Stability of circular plate shape memory alloy with the direct martensitic transformation taking into account variable cross-zone size additional phase transition | Mekhanika | kompozitsionnykh | materialov i konstruktsii
> Volume 11 > №3 / 2005 / Pages: 451-466

Stability of circular plate shape memory alloy with the direct martensitic transformation taking into account variable cross-zone size additional phase transition

Abstract:

It is known that the thermoelastic martensitic phase transformations occurring in the thin-walled elements of shape memory alloys (SMA), can lead to loss of stability. This is evidenced by the experimental data [1] and theoretical work [2-8]. At present, the theoretical analysis of loss of stability of elements of SPF are different concepts that may underlie the description of this phenomenon. This, on the one hand, a hypothesis “fixed phase composition”, following which the transition to the adjacent shape parameter equilibrium phase composition does not change, on the other hand – the concept of “ongoing phase transition”, following which the transition to the adjacent form accompanied by additional equilibrium phase transformation. The latter concept can in turn be used in various forms. Two opposite approaches identified [3,4] hypothesis, “continued loading”, following which the process of buckling may be present as small perturbations of the load, due to which an additional phase shift experienced the whole element of the SPF, or the concept of “elastic unloading” (in relation to the direct conversion ), following which the loss of stability are completely absent load variations, whereby one portion of the SMA member undergoes an additional phase change and the other – is free of additional transition. It should be noted that the concept of “elastic unloading” and “ongoing load” are not entirely opposed. So, it is quite obvious case where the process of loss of stability and load variations are present simultaneously in a bulging element of the SPF hold area with an additional phase change and without it. Most of the works devoted to the loss of stability of elements of SPF, for the sake of simplicity, it is assumed that the transverse dimension of the zone an additional transformation is constant on the element. Here we consider the case when this restriction was not used.

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