984 resultados para Tire Shear Force.
Effects of shear on eggs and larvae of striped bass, morone saxatilis, and white perch, M. americana
Resumo:
Shear stress, generated by water movement, can kill fish eggs and larvae by causing rotation or deformation. Through the use of an experimental apparatus, a series of shear (as dynes/cm2)-mortality equations for fixed time exposures were generated for striped bass and white perch eggs and larvae. Exposure of striped bass eggs to a shear level of 350 dynes/cm2 kills 36% of the eggs in 1 min; 69% in 2 min, and 88% in 4 min; exposure of larvae to 350 dynes/cm2 kills 9.3% in 1 min, 30.0% in 2 min, and 68.1% in 4 min. A shear level of 350 dynes/cm2 kills 38% of the white perch eggs in 1 min, 41% in 2 min, 89% in 5 min, 96% in 10 min, and 98% in 20 min. A shear level of 350 dynes/cm2 applied to white perch larvae destroys 38% of the larvae in 1 min, 52% in 2 min, and 75% in 4 min. Results are experimentally used in conjunction with the determination of shear levels in the Chesapeake and Delaware Canal and ship movement for the estimation of fish egg and larval mortalities in the field.
Resumo:
Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 bulk metallic glasses (BMGs) with significant difference in inherent plasticity and quite similar chemical composition was studied by depth sensitive macroindentaion tests with conical indenter. Well-developed shear band pattern can be found for both BMGs after indentation. Distinct difference in the shear band spacing, scale of plastic deformation region and the shear band branching in the two BMGs account for the different plasticity.
Resumo:
Models describing wet adhesion between indenters and substrates joined by liquid bridges are investigated. The influences of indenter shapes and various parameters of structures on capillary force are focused. In the former, we consider several shapes, such as conical, spherical and truncated conical indenter with a spherical end. In the latter, the effects of the contact angle, the environmental humidity, the gap between the indenter and the substrate, etc. are included. Different dependences of the capillary force on the indenter shapes and the geometric parameters are observed. Most interesting finding is that applying the present results to micro- and nano-indentation experiments shows the size effect in indentation hardness not produced but underestimated by the effects of capillary force.(4 refs)
Resumo:
The Taylor series expansion method is used to analytically calculate the Eulerian and Lagrangian time correlations in turbulent shear flows. The short-time behaviors of those correlation functions can be obtained from the series expansions. Especially, the propagation velocity and sweeping velocity in the elliptic model of space-time correlation are analytically calculated and further simplified using the sweeping hypothesis and straining hypothesis. These two characteristic velocities mainly determine the space-time correlations.
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:
本文集共收录了作者24篇期刊论文和研究报告。其中，1943～1955年期间发表的14篇论文内容涉及直管中的可压缩流动、有限振幅柱面和球面波的传播、可压缩流体二维无旋亚声速、超声速混合型流动和上临界马赫数、光滑跨声速绕流及其稳定性、斜激波从平板边界层的反射、中等雷诺数下绕平板的流动等。1956～1957年期间发表的5篇论文：绕平板和楔的高超声速流动、普朗特数和解离对高超声速流动的影响以及增补的5篇文章是作者在高超声速流动领域的研究成果以及他在回国后的学术报告和发表的文章，涉及现代空气动力学的发展方向、发射卫星和返地回收的科学和技术问题，体现了他在参与“两弹一星”技术领导工作中的学术思想。2 The flow of a compressible viscous fluid through a straight pipe.（可压缩黏性流体在直管中的流动1943年）
3 Two dimensional irrotational mixed subsonic and supersonic flow of a compressible fluid and the upper critical Mach number（可压缩流体二维无旋亚声速和超声速混合型流动及上临界马赫数1946年）
4 On the stability of transonic flows（论跨声速流的稳定性1947年）
5 The propagation of a spherical or a cylindrical wave of finite amplitude and the production of shock waves（有限振幅球面波或柱面波的传播及激波的产生1947年）
6 Two-dimensional irrotational transonic flows of a compressible fluid（可压缩流体二维无旋跨声速流动1948年）
7 On the hodograph method（关于速度图方法1949年）
8 Two-dimensional transonic flow past airfoils（绕翼型的二维跨声速流1951年）
9 On the stability of two-dimensional smooth transonic flows（论二元光滑跨声速流的稳定性1951年）
10 On the flow of an incompressible viscous fluid past a flat plate at moderate Reynolds numbers（中等雷诺数下不可压缩黏性流体绕平板的流动1953年）
11 Reflection of a weak shock wave from a boundary layer along a flat plate.I：Interaction of weak shock waves with laminar and turbulent boundary lavers analyzed by momentum-integral method（弱激波从沿平板的边界层的反射Ⅰ：用动量积分方法分析弱激波与层流和湍流边界层的相互作用1953年）
12 Reflection of weak shock wave from a boundary layer along a flat plate.Ⅱ：Interaction of oblique shock wave with a laminar boundary layer analyzed by differential-equation method（弱激波从沿平板的边界层的反射Ⅱ：用微分方程方法分析斜激波与层流边界层的相互作用1953年）
13 Plane subsonic and transonic potential flows（平面亚、跨音速势流1954年）
14 A similarity rule for the interaction between a conical field and a plane shock（锥型流和激波相互作用的相似律1955年）
15 Viscous flow along a flat plate moving at high supersonic speeds（沿高超声速运动平板的黏性流动【Ⅰ】1956年）
16 Viscous flow along a flat plate moving at high supersonic speeds（沿高超声速运动平板的黏性流动【Ⅱ】1956年）
17 The effects of Prandtl number on high-speed viscous flows over a flat plate（Prandtl数对绕平板高速黏性流的影响1956年）
18 Compressible viscous flow past a wedge moving at hypersonic speeds（楔的高超声速可压缩黏性绕流1956年）
19 Dissociation effects in hypersonic viscous flows（高超声速黏性流动中的离解效应1957年）
20 现代空气动力学的问题（1957年）
2l 在关于苏联发射成功第一颗人造卫星座谈会上的发言记录（1957年）
22 高超速钝体湍流传热问题（1963年）
23 宇宙飞船的回地问题（1965年）
24 激波的介绍
郭永怀生平
郭永怀传
