高分子流体の積分型構成式

概要

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Taking into account the effects of the flow history on the rate of formation and breaking of junction points, the memory function Lodge's equation is modified as follows : [numerical formula] here H(λ), λ and β are relaxation spectrum in the linear region, relaxation time and a dimension less parameter respectively. R(t';λ) and R_0(λ) are the rate of formation of junction points at time t' in the nonlinear and linear region, respectively. C^<-1>(t') is the Finger strain and I is the unit tensor. Using this memory function, the integral consititutive equation is represented by stress tensor, by [numerical formula] where τ, p and ε are stress tender, hydrostatic pressure and dimensionless parameter respectively. C(t') is the Cauchy-Green strain tensor. In the case of R(t';λ)=R_0(λ), this constitutive equation makes the following predictions. (1) The non-Newtonian viscosity curve for the broad box type relaxation spectrum is nearly the same as the Bueche-Harding stand curve. (2) The non-Newtonian viscosity curve for the narrow box type relaxation spectrum (including the case of single relaxation time) properly represents non-Newtonian viscosities of monodisperse polystyrene melts. (3) The first normal stress coefficient is proportional to γ^^・<-1.5> for large shear rate γ^^・.
社団法人日本材料学会の論文
1971-05-15