Investigation of small electrical resistance of NiTi shape memory alloys in the application of damage detection

Applications of shape memory alloys (SMAs) as damage sensors have been widely studied in structural health monitoring. Monitoring a significant change in electrical resistance of SMAs can indicate the phase transformation of SMAs. The possibility of using the electrical resistance of SMAs as an indicator of damage in the materials has been investigated. We continuously monitored the behaviour of electrical resistance, as well as the strain, under the tensile test which is used as the simulated crack propagation. Wavelet transform were used to extract the trend of the noisy electrical resistance raw data, measured by the four-point-probe technique. We determined that the electrical resistance variation of the SMA wire is correlated with the strain and can possibly be used in damage detection stage.