In this work, unidirectional carbon-fiber-reinforced polymers (CFRP) with embedded NiTi shape memory alloy (SMA) wire actuators were manufactured using a universal testing machine equipped with a thermally controlled chamber. Beam specimens containing cold-worked, annealed and trained NiTi SMA wires distributed along their neutral plane were fabricated. Several tests in a three-point bending mode at different constant temperatures were performed. To verify thermal buckling effects, electrical activation of the specimens was realized in a cantilevered beam mode and the influence of the SMA wire actuators on the tip deflection of the composite is demonstrated.

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The vibration control is an important area in the dynamic of structures that seeks to reduce the amplitude of structural responses in certain critical frequency ranges. Currently, the scientific development leads to the application of some actuators and sensors technologically superior comparing to the same features available on the market. For developing these advanced sensors and actuators, smart materials that can change their mechanical properties when subjected to certain thermomechanical loads can be employed. In this context, Shape memory alloys (SMAs) may be used for developing dynamic vibration dampers which are capable of acting on the system providing proper tuning of the excitation frequency and the natural frequency. This paper aims to analyze the behavior of the stiffness and damping of a SMA helical coil spring actuator coupled to a mechanical system of one degree of freedom (1 DOF) subjected to an unbalanced excitement force and a temperature control system. By analyzing the effect of these parameters on the structural response and considering the concept of complex stiffness, it can be possible to predict the system's behavior within certain acceptable ranges of vibration, already in the design phase.

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Abstract. Practical applications of the Shape Memory Effect (SME) involves frequently repetitive operations. Therefore, it's essential to have knowledge of the properties behavior related to SME under working conditions. The thermomechanical fatigue of Ti-Ni-Cu thin wires loaded by static uniaxial tensile stress and submitted to thermal cycling has been studied. The test samples were cycled until failure in oil bath, cooled by this one and heated by electrical current. One modified Wohler curve has been plotted and the influences of the applied stress and of the number of thermal cycles on the shape memory properties has been analyzed. It is shown that the martensitic transformation associated to SME changes according to stress level andlor number of thermal cycles.The degradation until failure of the Stress Assisted Two-way Memory Effect (SATWME) was set between 0 and 20% compared to initial value.

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