摩擦は粒状固体の弾力性を高めます
1School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel. isaac@eng.tau.ac.il
Nature
|May 13, 2005
まとめ
エンジニア エンジニア
科学分野:
- 固体力学 固体力学とは
- マテリアルサイエンス 材料科学
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 粒状固体の伝統的なエンジニアリングモデルは,弾性理論とプラスチック理論を使用しています.
- 最近の発見は,粒状の材料におけるストレスの伝播が,静的弾性 (円方程式) に挑戦する,ハイパーボリックな波形方程式に従う可能性があることを示唆しています.
研究 の 目的:
- 粒状固体反応のハイパーボリック対円モデルの妥当性を調査する.
- システムのサイズと静的摩擦がストレスの伝播に与える影響を判断する.
主な方法:
- 数値シミュレーションは,外部負荷にさらされた二次元粒状スラブ上で実行されました.
- シミュレーションでは,異なる長さのスケールでシステムの応答を分析しました.
主要な成果:
- ハイパーボリックモデルと円モデルの両方,長さスケールによって有効です.
- 小さなメソスコピックなシステムは,ハイパーボリックのようなアニソトロピックな反応を示します.
- エンジニアリングに特有の大型システムは,同位体弾力性に近い反応を示します.
結論:
- 粒状固体のモデル (ハイパーボリック対円型) の選択は,システムの長さスケールに決定的に依存します.
- 静的摩擦は,弾性範囲を拡大し,粒状の材料の同otropic 振る舞いを促進するために,非常に重要です.
関連する概念動画
01:07Frictional Force
When a body is in motion, it encounters resistance because the body interacts with its surroundings. This resistance is known as friction, a common yet complex force whose behavior is still not completely understood. Friction opposes relative motion between systems in contact, but also allows us to move. Friction arises in part due to the roughness of surfaces in contact. For one object to move along a surface, it must rise to where the peaks of the surface can skip along the bottom of the...
01:05Static and Kinetic Frictional Force
One of the simpler characteristics of sliding friction is that it is parallel to the contact surfaces between systems, and is always in a direction that opposes the motion or attempted motion of the systems relative to each other. If two systems are in contact and moving relative to one another, then the friction between them is called kinetic friction. For example, kinetic friction slows a hockey puck sliding on ice.
However, if two systems are in contact and are stationary relative to one...
However, if two systems are in contact and are stationary relative to one...
01:30Dry Friction
Dry friction occurs between two solid surfaces in contact as they attempt to move relative to one another. In daily life, dry friction is encountered in various forms, such as when walking on the ground, sliding an object across a table, or rubbing hands together. Despite its ubiquity, the underlying mechanisms behind dry friction are not readily visible.
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01:26Kinetic Friction
Consider a truck trying to pull a stationary car. As the truck exerts a force on the car, static friction is created at the point of contact between the two surfaces. This frictional force resists the car's movement and keeps it at rest. However, when the applied force by the truck surpasses the limiting static frictional force, an interesting phenomenon occurs. The frictional force at the interface reduces to a lower value, known as the kinetic frictional force. At this point, the car begins...
01:21Characteristics of Dry Friction
Dry friction occurs when two solid surfaces slide against each other without any lubrication or fluid present. It causes resistance when pushing objects along a surface, like a gardener pushing a wheelbarrow. The force applied to move the cart causes dry friction between the wheel and the ground.
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01:27Types of Friction Problems
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.