Is Elastance equal young modulus?

• fruitkiwi
In summary, the terms "young's modulus" and "elastance" are not directly related, but they are both used to describe the capabilities of a material to deform under pressure. "Compliance" is a term that is used in solid mechanics to describe the deformation of a material under axial load.
fruitkiwi
Hi, dear all,

Recently face some controversial issue with my supervisor and i cannot convince my self too.
is it time varying elastance equal to time varying young modulus?

Young modulus unit is Pa, however, elastance value is mmHg/ml, is both of them are equal?

Young's modulus, also known as the tensile modulus, is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds.
http://en.wikipedia.org/wiki/Young's_modulus

Compliance is calculated using the following equation, where ΔV is the change in volume, and ΔP is the change in pressure:[3]
http://en.wikipedia.org/wiki/Compliance_(physiology )

as in the engineering software like ansys, comsol, adina, we only can set young modulus, so i wondering whether they are the same?

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Is there anyone here can give me some hint or tips?

Elastance is not a very common term, so you are going to have to find the place where the term was defined in whatever equipment or paper it arises for you. You can also make a dimensional analysis of the units to see if they are the same, but that will only tell you if they are proportional to each other or not; it will not establish equality.

Dear OldEngr63,

The elastance unit is mmHg/ml, and Young modulus is Pa, in this case i understand as you say that they are not equal unit.

but that means the elastance unit = young modulus/ volume change?

or it means Elastance is just a description for us to justify how good is a material can deform, while young modulus can be applied quantitatively on the calculation?

From the wikipedia article you linked, it appears that "elastance" is the reciprocal of "compliance." "Compliance" is a term that is used in basic solid mechanics - though, in that field, it is referring to the deformation of a material under axial load. In your application, compliance is NOT referring to the deformation of a material under axial load. In your application, compliance is referring specifically to the ability of a vessel to expand. This may be the source of your confusion. It's interesting that the wikipedia article you posted uses veins and arteries as examples. I had a similar conversation about the term "compliance" one time with a doctor.
Colloquially, their definition of "compliance" is similar to ours.

Higher young's modulus of the artery material will result in a lower compliance, whether we use the physiology definition of compliance or the solid mechanics definition of compliance. Keep in mind, though, that the definitions of compliance are in fact totally different.

Higher young's modulus will result in a higher elastance, though the relationship is indirect.

As mentioned by a previous poster, the term "elastance" probably does not exist outside of physiology.

Thanks afreiden for your details explanation. I will read more on compliance term now.

Looking at the reference in the OP, "elastance" seems to be similar to the inverse of the bulk modulus of the material (i.e. the change in volume caused by a change in hydrostatic pressure in the fluid), which is a more relevant than Youngs modulus for describing a compressible fluid. http://en.wikipedia.org/wiki/Bulk_modulus

But I've never seem the term elastance before, and I don't claim to know anything about biomechanics.

Hi, AlephZero,

The elastance is one kind of term which used to describe the capabilities of blood vessel on how much the volume can be result due to large pressure pump in.

I just curious when is the term come out, as in the traditional solid mechanics book, they only mention about elasticity, maybe this word is discovered in physiology.

I find a interesting video

but as engineer, i need to apply this term in biomodelling, so wish to know more.

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1. What is elastance?

Elastance is the measure of a material's ability to resist deformation when a force is applied. It is the reciprocal of compliance and is often used to describe the stiffness or elasticity of a material.

2. What is Young's modulus?

Young's modulus, also known as the elastic modulus, is a measure of the stiffness or elasticity of a material. It is defined as the ratio of stress (force per unit area) to strain (change in length relative to original length) in a material when subjected to an external force.

3. Are elastance and Young's modulus the same thing?

No, elastance and Young's modulus are not the same thing. Elastance is the reciprocal of compliance, while Young's modulus is a measure of stiffness or elasticity. They are related, but not equivalent.

4. How are elastance and Young's modulus related?

Elastance and Young's modulus are related through the equation E = 1/C, where E is elastance and C is compliance. Compliance is the measure of a material's ability to stretch or deform under a given force, while elastance is the measure of a material's resistance to deformation. Therefore, a material with a high Young's modulus will have a low elastance and vice versa.

5. Is elastance equal to Young's modulus in all materials?

No, elastance is not equal to Young's modulus in all materials. Different materials have different properties and therefore, can have different elastance and Young's modulus values. For example, a rubber band has a high elastance and a low Young's modulus, while a steel rod has a low elastance and a high Young's modulus.

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