Help with curved specimen and mechanical loading.

[tom_biomech]

Background:
Rib fractures in infants are highly suggestive of child abuse. I am performing mechanical testing and finite element analysis on pig ribs with the aim of characterising the behaviour of ribs under anterior-posterior (from end to end rather from the side) loading.

Help needed:
I would greatly appreciate any suggestions on how to interpret my mechanical data. Perhaps someone has performed mechanical testing on curved specimens before? I have the loads to failure of the rib and rough geometry. I will assume the cross sections are eliptical and the ribs are C-shaped.

Thanks in advance.

 

[Skrambles]

I majored in Anthropology and my main area of study was in the physical/forensic side. We learned that human and ape rib cages are shaped much differently than those in quadrupeds, so pig ribs may not be the best analogy to human ribs. The bones in infants are also structurally different than those of adults, and this is true for all mammals. Have you done any research into osteology? You may be able to find some data that you could apply to your analysis. Also, was the bone fresh or had it been allowed to dry out? Dry bone will be more brittle than fresh or "green" bone.

 

[tom_biomech]

Thank you kindly Skrambles,

Yes indeed, I am using young pigs and obtaining my own input data for FEA (except possions ratio, which I'll assume to be 0.3). I have kept the ribs in saline from dissection until use and the ribs have been stored in the fridge. The forensic and medico-legal side is an aspect we are very interested in.

Currently I am trying to understand my data from a curved beam theory perspective to see if I can better understand the stresses, strains, deformations and energy to fracture. Any suggestions here?

Cheers.