Research On The Rate Correlation Of Shape Memory Polymer Based On The Effect Of Tensile Rate And Temperature

Shape memory polymer?SMP?is a kind of functional memory material with good biocompatibility and wide temperature adaptability range.It has wide application in medical,biological and aerospace fields.SMP,as a kind of polymer intelligent material,has strong temperature effect and strain rate effect.However,the constitutive models of SMP related to temperature and strain rate are seldom studied at present,and most of them focus on high-speed tensile and impact tests,and the researches related to low strain rate tensile are rarely reported at China and abroad.In this paper,the dynamic mechanical properties of SMP under low strain rate are tested,and the theoretical research and numerical model are compared with the experimental results.The specific research contents are as follows:?1?In view of the large fluctuation of mechanical properties near the glass transition temperature of SMP material,the temperature range of the experiment is reasonably determined to be 80?-100?,and the strain rate range is0.2mm/min-2mm/min.The effects of temperature and strain rate on the tensile mechanical behavior of SMP were studied.The stress-strain curves of SMP materials at different temperatures and strain rates show viscoelastic characteristics,which provides an important experimental basis for further study of the rate dependence of SMP materials.?2?On the basis of the existing theoretical results and the experimental results,a relaxation time model related to strain rate is proposed,which is embedded in the classical three element model,and can accurately describe the mechanical behavior of SMP materials in the range of large strain rate(1×10^-3s^-1-1×10⁴s^-1).By comparing the fitting results with the experimental curves,it is found that the model is in good agreement with the experimental results at low strain rate,and provides a theoretical basis for the prediction of mechanical behavior of SMP at high strain rate.?3?This paper summarizes the method of defining viscoelastic parameters by Prony Series in Abaqus software,and simulates the mechanical properties of SMP material under low strain uniaxial tension.The reliability of the simulation results is determined by comparing with the experimental results.The mechanical properties of SMP material at high strain rate are predicted by simulation and theory.The results show that SMP material shows a more obvious linear elastic trend at high strain rate.Through the above research,the regularity of temperature effect and strain rate effect of SMP materials is clearly understood,which is of great significance for the application of SMP in structural design.