Study On Damage And Deformation Of Fiber Reinforced Shape Memory Polymer Composites

Shape memory polymer(SMP)are a novel type of stimuli-responsive material which can change from their non-equilibrium shape to their permanent shape when expose to appropriate external stimuli,and it has a large recoverable deformation.But due to its poor mechanical property their applications in industry is greatly limited.Fiber reinforced shape memory polymer composites(SMPC)with greater comprehensive mechanical properties show up a higher value of stress during the shape recovery process.So far,there is still a little research on the damage and deformation of the fiber reinforced SMPC.In this paper,the damage and deformation properties of fiber reinforced SMP are studied.Firstly,the combination of the Mooney-Rivlin Hyperelastic model and the Prony series are used to defines the material viscoelastic properties.And fitting the material parameters by using the existing experimental data.The reliability of the fitting parameters has been confirmed by simulation of shape memory cycle of shape memory polymers has been completed in ABAQUS,and lay the foundation of the damage and deformation analysis of fiber reinforced composites in the next chapter.Secondly,based on the cohesive zone model,a finite element damage model for unidirectional SMPCs under transverse loading within finite strain range has been developed.The fiber/matrix interphase is characterized with a bi-linear cohesive law,and the fiber is treated as elastic and the matrix as visco-hyperelastic.Once calibrated,the material laws are implemented in ABAQUS finite element model to simulate the macroscopic response of the composite.It is shown that the temperature plays a crucial role in the onset of failure and the severity of fracture related to whether it is purely local or global failure.Then,the tensile damage failure process of unidirectional reinforced SMP composites is simulated by using subroutine VUSDFLD in ABAQUS.Three failure modes including fiber fracture,interfacial debonding and matrix cracking are considered at the same time.The effects of temperature,loading rate and interfacial phase strength on the composite damage failure are studied.Finally,based on the above two sections’ study,a composite impact damage model is established.The model is built based on the test piece owned in our research group.And in this study we take interfacial delamination failure and damage in the layer into account.The effects of temperature and impact rate on the impact damage performance of the material are discussed and analyzed.