Exponential behavior in elasticity?

In summary, the conversation discusses various constitutive models for elastic materials, including Neo-Hooke and Mooney-Rivlin. The speaker also proposes a new model using the differential definition of strain and assuming a constant Young's modulus. They ask if this model is conceptually incorrect.
  • #1
mresimulator
2
0
Hi!
I know some constitutive models for elastic materials like Neo-Hooke or Mooney-Rivlin, which give a relation between elongation ##\lambda=y/y_o## (where ##y## and ##y_o## are the length of the elastic material in a uniaxial compression test in the direction of the compression at stress ##P## and ##P=0##, respectively).

I propose the next model of elasticity:

1) Using the differential definition of strain ##d\epsilon \equiv \frac{dy}{y}##

2) Using the equality ##-\frac{dP}{E} = d\epsilon##, assuming ##E## is the 'Young's modulus' of the material.

3) Using this two equations, taking ##E## constant, and using the boundary conditions ##y(P=0)=y_o## we get ##y(P)=y_o e^{-P/E}##.

This exponential curve fits very well for many of my elastic materials.

My question is: Is wrong this model? (conceptually speaking).

Best regards.
 
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  • #2
Perhaps I'm not understanding your idea (the text is somewhat garbled), but I don't see where you are proposing a 'new' constitutive relation- you simply used Hooke's law (sort of generalized to 3-D, I suppose).
 
  • #3
mresimulator said:
Best regards
Use ## for inline latex
 

1. What is exponential behavior in elasticity?

Exponential behavior in elasticity refers to the relationship between stress and strain in a material, where a small increase in stress can result in a large increase in strain. This is due to the material's ability to store and release energy as it is deformed.

2. How is exponential behavior different from linear behavior in elasticity?

In linear behavior, stress and strain have a proportional relationship, meaning that a small increase in stress will result in a small increase in strain. However, in exponential behavior, stress and strain have an exponential relationship, where a small increase in stress can result in a much larger increase in strain.

3. What materials exhibit exponential behavior in elasticity?

Materials that exhibit exponential behavior in elasticity are typically polymers, rubbers, and other elastic materials. These materials have long molecular chains that allow them to stretch and deform easily, resulting in exponential stress-strain curves.

4. How is exponential behavior in elasticity measured?

Exponential behavior in elasticity can be measured using stress-strain curves, where the stress (load per unit area) is plotted against the strain (change in length per unit length). The slope of the curve at any point represents the material's stiffness, and the higher the slope, the stiffer the material.

5. What are some real-world applications of exponential behavior in elasticity?

Exponential behavior in elasticity is important in many real-world applications, such as in the design of rubber tires, rubber bands, and elastic clothing. It also plays a crucial role in the functioning of biological tissues, such as muscle fibers and blood vessels, which need to be able to stretch and recoil in response to external forces.

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