2000-04-13
17:30 at CHN E7

Simulation of Large Strain Deformations of Filled Polymers

Victor Oshmyan

Institute of Chemical Physics, Russian Academy of Sciences, 117343 Moscow, Russia

Structure-based constitutive equations for the large strain deformations of polymer solids are introduced. All the constitutive equations are governed by a unique characteristic of the polymer chains, namely, by the orientational distribution of their fragments. The orientational distributions commonly transform during the deformation process. For example, because of the fibrillation of the polymer chains upon drawing, an initially uniform distribution describing an isotropic polymer solid is generally transforming into an anisotropic one. Here, the constitutive equations proposed are employed for predicting the large strain deformation behavior of filled polymers, in the framework of the composite-sphere model of Hashin. Various loading conditions - constrained and semi-constrained tension, compression, shear, relaxation, unloading, etc. - are considered. A finite element algorithm is introduced and numerical results on strain softening and hardening upon uniaxial drawing are presented. Numerical calculations have been carried out assuming perfect adhesion and complete debonding at the matrix-inclusion interfaces. Both large strain deformation behavior and accompanying transformations in the orientational distributions are discussed.