Axi-symmetric geometrically nonlinear in hoop direction

[dollarbulldog]

Hi all,

Can anyone give me an idea how to incorporate geometric effect of large displacement in hoop direction of axisymmetric problem.

1. Since most constitutive law in finite strain is described in cartesian bases x,y,z, which is an appropriated way to related the hoop stress with those model?

I think it should not be a stress in z direction as in small displacement case, but we need those constitutive form in cylindrical coordinate providing hoop stress and eliminate the vanishing shear terms. How can I obtain those formula (source?) in case of finite elasticity.

2. In calculation of tangent stiffness, we need to define the updated domain of integration i.e. updated Lagrangian approach, how to take into account this change of radius systematically? Is there any books provide this information?

3. Does anyone know what have the commercial softwares done in this case?


Thanks

 

[izax1]

If you have large displacement in the hoop direction, then I do not think you have an axisymmetric problem. In MSC/NASTRAN you can use Cyclic Symmetry option in this case

 

[nagi]

Hi dollbulldog,

In large deformation axisymmetric analysis the equation relating the hoop strain to the radial displacement changes, so that must be taken into account in the FE code.

Nagi