POLYFLOW 3.11 Extends its Complex Physics in a Userfriendly Way

POLYFLOW 3.11 further extends the the vast library of viscoelastic models by adding the Leonov viscoelastic model and a simplified viscoelastic model for extrusion. For thermoforming and blow molding applications, POLYFLOW 3.11 offers a simplified thermo-mechanical stress capability to calculate deformations during cooling. Finally, key enhancements to the 3D adaptive meshing technique make the simulation of glass pressing and blowing faster and more robust than ever before. POLYFLOW technologies are now part of the ANSYS® suite, from the company’s recent acquisition of Fluent Inc

The simplified viscoelastic model for extrusion

POLYFLOW has been well-known for the last two decades for its unmatched library of viscoelastic and complex rheology models. Because of the CPU cost and memory requirement of traditional viscoelastic models for 3D extrusion simulation, viscoelasticity was often restrained to extrusion R&D centers. In order to allow a large number of designers in polymer processing to include the viscoelastic dimension in their analyses, a revolutionary model that is able to properly reproduce the true viscoelastic die swell at a much lower cost has been developed.

The simplified viscoelastic model for extrusion is able to accurately reproduce large die swell typical of viscoelastic flow while running much faster simulations and requiring much less memory than traditional viscoelastic models. Benchmarking this new capability against traditional viscoelastic models revealed than the simplified viscoelastic model for extrusion requires 6 times less memory and could run 16 times faster for typical extrusion processes involving free surface.

The Leonov viscoelastic model for filled rubber

The Leonov model is recognized for its ability to accurately reproduce the complexity of the viscoelastic behavior of rubber filled with carbon black, for example, typical in the tire industry, and to identify the transition from trapped to free molecules during the extrusion process, which, up to this point, no commercially available code has been able to identify.

Simplified thermo-mechanical stress analysis for thermoformed and blow molded parts

Polymer thermoforming and blow molding is an application of growing importance to POLYFLOW users. Considering the thinness of the sheet or the parison compared to other dimensions of the part, a shell element is used for the simulation to reduce the computational time. Although the thickness of the sheet or the parison is calculated as a standard output, it has not been straightforward enough to export the results to typical structural codes for performing stress analysis. POLYFLOW 3.11 offers two new options. First, it creates a 3D geometry out of the deformed shell and the calculated thickness that can then be used for advanced shrinkage and warpage simulation with structural codes. Second, it is possible to conduct some simplified thermo-mechanical stress and deformation analyses directly in POLYFLOW to obtain a qualitatively good estimation of these quantities.

Enhancements to 3D adaptive meshing

Glass forming applications, whether related to gob forming, bottle blowing, pressing, or making drinking glass, increasingly use numerical simulation to provide better insight to the complex deformations and thermal patterns that occur during the process. These simulations are extremely challenging as they involve very large deformations coupled with steep thermal gradients. In order to successfully address these challenges, POLYFLOW has been continuously refining its 3D adaptive meshing techniques for the last few years. POLYFLOW 3.11 enhancements ensure an improved balance between a mesh sufficiently fine to capture important local effects, yet coarse enough to keep the computational time within acceptable limits.