  In a recent article the author presented a method to measure the snapping
capability -- shortly called snappability -- of bar-joint frameworks based on
the total elastic strain energy by computing the deformation of all bars using
Hooke's law and the definition of Cauchy/Engineering strain. Within the paper
at hand, we extend this approach to isostatic frameworks composed of bars and
triangular plates by using the physical concept of Green-Lagrange strain. An
intrinsic pseudometric based on the resulting total elastic strain energy
density cannot only be used for evaluating the snappability but also for
measuring the distance to the closest singular configuration. The presented
methods are demonstrated on the basis of the 3-legged planar parallel
manipulator.
