  We use micro-Raman spectroscopy to study strain profiles in graphene
monolayers suspended over SiN membranes micropatterned with holes of
non-circular geometry. We show that a uniform differential pressure load
$\Delta P$ over elliptical regions of free-standing graphene yields measurable
deviations from hydrostatic strain conventionally observed in
radially-symmetric microbubbles. The top hydrostatic strain $\bar{\varepsilon}$
we observe is estimated to be $\approx0.7\%$ for $\Delta P = 1\,{\rm bar}$ in
graphene clamped to elliptical SiN holes with axis $40$ and $20\,{\rm \mu m}$.
In the same configuration, we report a $G_\pm$ splitting of $10\,{\rm cm^{-1}}$
which is in good agreement with the calculated anisotropy $\Delta\varepsilon
\approx 0.6\%$ for our device geometry. Our results are consistent with the
most recent reports on the Gr\"uneisen parameters. Perspectives for the
achievement of arbitrary strain configurations by designing suitable SiN holes
and boundary clamping conditions are discussed.
