Prediction And Analysis Of Free Recovery Behavior Of Shape Memory Polymers

Shape memory polymers is an intelligent active material,which can recover temporary deformation to permanent shape according to external factors(such as temperature,humidity,light or magnetism,etc.).Shape memory polymer can be applied to driving components,biomedical devices,deployable structures and deformed structures in micro systems.By establishing a theoretical model to predict and analyze the free recovery behavior of shape-memory polymers,its application function can be developed,and the properties of free recovery can be applied to various engineering applications.In this paper,the temperature-dependent recovery behavior of shape memory polymers is studied,and its free recovery behavior through theoretical derivation of different time-temperature equivalent models and different constitutive models is predicted and analyzed.The main results of this paper are listed as follows:(1)Different time-temperature equivalent models are applied to the theoretical formula of shape memory polymers free recovery rate,and the free recovery curve is compared with the experimental curve to obtain a simpler and more accurate time-temperature equivalent model.(2)The formula of the free recovery rate of the single-branch model under the power function heating condition is deduced.Through the comparison of theoretical solution and experimental data,the influence of different heating conditions on the free recovery of the single-branch model of shape memory polymers is revealed and the influence of various parameters on the free recovery under this heating condition is discussed.(3)Through theoretical derivation,a multi-branch model is established to describe its free recovery behavior.The simulation results obtained by the model are similar to the experimental results.In this way,by modifying the relevant parameters in the actual project,the time spent in the free recovery phase of shape memory polymers can be reduced.(4)The strain recovery rate curves of multi-branch model and single-branch model under different conditions are compared,and the differences and applicable conditions of different constitutive models are analyzed.