This page showcases some of Drew Hall's research (thesis here). His primary interest was investigating how lung epithelial cell biomechanics affect injury mechanisms. For his thesis he performed experiments involving stretching a silicone membrane and characterizing regions in an equibiaxial strain state. The experiment shown below performs a "stretching" in tension at 6 equiangularly spaced directions:

The evolution of these strain components is shown below (click to enlarge and get colorbar):

Eyy Strain	Exy Strain	Exx Strain

One interesting aspect of the experiment done above is finding the region where biaxial strain state actually exists. Near the periphery of the ROI, there are strain gradients for all strain components. Near the center, the E_yy and Exx look homogeneous while the E_xy component has a near zero value. An approximate biaxial strain region is traced below:

Determining this region in an automated way could definitely be an interesting topic of future research.