Shear and Tensile Strength of Bones

  • #1

Summary:

why are most bone fractures not caused by compression but by twisting and or bending (shear modulus of bones is far greater than their Young's modulus)

Main Question or Discussion Point

Hello there,

I'm currently studying shear and compression. I am wondering, in my textbook, it says that most bone fractures are not caused by compression but by twisting or bending?? I mean bone's shear modulus is as great as that of a steel's, but its young modulus is far smaller than its shear modulus. Is it correct if I assume that this is because this twisting or bending that causes most of bone fractures are generated with great velocity, while compression subjected to bones in general does not generated with great velocity??
 

Answers and Replies

  • #2
256bits
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Summary:: why are most bone fractures not caused by compression but by twisting and or bending (shear modulus of bones is far greater than their Young's modulus)

Hello there,

I'm currently studying shear and compression. I am wondering, in my textbook, it says that most bone fractures are not caused by compression but by twisting or bending?? I mean bone's shear modulus is as great as that of a steel's, but its young modulus is far smaller than its shear modulus. Is it correct if I assume that this is because this twisting or bending that causes most of bone fractures are generated with great velocity, while compression subjected to bones in general does not generated with great velocity??
Hi Enrico,
Shear modulus tells you the stress-strain ratio, not the strength of the material.
You should look at the USS /UTS ( Ultimate shear to Tensial strength ) or SYS/TYS ( shear yield strength to tensile yield strength ) ratios for a material to get a shear strength, as long as the material is homogenous and isotropic.
 
  • #3
Hi Enrico,
Shear modulus tells you the stress-strain ratio, not the strength of the material.
You should look at the USS /UTS ( Ultimate shear to Tensial strength ) or SYS/TYS ( shear yield strength to tensile yield strength ) ratios for a material to get a shear strength, as long as the material is homogenous and isotropic.
I see...does the young modulus also work that way?? I mean does Young's modulus only tell us the stress-strain ratio?? thanks
 
  • #4
256bits
Gold Member
2,963
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I see...does the young modulus also work that way?? I mean does Young's modulus only tell us the stress-strain ratio?? thanks
Young's Modulus, also called Modulus of elasticity.
It is a measure of the rigidity, or stiffness, of the material.
Wiki has a a brief description.
See the part of "Not to be confused with "
 

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