What is the density of a constant? (spring constant)

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Discussion Overview

The discussion revolves around the concept of the "density of a constant," specifically focusing on the spring constant or stiffness constant in the context of biomechanics and material properties. Participants explore theoretical and mathematical aspects of this concept, seeking clarification and deeper understanding.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant inquires about the nature of the density of a constant, suggesting it may relate to a probability function.
  • Another participant references a paper discussing the spring constant in the context of tooth movement and stress distribution in the periodontal ligament.
  • A participant proposes that intervertebral disks can be modeled as springs, with the concept of density arising from the distribution of these springs and the type of model used (continuity vs. discontinuity).
  • There is a mention of using Young's modulus as a spring constant, with a suggestion that the ratio of Young's modulus to length (Y/L) could be interpreted as a density related to the number of springs in a given length.
  • One participant expresses confusion regarding the interpretation of Y/L as a density and seeks further explanation.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of the density of a constant, with multiple competing views and uncertainties remaining regarding its definition and application.

Contextual Notes

Limitations include the lack of clarity on the definitions of density in this context, the dependence on specific models of springs, and unresolved mathematical interpretations related to Young's modulus.

Who May Find This Useful

This discussion may be of interest to those studying biomechanics, material science, or anyone exploring the mathematical modeling of physical systems involving spring constants and their properties.

zazi77
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Hi, I could you explain me what is the density of a constant (particurarly the spring constant, or should I say "stiffness" constant)? I guess it's a probability function but would like more details. I would like an answer that at first describe the concept and later refine the mathematical explanation . Thank you
 
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Welcome to the PF. :smile:

Can you post a couple links to where you have seen this?
 
I'm reading this paper written by an engineer(I'm a dentist passionate with biomechanics). From theorem of reciprocal synatrosis a theory of tooth movement has been derived (a constant of center of rotation based on stress distribution function of periodontal ligament). I can understand the calcultions more or less, but I'm curious about this density because I could
Schermata 2019-08-05 alle 18.42.59.png
find no explanation about it.
 
I guess the concept is more or less this one. In the first part of the paper an intervertbral disk is considered. It can be assumed to be a spring and each infinite element is a small spring . These little springs can be distributed in some ways, so that is it possible to define a "density". Moreover it also depends on the kind on model of disk (continuity, discontinuity). If you can explain me these concepts and link me something to study (for someone approaching the subject) it would be great.
 
Hi @zazi77
Here is a brief consideration on using Young's modulus as a spring constant, which is what the article is doing.
https://ccrma.stanford.edu/~jos/pasp/Young_s_Modulus_Spring_Constant.html
Note that F/S is pressure, where S is an area.
If you move S to the right hand side you have ΔL [ the dy ] times Y ( Young's Modulus ) / L( length) times S(area)

If you consider upon the Y/L as a density, that is related to the number of little springs that are in the total length L, and acting upon the area.

Maybe someone can explain that better.
 
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thank you for your reply, I already saw that link. What I don't get is why Y/L is a density
 
Please give us a reference to the source of the .png in post #3.

Do you also have a download link ?
 

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