Difference between elastic plastic deformations

Elastic and plastic deformation

Are you wondering what the difference between elastic and plastic deformation is? In this video we explain it to you!

  • Explanation and difference between elastic and plastic deformation when forces act on materials
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  • Here is a little summary for you:
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Explanation and difference between elastic and plastic deformation when forces act on materials

When mechanical components are under load, they normally act on them Powers or Torques. These forces cause tension in the material. The Size of these tensions is calculated from the force acting per area:

Since materials are usually not completely rigid, they deform when the forces act on the body. The Deformations can, for example, be elongations, bends, twists or compressions. The type and strength of the deformation depend on the material itself, its deformability and the type of load.

Basically, in mechanics, between two types of deformation differentiated:

  1. the elastic and
  2. the plastic deformations.

Elastic deformation

We start with the elastic deformation.

One speaks of this when a material returns to the original initial state going back. The deformation only lasts as long as there is a load.

So our bar will be with a Force F burdened. In doing so, he bends over downward. As soon as the bar is again unloaded, it goes back to its original state.

Example: You can also imagine this on a rubber ball. Let's say you throw this against a wall. Upon impact, the atomic lattice of the material is compressed, but no atoms migrate from their places in the lattice. The ball is squeezed together. After the pressure has ended, the ball jumps back to its original state.

With the help of Hooke's law you can calculate the deformation.

Plastic deformation

Now we come to the second deformation group, the plastic deformations.

Basically, a component should only be deformed elastically and never plastically. If the stresses on the component are too high, the component will deform irreversibly. This is called Shape change designated. But be careful! There is still an elastic part of the deformation. That means it's only one certain portion of the deformation permanent.

Let's look again at the bar from earlier. With the burden of the Force F it bends downwards around an elastic and around a plastic part. If the power is now taken away, only that remains plastic part .

A example for this, bending is a paper clip. You can bend it back, but it will never get exactly the same shape again. This is because there has already been a nuclear migration and these cannot move back to their place of origin. In extreme cases, the material can even break.

It wasn't that difficult after all. Now you know what the difference between elastic and plastic deformation is.

Here is a little summary for you:

  1. At a elastic deformation the material returns to its original state after deformation.
  2. At plastic deformations there is a change in shape. However, due to the elastic deformations present at the same time, only part of the deformation is permanent.