OS1609 形状記憶合金の塑性変形挙動の温度依存性を表すモデル

Abstract

To give the two-way shape memory effect to shape memory alloy (SMA), shot peening treatment is locally applied to SMA. Plastic deformation occurs on the shot region, and the region behaves like a bias-spring. To design the two-way SMA actuator optimally, we need a constitutive model of SMA which can capture the plastic deformation as well as elastic deformation and phase transformation. The authors proposed a simple constitutive model which could express the feature of plastic deformation. However, this model could not express temperature dependence of the plastic deformation. In this paper, a new constitutive model of SMA, which can express temperature dependence of plastic deformation, is developed by considering plastic deformation of austenite phase. Stress-strain curves of SMA wire including plastic deformation and fracture are measured and simulated by using the developed model. Comparison between them shows this model can express the feature of the stress-strain curves well.