Name: types of structural supports
Uploaded: 2023-09-22T11:49:22.000Z
Duration: 1 min 30 s
Channel: JoVE

En mécanique, un système de force coplanaire subit différents types de réactions entre le point de contact et les supports.
Le support empêche le mouvement de translation du système en appliquant une force égale et opposée. Il empêche également la rotation du système en appliquant quelques moments dans la direction opposée.
Le support de rouleau permet à la structure de se déplacer dans une seule direction. La réaction au niveau du support du rouleau sera une force unique agissant normalement au support.
Un support de goupille ne permet que la rotation du faisceau, limitant ainsi son mouvement de translation. Il produit une réaction à la force appliquée dans le plan perpendiculaire à l’axe de la goupille. Cette force peut être résolue en ses composantes rectangulaires.
Le support fixe empêche la structure de se déplacer et de tourner dans n’importe quelle direction en fournissant deux forces de réaction et un moment à toute force appliquée. La force Fx agit dans le sens horizontal le long de l’axe du support, tandis que Fy agit normalement au support.

<ol>
	<li>Hibbeler, R.C. (2016). Génie mécanique \u2012 Statique et dynamique. Hoboken, New Jersey : Pearson Prentice Hall. p. 209 à 211</li>
</ol>

réactions de support

Support Reactions

Un système de forces coplanaires fait référence à un ensemble de forces qui se trouvent toutes dans le même plan et sont soumises à différentes réactions entre le point de contact et les supports. Comprendre comment différents types de supports affectent les forces coplanaires est crucial pour la conception de structures sûres et fiables qui peuvent supporter des charges externes.
Le but des supports est d’empêcher le mouvement de translation du système en appliquant une force égale et opposée, ainsi que d’empêcher la rotation du système en appliquant des moments couple dans la direction opposée. Selon leur objectif et leur application, il existe trois principaux types de supports : le support à rouleau, le support à goupille et le support fixe. Le support à rouleau permet la translation dans une seule direction en fournissant une force de réaction unique perpendiculaire à sa surface. Ce type de support est souvent utilisé lorsque le mouvement doit être restreint, comme les ponts qui se dilatent ou se contractent en fonction des variations de température. Le support à goupille fournit une force de réaction dans le plan perpendiculaire à son axe lorsqu'il est soumis à une force appliquée. Cela permet la rotation mais restreint le mouvement de translation, ce qui en fait un choix adapté pour les structures avec des porte–à–faux ou des conditions de charge uniforme le long de sa longueur. Enfin, le support fixe empêche à la fois la translation et la rotation en fournissant deux forces de réaction et un moment à toute force appliquée. Ce type de support est souvent utilisé dans les bâtiments en raison de ses exigences élevées en termes de stabilité.

Réactions de support

Un système de forces coplanaires fait référence à un ensemble de forces qui se trouvent toutes dans le même plan et sont sujettes à des réactions différentes entre le point de contact et ...

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Mechanical Engineering

Génie mécanique

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Equilibrium of a Rigid Body

Équilibre d'un corps rigide

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types of structural supports

Types of structural supports control how a coplanar force system moves and reacts under load. A coplanar force system is a set of forces that all lie in the same plane. The supports create reactions at the point of contact. These reactions help keep a structure stable under external forces.

Supports work by stopping translation with an equal and opposite force. They can also stop rotation by applying a couple moment in the opposite direction. In structural design, these reactions are important for safe and reliable systems. They help structures resist loads without unwanted motion.

There are three main support types: roller support, pin support, and fixed support. A roller support allows translation in only one direction. It provides a single reaction force normal to its surface. This support is useful where movement must still happen in a controlled way, such as in bridges that expand or contract with temperature changes.

A pin support provides a reaction force in the plane perpendicular to its axis when force is applied. It permits rotation but restricts translational motion. This makes it useful for structures with cantilevers or with uniform loading conditions along their length. A fixed support prevents both translation and rotation. It provides two reaction forces and a moment, so it is often used in buildings where high stability is needed.

