In the contribution at hand, a new formulation for finite strain viscosity rela-
tive to the viscous intermediate configuration is presented. The evolution of the
viscous deformations is based upon a new numerical approach, which allows
for a consistent consideration of anisotropic finite strain viscoelasticity, accord-
ing to the authors knowledge. A standard Maxwell model is used to describe viscous behaviour at finite deformations. Furthermore, the orthotropic Yeoh
material model is extended to include a distinction between behaviour under
tensile and compression loading. The proposed formulation is validated, and
parameters of the model are identified by material tests on Sorghum bicolor
plants. Subsequently, numerical examples are shown to demonstrate the capa-
bilities of the model. In general, the proposed Yeoh material formulation is
shown to accurately represent the inability of fibres to carry compression load-
ing. Furthermore, the viscoelastic approach, developed relative to the viscous
intermediate configuration, is demonstrated to be capable of producing plausible
results. Additionally, the mechanical behaviour of Sorghum bicolor plants is sim-
ulated using the introduced formulation. The results show that the contribution
at hand describes a novel methodology to simulate the viscoelastic behaviour of
plant materials reliably.