  In this paper we present the homogenization for nonlinear viscoelastic
second-grade non-simple perforated materials at large strain in the quasistatic
setting. The reference domain $\Omega_{\varepsilon}$ is periodically perforated
and is depending on the scaling parameter $\varepsilon$ which describes the
ratio between the size of the whole domain and the small periodic perforations.
The mechanical energy depends on the gradient and also the second gradient of
the deformation, and also respects positivity of the determinant of the
deformation gradient. For the viscous stresses we assume dynamic frame
indifference and is therefore depending of the rate of the Cauchy-stress
tensor. For the derivation of the homogenized model for $\varepsilon \to 0$ we
use the method of two-scale convergence. For this uniform a priori estimates
with respect to $\varepsilon$ are necessary. The most crucial part is to
estimate the rate of the deformation gradient. Due to the time-dependent frame
indifference of the viscous term, we only get coercivity with respect to the
rate of the Cauchy-stress tensor. To overcome this problem we derive a Korn
inequality for non-constant coefficients on the perforated domain. The crucial
point is to verify that the constant in this inequality, which is usually
depending on the domain, can be chosen independently of the parameter
$\varepsilon$. Further, we construct an extension operator for second order
Sobolev spaces on perforated domains with operator norm independent of
$\varepsilon$.
