Assistant Professor of Solid and Structural Mechanics

Instability of a penetrating blade

Application of a dead compressive load at the free end of an elastic rod (the ‘blade’) induces its penetration into a sliding sleeve ending with a linear elastic spring. Bifurcation and stability analysis of this simple elastic system shows a variety of unexpected behaviours: (i.) an increase of buckling load at decreasing of elastic stiffness; (ii.) a finite number of buckling loads for a system with infinite degrees of freedom (leading to a non-standard Sturm-Liouville problem); (iii.) more than one bifurcation loads associated to each bifurcatio mode; (iv.) a restabilization of the straight configuration after the second bifurcation load associated to the first instability mode; (v.) the presence of an Eshelby-like (or configurational) force, deeply influencing stability. Only the first of these behaviours was previously known, the second and third ones disprove common beliefs, the fourth highlights a sort of ‘island of instability’, and the last one shows surprising phenomena and effects on stability.



If you're having trouble playing videos on YouTube, click here to watch it.


Related papers:
  • Bigoni, D., Bosi, F., Dal Corso, F. and Misseroni, D. (2014).
    Instability of a penetrating blade.
    Journal of the Mechanics and Physics of Solids, 64, 411-425.
    doi: http://dx.doi.org/10.1016/j.jmps.2013.12.008

Back to main page