How to utilize Hyper74 or Hyper84 modeling torsion in ANSYS

[jenny]

Hi, all
The help documentation says the axisymmetric option has an additional degree of freedom at each node: translation in the z direction allowing torsion in the model for HYPER74 and HYPER84.
currently i am modeling a rubber bushing consisting of cylindrical rubber tubes bonded on it outer and inner curves surfaces to rigid metal cylinders. Fixing the outer cylinder while the inner one undergoes Torsional deflection. I use Hyper74 with axisymmetric option.
i applied the z direction displacement but the result showed this displacement is not circumferential.
could anynone help me?
thanks

jenny

[Armin]

Hi jenny,

the hyper74 is a so called harmonic element with the axisymmetric option. Therefore the command "mode" is essential. All necessary you can find under

Element Reference | Chapter 2. General Element Features | 2.12. Axisymmetric Elements and 2.13. Axisymmetric Elements with Nonaxisymmetric Loads

here is a small example for a torsional displacement:

fini
/clear

/prep7

et,1,74,,,1

mp,nuxy,1,0.499

tb,mooney,1,
tbtemp,0
tbdata,,10,5

rect,90,110,,200

esize,10
amesh,all

nsel,s,loc,y
d,all,all

/solu
nlgeom,on
mode,0,

nsel,s,loc,y,200
d,all,uz,20
alls
nsubst,100,1000,1
outres,all,all
solve


I hope that helps..

Armin

[jenny]

hi, Armin
Thank you for your reply!
now i am still confused. The chapter 2.13. Axisymmetric Elements with Nonaxisymmetric Loads does not mention Hyper74 or Hyper 84. The analysis with Mode command and without Mode command seem to be identical results. Furthermore i cann't relate the FEM deformation to the torsion. Could anyone explain it for me.
thanks