Types of Structural Supports

conditions of equilibrium

Rigid Body Force Balance in Equilibrium

Rigid body equilibrium depends on a balance of external forces and moments. A rigid body is in equilibrium when it has no translational motion and no rotational motion. This happens when the net force and the net couple acting on the body are both zero. Internal forces are not used when checking equilibrium. These forces act in equal and opposite pairs inside the body, so they cancel each other. Because of that, they do not affect the overall motion or change in motion of the rigid body. The...

support reactions

Types of structural supports control how a coplanar force system moves and reacts under load. A coplanar force system is a set of forces that all lie in the same plane. The supports create reactions at the point of contact. These reactions help keep a structure stable under external forces. Supports work by stopping translation with an equal and opposite force. They can also stop rotation by applying a couple moment in the opposite direction. In structural design, these reactions are important...

internal forces and center of gravity

Forces Inside a Body and Balance

Internal forces and the center of gravity help explain how objects stay in balance. These mechanics ideas matter for structures, machines, and vehicles that must remain stable under different loads and conditions. Internal forces are created inside a body when its particles interact. They can appear as tension, compression, or shear forces. These forces act in collinear pairs with equal magnitude and opposite direction. Between connected parts, they cancel each other and help keep the body in...

alternative sets of equilibrium equations

alternative-sets-of-equilibrium-equations

Equilibrium Conditions for a Supported Plate

Equilibrium conditions for a supported plate are used to describe when forces and moments balance. In this state, the plate has no net movement and no rotation. Engineers use these equations to study how structures behave under external loads. In many cases, the standard equilibrium equations are enough. But some systems need an alternative set of equations to match the geometry of the support points. A rectangular plate supported at points A, B, and C is one example. For this plate, the...

two force member

Two-Force Body Equilibrium

A two-force body is a rigid body acted on by only two external forces. In equilibrium, those two forces must have the same magnitude, the same line of action, and opposite directions. This balance is what keeps the body at rest. For a plate with forces F1 and F2 applied at points A and B, equilibrium means the sum of moments about any axis is zero. If moments are summed about point A, the moment from F2 must be zero. That means the line of action of F2 must pass through point A. The same idea...

three force member

Solving a Three-Force Member Example

A three-force member is a rigid body acted on by three forces at three points. The forces must have concurrent lines of action. If the forces are parallel, their lines of action stay parallel instead. A dumpster provides the example used here. It is connected to a pin support at point A and to a pin on a hydraulic cylinder at point B. The hydraulic cylinder acts as a two-force member in equilibrium. The dumpster weight acts through the center of gravity, and the support reaction acts at point...

equations of equilibrium in three dimensions

equations-of-equilibrium-in-three-dimensions

Checking Force Balance in 3D Structures

Checking force balance in 3D structures is a key step when a system is at rest. The vector and scalar equations of equilibrium are used to test whether a body is stable and will not collapse or fall apart. These equations give a clear way to study the forces acting on a body. The vector equations of equilibrium require the vector sum of all external forces on a body to equal zero. They also require the vector sum of the couple moments and the moments of all forces about a point to equal zero.

support reactions in three dimensions

3D Support Types for Stability and Motion

Support reactions in three dimensions keep structures stable and in equilibrium. They stop unwanted translation and rotation, so a design can handle external forces safely and work as intended. These reactions are important in many structures and systems. A ball and socket joint is one support that allows free rotation about any axis. It does not provide a moment that resists turning. At the same time, it restricts motion in space with three reaction forces along the three dimensions. A...

constraints and statical determinacy

Constraints in Structural Equilibrium

Constraints in structural engineering control how a body can move and help keep it in mechanical equilibrium. A constraint is a restriction on motion. When the right number of constraints is used, the system can stay balanced with the fewest supports needed. A system with the proper number of supports is called statically determinate. In that case, the unknown reaction forces can be found from equations of equilibrium. These systems are the easiest to analyze and design because the forces can...

key terms and concepts

Learn how roller, pin, and fixed supports react to coplanar forces, and how each one limits translation or rotation in structures.

Types of Structural Supports | 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

Types of Structural Supports

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