Humidity and thermal triggered Shape Memory Effect - Rheology-based numerical modelling - Thermal Humid Mechanical Cycle

This data contains a Thermal Humid Mechanical Cycle (THMC) of Shape Memory Polymers (SMP). The SMP is a polyurethane-based Polymer, which is produced from SMP Technologies Inc. The SMP filament were processed with a 3D printer (Ultimaker 3, Ultimaker, Geldermarsen, Netherlands). The THMC is divided into a preheating step, a programming step and a stress-free recovery step. A preheating step was performed before the THMC, to relieve residual stresses stored by the manufacturing process. Then the temperature is set to T_trans = 55 °C and waited until the sample is in thermodynamic equilibrium. A displacement of s_max = 2.5 mm is performed and fixed. In the same step, the thermal chamber is set to cooling, by setting a lower temperature T_1 = 50 °C, to speed up the cooling process. In the next step the displacement s_max is kept fixed and the temperature is decreased to T_low = 30 °C. Once the sample is in thermodynamic equilibrium, the fixation is released and the stress free recovery step by setting the normal force to F_N = 0 N is performed. Humidity-dependent recovery of the initial geometry is performed by increasing the relative humidity to RH = 70 %. By performing a THMC, the thermal shape fixation and humidity-dependent shape recovery are captured. Here it can be seen that the programmed shape can also be recovered by higher humidity.