Shape Memory Alloy Cables: Exploratory Experiments

Conventional structural cables (or wire ropes) are composed of steel wires helically wound into strands, which, in turn, are wound around a core. Cables made from NiTi shape memory alloy (SMA) wires are a new structural element with promising adaptive and enhanced structural properties for a broad range of applications. Potential advantages of this form include increased bending flexibility for spooling/packaging, better fatigue performance, energy absorption and damping, reduced thermal lag, redundancy, and significant design flexibility. Exploratory thermomechanical experiments were performed on a conventional cable construction: the right regular lay 7 × 7, consisting of 7 strands with 7 wires per strand. Uniaxial tension experiments characterize the cables’ sensitivity to strain rate, temperature, and lubrication. Experiments were also performed on individual strands and wires from the cable to study the hierarchical nature of the cable construction. Special attention was paid to the propagation of phase transformation fronts, similar to that seen previously in uniaxial tension of NiTi wire.