Name: axial load stress on inclined sections
Uploaded: 2024-03-07T13:22:32.000Z
Duration: 1 min 16 s
Channel: JoVE

Considérons un membre soumis à des forces axiales. Introduisez un plan de section incliné par rapport au plan normal, appelé plan oblique.
Les contraintes agissant sur ce plan oblique peuvent être résolues en deux composantes : normale et tangentielle à la section.
La composante normale représente la résultante des forces normales réparties sur la section, tandis que la composante tangentielle représente la résultante des forces de cisaillement.
Les contraintes normales et de cisaillement moyennes peuvent être calculées en divisant les forces normales et tangentielles par l’aire de la section.
La contrainte normale est maximale lorsque le plan de la section est perpendiculaire à l’axe de la barre et tend vers zéro lorsque le plan de section est parallèle à l’axe.
La contrainte de cisaillement est maximale lorsque le plan de section est incliné de 45 degrés et tend vers zéro lorsque le plan de section est parallèle ou perpendiculaire à l’axe de l’élément.
Selon l’orientation du plan, la même charge peut produire soit une contrainte normale sans contrainte de cisaillement, soit des contraintes normales et de cisaillement d’égale amplitude.

contrainte sur un plan oblique

Stress on an Oblique Plane

Comprendre les contraintes sur un plan oblique sous chargement axial est essentiel en mécanique des matériaux. Cette analyse donne un aperçu de la durabilité et de la résistance d'un matériau, ce qui est crucial pour la génie civil et la conception structurelle. Le chargement axial fait référence à l'application d'une force le long de l'axe central du matériau, provoquant une compression ou un allongement et conduisant à une contrainte normale. Une contrainte normale se produit lorsqu'une force agit perpendiculairement à la surface du matériau, entraînant une contrainte de compression ou de traction. Lorsque le plan de contrainte n'est pas perpendiculaire à la charge, il s'agit d'un plan oblique et l'état de contrainte inclut à la fois les contraintes normales et les contraintes de cisaillement. La contrainte de cisaillement se produit lorsque la force agit parallèlement à la zone, déformant ainsi le matériau sans qu’il change de volume.

En considérant un élément à deux forces soumis à une force axiale P et en examinant une section faisant un angle θ par rapport au plan normal, les contraintes sur ce plan oblique peuvent être divisées en composantes normales (F) et tangentielles (V). En divisant F et V par la surface de la section, nous obtenons les contraintes moyennes normale et de cisaillement. L'orientation du plan a un impact significatif sur l'état de contrainte du matériau. Selon l'orientation du plan, la même charge peut induire uniquement des contraintes normales ou des contraintes normales et de cisaillement d'égale ampleur. Une telle compréhension est cruciale pour concevoir des structures robustes et efficaces.

Contrainte sur un plan oblique

Considérons un membre soumis à des forces axiales. Introduisez un plan de section incliné par rapport au plan normal, appelé plan oblique.
Les contraintes agissant sur ...

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Mechanical Engineering

Génie mécanique

Unit 1

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Concept of Stress

Le concept de stress

KEY TERMS AND CONCEPTS

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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 volume.

A two-force member under an axial force P can be cut by a section at an angle θ to the normal plane. The force on that section can be resolved into a normal component F and a tangential component V. Dividing F and V by the section area gives the average normal stress and average shearing stress.

The orientation of the plane strongly changes the stress on the material. For some angles, the same load produces only normal stress. For other angles, it produces both normal and shearing stress, and these stresses may be equal in magnitude. This idea is important in civil engineering and structural design, where strength and durability matter.

Axial Load Stress on Inclined Sections

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

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...

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 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 axial loading creates normal and shearing stress on inclined sections, and how plane angle changes the stress state in materials.

Axial Load Stress on Inclined Sections | 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

Axial Load Stress on Inclined Sections

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