Multi-Scale Modelling And Micromechanical Properties Of Semi-Crystalline Polymers

This work proposed multi-scale modelling to predict the micromechanical properties of semi-crystalline polymers. Semi-crystalline polymers are usually spherulitic crystal structure, which is, however, not completely radially symmetric. In the initial stage of spherulite growth, its structure is manifested as multilayer wafers with a certain orientation namely sheaf structure. The size and orientation of sheaf structure are affected by various processing parameters. Previous research considered spherulite as completely radially symmetric structures, ignoring the effects of structures anisotropy on mechanical properties. In this work, the microstructure of single spherulite was first modelled with different initial orientations. The crystal plasticity constitutive model together with the Arruda-Boyce model was used to describe the micromechanical behaviors of the crystalline lamellae and amorphous lamellae, respectively. Based on the deformation behaviors of single spherulite, the Voronoi tessellation was then used to characterize the multi-spherulites, the evolution of inhomogeneous plastic deformation and inter-lamellae deformation was observed under tension. Achieving the cross-scale analysis from micro-modeling to meso-modeling. The results shown by this work improve the understanding of the micromechanical properties of semi-crystalline polymers, which, in turn, provides theoretical guides to improve their fracture resistance in manufacturing.