Publication de 4 numéros par an
ISSN Imprimer: 2152-2057
ISSN En ligne: 2152-2073
Indexed in
CLOSED TWO-WAY SHAPE MEMORY EFFECT IN UNIDIRECTIONAL COMPOSITE WITH SHAPE MEMORY ALLOY FIBERS AND ELASTIC MATRIX
RÉSUMÉ
Processes of changing the stress–strain state of a unidirectional composite with an elastic matrix and fibers of titanium nickelide during fibers heating and cooling are described in the framework of modified model of nonlinear thermomechanical behavior of the shape memory alloy in phase and structural transformations. Using the approaches of composite materials micromechanics, taking into account the variability of the Young modulus of titanium nickelide and influence of acting stress on the phase transition, the processes of changing the stress–strain state of such a composite as a whole and its components, as well as changes in the phase composition of fibers were studied. Special attention is paid to the research of the possibility of implementing a closed two-way shape memory effect in this system in which the internal stresses disappear completely in the system at the point of direct thermoelastic phase transformation termination in fibers. It is shown that this phenomenon can be described only in the framework of the shape memory alloy behavior model, which takes into account not only the process of martensitic meso-elements nucleation, but the process of their development under direct transformation, i.e., in the case of using systems of constitutive equations correctly describing the phenomenon of oriented transformation. It is shown that a closed two-way shape memory effect takes place at a certain value of the shape memory alloy fiber volume fraction, which is a decreasing function of a given initial fibers deformation.