Simplified Mechanical Model Construction And Finite Element Analysis Of Hyperelastic And Brittle Polymer Materials

Hyperelastic materials and brittle composite materials have excellent properties,which are widely used in various fields of national production.Their mechanical properties show isotropic nonlinear mechanical response behavior.Numerical simulation has been applied in the field of polymer materials because of its low cost,high operability and repeatability.Using numerical simulation technology to analyze the mechanical properties of hyperelastic materials and brittle composite materials,numerical model construction and optimization has a certain engineering significance and practical value.Therefore,in this paper,the thermoplastic polyurethane elastomer(TPU)and nano particle reinforced epoxy composite as typical hyperelastic material and brittle composite material,were taken as the research objects,the simplified models of isotropic hyperelastic materials and brittle composite materials were constructed,the constitutive model of TPU and the damage and failure model of epoxy nanocomposite were studied.The main achievements of this research are displayed as follows:1.Three TPUs with different hard segment contents(15.19,22.54 and 38.51 wt%)were prepared by prepolymer method.The technological process and attentions of TPU preparation in laboratory were described in detail.The mechanical response behavior of TPU was studied by uniaxial tensile test and SEM cross-section scanning.The results shows that its mechanical properties changed with the increase of hard segment content significantly,that is,the rigidity increased and the toughness decreased.2.Based on a series of classical strain energy density functions of hyperelastic materials,the hyperelastic constitutive models of TPU were studied.These models were fitted to the experimental curves by Abaqus finite element analysis software,and the best fitting constitutive model is generalized Mooney-Rivlin model.The threedimensional model and finite element analysis of the materials were carried out,and the stress-strain curves under the set conditions were obtained.3.A "one-step" transformation algorithm from the original force-displacement experimental data to the simplest constitutive model was proposed,and a simplified constitutive model with three parameters was obtained.The fitting errors of the simplified model to three TPUs are 0.95,0.81 and 0.98%,respectively.By combining the simplified model with the finite element analysis,the mechanical behavior of TPUs under uniaxial tension can be predicted accurately.4.The cohesion model was embedded in Abaqus software by python programming.By combining of three-point bending experiment and numerical simulation,the influence of the interface force,the number of particles and the thickness of particle film on the overall mechanical properties of the nanoparticles reinforced epoxy composite was explored systematically.The enhancement mechanism of nanoparticles was given.