Analysis of certain aspects of a falling pomelo

This study of a pomelo falls, somewhat and so to speak, in the tradition of the Ig Nobel Prize-winning study “Injuries Due to Falling Coconuts“:

“Viscoelasticity and compaction behaviour of the foam-like pomelo (Citrus maxima) peel,” Marc Thielen, Thomas Speck, Robin Seidel, Journal of Materials Science, vol. 48, no. 9, May 2013, pp. 3469-3478.  The authors, at the University of Freiburg, Germany, report:

“The pomelo (Citrus maxima) is the largest and heaviest fruit of the genus Citrus and can acquire considerable potential energy as it ripens hanging up to 15 m height. Its thick foam-like structured peel presumably acts inter alia as a shock absorbing layer, protecting the fruit as it impacts on the ground upon being shed. Thereby the peel dissipates kinetic energy by being compacted. In order to elucidate the compaction mechanism of the highly heterogeneous pomelo peel, we conducted incremental stress relaxation tests…. [Our analysis] indicates the strong influence of the peel samples’ geometry and composition which is attributed to the fruit shape, a gradual changing density of the peel, which can be considered as a stacked array of foam layers differing in density, and the turgescence of the biological cells.”

Here is detail from the study:

(Thanks to investigator Eugenie Reich for bringing this to our attention.)