科研之友
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摘要
The thermomechanical properties of nickel-titanium-based Belleville washers have been analyzed in this investigation, together with their unusual mechanical and functional features, which can be attributed to the reversible phase transformation mechanisms of nickel-titanium alloys. In particular, numerical simulations have been carried out for a preliminary design of the Belleville washer, using a commercial finite element software and a special constitutive model for shape memory alloys. Subsequently, Belleville washers have been manufactured from a commercial pseudoelastic nickel-titanium alloy, by disk cutting and a successive shape setting by a thermomechanical treatment. Finally, the thermomechanical response of the washers, in terms of isothermal force-deflection curve and thermal cycles between phase transition temperatures, has been experimentally analyzed. The results highlighted a marked effect of the temperature on the characteristic curve, as well as good recovery capabilities under both mechanical and thermal cycles. In addition, nickel-titanium Belleville washers exhibit a marked hysteretic behavior, as a consequence of the hysteresis in the stress-strain response of the alloy. Thanks to these features, nickel-titanium Belleville washers can be used as smart elastic elements, that is, with tunable stiffness and damping properties, as well as solid-state actuators, due to their recovery capabilities.
- 出版日期2013-4
