Name: bolt-to-plate contact pressure
Uploaded: 2025-05-22T09:06:17.000Z
Duration: 1 min 22 s
Channel: JoVE

La contrainte exercée sur un matériau en raison de la pression de contact créée lors de l’interaction avec un autre objet est appelée contrainte de roulement.
Considérons deux plaques reliées par un boulon. Le boulon applique une force interne sur l’une des plaques. Cette force interne est équivalente mais opposée à la force que la plaque exerce sur le boulon.
Ici, la force interne n’est pas unique, mais résulte de nombreuses forces plus petites qui sont réparties sur la surface intérieure du demi-cylindre.
En raison de la complexité des forces plus petites et des contraintes correspondantes, une contrainte nominale moyenne, connue sous le nom de contrainte d’appui, est souvent utilisée à des fins de simplification.
La contrainte d’appui est calculée en divisant la force interne par l’aire du rectangle qui représente la projection du boulon sur la section de la plaque. Cette zone est le produit de l’épaisseur de la plaque et du diamètre du boulon.
Le concept de contrainte portante est essentiel pour garantir des conceptions structurelles sûres et efficaces et améliore ainsi la durée de vie de la structure.

contrainte d’appui/pression

Bearing Stress

La contrainte d'appui fait référence à la pression de contact entre deux corps distincts. Pour visualiser cela, imaginez un boulon enfoncé dans une plaque. Le boulon applique une force à la plaque, qui exerce une force égale mais opposée sur le boulon. Cette force n'est pas seulement une entité singulière mais une compilation de nombreuses forces plus petites réparties sur la surface de contact entre le boulon et la plaque.

En raison de la complexité de ces microforces, une valeur moyenne, appelée contrainte d’appui, est souvent utilisée par les ingénieurs à des fins de simplification. La contrainte d’appui est déterminée en divisant la charge appliquée du boulon par la surface projetée du boulon sur la plaque.

<img alt="Equation 1" src="/files/ftp_upload/15581/15581_Equation_1.svg" style="text-align: center; height: 46px;">
La compréhension des contraintes portantes est une partie essentielle de l’ingénierie structurelle. Il donne aux ingénieurs une compréhension critique de la manière dont les différentes forces interagissent au sein d’une structure. Ces connaissances sont cruciales lors de la conception de structures car elles contribuent à garantir la sécurité et l’efficacité de leur conception.
En calculant avec précision la contrainte d’appui, les ingénieurs peuvent prévenir les défaillances potentielles dues à une force excessive ainsi que prolonger la durée de vie de la structure. En conclusion, cette contrainte est un concept central en ingénierie des structures. C’est un facteur clé pour déterminer la durabilité et la sécurité d'une structure.

Contrainte d’appui/pression

La contrainte exercée sur un matériau en raison de la pression de contact créée lors de l’interaction avec un autre objet est appelée contrainte de roulement.
Considérons deux assiettes...

Education

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JoVE Core

Mechanical Engineering

Génie mécanique

Unit 1

Unité 1

Concept of Stress

Le concept de stress

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

bolt-to-plate contact pressure

Bearing stress is the contact pressure between two separate bodies. A common example is a bolt pushed through a plate. The bolt applies a force to the plate, and the plate pushes back with an equal and opposite force.

That force is not a single point load. It is made up of many smaller forces spread across the contact surface between the bolt and the plate. Because these microforces are complex, engineers use an average value called bearing stress.

Bearing stress is found by dividing the bolt’s applied load by the projected area of the bolt on the plate. This calculation helps engineers understand how forces act inside a structure. It is an important part of structural engineering because it supports safe and efficient design.

By calculating bearing stress correctly, engineers can reduce the risk of failure from too much force. It also helps them improve the lifespan of a structure. Bearing stress is a key factor in judging durability and safety.

Bolt-to-Plate Contact Pressure

normal stress

Normal Stress in Axial Loading

Normal stress acts perpendicular to a material’s cross-sectional area. It appears when a force is applied along the axis of an object, which is called axial loading. Bridge truss members are a practical example of this kind of loading. When a rod carries axial load, internal forces develop across the section. Because these forces act normal to the plane of the section, the stress is called normal stress. Stress here means the average stress over the whole cross-section, not the value at one...

shearing stress

Shear Forces in Bolts and Rivets

Shearing stress is caused by transverse forces acting on an object. These forces create internal forces in the plane where the external forces are applied. The total internal force in that section is called the shear. Average shearing stress is found by dividing the shear by the cross-sectional area. This value is only an average, because shear stress is not spread evenly across the section. It can be zero at the surface and much higher than the average in other areas. Bolts, pins, and rivets...

bearing stress

Bearing stress is the contact pressure between two separate bodies. A common example is a bolt pushed through a plate. The bolt applies a force to the plate, and the plate pushes back with an equal and opposite force. That force is not a single point load. It is made up of many smaller forces spread across the contact surface between the bolt and the plate. Because these microforces are complex, engineers use an average value called bearing stress. Bearing stress is found by dividing the...

applications of stress

Boom and Rod Stress Analysis

Boom and rod stress analysis shows how a pinned support structure carries a load. The boom and the rod are connected by a pin and held in place by brackets and pins. The structure is then separated from its supports so the forces can be studied clearly. A free-body diagram is drawn to identify every force on the boom, the rod, and the load. The reaction forces on both members are found using equilibrium equations. At point P, the reaction causes compression in the boom. At point R, the...

stress on an oblique plane

Axial Load Stress on Inclined Sections

Axial loading creates stress in a material along its central axis. This kind of load can cause compression or elongation, and it produces normal stress. Normal stress acts perpendicular to the material area and can be either tensile or compressive. When the section is not perpendicular to the load, it becomes an oblique plane. On this inclined plane, the stress state includes both normal stress and shearing stress. Shearing stress acts parallel to the area and changes shape without changing...

stress: general loading conditions

Stress Components on a Loaded Body

Stress components on a loaded body can be found by cutting the body through a point with a plane parallel to the xy plane. That section carries the original loads, along with normal forces and shearing forces. The result is a simple way to describe how a structure responds under combined loading. The shearing force in the section can point in different directions within the plane. It is split into two parts that run parallel to the x and y axes. Each part is divided by the area, and as that...

components of stress

Stress Components on a Cube at a Point

Stress components on a small cube help describe how a body behaves under multiple loading. The cube is centered at point O and has stress acting on all six faces, whether the faces are visible or hidden. Normal stress components σx, σy, and σz act perpendicular to the x, y, and z axes. Shearing stress components also act on the cube faces. The visible faces carry shear stresses such as τxy and τxz. The hidden faces carry equal and opposite stresses. This balance keeps the cube in equilibrium.

design consideration

Safety Factors in Structural Design

Safety factors in structural design help engineers choose a material and loading limit that can be used safely. The process begins with a material’s ultimate strength. This value comes from tests that increase force until the material reaches its breaking point or limit. The ultimate load is then divided by the original cross-sectional area to find the ultimate normal stress, or strength. Ultimate shearing stress is another key value used in design. These limits show how much stress a material...

key terms and concepts

Learn how bearing stress describes contact pressure between a bolt and a plate, how it is calculated, and why it matters in structural engineering.

Bolt-to-Plate Contact Pressure | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

Bolt-to-Plate Contact Pressure

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