what are the input variables of the subroutine viscoe in material.f?

[Duo Xu]

Dear Prof. Taylor/ FEAP admin/users of FEAPpv:

I was triying to understand the code for viscoelastic material law in FEAPpv and have so far figured out how it works in general. But I'm a little confused with the input variable of the subroutine viscoe. When viscoe is called by modlsd in line 2695 of material.f, the variable h2(1) and h2(i+1) are used as input and are assigned to en and qi in viscoe. Could you please tell me what these variables stand for? What are the corresponding dimensions of these variables?

Thanks a lot in advance!

p.s. I understand h1 and h2 comes from hr(nh1+nn) and hr(nh2+nn) in sld3d1.f, but I somehow couldn't find where hr is created?

[Prof. R.L. Taylor]

The variables have the dimensions of the number of viscoelastic terms: 1,2, or 3 depending on inputs.

The theory follows from developmens in the FE text (second volume) by Zienkiewicz, et al.

[Duo Xu]

Dear Prof. Taylor,

thanks a lot for your quick reply and also for providing this software online. It's very helpful.

I'd like to ask another question. Is the viscoelasticity also implemented on neo-Hookean and Ogden material law in FEAP and FEAPpv, or so far only on the linear isotropic material?

Thanks again.

[Prof. R.L. Taylor]

FEAP has viscoelastic in the neohookean, Ogden and Mooney-Rivlin models.  The viscoelasticity is based on work by Simo, not later work by others.  Thus there is room for improvement in what is currently implemented.

FEAPpv does not have any viscoelasticity in finite deformation.

[Duo Xu]

Thanks again!