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I read in my student's book that elastic waves can be transverse and longitudinal. After a little research I knew that there is an elastic solid (not an elastic wave).

I can imagine a longitudinal wave (the horizontal spring example), but was interested in the case of transverse elastic wave.

Here, "Transverse waves commonly occur in elastic solids", I want to see the effect of elasticity in a transverse wave. The easiest example to me of a transverse wave is the experiment of a rope, fixed in one end, and in the other end moved up and down fast vertically (back to the original horizontal level). But this is not applicable for the concept of elasticity, since each set of particles of the rope are due to constantly (continuously) driving force which finally sets the particles back to their original calm horizontal level with a null force (as far as I can imagine), so the question of elasticity doesn't hold here since it deals with the case of what comes after a non-null force with deformation of the object.

Can someone give an example? Is the book's sentence correct ?

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  • $\begingroup$ Not sure if I understand the question, but you seem to be confusing elasticity with plasticity. $\endgroup$ – Ruslan Jan 14 at 16:46
  • $\begingroup$ Not really, I understand there is a limit between elasticity and plasticity. I'm arguing about the sentence I read and the example I tried to make compatible with the sentence. I haven't found a valid example for an elastic transverse wave. So I'm asking for one. I'm saying that a rope can be plastic (non-elastic) and would still behave the same. As if elasticity has no effect on (any ?) transverse wave. $\endgroup$ – YoussefDir Jan 14 at 16:58
  • $\begingroup$ Consider a thick metal plate. Hit it with a hammer over the large side (as if the plate were a drum), somewhere near the border. The displacement will appear at the other border after some time. It'll have travelled there as a transverse wave. $\endgroup$ – Ruslan Jan 14 at 17:12
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    $\begingroup$ The deformation of the plate is elastic (unlike the rope, whose shape is restored by gravity — if I understand your example correctly) $\endgroup$ – Ruslan Jan 14 at 17:37
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    $\begingroup$ maybe this link will help encyclopedia2.thefreedictionary.com/Elastic+Wave $\endgroup$ – anna v Jan 14 at 19:12
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Earthquakes produce both compression waves and transverse waves which travel through the earth at different speeds. The time gap between their arrival can be used to estimate the distance between the seismograph and the quake. The compression waves can travel through the liquid core of the earth. The transverse waves do not.

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The transverse wave in an elastic body in 3D. For animation, the equations of the theory of elasticity, FEM and Mathematica 12 are used. Figure 1

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As @anna v pointed out in the comment, according to the definition in this link,

the displaced particles transfer momentum to adjoining particles, and are themselves restored to their original position.

I was considering this force that restores them back to their original position as a foreign force, this is why I was wondering where the elasticity is. The source of confusion was that this momentum transfer incident was itself the cause of wave propagation (not only was it the restoring cause), which was a little non-evident with the definition of elasticity, where the cause or force is usually an outsider one.

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