Which is the best criterion to analyse bone?
Which is the best criterion to analyse bone?
(OP)
Hello all!
Bone is an anisotropic material and it is considered to be brittle. However, it is modeled in most times as isotropic, as the anisotropic properties are not clear. Many times we analyse bone not to asses the simple risk of fracture, but to identify areas under high microstrains caused by repeated loads, which may lead to bone resorption.
Von Mises criterion has been used, but as bone react completely different under tension and compression, this criterion is no longer recommended. Mohr-Coulomb seems appropriate, but Ansys (14) does not have this tool... What criterion would you recommend? Principal 1?
Thanks!
Bone is an anisotropic material and it is considered to be brittle. However, it is modeled in most times as isotropic, as the anisotropic properties are not clear. Many times we analyse bone not to asses the simple risk of fracture, but to identify areas under high microstrains caused by repeated loads, which may lead to bone resorption.
Von Mises criterion has been used, but as bone react completely different under tension and compression, this criterion is no longer recommended. Mohr-Coulomb seems appropriate, but Ansys (14) does not have this tool... What criterion would you recommend? Principal 1?
Thanks!





RE: Which is the best criterion to analyse bone?
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RE: Which is the best criterion to analyse bone?
thanks again
RE: Which is the best criterion to analyse bone?
What kind of analysis are you performing? Static, quasi-static, implicit dynamic or explicit? What kind of material model are you assuming? Linear elastic? Hyperelastic? Hyperviscoelastic? Poroelastic? Is plasticity incorporated at all?
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RE: Which is the best criterion to analyse bone?
RE: Which is the best criterion to analyse bone?
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RE: Which is the best criterion to analyse bone?
The mech. engineer who helps me will define the Mohr´s circle and we will be able to apply this criterion.
Thanks again
RE: Which is the best criterion to analyse bone?
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RE: Which is the best criterion to analyse bone?
/post,1
cmsel,s,mm3
cmsel,a,mm4
aslv,s
lsla,s
ksll,s
eslv,s,1
nsle,s,1
St=135 !tensile strength of the material being analysed (MPa)
Sc=205 !compressive strength of the material being analysed (MPa)
SABS,1 !SABS,x (x=1 absolute value; x=0 algebric value)
ETABLE, ,S,1 !1st principal stress
ETABLE, ,S,2 !2nd principal stress
ETABLE, ,S,3 !3rd principal stress
SADD,TalMax,S1,S3,.5,-.5,, !creates element table for Talmax (TalMax)(TalMax=S3-S1)
SADD,C,S1,S3,.5,.5,, !creates element table for normal (C)(C=(S3+S1)/2)
SABS,1 !SABS,x (x=1 absolute value; x=0 algebric value)
SADD,Seq,S1,S3,1,-St/Sc,, !creates element table for equivalent stress (Seq) (Seq=S1-St/Sc*S3)
SADD,IU,Seq,,1/St,,, !creates element table for Mohr-Coulomb (IU) (IU=Seq/St)
!SigmaEq=(S1-St/Sc*S3)
!S1> 1st principal stress (maximum)
!S3> 3rd principal stress (minimum)
!St> tensile strength
!Sc> compressive strength
RE: Which is the best criterion to analyse bone?
RE: Which is the best criterion to analyse bone?
RE: Which is the best criterion to analyse bone?
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