2546961Plate mechanics lab: Kirchhoff-Love plates solved by numbl in the browserJeremy Magland 1function [wxx, wyy, wxy] = plate_curvature(wp, dx, dy)
2% PLATE_CURVATURE Second derivatives of a padded displacement field.
3%
4% [wxx, wyy, wxy] = plate_curvature(wp, dx, dy) returns second-order central
5% differences at every node of the original ny x nx grid, given the padded
6% (ny+2) x (nx+2) field wp from plate_pad. Rows index y, columns index x.
8c = wp(2:end - 1, 2:end - 1);
9wxx = (wp(2:end - 1, 3:end) - 2 * c + wp(2:end - 1, 1:end - 2)) / dx^2;
10wyy = (wp(3:end, 2:end - 1) - 2 * c + wp(1:end - 2, 2:end - 1)) / dy^2;
11wxy = (wp(3:end, 3:end) - wp(3:end, 1:end - 2) - wp(1:end - 2, 3:end) + wp(1:end - 2, 1:end - 2)) / (4 * dx * dy);
12end