Helper function for ElasticMembrane
Helper function for ElasticMembrane

We need to specifically grab only 2D elements from the context, so
we're creating a helper function to encapsulate that.

vikramvgarg/grins,cahaynes/grins,nicholasmalaya/grins,nicholasmalaya/grins,vikramvgarg/grins,nicholasmalaya/grins,cahaynes/grins,vikramvgarg/grins,vikramvgarg/grins,cahaynes/grins,nicholasmalaya/grins,cahaynes/grins,vikramvgarg/grins,vikramvgarg/grins,cahaynes/grins,cahaynes/grins