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

In meccanica, un sistema di forze complanari subisce diversi tipi di reazioni tra il punto di contatto e i supporti.
Il supporto impedisce il moto di traslazione del sistema applicando una forza uguale e contraria. Impedisce inoltre la rotazione del sistema applicando un paio di momenti nella direzione opposta.
Il supporto a rulli permette alla struttura di traslare in una sola direzione. La reazione al supporto del rullo sarà una singola forza che agisce perpendicolarmente al supporto.
Un supporto a perno consente solo la rotazione della trave, limitandone il movimento di traslazione. Produce una reazione alla forza applicata nel piano perpendicolare all'asse del perno. Questa forza può essere risolta nelle sue componenti rettangolari.
Il supporto fisso impedisce alla struttura di traslare e ruotare in qualsiasi direzione fornendo due forze di reazione e un momento a qualsiasi forza applicata. La forza Fx agisce in direzione orizzontale lungo l'asse del supporto, mentre Fy agisce in direzione normale al supporto.

<ol>
	<li>Hibbeler, R.C. (2016). Ingegneria Meccanica \u2012 Statica e Dinamica. Hoboken, New Jersey: Pearson Prentice Hall. pagine 209-211</li>
</ol>

reazioni di supporto

Support Reactions

Un sistema di forze complanari si riferisce a un insieme di forze che giacciono tutte sullo stesso piano e sono soggette a diverse reazioni tra il punto di contatto e i supporti. Comprendere come diversi tipi di supporto influenzino le forze complanari è cruciale per la progettazione di strutture sicure e affidabili in grado di resistere a carichi esterni.

Lo scopo dei supporti è quello di prevenire il movimento traslatorio del sistema, applicando una forza uguale ed opposta e di prevenire la rotazione del sistema, applicando una coppia di momenti nella direzione opposta. A seconda del loro scopo e dell'applicazione, ci sono tre tipi principali di supporti: supporto a rullo, supporto a perno e supporto fisso.

Il supporto a rullo consente la traslazione in una sola direzione fornendo una singola forza di reazione normale alla sua superficie. Questo tipo di supporto viene spesso utilizzato dove è necessario limitare il movimento, come ad esempio ponti che si espandono o si contraggono a causa dei cambiamenti di temperatura.

Il supporto a perno fornisce una forza di reazione nel piano perpendicolare al suo asse quando sottoposto a una forza applicata. Ciò permette la rotazione ma limita il movimento traslatorio, rendendolo utile per strutture con sbalzi o condizioni di carico uniformi lungo la loro lunghezza.

Infine, il supporto fisso previene sia la traslazione che la rotazione fornendo due forze di reazione e un momento ad una qualsiasi forza applicata. Questo tipo di supporto viene spesso utilizzato negli edifici a causa delle elevate esigenze di stabilità.

Reazioni di supporto

Un sistema di forze complanari si riferisce a un insieme di forze che giacciono tutte sullo stesso piano e sono soggette a reazioni diverse tra il punto di contatto e ...

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Ingegneria Meccanica

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Equilibrium of a Rigid Body

Equilibrio di un corpo rigido

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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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