Reduced Time Polymer Simulation in Commercial FEA codes
My previous post discussed the rich technical literature on reduced time polymer simulation. They have been shown to effectively model structural plastics & rubbers, accommodating time & environment complications to mechanical behavior, including:
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Compression set
So why aren’t reduced time models native in a finite element code as advanced as ABAQUS?* I believe it is because the experimental data is so difficult to produce. Over the decades, these research groups all developed in-house experimental techniques to produce the necessary data.
(Cartoon of a Dogbone Sample with an internal “clock”)
Reduced time models require the complete, linear viscoelastic property matrix. Materials can be thought of as having an internal time clock, which is accelerated or decelerated (ie, reduced) based on thermodynamic state variables like strain, temperature or pressure. The sole commercially available alternative is a Dynamic Mechanical Analyzer, but DMA’s only produce one viscoelastic material property, when the entire time dependent stiffness tensor is needed.
Psylotech has proprietary test equipment to produce a time & temperature dependent, thermodynamically self-consistent, 3D material property matrix. This material time clock is then applicable to any reduced time model, including VISCA, our entropy-based UMAT & VUMAT.
*the one exception is WLV, offering small strain temperature dependence for thermorheologically simple materials.
