Hi,

both TL snd UL approaches play a role in large deformation analysis only (there is no difference between them for small deformations and small strains). I don't really know the procedure used in Abaqus, but several FE codes prefer a TL approach for hyperelasticity resp. if the constitutive equations are functions of the deformation history as a whole. UL approach is used e.g. for rate constitutive equations, including the case of hypoelasto-plasticity where the "elastic" part is not derived from a potential (also referred to as the "ad hoc" extension of small strain elasto-plasticity to large deformations). Hope this helps.

Regards

Ansys uses TL for hyperelasticity. If you have dissipative effects (more generally where the constitutive model requires history dependent variables), as in plasticity, creep etc UL is normally used. 

Thanks

Sincerely

-Sidd

Dr Siddhu

excellent work - Panda da

Thanks, Dr. Panda.

ABAQUS uses updated Lagrangian formulation as Bazant stated in a recent publication.

Hi guys, sorry for my late response ... and eventually heating-up again that (many decades old) discussion:

Have you ever tried to re-compute the BAZANT results for simple shear example (in plane strain, neoHooke hyperelasticity)?

I am not able to obain the "well known" (?) oscillating shear stress results ... ;-(

Greetings !

I have an additonal question. Programming hyperelasticity in Ansys or Abaqus, there exist two ways:

UserMat

UserHyper

In the case that the usermat and the tangent is correctly programmed in terms of the Jaumann rate. Why is the convergence behavior of usermat not as good as for userhyper? What are the differences between UserMat and UserHyper? The documentation is rare on this topic. Is Userhyper utilizing a TL formulation and UserMat a UL?