Comparison of internal friction measurements on Ni-Ti reinforced smart composites prepared by additive manufacturing

Polymer 3D printing has been utilised in aerospace to produce complex lightweight structures, in medical fields to print tissues and organs, and in a number of other industries to combat the rising demand for weight-saving engineering solutions. Pure polymer goods created through 3D printing, on the other hand, lack strength and functionality. Therefore, by combining matrix and reinforcing materials, 3D printing of polymer composites can overcome these problems. Also various researchers have used matrix system either epoxy resin or vinyl ester resin. Despite its wide usage, resins have few drawbacks like microleakage and high curing time which could be eliminated by 3D printing. In this work, we have focused on using 3D printed polymer matrix system. To enhance the property, shape memory alloys (SMAs) are introduced in the structure as a reinforcement. Shape memory alloys are a class of smart material that, when heated over a certain temperature, can recover deformation. SMAs exhibit two main characteristics i.e., shape memory effect (SME) and superelasticity (SE). SMAs are available in a variety of shapes, including wires, springs, sheets, and tubes. The SMA wires can be embedded in the composites for a variety of reasons, such as enhancing mechanical properties, shape morphing of structures and for use as actuators. Damping is one such mechanical property which can enhanced by reinforcing SMA wires. In this research work, the samples were fabricated using 3D printing of PLA and PETG with SMA wires embedded in two different forms i.e., continuous and discontinuous. The samples were then examined under a dynamic mechanical analyzer to study the damping (internal friction) behaviour of the smart composites. It has been found that the incorporation of SMA wires into the matrix had a significant influence on the dynamic mechanical properties. Also, the samples with SMA reinforced in continuous manner had the higher value of tan δ i.e., it had good damping properties in comparison to short fibre reinforced composites.