Viscoelastic simulations

R. Zheng et. al., Thermo viscoelastic Simulation of Thermally and Pressure Induced Stresses in Injection Moulding for the Prediction of Shrinkage and Warpage for... 

Figure 2.10 Model elements for viscoelastic simulations (from left linear spring element, linear dash pot element, nonlinear spring element, nonlinear dash pot element, sliding block (Saint-Venant body) with yield stress 9 (after Hennicke, 1978).

The narrow molecular weight distribution of metallocene homopolypropylene directly translates into narrow stress relaxation time spectra of the molten polymer. In a spinning process, where the polymer melt is stretched and subsequently crystallized, this means a more rapid decay of the stress in the fibers, and as a consequence, allows higher spinning speeds and finer fibers. A fully viscoelastic simulation of the spinning process indicates that metallocene polymers exhibit a more pronounced spinline profile, allowing the production of thinner filaments than can be achieved using conventional polypropylene (Fig. 43). 

Figure 4.12 Viscoelastic simulation of flow patterns for the melts of Figure 4.11 using the K-BKZ integral model (Eq. (4.12)) [34].

Schmidt, F.M., Agassant, J.F., Bellet, M., and Desoutter, L. (1996) Viscoelastic simulation of PET stretch/blow molding process. J. Non-Newtonian Fluid Mech., 64, 19-42. 

Similarly to Kwok et al. (2007), Amorosi et al. (2010) performed a parametric investigation using two different finite element codes (i.e., PLAXIS 2D and SWANDYNEII) and compared the results of 2D FE viscoelastic simulations with ID linear equivalent solutions (i.e., EERA). In order to provide a useful framework for finite element users, some of the factors potentially influencing the numerical results were critically discussed. In particular, the amount of viscous damping adopted in FE viscoelastic analyses, the spatial and time discretization, and the nature of boundary conditions were examined. The investigation showed that ... 

Satoh, N., H. Tomiyama and T. Kajiwara (2001). Viscoelastic Simulation of Film Casting Process for a Polymer Melt, Polymer Engineering and Science, 41(9) 1564-1579. 

Viscoelastic simulations with the parameters laid out above were carried out for the experimental flow conditions using the2-D geometry shown in Figure 2. The... 

Figure 5b First normal stress difference in PC and PC-ABS layers near the developing interface. Obtained from PTT viscoelastic simulation of the Cap-PC-PCABS-1 film coextrusion.

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