机械接触的连续模型的分解
1Department of Physics & Astronomy, Johns Hopkins University, 3400 N. Charles Streeet, Baltimore, Maryland 21218, USA.
Nature
|June 17, 2005
概括
连续接触力学由于表面粗而在原子尺度上崩,显著改变了纳米系统中接触面积,摩擦和粘附的预测.
科学领域:
- 部落学 (tribology) 是一个学科.
- 纳米机械学 纳米机械学
- 材料科学 材料科学 材料科学
背景情况:
- 原子接触区域的力对摩擦和粘附至关重要.
- 连续接触力学在原子尺寸上失败,但适用于纳米系统.
研究的目的:
- 为了研究连续接触力学在原子尺度上的分解.
- 确定原子离散度和表面粗度对接触力学预测的影响.
主要方法:
- 在理想条件下利用分子模拟.
- 在纳米级测试了连续接触力学的有效性.
主要成果:
- 大体固体中的原子离散度的影响很小.
- 原子尺度的表面粗度导致了连续理论的显著偏差.
- 接触面和应力变化了两倍;摩擦和刚性变化了数量级.
结论:
- 原子尺度的表面粗度,而不是大量的离散度,使连续力学在小尺度上无效.
- 研究结果影响了对具有小接触区域的宏观粗表面的预测.
相关概念视频
An Introduction to Mechanics
7.2K
Humans have been making ships, shelters, pyramids, weapons, agricultural equipment, and many more items without recording the process or theory behind them for centuries. It would be challenging to document the evolution of mechanics from its origin to the present.
According to records, the history of mechanics starts with Aristotle (384–322 BC). He related mechanics to physical theory, aiming for a universal synthesis.
Newton defined mechanics as the branch of physical science that...
According to records, the history of mechanics starts with Aristotle (384–322 BC). He related mechanics to physical theory, aiming for a universal synthesis.
Newton defined mechanics as the branch of physical science that...
7.2K
System of Forces and Couples
782
In the analysis of structural systems, it is common to encounter members subjected to various forces and couple moments. Simplifying these systems can make the analysis more manageable and easier to understand. One approach to achieve this simplification is by moving a force to a point O that does not lie on its line of action and adding a couple with a moment equal to the moment of the force about point O.
The principle of transmissibility plays a crucial role in this process. According to...
The principle of transmissibility plays a crucial role in this process. According to...
782
Types of Friction Problems
1.1K
Friction is an essential concept in physics, engineering, and everyday life. It is the force that opposes the relative motion or tendency of such motion between two surfaces in contact. One of the most common types of friction encountered in various applications is dry friction. Dry friction problems can be broadly categorized into three types, each with unique characteristics and challenges.
The first type of dry friction problem involves situations where there is no apparent impending motion....
The first type of dry friction problem involves situations where there is no apparent impending motion....
1.1K
Stability of structures
679
In mechanical engineering, the stability of systems under various forces is critical for designing durable and efficient structures. One fundamental way to explore these concepts is by analyzing systems like two rods connected at a pivot point, O, with a torsional spring of spring constant k at the pivot point. This system is similar in appearance to a scissor jack used to change tires on a car. In this case, the arms of the linkage (equivalent to the rods in this system) are entirely vertical,...
679
Mechanical Systems
904
Mechanical systems are analogous to to electrical networks where springs and masses play similar roles to inductors and capacitors, respectively. A viscous damper in mechanical systems functions similarly to a resistor in electrical networks, dissipating energy. The forces acting on a mass in such systems include an applied force in the direction of motion, counteracted by forces from the spring, a viscous damper, and the mass's acceleration. This interplay of forces is mathematically...
904
Mechanistic Models: Overview of Compartment Models
588
Mechanistic models, a category encompassing both physiological and compartmental modeling, differ from empirical models' approaches to incorporating known factors about the systems being modeled. Empirical models describe data with minimal assumptions, while mechanistic models aim to provide a robust description of available data by specifying assumptions and integrating known factors about the system. Compartmental analysis is a key example of a mechanistic model in pharmacokinetics and...
588


