Spatially resolved Poisson strain and anticlastic curvature measurements in Si under large deflection bending

A scanning-monochromatic form of differential-aperture x-ray microscopy (DAXM) has been developed that provides micron-resolution depth-resolved dilatational strain measurements. This scanning-monochromatic DAXM technique is applied to measurements of Poisson dilatational strain in 25-μm-thick Si bent into an arch with an apex radius of $\text{R=3\hspace{0.17em}}\mathrm{mm}.$ Poisson strain measurements agree with anisotropic linear elasticity calculations for a Searle parameter as large as $\text{β=1009.}$ Local anticlastic bend radii were shown to oscillate across the arch and reach the $\mathrm{R/\nu }$ limit for distances less than the plate thickness from the edges, where ν is the anisotropic Poisson’s ratio.