祥瑞］
- 网格与高精度差分计算问题［张涵信 呙超 宗文刚］
- 植被层湍流的大涡模拟［李家春 谢正桐］
- 半浮区液桥热毛细振荡流［唐泽眉 阿燕 胡文瑞］
- 再入湍流尾迹及其对雷达散射的影响研究［牛家玉 于明］
- 超声射流中CS2分子态分辨转动弛豫研究［陈从香 刘世林 戴静华 张志萍 马兴孝］
- 37mm冲压加速器实验和计算［柳森 简和祥 白智勇 平新红 部绍清］
- 化学体系中噪声诱导的时空有序结构和随机共振［辛厚文 侯中怀 杨灵法］
- 根据守恒律计算热流和摩阻的有限元提法［童秉纲 段占元］
- 高阶精度线性耗散紧致格式的渐近稳定性［邓小刚 毛枚良］
- 离散流体力学：理论和数值方法［高智］
- 2号复合离心机自动控制系统研制［王磊 林明 冯晓军］
- 海沧大桥气动弹性特性风洞试验研究［李明水 陈忻 张大康 王卫华］
- 内爆炸载荷下圆管变形、损伤和破坏规律的研究［李永池 李大红 魏志刚 孙宇新］
- 两种凝聚炸药的静态断裂性能实验研究［罗景润 韦日演 马丽莲］
- 圆柱体侵彻薄靶极限击穿速度估算探讨［吴应白 唐平］
- 动力学修改方法在夹具设计中的应用研究［蒲怀强 唐定勇］
- Numerical simulation of non-linear stability of two-dimensional supersonic boundary layer［Shen Qing Yuan Xiangjiang］
