Figure 1.

Prominent, qualitatively different examples for isochoric deformations ${\mathbf{r}}^{\prime }$ (red) of a unit cell $\mathbf{r}$ (blue) in shearfree flows: (i) uniaxial extension ($b=0$), (ii) planar extension ($b=1$), (iii) elliptical extension ($b=2$), and (iv) equibiaxial extension ($b=3$). For each scenario the situation is depicted both in (a) 3D and (b) projected to the x–y–plane. Coordinates are related via ${\mathbf{r}}^{\prime }=\mathbf{E}·\mathbf{r}$ by the deformation gradient tensor $\mathbf{E}=exp(\mathit{\kappa }t)$, c.f. Equation (3), here shown for $\dot{ϵ}t=0.5$.