Finite element simulations to select membrane dimensions.

<p>(A) Cross sectional sketch of proposed membrane with wall (not to scale). Red arrows indicate the region near the junction of the wall and the membrane, where strain heterogeneity can arise. To reduce this heterogeneity, values for the wall thickness (i) and the wall height (ii) were selected by varying them in finite element simulations. (B) Deformation of the PDMS membrane for Design 1 (top) and Design 2 (bottom) computed by asymmetrical finite element modeling. Colors indicate magnitude of total displacement. Wall thicknesses for Design 1 and 2 are 0.5 mm and 1 mm, respectively. For both Designs 1 and 2, the thickness of the base membrane is 0.5 mm, and the wall height is 10 mm. (C) Normalized radial strain (<i>e_r</i>/<i>e_r0</i>) profiles for both designs near the wall-membrane junction. Design 1: <i>e_r0</i> = 8.24%, Design 2: <i>e_r0</i> = 7.76%. Note the smaller variation near the wall interface in Design 2 as compared to that in Design 1.