有理連続体力学に基づく延伸高分子材料の異方弾性構成式の定式化 Formulation of Anisotropic Elastic Constitutive Equation for Drawn Polymers Based on Rational Continuum Mechanics
An anisotropic elastic constitutive equation for drawn polymers is derived from a rational continuum mechanics point of view. The strain-energy function depends on elastic strain and internal variable tensor, and can be expressed as a function of the ten traces of the tensor products. The free energy plays the role of potential and its partial derivative with respect to the elastic strain is equal to the stress tensor. In amorphous polymers, evolution equation of internal variable for stretched polymers is expressed by modified Hencky strain and a loading surface. The loading surface is defined by the first invariant of the Cauchy-Green strain tensor (entropy elasticity) in principal draw ratio space. A loading-unloading criterion is introduced using the loading surface. It is shown that this model can describe the experimental results of anisotropic elastic constants reported by Matsumoto and co-workers for the uniaxially stretched, the two-way successively biaxially stretched and the simultaneously stretched films of amorphous polymers such as polyvinyl-chloride.
成形加工 18(4), 300-305, 2006-04-20
The Japan Society of Polymer Processing