Strength of discontinuous reinforced composites: II. Isotropic crystalline polymers

摘要: Crystalline polymers are heterogeneous materials consisting of two distinct phases. They may therefore be treated as molecular versions engineering composite materials. This paper summarizes the physical model which, when used in conjunction with theory, yields a complete calculational format for stiffness, expansion strain, and yield strength. The important input parameters to calculation mechanical properties individual constituent phases (crystalline amorphous), crystallite aspect ratios, volume fraction crystallinity, allowable failure strains continuous crystal system, measure stress concentrations strength reduction caused by discontinuous nature actual crystalline reinforcing phase. An expression factor is developed details stiffness calculations presented high density polyethylene (HDPE). Comparison experiment HDPE excellent agreement well within necessary design accuracy. Agreement case low (LDPE) not good, but expectations considering degree theory refinement poorer morphological data base LDPE.