Stiffness and vibration characteristics of SMA/ER3 composites with shape memory alloy short fibers

Shape memory alloys (SMAs) possess both sensing and actuating functions due to their shape memory effect, pseudo-elasticity, high damping capability and other remarkable characteristics. Combining the unique properties of SMAs with other materials can create intelligent or smart composites. In this paper, epoxy resin composites filled with Ni–Ti alloy short fibers were developed. Microstructure was observed using digital HF microscope. The dynamic mechanical properties were investigated by measuring the first vibration mode of clamped cantilever beams and by dynamic mechanical analysis (DMA). Moreover, the natural frequency of SMA composites was predicted theoretically. As a result, the temperature dependency of vibration property and DMA characteristics is affected largely due to the addition of SMA short fibers. The vibrational characteristics of SMA composites can be improved by the addition of small amounts of SMA short fibers. The addition of 3.5 wt.% of SMA short fiber content to epoxy resin resulted in the maximum increment in both natural frequency and storage modulus. This suggested that there exists an optimum SMA fiber content for vibration characteristics.