UMAT for Zener model and Kelvin-Voigt model

Dear iMechanica community,

you can find the UMAT-implementation of a Zener model, i.e. a Maxwell model parallel to a spring, in my PhD thesis:

“Upsetting and Viscoelasticity of Vitreous SiO2: Experiments, Interpretation and Simulation“
Technische Universitaet Berlin, Germany, 2006
https://depositonce.tu-berlin.de/handle/11303/1574
http://dx.doi.org/10.14279/depositonce-1277

The footnote g on page 33 is clearly insufficient. The theory is written up in 'Theorie-Alexandru.pdf' and is like the one in:
author: Rudolf Trostel
titel: Mathematische Grundlagen der Technischen Mechanik III, Materialmodelle (in German, translation: Mathematical foundations of Technical Mechanics III, material models)
publisher: Vieweg+Teubner Verlag, Germany, 1999
ISBN: 978-3-528-03912-7 (Print), 978-3-322-93842-8 (Online)

The table of contents of this book is available from
http://link.springer.com/book/10.1007/978-3-322-93842-8
Clicking on the chapiters "Maxwell-Koerper" or "Kelvin-Koerper" will open the first page of the respective chapter.

Further, I post a follow-up to my PhD thesis which derives in an analogous procedure the implementation of a UMAT for a Kelvin-Voigt model.

Sincerely

Frank Richter