Anti-thermal buckling behavior of NiTi shape memory alloy thin plates: Experiment and modeling

Thermal buckling presents a significant challenge to the stability of thin-walled structures exposed to elevated temperatures. The thermally induced phase transformation deformation of NiTi shape memory alloys can counteract thermal expansion, thereby exhibiting the so-called anti-thermal buckling behavior. This study experimentally investigates the out-of-plane thermal buckling deformation, as well as the stress and strain responses, of NiTi alloy thin plates under increasing temperature. The anti-thermal buckling mechanism is systematically elucidated. Through the introduction of appropriate pre-strain, thermally induced phase transformation deformation can eliminate out-of-plane deformation caused by thermal buckling and also reduce thermal stress. A theoretical model was developed based on elastic buckling theory and quadruple strain decomposition to explain the deformation mechanism and to predict the effects of pre-strain on the stress and strain responses of NiTi alloy thin plates. The comparison between experimental results and theoretical predictions confirms the accuracy and effectiveness of the proposed model. This study offers both theoretical and experimental foundations for the design of thermally stable structures reinforced with SMA thin plates.