Constitutive model taking into account the strain rate for uniaxial NiTi shape memory alloy under low velocity impact conditions

Under external impact load, due to the high strain rate at which a shape memory alloy (SMA) is loaded, the stress-strain behaviour under impact conditions differs from that at quasi-static loading as a consequence of the self-heating of SMAs at high strain rate loading. The present paper presents a constitutive model based on that of Liang and Rogers that is capable of representing the uniaxial superelastic stress-strain behaviour of an SMA wire under low velocity impact conditions. The strain rate dependence is accomplished by a temperature estimation method based on experimental observations under structural impact conditions achieved by the tensile impact technique; good agreement is observed with experimental results.