Hi Everyone,
I know this question has been asked a couple of times here: what is the difference between Young's modulus and storage modulus?
But the reason hasn't sunk in for me yet, so I am looking to try and answer this with a practical example to see if I am understanding it. I believe the reason it hasn't sunk in for me yet is because the values can be very different from each other and I really want to understand why.
I've read a few examples that use a rubber ball. You bounce the ball and the height of the bounce is the storage modulus while the distance that was lost can be thought of as the loss modulus. This example makes sense to me. To tie in Young's modulus to this example it would be the energy needed to stretch the ball to the point of almost ripping apart but having it go back into shape, right?
If that is the case, then I have seen materials with a Young's modulus of 120 MPa, but a Storage modulus of 900 MPa. This would make the ball relatively stretchy, but somewhat rigid since it has a high Storage modulus...and this where I get myself confused. How can a somewhat stretchy material be rigid at the same time? I feel this is where I am getting hung up. I feel these two values should be closely related...not exact...but close, but they aren't.
So, I am looking for a way to relate both of the properties. I also understand that the tests for these properties are very different and it may not be possible to do this.
I appreciate any and all methods of explaining these two properties to me.
Thanks!
Young's modulus is referred to as tensile modulus. It is totally different material property other than the storage modulus. The storage modulus refers to how much energy was stored by the material when subjected to oscillating/ periodic loads. Modulus is simply related to the stress and strain in particular conditions.
Dear Sir,
Please see following video....hope it work
Also, be very clear during studying, Young's Modulus and Storage Modulus, in case of bulk and nano-materials. Same properties will be different in case of nano of identical materials.
1. https://youtu.be/Kh4zHl0XydA
2. https://youtu.be/DLE-ieOVFjI
3.https://youtu.be/5f1n6VAtZmo
Young's modulus - stiffness; storage modulus - store energy elastically
Although conceptually similar, Young's (or elasticity) modulus and dynamic storage modulus are not the same. The elasticity modulus is determined from the initial slope of the stress-strain plot obtained at low constant strain rates (around 2e-4 s-1 to ISO and ASTM standards), while the storage modulus is calculated from applied sinusoidal strain waveform.
During a monotonic test, Young's modulus - computed from the stress response - captures all the viscoelastic phenomena taking place in the sample. The storage modulus - calculated from material's stiffness - represents only the elastic portion of the material's response. In that respect, it is the dynamic complex modulus that corresponds best to Young's modulus determined from a quasi-static test, even though the deformation forms and strain rates differ significantly in both types of test.
For rigid solids, however, the main factor affecting the complex modulus is the storage modulus. One can easily prove that if the tan delta is 0.1, which applies to most rigid solids, the ratio of the storage to complex moduli is 0.995, hence close to unity. Thereby, the storage modulus from DMA and Young's modulus from monotonic testing are numerically equivalent for rigid solid materials. This relationship deviates for conditions where the tan delta increases considerably, though, such as in the temperature regions of relaxation or phase transitions as well as under extreme frequencies of oscillatory deformations (in both directions).
While Young's modulus is stress over strain in tensile test,dynamic storage modulus is obtained by sinusoidal deformation of a solid. A common way to measure a tensile modulus is with the Instron tensile tester, an image of which is shown below. The sample is actually the tiny white dog bone in the middle, and the rest is hardware to accurately measure stress and displacement.The mechanical behavior of conventional solids is usually described by their elastic behavior (limiting case of ideal elastic behavior). As long as the deformations are not too large Hooke's Law is applicable.
As the storage modulus indicates the capacity of material to store the input mechanical energy, it decreases with the increase of temperature . The storage modulus is generally used for determining elastic properties of a polymeric based material
Good question. while Young's modulus is a mechanic parameters. Solid materials has Young's modulus, no matter it is big or small.
However, storage modules is the ability that the materials which could store energy, while only Viscoelastic body such as rubber or gel or maybe just liquid could have store energy. You could figure that the plastic has Young's modules, but you can not say that it has storage modules.
Only in the case of viscoelastic materials, the young's modules has the same value to the storage modules.
Hope it could help to you.
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