Superelastic Fastening by NiTi Micro-Hooks

Thursday, May 23, 2013: 16:15
Congress Hall 2 (OREA Pryamida Hotel)
Dr. David Vokoun , Institute of Physics ASCR, Prague 8, Czech Republic
Dr. Petr Sedlák , Institute of Thermomechics ASCR, Prague, Czech Republic
Mr. Miroslav Frost , Institute of Thermomechanics, Prague, Czech Republic
Dr. Jan Pilch , Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
Dr. Petr Sittner , Institute of Physics ASCR, Prague 8, Czech Republic

Detachable fastening of two distinct objects using two interlocked NiTi hook arrays represents a novel NiTi functionality.  Recently developed superelastic Velcro-like fasteners [1] may find engineering applications in e.g. medical devices, specialized fasteners for space or firefighter applications.   In this presentation, in order to introduce this novel functionality, we will discuss the mechanics of the unhooking process based on the results of mechanical tests (evaluation of normal detachment force at different temperatures) and mechanics modeling (simulation of unhooking by FE implemented SMA model [2]).  It will be shown how the unique features of NiTi hook fasteners (high strength (~15000 kg/m2, increase of strength with increasing temperature, absorption of impact loads, damping of mechanical vibrations, forceless contact, silent release or excellent functioning in dirty environments) originate from the nonlinear superelastic deformation of NiTi.

References

[1]        D Vokoun, P Sedlak, M Frost, J Pilch, D. Majtas and P Sittner, Velcro-like fasteners based on NiTi micro-hook arrays, Smart Mater. Struct. 20 (2011) 085027

[2]        P. Sedlák, M. Frost, B. Benešová, T. Ben Zineb, P. Šittner, Thermomechanical model for NiTi-based shape memory alloys including R-phase and material anisotropy under multi-axial loadings, International Journal of Plasticity (39) 2012, 132–151

 

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