D. Palmeri, A. Barcellona, B. Zuccarello, L. Cannizzaro, University of Palermo, Palermo, Italy
Composites combine best properties of matrixes and fibers. In order to expand the applications fields of these materials, new filler have been developed enabling more advanced applications for composite materials with polymeric matrix. Shape Memory Alloys wires can be integrated in fiber reinforced polymer composites. SMAs possess three inherent properties such as shape memory effect, superelasticity, and damping capacity that enable both sensing and actuating properties, useful to create intelligent composites. These hybrid composites own high potentiality in different fields as the noise and vibrations control. In this study different kinds of SMA composites have been made. Two polymeric matrixes were used, epoxy resin and polyethylene. The fillers SMA wire have been choice of kind shape memory using two different diameters equal to 25 mm and 0.5 mm and of kind superelastic with the same diameters. For each combination matrix-filler, two kinds of composites have been realised; the first one with long aligned fibers and the second one with short casually oriented fibers. The determination of the length of short fibers was established considering the ultimate tensile strength and the diameters of SMA wire and the strength of tie between fibres and matrix. The mechanical properties of each composite, valued by means of tensile and delaminating tests at the varying of the temperature, allowed to highlight the effect of material matrix, material and diameter of wire and filler length on the properties of these intelligent composites. The test temperatures were choice below and above the transformation temperatures of the SMAs.
Summary: In this study the mechanical characteristics of different composites materials with polymeric matrix and filled with short or long fiber of shape memory and superelastic NiTi alloys were evalued. Tensile and delaminatig tests allowed to evaluate the effect of fibers geometry and properties on the finals mechanical characteristics of composites materials that have been made.
