Compressive force of a shorter cylindrical bone vs a longer one

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Discussion Overview

The discussion centers on the comparative compressive strength of shorter versus longer cylindrical bones when subjected to vertical loading. Participants explore the mechanics of bone failure, particularly focusing on factors influencing fracture resistance and the implications of bone geometry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that longer bones are generally weaker due to being more susceptible to buckling and having larger flaws.
  • Others propose that the geometry of the bone, including its cylindrical shape and wall structure, influences its compressive strength, with shorter bones potentially being stronger under pure compression.
  • There is a discussion about the application of force to the femur, questioning whether it is applied through joints or directly, and how this setup affects the results.
  • Participants express uncertainty about the specific parameters of the bone specimens, such as diameter and length, which are crucial for understanding the compressive strength.
  • Some participants argue that both samples should exhibit similar strength under pure compression, as the longer bone is not slender enough to be affected by buckling.
  • There are references to external resources and formulas related to buckling and compressive strength, indicating an interest in theoretical models.
  • Age of the animal is mentioned as a potential factor affecting bone strength and fracture type, with older bones possibly being more fragile.
  • Conflicting data is presented regarding the maximum compressive force for human femurs, highlighting discrepancies in research findings.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether shorter cylindrical bones are inherently stronger than longer ones under vertical compression. Multiple competing views remain, with some arguing for equal strength while others highlight the potential advantages of shorter bones.

Contextual Notes

Participants note the importance of specimen preparation and the need for precise measurements of diameter and length to accurately assess compressive strength. There are also concerns about the assumptions made regarding the uniformity and structural integrity of the bone samples.

Who May Find This Useful

This discussion may be of interest to those studying biomechanics, material science, or veterinary medicine, particularly in relation to bone mechanics and fracture analysis.

  • #61
Rev. Cheeseman said:
In order for global buckling to occur, the length-to-diameter ratio needs to be less than 6.
No. You have that backwards.
"In general, to avoid global buckling of galvanized and cold-formed
steel tubes in the structural applications, the L/D ratio needs to be < 6."

Rev. Cheeseman said:
I'm trying to find articles or studies that said the compressive force to break a whole femur is the same as breaking a midshaft only segment but still can't find it.
Probably because it is false.
 
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  • #62
Baluncore said:
No. You have that backwards.
"In general, to avoid global buckling of galvanized and cold-formed
steel tubes in the structural applications, the L/D ratio needs to be < 6."
Sorry for the mistake. Thank you for noticing. I was rushing when typing and sleepy

Baluncore said:
Probably because it is false.

Sorry, why is it false.
 
  • #63
Rev. Cheeseman said:
Sorry, why is it false.
You are cherry-picking with a search engine.
If it were true, you would expect to find a cherry.
 
  • #64
Baluncore said:
You are cherry-picking with a search engine.
If it were true, you would expect to find a cherry.
Is there a study where they demonstrated the compressive force of whole humeri?
 
  • #65
Rev. Cheeseman said:
Is there a study where they demonstrated the compressive force of whole humeri?
Probably yes.
But finding that research is your problem.
 
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