Structures

Definition

A structure is the set of elements in a body that are intended to resist the efects of the forces that act on it.

Structures are necessary because all bodies are subjected to the effects of forces that tend to deform them

Loads are the forces that act on a structure

Types of loads

• Fixed or permanent loads

• Variable loads

They always affect the structure in the same way

Are occasional and changeable

Stresses

When you make a physical effort you may notice that you can feel tension that increases as the effort increases

Objects do not have feelings, but forces act on them in a similar way and produce deformations. In both cases this internal tension is called stress.

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1.Link your two index fingers and pull on them.

  1. Press the palms of your hands together

3.Use your index finger and thumb of one hand to bend a finger on the other hand.

4.Twist one of your fingers

This tension varies depending on:

The shape of the object bearing the loads.

The characteristics of the loads

Main types of stresses

Compression compresion

flexion Bending

torsion Tosion

Cortar-300x199 Cutting

Forces try to bend a body. This stress acts on elements that are supported at their extremites and have a weight applied to them

Forces try to flatten or copress a body. Opposing forces move inwards towards one another along the same trajectory and in opposite directions.

Forces try to twist a body. They try to turn the ends of the ends of the body in opposite directions.

The forces act like two scissor blades: they are very close together, moving in opposite directions, as they try to cut an object