Name: 3d support types for stability and motion
Uploaded: 2023-09-22T11:49:23.000Z
Duration: 1 min 27 s
Channel: JoVE

En fonction de leur application, les supports sont utilisés dans la construction mécanique. Ces réactions de support dans un système de force tridimensionnel empêchent le système de se déplacer et de tourner.
Considérez un bras robotique soulevant un poids. Ici, l’articulation A est une articulation à rotule. Le bras est libre de tourner autour de n’importe quel axe car il n’y a pas de moment pour restreindre la rotation dans l’articulation à rotule. Cependant, il restreint le mouvement de translation en raison des trois forces de réaction le long des trois dimensions.
Alternativement, l’articulation B sur le bras est un support de goupille lisse unique. Ce support crée trois forces de réaction et deux moments de couple et permet le mouvement de rotation le long de l’axe de la goupille.
La base du bras robotique est un support fixe, ayant des forces et des moments de réaction dans les trois directions.
Un autre type de support est le support de charnière, couramment utilisé dans une porte. Trois forces de réaction sur le support limitent le mouvement de translation de la porte, tandis que deux moments limitent la rotation de la porte.

<ol>
	<li>Hibbeler, R.C. (2016). Génie mécanique \u2012 Statique et dynamique. Hoboken, New Jersey : Pearson Prentice Hall. p. 245 à 248</li>
	<li>Bière, F.P. ; Johnston, E.R. ; Mazurek, D.F ; Cromwell, P.J. et Self, B.P. (2019). Mécanique vectorielle pour les ingénieurs \u2012 Statique et dynamique. New York : McGraw-Hill. p. 208</li>
	<li>Meriam, J.L. ; Kraige, L.G. et Bolton, J.N. (2020). Génie mécanique \u2012 Statique. Hoboken, New Jersey : John Wiley. page 145</li>
</ol>

réactions de support en trois dimensions

Support Reactions in Three Dimensions

Les réactions de support en trois dimensions aident à maintenir la stabilité et l'équilibre de différentes structures et systèmes. Ces réactions empêchent le système de se déplacer et de tourner, garantissant que la conception puisse résister aux forces externes et remplir sa fonction prévue de manière efficace et sécurisée. Certains des supports fournissant des réactions de support en trois dimensions sont discutés ci-dessous : L'articulation à rotule est l'un des supports permettant une rotation libre autour de n'importe quel axe. Cette liberté de rotation est possible car il n'y a pas de moment restreignant la rotation dans l'articulation à rotule. Cependant, l'articulation restreint le mouvement de translation en raison de trois forces de réaction le long des trois dimensions. Un autre type de support est le support à goupille lisse unique. Ce support crée trois forces de réaction et deux moments couples, permettant un mouvement de rotation le long de l'axe de la goupille tout en restreignant le mouvement dans d'autres directions. Les supports fixes fournissent des forces et des moments de réaction dans toutes les trois directions. Ce type de support garantit que l'ensemble du système reste stable et sécurisé sous diverses charges et conditions, prévenant tout mouvement ou déformation indésirable qui pourrait compromettre la fonctionnalité du système. Le support à charnière est un autre type de support couramment utilisé en génie mécanique, souvent utilisé dans les portes et autres applications similaires. Avec le support à charnière, trois forces de réaction au niveau du support restreignent le mouvement de translation de la porte, tandis que deux moments restreignent la rotation de la porte. Cette disposition permet à la porte de tourner autour d'un seul axe tout en maintenant stabilité et contrôle.

Réactions de support en trois dimensions

Les réactions de support en trois dimensions aident à maintenir la stabilité et l’équilibre de diverses structures et systèmes. Ces réactions empêchent le système ...

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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 single smooth pin support works differently. It creates three reaction forces and two couple moments. This setup allows rotation along the axis of the pin while restricting movement in the other directions.

Fixed supports provide reaction forces and moments in all three directions. They help keep the system stable and secure under different loads and conditions. This also helps prevent unwanted movement or deformation that could affect function.

Hinge support is another common support used in mechanical engineering, especially in doors and similar applications. It produces three reaction forces that block translational motion of the door. Two moments restrict the door’s rotation, but it can still turn about one axis.

3D Support Types for Stability and Motion

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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...

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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...

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

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 ball and socket joints, smooth pin supports, fixed supports, and hinge supports control movement and keep 3D structures stable under load.

3D Support Types for Stability and Motion | 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.

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3D Support Types for Stability and Motion

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